of the floppy disk drive. This key is used to access nearly all user selectable features associated with any other control knob, key or softkey. For accessing advanced features, the 'MMODIFY'N key is the most important control of the 7200 . The 'MMODIFY'N key is used as a prefix to (is pressed just before) another control, and causes the 7200 to enter the screen for setting options associated with that control.

For example: the 'MHARDCOPY'N key initiates a plot or printout, without prompting for the various hardcopy options. In order to change the hardcopy options, the 'MMODIFY'N key is pressed first, then the 'MHARDCOPY'N key. Subsequent presses of the 'MHARDCOPY'N key use the options chosen. In this case the key initiates an action. The 'MMODIFY'N key is used to modify that action.

The principal controls for modifying settings of the 7200 are the pair of concentric knobs, located directly below the center of the display. The detented knob labeled, 'MMove Box'N is used to move a small box to each of the fields which can be changed. The continuous knob, which is commonly referred to as 'MModify Value'N is used to modify the value of the field displayed in the box. The list of possible values is shown on the screen in connection with this knob.

To exit any menu, press the 'MReturn'N soft key, located near the lower left of the display. Alternately, pressing 'MCancel Changes'N restores the values to their previous state before exiting the menu.

If a screen contains text which may be modified, the 'MEdit Text'N label appears next to the upper-left soft key when the box is moved onto the text field. Pressing the 'MEdit Text'N soft key will cause the box to enclose an individual character in the text field to allow editing of the string letter-by-letter.

The 'MModify Value'N continuous knob scrolls through all allowable letters.

7.3.2 Modify Field

The 'MModify Field'N detented knob moves the box from letter to letter.

7.3.3 Insert Character

The 'MInsert Character'N softkey adds a character after the box.

7.3.4 Delete Character

The 'MDelete Character'N softkey deletes the character surrounded by the box.

7.3.5 Default Text

The 'MDefault Text'N softkey restores the text which appears when default settings is selected. For example, in the Trace Edit screen, it is "TRACE1" for Trace 1, "TRACE2" for Trace 2, and so on.

7.3.6 Return

The 'MReturn'N softkey keeps all changes made to the text string and re-positions the box on the entire text field.

7.3.7 Cancel Changes

The 'MCancel Changes'N softkey will cancel all changes made to the text string since the Edit Text key was pressed and re-positions the box on the entire text field. Once 'MReturn'N or 'MCancel Changes'N is selected, the 'MModify Field'N detented knob will move the box onto the next field in the current menu. To re-edit the text string, move the box onto the text field and press the 'MEdit Text'N softkey.

7.4 Using Edit Arguments

Some screens, like the Extended Parameter screen, have fields which require arguments to further specify them. When the box is moved onto such a field, the arguments will appear at the bottom of the screen and the 'MEdit Arguments'N label will appear next to the upper-left softkey. Pressing this softkey will re-locate the box onto the arguments and allow you to change them using the 'MModify Value'N continuous knob. The 'MModify Field'N detented knob will move the box from argument to argument.

7.4.1 Return

The 'MReturn'N softkey will keep all the changes made to the arguments, remove the cursor from the arguments and re-locate it back to the original field.

7.4.2 Cancel Changes

The 'MCancel Changes'N softkey will cancel all changes made to the arguments, restore the value before 'MEdit Arguments'N was pressed, and relocate the box off the arguments field and onto the original field.

7.5 Displaying Traces

The fundamental purpose of the LeCroy 7200 Precision Oscilloscope is to display traces. Up to 8 traces may be displayed simultaneously. If a trace is off, pressing the 'MTRACE'N key to the right of the display turns the corresponding trace on. If the trace is on, pressing the 'MTRACE'N key makes it the Selected trace as indicated by the rectangle around its label. Pressing its key turns it off. While a trace is displayed, the on-screen labeling next to the trace On/Off key indicates the trace label, the horizontal and vertical scaling per division or the cursor values. Unless you specify a trace label, the source of the data and a summary of any processing on it is shown. Also, if needed, the trace label is preceded by arrows indicating if the trace is vertically and/or horizontally expanded or repositioned. Additional data associated with the trace may also appear: the number of sweeps currently being used in an average; or the number of the segment being displayed, if one segment of a segmented waveform is displayed. To change the trace's source or processing you must press the 'MMODIFY'N key and then the 'MTRACE'N key associated with the trace to bring up its Trace Edit Screen. The source of the traces may be either acquired data from a digitizing channel or previously stored data. Various processing functions, such as averaging, smoothing, etc., may be applied to the data before it is displayed.

7.6 Identifying Channels

Different 7200 plug-in types may have a different number of channels. Data from each acquisition channel is labeled according to: the position of the plug-in used to acquire the data, and the position of the BNC input connector on the plug-in's front panel. The plug-in slot in the mainframe closest to the display is called the A-slot. The B-slot is located to the right of A. For any plug-in occupying slot-A, the uppermost left BNC connector is channel A1. The next lower connector is channel A2, and so on.

7.7 Front Panel Controls

Following are descriptions of the front panel controls and the controls on the Main screen which appears each time the 7200 is turned on.

7.8 Using the On-line Help Manual

The on-line Help Manual provides information on manual control of the LeCroy 7200 Precision Oscilloscope.

To display an explanation of any key, softkey or knob, simply press the 'MHELP'N key, then press or turn that key or knob. Once Help is displayed, there are several options available.

The manual may be read like a book by using the 'MNext Topic'N and 'MNext Line'N knobs at the bottom of the display. The 'MNext Topic'N knob skips forward or backward in the manual by topics, while the 'MNext Line'N knob scrolls forward or backward by lines.

The on-line Help Manual is divided into two major sections, a table of contents and the main text of the manual. When in the table of contents, pressing the 'MRead Topic'N softkey will display the topic which is in the box at the top of the display. When not in the table of contents, pressing the 'MTable of Contents'N softkey will display the table of contents. While displaying the on-line Help, each front panel control (other than Help soft keys) gives direct access to the section of the manual which describes that control. None of these controls will affect the operation of the 7200.

To exit Help, press the 'MReturn'N softkey.

7.9 Auto Setup

The 'MAUTO SETUP'N key will automatically set up the 7200 to display repetitive input signals. Press this key to have the 7200 automatically set the time base, trigger, and vertical settings to fit the traces on the display. 'MAUTO SETUP'N does not change the input's vertical coupling. 'MAUTO SETUP'N sets up all channels which are used in currently displayed traces. Vertical settings are selected for each channel individually. Time base and trigger settings for each plug in are adjusted for the first channel on which a suitable repetitive input signal is found.

Signals detected must have an amplitude between 2 mV and 8 V, frequency above 50 Hz, and a duty cycle greater than 0.1%. 'MAUTO SETUP'N time depends on the signal frequency. It is generally between 300 msec and 10 sec.

The 'MTRIGGER MODE'N is set to NORMAL. If a pure DC signal is found, the 'MTRIGGER MODE'N will be switched to AUTO and the Time base set to 10 ¢sec.

7.10 Record Traces

The 'MRecord Traces'N softkey automatically records all displayed traces each time they are updated with a new acquisition. Up to 4 Mbytes of the most recently displayed traces are saved in a non-volatile circular buffer.

To start the automatic record process, press the 'MRecord Traces'N softkey on the 7200's Main Screen. The soft key's label will change to 'MStop Record Traces'N and the 'MREC'N icon will be displayed at the bottom of the screen. All traces which are turned on are recorded each time they are updated on the screen. The traces are saved in groups. For each acquisition by a plug-in, all traces which display or process data from that plug-in are updated and recorded as a group. The number of trace groups which are saved depends on the number of points per trace and the number of traces which are on. After the buffer is filled, the oldest traces are overwritten. To stop recording traces, press the 'MStop Record Traces'N softkey.

7.11 Clearing the Record Traces Buffer

The Record Traces buffer is non-volatile and maintains its contents while the power is off. However, it may be cleared and reset by pressing the 'MClear Memories'N softkey in the System Configure Screen. NOTE: The 'MClear Memories'N softkey also clears the eight internal memories M1...M8 (see description of Waveform Storage).

7.12 Replay Traces

The 'MReplay Traces'N softkey retrieves traces that 'MRecord Traces'N saved in the buffer. Replayed traces may be examined, processed, or stored to floppy diskette. The 'MReplay Traces'N softkey is not present when the Record Traces buffer is empty. To retrieve traces which have previously been recorded, press the 'MReplay Traces'N softkey in the 7200's Main Screen. The soft key's label will change to 'MStop Replay Traces'N and the 'MPLAY'N icon will be displayed at the bottom of the screen. In Replay Traces mode, traces are retrieved in the same groups in which they were originally recorded. When the 7200 retrieves a trace group, it puts the trace waveforms in the corresponding memories M1...M8. For example, if the 7200 retrieves a trace group containing traces 1 and 2, the trace 1 waveform is put in memory M1 and the trace 2 waveform is put in memory M2, overwriting the previous contents of the memories.

In Replay Traces mode, the 7200 stops acquiring data and switches from the acquisition set of trace equations to the

replay set of trace equations. (Each trace is defined by a mathematical trace equation which specifies the source(s) of data and optional processing.) The default values of the replay trace equations are T1=M1, T2=M2,...T8=M8.

Thus, by default, all replayed trace waveforms will be displayed in the same traces they originally came from. The replay trace equations may be modified in the Trace Setup screens to perform processing on the replayed waveforms in the memories. All operations which can be performed on the acquisition traces may be performed on the replay traces, including waveform processing, vertical and horizontal expansion and reposition, cursor measurements, waveform parameters, and storage to floppy diskette. The 7200 provides sequential access to the trace groups which have been recorded. Soft keys are provided to step or scan backward and forward in the Record Traces buffer. On each step backward or forward the 7200 retrieves the group of traces recorded earlier or later and places the waveforms in the

corresponding memories M1...M8. It automatically turns on all traces which display or process data from these memories and turns off all other traces. The time at which the trace group was originally recorded is displayed in the upper left corner of the screen along with the index of the trace group in the Record Traces buffer. The most recently recorded group of traces has index 0, the next older group index -1, etc. When Replay Traces mode is first turned on, the 7200 retrieves the most recently recorded trace group.

The following soft keys provide sequential access to the other recorded trace groups:

7.12.1 Step Backward

Press the 'MStep Backward'N softkey to retrieve the group of traces which was recorded previous to the current group. The 'MStep Backward'N softkey is not present when there are no older trace groups.

7.12.2 Step Forward

Press the 'MStep Forward'N softkey to retrieve the group of traces which was recorded after the current group. The 'MStep Forward'N softkey is not present when there are no newer trace groups.

7.12.3 Switch To Scan Mode

Press the 'MSwitch To Scan Mode'N softkey to switch from Step mode to Scan mode. The softkey's label will change to 'MSwitch To Step Mode'N and the 'MStep Backward'N and 'MStep Forward'N soft keys will change to 'MScan Backward'N and 'MScan Forward.'N

7.12.4 Scan Backward

Press the 'MScan Backward'N softkey to start scanning backwards in the Record Traces buffer. The 7200 will automatically retrieve, display, and process (if configured in the replay trace equations) successively older trace groups. The softkey's label will change to 'MStop Scanning.'N Press it again to stop scanning.

7.12.5 Scan Forward

Press the 'MScan Forward'N softkey to start scanning forward in the Record Traces buffer. The 7200 will automatically retrieve, display, and process (if configured in the replay trace equations) successively newer trace groups. The softkey's label will change to 'MStop Scanning.'N Press it again to stop scanning.

7.12.6 Switch To Step Mode

Press the 'MSwitch To Step Mode'N softkey to switch from Scan mode to Step mode. The softkey's label will change to 'MSwitch To Scan Mode'N and the 'MScan Backward'N and 'MScan Forward'N soft keys will change to

'MStep Backward'N and 'MStep Forward.'N To stop replaying recorded traces and resume data acquisition, press the 'MStop Replay Traces'N softkey.

7.13 Trigger Mode keys

These keys select Single, Auto, Normal, or Sequence trigger modes for all input channels. The trigger conditions (source, slope, etc.) are independently selected for each plug-in. As keys are pressed to step through each

Trigger Mode, LEDs indicate the mode selected. Each mode operates as follows:

7.13.1 Single

Pressing 'MTRIGGER MODE'N to select Single arms the trigger circuit; that is, it starts acquisition of the waveform data. When a valid trigger signal is detected acquisition completes and the waveform is displayed. To arm the circuit again for another sweep, press 'MTRIGGER MODE'N again to re-select Single. When a valid trigger is detected, the

acquisition completes and the new waveform then replaces the one previously displayed. Pressing the key before a valid trigger occurs forces a trigger and causes the acquisition to complete.

7.13.2 Normal

In Normal Trigger Mode, the 7200 re-arms the trigger circuit and starts data acquisition after each valid trigger. Normal mode updates the display with newly acquired data after each valid trigger is detected.

7.13.3 Auto

Auto Trigger Mode differs from Normal Trigger Mode in one way: if a valid trigger signal is not detected within 100 msec, an internal trigger signal is generated.

7.14 Sequence

Sequence Trigger Mode partitions the acquisition memory into 2, 5, 10, 20, 50, 100, or 200 segments as selected from within the plug-in Status or Time base Setup screen. Each time a trigger occurs, acquisition for the current segment completes, and acquisition for the next segment begins. When all segments are completed, the result is displayed. Selecting Sequence Mode again before all segments have been acquired causes the acquisition to halt and those segments which have been acquired to be displayed. If Sequence Mode is selected a third time, acquisition is enabled again, overwriting all previous segments. Sequence Trigger Types are selectable in the Acquisition Setup screen. This may be accessed either from the Configure System screen or by pressing the 'MMODIFY'N key and then a 'MTRIGGER MODE'N key. The Sequence Trigger Type options are Single and Normal. Single Sequence acquires the requested number of segments and displays the sequence waveform. To arm the circuit again for another sweep,

press 'MTRIGGER MODE'N again to re-select Sequence. Normal Sequence will keep acquiring and displaying sequence waveforms until the 'MTRIGGER MODE'N key is pressed again to re-select Sequence.

7.15 Grids

If all eight traces have different vertical magnitudes, displaying them on different grids simplifies trace interpretation. Placing them on a common grid helps trace comparison. Each time the 'MGRIDS'N key is pressed a different grid size appears. For full screen displays, the choices are Single, Dual, Quad, and Octal grids. For half screen displays,

such as when a setup screen or waveform parameters are displayed, the choices are Single, Dual, and Quad grids. The 7200 automatically maps the traces to the grids, placing the lowest numbered trace which is displayed on the upper most grid, the next trace on the next grid, etc. Although traces are initially allocated to grids, they can be moved into other grids for comparisons by using the 'MVertical Position'N knob.

7.16 Display Options

To access the Display Options Setup screen, press 'MMODIFY'N and then 'MGRIDS.'N The fields of the Display Setup screen are:

7.17 Axis Labels

When this field is set to ON and the grid is single or dual, the 7200 prints the value of the end points for the active trace on both the horizontal and vertical axes.

7.18 Histogram Orientation

Specifies how histograms will be displayed by the 7200. The selections are STANDARD and INVERT. In the standard orientation, the histogram is drawn with the zero baseline at one division up from the bottom of the grid

and the peaks grow upward. When INVERT is selected, the baseline is drawn one division down from the top of the screen and the peaks grow downward.

Return

Pressing the Return key will save all the changes in non-volatile memory and exit the menu

Cancel Changes

Pressing the Cancel Changes key cancels all modifications. It exits the menu and restores the original setup.

7.19 Vertical Position

This continuous knob moves the Selected trace vertically anywhere on the screen, allowing you to separate or overlay the traces. (The Selected trace is indicated by a rectangle around its trace label. If a trace is not Selected, pressing its 'MTRACE'N key makes it the Selected trace.) This control does not affect the vertical offset of the acquisition channel.

7.20 Vertical Expand

This detented knob vertically expands the Selected trace around the center of its home grid. (The Selected trace is indicated by a rectangle around its trace label. If a trace is not Selected, pressing its 'MTRACE'N key makes it the Selected trace.) The vertical scale factor indication under the trace label is automatically adjusted. The expansion does not affect the amplifier settings of the acquisition channel. The trace can be expanded or contracted vertically in steps that are multiples of one, two, and five.

7.21 Vertical Reset

If the Selected trace is vertically expanded or off the center of the grid, pressing the 'MVERTICAL RESET'N key un-expands the trace and positions it on the vertical center of the grid. Pressing the key again returns the trace to its previous expansion and position.

7.22 Horizontal Position

This continuous knob moves the Selected trace horizontally anywhere on the screen, allowing you to align traces in time. (The Selected trace is indicated by a rectangle around its trace label. If a trace is not Selected, pressing its 'MTRACE'N key makes it the Selected trace.) This control does not affect the trigger delay of the acquisition

channel. If part of the trace is positioned off the display grid, the View Finder can help determine the position of the displayed section relative to the grid. If you are displaying one segment of a trace acquired with Sequence 'MTRIGGER MODE,'N rotate the 'MHORIZONTAL POSITION'N knob to display other segments. When a segment

boundary is reached, an extra turn of the knob is required to display the next segment. The number of the displayed segment is indicated next to the trace label. As discussed below, horizontal position and expansion actually change the number of points of the Selected trace.

7.23 Horizontal Expand

Use this detented knob to horizontally expand (i.e. magnify) the Selected trace around the center of the grid. (The Selected trace is indicated by a rectangle around its trace label. If a trace is not Selected, pressing its 'MTRACE'N key makes it the Selected trace.) As the Selected trace is expanded, the View Finder shows a shorter portion of the trace inside the grid box to indicate that there is data which is currently not on the screen. The horizontal scale factor indication under the trace label is automatically adjusted. The expansion does not affect the time base of the acquisition

channel. The trace can be expanded or contracted horizontally in steps that are multiples of one, two, and five.

Horizontal expansion determines the number of points of the trace that is displayed. The horizontal expansion can be used to display as few as 40 points at a time. For example, with 50k acquired samples, 50 points represents a

magnification of 1000 times. When the number of data points is less than the number of display pixels across the screen, linear interpolation is used to connect the data points. The actual data points are displayed with greater intensity than their inter-connections in order to distinguish the actual samples. When displaying a trace acquired with

Sequence 'MTRIGGER MODE,'N rotating the 'MHORIZONTAL EXPANSION'N knob clockwise one

click displays the first segment of the trace. Additional rotations will expand that segment. Rotating the 'MHORIZONTAL POSITION'N knob moves to the other segments. The number of the displayed segment is indicated next to the trace label.

Unlike the vertical controls, 'MHORIZONTAL POSITION'N and 'MHORIZONTAL EXPANSION'N actually change the number of points of the Selected trace. Only the points displayed on the screen as selected by the horizontal

controls are used for processing in subsequent trace equations, for storing the trace (to floppy, a memory, or Record Traces), or for remote read-out. This means that if trace 2 is defined to be trace 1 (i.e. T2 = T1), horizontally expanding and repositioning trace 1 will also horizontally expand and reposition trace 2 the same amount. Selecting trace 2 and changing its horizontal expansion and position (relative to trace 1), will not affect trace 1. When trace 2 is expanded, however, the corresponding area on trace 1 is highlighted.

7.24 Horizontal Reset

If the Selected trace is horizontally expanded or off the center of the grid, pressing the 'MHORIZONTAL RESET'N key un-expands the trace and positions it on the horizontal center of the grid. Pressing the key again returns the trace to its previous expansion and position.

7.25 Common Expand/Multi Zoom

Press the 'MTurn On Multi Zoom'N softkey to simultaneously expand and reposition the selected group of traces. The Common Expand Setup screen lets you select which traces are in the selected group. You can also select whether the group applies to the horizontal or vertical controls or both. The Common Expand Setup screen is accessed by pressing

'MMODIFY'N followed by 'MTurn On/Off Multi Zoom'N or either of the expand or position controls. Press the 'MTurn Off Multi Zoom'N to individually expand and reposition each trace.

7.26 Common Expand Setup

The softkeys and fields on the Common Expand Setup are:

7.26.1 Clear All

This softkey removes all of the traces currently selected in the trace group.

7.26.2 Set All

This softkey is a short cut to allow you to select all of the traces.

7.26.3 Set On

This softkey selects all the traces which are on to be in the trace group.

7.26.4 Lock

Is used to select whether the Horizontal and/or Vertical expansion controls are locked together for the selected group of traces.

7.27 T1 ... T8

Eight fields which permit you to select any combination of traces to controlled together. Every time a trace is added to this group, all of the traces in the group are automatically reset to their unexpanded position in order for all the traces to start at the same expansion. When any of the traces in this group is the selected trace and a expansion control is changed, the control is applied to all of the traces in the group. Note that a dotted select box is used to indicate the

other traces in the group. When a trace, which is not in the group of traces for common expansion, is selected, changing an expansion control only affects that trace.

7.28 Clear Display

When averaging, enveloping, histograms, trends, or persistence mode is enabled, the 'MClear Display'N key appears on the Main Screen. Pressing this softkey clears the accumulated results. Accumulation of data restarts with the next acquisition.

7.29 Persistence Display

Typically, each sweep of displayed traces is erased before the next sweep is displayed. Persistence mode keeps prior sweeps on the display to allow comparison of successive acquisitions. The number of sweeps remembered in the persistence display is set from the Persistence Setup screen which is accessed by pressing 'MMODIFY'N and then the 'MTURN ON PERSISTENCE'N key. The number of sweeps may be set in a 2, 5, 10, 20, ..., 200, INFINITE,

AUTO_STOP sequence. The AUTO_STOP setting is infinite persistence with automatic stop of acquisition when any bin in the persistence array reaches full scale. The current setting for the number of sweeps will be displayed under the grid along with the number of sweeps currently contained in the persistence array. Note that if XY mode is active, only INFINITE persistence is possible. The persistence display is cleared whenever a control, mainframe or plug in, which affects the display is changed or when the 'MClear Display'N key is pressed. The vertical and horizontal cursors are

available on the persistence display grid, and can be used to make absolute and relative voltage and time measurements.

7.30 XY Display Mode

The X versus Y (XY) display mode allows you to display one trace against another. The technique is normally used to compare the amplitude information of two waveforms and can reveal phase and frequency information through the analysis of patterns called Lissajous figures. When XY display is enabled, a square grid, in the top half of the screen is used for the XY display while the rectangular grid underneath simultaneously shows the original source waveforms. The rectangular grid can be either a single or dual grid and may be selected by the GRIDS key. To select the two

waveforms for display in the XY mode, simply use the TRACE ON/OFF keys. If both traces are off, the first trace selected is automatically assigned to the X (horizontal) axis of the XY display. The second trace selected is assigned to the Y (vertical) axis. Both selections are indicated to the left of the square grid. Selecting another trace key assigns the newly selected trace to the Y axis and turns off the previous Y trace. For the XY display to be correctly generated, the traces selected must be of the same time or frequency interval/point and have the same horizontal unit (seconds or hertz). As soon as two compatible traces have been selected, the XY display is automatically generated. If incompatible traces are selected. a warning message is displayed at the top of the screen. If two compatible traces are selected that have different trigger points , then the common part of each trace is highlighted and only that part is plotted in the XY display. If Persistence is on when XY mode is enabled or if 'MTURN ON PERSISTENCE'N is pressed while the XY display is active, the X vs Y plot is not cleared after each sweep to allow comparison of successive acquisitions. In this mode, the X vs Y display is only cleared when a control, mainframe or plug in, which affects the display is changed or when the "Clear Display" key is pressed. As with the standard waveform display, time and voltage cursors can be used with the XY display. The time cursors are similar to those of the standard waveform display, with additional cursors at the corresponding XY position in the square XY display. To make a measurement, press the 'MCURSOR MEASUREMENTS'N key to activate the cursors. The vertical value of each cursor is shown below the trace label. The time cursor value, which is common to both traces, is shown below the grids. In addition, combinations of the vertical values are shown to the right of the XY grid. These measurements are:

The ratio of Y/ X

The ratio in dB (20 * log10(ratio))

The product of Y * X

The distance to the origin

r = sqrt( X* X + Y* Y)

The angle theta = arctan( Y/ X) where X and Y are defined by cursor type as follows:

vertical relative Vdif - Vref

vertical absolute Vref - 0

horizontal relative Vdif - Vref

horizontal absolute Vref - 0 or Vref - Voffset

For the horizontal absolute cursor, you can choose between 2 references. The reference can either be at X = 0, Y = 0 or X and Y equal to their values at the center of the grid square.

Program

The 'MProgram'N softkey in the main screen is used to access the automatic control features of the LeCroy 7200 Precision Oscilloscope. Programming allows you to store a sequence of front panel commands in a program. The

program can be stored on the internal disk or a floppy disk for use later, or can be executed right away.

7.31 Modifying Program Parameters

When preceded by the 'MModify'N key, the 'MProgram'N softkey brings up the program setup screen. This is used to set program parameters, examine programs, and store or recall programs on disk.

7.31.1 Actions

Next to the 'MProgram'N softkey in the main screen is a description of what will happen when you press it.

The 'MLearn'N option is only shown when there is currently no program. When the softkey is pressed, succeeding key presses and knob changes are saved for execution later. While commands are being collected in this way, the 'MStop Learn'N option is displayed. The 'MRun'N option is displayed when a program is ready to be executed. When the

softkey is pressed, the option is changed to 'MStop Run,'N and the program is started. During execution, pressing any key or turning any knob will suspend the program with a message asking if you want to abort the program. At this point you must press either the 'MYes'N or the 'MNo'N softkey to indicate your choice.

7.31.2 Program Setup Screen

The upper half of the screen shows a portion of the program. If a program is terminated due to an error, the line containing the error will be highlighted the next time you enter the program setup screen to show you where the error occurred. A brief message describing the problem will be displayed at the top of the screen.

7.31.3 Speed

The 'MSpeed'N option has three choices:

FAST, MEDIUM, and SLOW. Normally, the FAST speed is appropriate for running programs. It executes the program as fast as possible. When first testing a program, the SLOW speed is useful. It executes the program one command

per second, and displays the text of each command as it is executed. With MEDIUM speed, a small delay is added after each command is executed. This gives the display a chance to be updated, so you can see the effect of individual commands.

7.32 Disk

This control is used to select which disk the 'MRecall File'N and 'MStore File'N controls refer to. Choices are INTERNAL and FLOPPY. If FLOPPY is selected, the directory of the floppy disk will be read when the

program setup screen is entered.

7.33 Recall File

All programs which are found on the selected disk are available for recall through this control.

7.34 Store File

Before storing a program on disk, you should set the name of the 'MStore File'N using this control. When the cursor box is on this field, the softkey 'MEdit Text'N appears. By pressing this key, you may change, add or delete characters from the 'MStore File'N name.

7.35 Clear

This softkey erases the current program. It causes the displayed program to be erased from the screen, but has no effect on any copy which may have been stored on disk.

Prev Page

Press this softkey to scroll the program down in the window. This displays the eight lines prior to the text currently displayed.

Next Page

Press this softkey to scroll the program up in the window. This displays the eight lines after the text currently displayed.

7.36 Learn Append

After collecting a sequence of commands, the 'MLearn'N option is not available with the 'MProgram'N softkey in the main screen. To allow you to append more commands to the program, the 'MLearn Append'N softkey appears in the program setup screen. When this softkey is pressed, key presses and knob changes are saved at the end of the current program. The option of the 'MProgram'N softkey is changed to 'MStop Learn'N to indicate that a program is being learned.

7.37 Learn Setup

This softkey may be used to learn the current state of the 7200. It appears whenever it is permissible to learn a new program using the 'MLearn Program'N softkey in the main screen or to append to an existing program using the 'MLearn Append'N softkey in the program setup screen. The 'MLearn Setup'N softkey causes commands to be generated at the end of the current program. When executed, these commands will reset the 7200 to the state which existed when the 'MLearn Setup'N soft key was pressed.

7.38 Store

Press this softkey to store the current program on disk. The disk and file name should be selected first using the 'MDisk'N and 'MStore File'N controls.

7.39 Recall

Press this softkey to recall a program from disk. The disk and file name should be selected first using the 'MDisk'N and 'MRecall File'N controls. After the program is recalled, the first few lines of the program are displayed.

To make it easier to copy programs between disks, the 'MStore File'N name is set to the 'MRecall File'N name when this softkey is pressed.

Return

Press this softkey to leave the program setup screen and accept the changes you made.

7.40 Disk Utilities

The disk utilities screen can be entered by pressing this softkey. It may be used to examine or delete files on a disk (including those other than programs).

7.40.1 Read New Floppy Disk

If you change floppy disks while in the program setup screen, press this softkey to indicate that the directory should be read again.

Related Remote Commands

The following commands are available for control of programs remotely via GPIB or RS-232:

Command Name Alias Function

PROG_CLEAR PRCL Clears the program

PROG_LIST? PRLI? Lists program files

PROG_MODE PRMO Select operating mode

PROG_RECALL PRRC Recall program from disk

PROG_STORE PRST Store program on disk

PROG_SETUP PRSU Set options

PROG_ARG PRAR Sets an argument string for a chained program.

7.41 Making Measurements on Waveforms

The 7200 can perform waveform parameter, horizontal, or vertical measurements each time a trace is updated on the display. Pressing the 'MCursor Measurements'N key turns on the currently selected measurement type. Subsequent presses cycles through the possible measurement types. To stop the measurements, press the 'MTurn Off'N softkey at the lower left of the screen. Cursor Measurements can be made while any number of traces are displayed.

Moving the cursors.

The continuous knob, under the center of the display, is used to move the cursors around on the screen. The continuous knob is labelled 'MMove'N followed by a picture of the cursor which you can move. For all cursor types,

except MARKER, there are two cursors, the Reference and the Difference cursor. The detented knob under the screen is labelled 'MSelect Cursor'N . Rotating this knob changes which cursor the continuous knob moves. It also allows you to move both cursors by selecting the picture with both cursors drawn.

7.41.1 Types of Measurements

The types of measurements which can be made with each cursor type are described below:

7.41.2 Basic Parameters

When you choose 'MBasic Param'N a set of 14 waveform parameters are calculated for the selected trace. To display the results, the grid is automatically reduced to half size. The parameters are recalculated each time the trace is updated or the cursor is moved. To change the selected trace, press the desired trace key. The section of the trace used in computing the parameters lies between two cursors. You can choose to have independent cursors for each trace or have all the cursors "locked" together so that they are on the same place on all the traces, by pressing 'MMODIFY'N and

then the 'MCURSOR MEASUREMENTS'N key. The cursors are represented by:

Cursor Locked Independent

Reference 'f2Ñ'f0 'f2Ô'f0

Difference 'f2à'f0 'f2Õ'f0

both cursors 'f2ú'f0 'f2ý'f0

Note that the Reference and Difference cursors merely delineate a region of the trace; their relative ordering is irrelevant.

For time domain waveforms, the parameters computed are:

frst - time at first point

last - last point

max - maximum

freq - frequency

min - minimum

per - period

pkpk - peak to peak

wid - width

mean - mean

dly - delay

sdev - standard deviation

rise - 10-90% rise time

rms - root mean square

fall - 90-10% fall time

For frequency domain waveforms, the parameters computed are:

frst - time at first point last - last point

max - maximum tpwr - total power

xamn - frequency at min xamx - at max

For histogram waveforms, the parameters

computed are:

frst - time at first point last - last point

max - maximum mean - mean

min - minimum medi - median

pkpk - peak to peak mode - mode

sdev - standard deviation totp - population

rms - root mean square

maxp - maximum value

fwhm - full width at half max

For a detailed description of each parameter refer to the Waveform Parameter Definitions

section below.

Parameter Notation

A graphic symbol may appear between the

parameter name and its value to indicate

additional information. The symbols and their meanings are:

waveform is partially in overflow

waveform is partially in underflow

waveform is part overflow, part underflow

upper limit shown, actual value may be less

lower limit shown, actual value may be more

value is average over up to 500 periods

computed on integral number of periods

waveform is not a pulse

parameter calculated on histogram -

parameter calculated on fft waveform

parameter does not apply to this waveform

waveform contains undefined points,

displayed value is suspect ?

insufficient data to compute parameter --- Parameter Averaging

When Basic or Extended Parameters are enabled, the 'MAverage Parameters'N softkey appears. The parameter averaging feature transforms the parameter display from instantaneous values to average values. When parameter averaging is off, the parameter values displayed are the instantaneous values for the currently displayed waveform sweep. When parameter averaging is on, the parameter values computed for each waveform sweep are averaged with the parameter values from the previous sweep with a weight of 1/20. The displayed values are thus a continuous or

running average of the values of successive acquisition sweeps.

To turn on parameter averaging, press the 'MAverage Parameters'N softkey. Its label will change to 'MStop Average Parameters.'N To turn off parameter averaging, press the 'MStop Average Parameters'N softkey.

7.41.3 Extended Parameters

With extended parameters, the 7200 will calculate up to twenty parameters on any combination of traces. Their values are displayed under a half screen grid. The cursors are the same as those used for Basic Parameters. To choose the parameters and the traces they are calculated on press 'MMODIFY'N and then the 'MCURSOR MEASUREMENTS'N key.

7.41.4 Extended Parameter Setup

The Extended Parameter Setup Screen contains selection fields for choosing up to twenty trace-parameter combinations. Each selection has two fields separated by a colon (:). The left field specifies the trace to be measured and the right field specifies the parameter to be calculated. The parameter values will be displayed on the Main Screen (when Cursor Type EXT PARAM is enabled) in the same locations as selected in the setup screen. The 'MMove Box'N knob is used to select a field for modification. The options list in the lower right screen will indicate available choices with the current selection in the center. To change the selection, rotate the 'MModify Value'N knob to move the desired choice to the center of the list. The new choice will also replace the previous selection in the box. When "-" is selected from the Options List for either the trace or parameter field, no parameter will be calculated and the

corresponding location in the Extended Parameter display on the Main Screen will be blank. The 'MClear All'N softkey deselects all the traces and parameters and replaces them with "-". The section of the trace used in computing the parameters lies between two cursors. The 'MUnlock/Lock Cursors'N key allows you to

choose to have independent cursors for each trace or have all the cursors "locked" together so that they are on the same place on all the traces. As shown in the basic parameters section above, different cursors are used to distinguish the two modes. After selecting traces and parameters, press the 'MReturn'N softkey to save the changes and display the Main Screen. The 'MCancel Changes'N softkey cancels all changes, restores the original setup, and displays the Main Screen.

7.41.5 Waveform Parameter Definitions

The waveform parameters available are briefly described below. The parameters are grouped according to the types of waveforms on which they operate: General (all types of waveforms), Time Domain, Frequency Domain, and Histogram parameters. Some parameters have arguments which may be specified in the Extended Parameter Setup Screen. These are described below. More detailed definitions of the parameters appear in the 7200 Users Manual. Parameter Calculation for Basic/Extended Display Parameters displayed in Basic or Extended Parameters are calculated only on the section of the trace delineated by the two cursors. If the trace is a sequence waveform, the parameters are calculated only on the first segment between the cursors (i.e., the segment in which the leftmost cursor is located).

7.41.6 Parameter Calculation for Histogram and Trend

For histograms and trends, parameters may be calculated on traces, channels, or memories. (See the Histogram and Trend sections.) Parameters on traces are calculated only on the section of the trace delineated by the parameter cursors. If the trace is a sequence waveform, the parameters provide a list of values for all segments between the cursors (including the segments in which the left and right cursors are located). Parameters on

channels and memories are calculated on the entire waveform.

7.41.7 General Parameters

data - data value at left cursor; this parameter is useful for histograms, where it can be used to provide all of the data values in a waveform

date - date of acquisition of the waveform

dur - acquisition duration. For a sequence or history waveform, time from first trigger to last trigger. For a single segment of a sequence, time from trigger of previous segment to trigger of current segment.

frst - horizontal position of first (left) cursor

last - horizontal position of last (right) cursor

pnts - number of points between the cursors

time - time of acquisition of the waveform

Time Domain Parameters

ampl - amplitude; top minus base

area - area under waveform between cursors; sum of sampled values times duration of a sample

base - the lower most probable state (for rectangular waveforms)

cycl - cycles; the number of pairs of transitions in the same direction between the cursors

dly - delay; time from trigger to midpoint of first transition

duty - duty cycle; average duration above midpoint value as percentage of period

dnl - differential non-linearity; maximum absolute difference between adjacent specified code levels and the ideal

code level. The input is assumed to be a Digital to Analog Converter output. The portion of the waveform to be processed is assumed to be displayed between the vertical cursors. The steps argument is the number of ideal quantization levels. The results is measured in terms of LSB's.

fall - fall time; duration of pulse waveform's falling transition between two user-specified thresholds, averaged for

all falling transitions between the cursors. The thresholds are specified as a percentage of the amplitude. Default values are 90% and 10%.

freq - frequency; reciprocal of period

inl - integral non-linearity; maximum absolute difference between specified code levels and the ideal code level. The input is assumed to be a Digital to Analog Converter output. The portion of the waveform to be processed is assumed to be displayed between the vertical cursors. The steps argument is the number of ideal quantization levels. The

results is measured in terms of percentage.

lmax - local maximum; average of all local maxima between the cursors. The hysteresis argument may be used to

discriminate peaks from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

lmin - local minimum; average of all local minima between the cursors. The hysteresis argument may be used to

discriminate troughs from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

lnum - number of local peak pairs. The hysteresis argument may be used to discriminate peaks from noise in the

data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

lpp - local peak to peak (lmax-lmin); average for all pairs of local maxima and minima between the cursors. The

hysteresis argument may be used to discriminate peaks from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

ltbp - local time between peaks; average for all features between the cursors. The hysteresis argument may be used to

discriminate features from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

ltbt - local time between troughs; average for all features between the cursors. The hysteresis argument may be used to

discriminate features from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

ltmn - local time at minimum; time from trigger to first local minimum between the cursors. The hysteresis argument

may be used to discriminate troughs from noise in the data. It is specified in divisions in the range 0.01 to 8.0. The default hysteresis is 0.5 divisions ltmx - local time at maximum; time from trigger to first local maximum between

the cursors. The hysteresis argument may be used to discriminate peaks from noise in the data. It is specified in

divisions in the range 0.01 to 8.0. Th default hysteresis is 0.5 divisions.

ltot - local time over threshold; time over a user-specified percentage of the local peak-to-peak range, averaged for all

features between the cursors. Default percentage is 50%. The hysteresis argument may be used to discriminate

peaks from noise in the data. It is specified in divisions in the range 0.0 to 8.0. The default hysteresis is 0.5 divisions.

ltut - local time under threshold; time under a user-specified percentage of the local peak-to-peak range, averaged for

all features between the cursors. Default percentage is 50%. The hysteresis argument may be used to discriminate peaks from noise in the data. It is specified in divisions in t range 0.01 to 8.0. The default hysteresis is 0.5 divisions.

max - maximum value of the waveform between the cursors

mean - average or DC level of the waveform. If waveform is periodic, computed over integral number of periods

medi - median value of waveform. If waveform is periodic, computed over integral number of periods

min - minimum value of the waveform between the cursors

mode - mode of waveform. If waveform is periodic, computed over integral number of periods

nbph - narrow-band phase in degrees relative to start of waveform (left parameter cursor changes the starting point) for

a selectable frequency; an integer number of cycles is used.

nbpw - narrow-band power in dBV (relative to 1V rms) for a selectable frequency; an integer number of cycles is used

ovsn - overshoot negative; base value minus minimum sample value, as a percentage of amplitude

ovsp - overshoot positive; maximum sample value minus top value, as a percentage of amplitude per - period; time of a full cycle, averagedfor all full cycles between the cursors pkpk - peak-to-peak; difference between maximum and minimum values rise - rise time; duration of pulse waveform's rising transition between two user-specified thresholds, averaged for all rising transitions between the cursors. The thresholds are specified as a percentage of the amplitude. Default values are 10% and 90%.

rms - root mean square; square-root of sum of squares divided by number of points. If waveform is periodic, computed over integral number of periods

sdev - standard deviation; square-root of sum of squares of difference from mean, divided by (number of points - 1).

If waveform is periodic, computed over integral number of periods.

tafl - time at fall; time from trigger to midpoint of first falling transition

tars - time at rise; time from trigger to midpoint of first rising transition

top - the higher most probable state

wid - width of the first pulse (either positive or negative), averaged for all similar pulses between the cursors

xamn - time from trigger to minimum value

xamx - time from trigger to maximum value Frequency Domain Parameters

max - amplitude of the largest frequency component

npwr - noise power; total power minus power in fundamental minus power in harmonics Applies only to FFTPWD waveforms.

tpwr - total power; area under the power density spectrum. Applies only to FFTPWD waveforms.

xamn - frequency at minimum amplitude

xamx - frequency at maximum amplitude

Histogram Parameters

ampl - amplitude; top minus base

base - centroid of leftmost significant peak

fwhm - full width at half max; the width of the distribution surrounding the mode including values which are at least

1/2 of the maximum bin population

fwxx - full width at user-specified percentage of the maximum bin population. Default percentage is 50%.

max - horizontal coordinate of rightmost non-zero bin

maxp - maximum population in any bin (vertical value at the mode)

mean - horizontal centroid of the distribution medi - horizontal median (horizontal value of midpoint of distribution)

min - horizontal coordinate of leftmost non-zero bin

mode - horizontal coordinate of bin with maximum population

pctl - percentile; horizontal coordinate to the left of which lies a user-specified percentage of the distribution. Default percentage is 95%.

pkpk - peak-to-peak; horizontal difference between maximum and minimum values

pks - number of peaks in the histogram

rms - histogram root mean square; square-root of sum of squares divided by number of values, computed on the distribution

sdev - histogram standard deviation; square- root of sum of squares of difference from mean, divided by (number of values - 1), computed on the distribution

top - centroid of rightmost significant peak

totp - total population in the histogram

xapk - Horizontal mean of the user-specified

peak. Peak is specified by number, where largest area peak is number 1, next largest is number 2, etc. Default peak number is 1.

7.42 Vertical Cursors

These cursors measure the vertical distance between two horizontal lines on one grid. The difference, in the trace's units is indicated under the trace labels for all traces on the same grid. For traces not on the same grid,

the trace's units per division, for both the vertical and horizontal dimensions are shown. The vertical cursors are represented by:

Reference 'f2Ó'f0

Difference 'f2Ò'f0

both cursors 'f2þ'f0

NOTE: If the Reference cursor is above the Difference cursor, the resulting value is indicated as a negative value.

7.43 Marker

The MARKER cursor Ö measures the absolute vertical and horizontal position of a point on a trace. All traces with the same horizontal units are measured simultaneously. A marker cursor is located at the same horizontal position on each trace. Cursors appearing on each trace are simultaneously moved by rotating the continuous knob under the

display. If traces with different horizontal units are displayed, moving the cursor past the end of trace its on, will cause it to go to the trace with different horizontal units. If all traces on the screen have the same units, when the cursor is moved to the edge of the screen it remains there. The vertical measurement reflects the actual amplitude of the trace at the marker. The amplitude is indicated under the trace label(s) for the trace(s) being measured. The marker's horizontal position is expressed as the time (or frequency of the trace) between the trigger and the marker. It is indicated in the Time or Frequency Field and has the same units (in time or frequency) as the trace(s) being measured.

7.44 Horizontal Cursors

The horizontal cursors display the horizontal distance between the two cursors and its reciprocal below the grid. The

difference between the vertical values at each cursor is shown under the trace label for each trace which have both arrows. All traces with the same horizontal units are be measured simultaneously. Each horizontal cursor is located at the same horizontal position on every trace. The selected cursor on each trace is simultaneously moved by rotating the

continuous knob under the display. You can use the 'MSelect Cursor'N detented knob to change which cursor can be moved. If traces with different horizontal units are displayed, moving the cursor past the end of trace its on, will cause it to go to the next trace with different horizontal units. If all traces on the screen have the same units, when the

cursor is moved to the edge of the screen it remains there. The horizontal cursors are represented by:

Reference 'f2Ø'f0

Difference 'f2×'f0

both cursors 'f2Ø×'f0

NOTE: If the Reference cursor is to the right of the Difference cursor, the resulting value is indicated as a negative value.

7.45 Waveform Storage

The 7200 has several options for storing trace waveforms:

Any waveform display with its annotation can be preserved on hard copy with a printer or color plotter. Alternately, a tabular printout of the waveform data points and acquisition information can be produced. Trace waveforms can be stored on MSDOS formatted 3.5" floppy diskettes. These diskettes can be read by any MSDOS compatible machine. Conversely, waveform data previously stored on a diskette can be recalled, displayed, and processed. The 7200 has 8 internal non-volatile memories, M1...M8, available for individual waveform storage.

In Record Traces mode, all displayed traces are automatically recorded in an internal 4 Mbyte non-volatile circular buffer each time they are updated with a new acquisition. The recorded traces may subsequently be replayed, examined, processed, or stored to floppy diskette.

Clearing Memories and Record Traces Buffer

The 8 internal memories M1...M8 and the Record Traces buffer are non-volatile, i.e., they maintain their contents when the power is off. They may be cleared by pressing the 'MClear Memories'N softkey in the System Configure Screen.

7.45.1 Store

To store trace waveforms to MSDOS compatible floppy diskettes or to the non-volatile internal memories M1...M8, press the 'MSTORE'N key. The particular storage operation which will occur is that which has been previously

selected in the Waveform Storage Setup, accessed by pressing the 'MMODIFY'N key and then the 'MSTORE'N key.

NOTE: Only those traces which have been selected in the Waveform Storage Setup and which are displayed when the 'MSTORE'N key is pressed will be stored.

7.45.2 Waveform Storage Setup

To specify the traces to be stored and their destinations, press 'MMODIFY'N and then 'MSTORE'N .

Traces may be stored to files on floppy diskette or to non-volatile internal memories M1...M8. In the Waveform Storage Setup screen, a rectangular box is displayed around the selected field. To move the box, rotate the

'MMove Box'N detented knob. The options list in the lower right presents the available choices for the selected field, with the current value indicated. To change the current value, rotate the 'MModify Value'N continuous knob. Press the 'MReturn'N softkey to save all changes and return to the Main Screen. Press the 'MCancel Changes'N softkey to restore the original setup and return to the Main Screen. The Waveform Storage Setup fields follow:

7.45.3 Disk Drive

This read-only field indicates that traces can be stored to the floppy diskette but not the internal disk.

7.45.4 Filename Extension

Selects the numeric extensions for the filenames used for storing to floppy.

A filename has two parts which are separated by a period. For storing traces, the first part of the filename corresponds to the trace label. The trace label is selected in the Trace Setup screen. The default labels are Trace1, Trace2, etc.

The second part of the filename is called the extension. Traces are always stored to files with numeric extensions which range from .000 through .999. Use the Filename Extension field to choose the numeric extensions of the filenames to

which the selected traces will be stored. Filename Autoincrement Selects whether repeated presses of the

'MSTORE'N key will write the data into different files or will overwrite the same file. If Filename Autoincrement is OFF, repeated presses of the 'MSTORE'N key will write the trace to the same filename. Thus only the latest data will be saved. If Filename Autoincrement is ON, for each press of the 'MSTORE'N key a new filename is generated by incrementing the extension of the previously used file. This feature allows you to store a series of files without reconfiguring the Waveform Storage Setup in between each store operation.

T1,...T8

For each trace, choose ENABLED to enable storage of that trace, or DISABLED to disable its storage.

To

If you enable storage of a trace, the "To" field appears and allows you to choose where to store the trace waveform. The choices are FILE, M1, M2, M3, M4, M5, M6, M7, M8, T1=M1, T2=M2, T3=M3, T4=M4, T5=M5, T6=M6, T7=M7, T8=M8.

FILE

Choose FILE to store the trace to a file on the floppy disk. The filename to be used for the next store will be displayed to the right of FILE. The filename is equal to the trace label with a three digit numeric extension.

M1...M8

Choose Mx to store the trace to the specified internal memory.

T1=M1...T8=M8

Choose Tx=Mx to store the trace to the specified internal memory and automatically change the indicated trace equation to Tx=Mx in order to display the waveform in Mx.

7.45.5 Recall

To recall waveforms from floppy diskette to the internal memories M1...M8, press the 'MRECALL'N key. The particular recall operation which will occur is that which has been previously selected in the Waveform Recall Setup, accessed by pressing the 'MMODIFY'N key and then the 'MRECALL'N key. Waveforms in the memories can be displayed and/or processed as traces.

7.45.6 Waveform Recall Setup

To select the waveform files to be recalled and to assign where they will be placed, press 'MMODIFY'N and then 'MRECALL'N . Waveforms may be recalled from files on floppy diskette and placed in internal memories M1...M8.

In the Waveform Recall Setup screen, a rectangular box is displayed around the selected field. To move the box, rotate the 'MMove Box'N detented knob. The options list in the lower right presents the available choices for the selected field, with the current value indicated. To change the current value, rotate the 'MModify Value'N continuous knob. Press the 'MReturn'N softkey to save all changes and return to the Main Screen. Press the 'MCancel Changes'N softkey to restore the original setup and return to the Main Screen. The Waveform Recall Setup fields follow:

Disk Drive

This read-only field indicates that waveforms can be recalled from floppy diskette only.

7.45.7 Filename Autoincrement

When recalling waveforms from files on disk, you may choose whether repeated presses of the 'MRECALL'N key will read the waveform from sequential files or not. A filename has two parts which are separated by a period: base.extension. If Filename Autoincrement is OFF, repeated presses of the 'MRECALL'N key will recall the waveform from the same filename. If Filename Autoincrement is ON, the first press of the 'MRECALL'N key will recall the waveform from the chosen filename; subsequent presses will recall the waveform from files with the same base but

auto incrementing numeric extensions. This obviates the necessity of reconfiguring the Recall Setup between recalls when you wish to recall a sequence of files.

M1 or T1=M1, M2 or T2=M2, ... M8 or T8=M8

Specifies whether a waveform will be recalled to the corresponding memory and whether or not the corresponding trace equation will automatically be changed. If Mx is chosen, the waveform is simply recalled to memory Mx. If Tx=Mx is chosen, the waveform is recalled to memory Mx and the trace equation of Tx is automatically changed to Tx=Mx in order to display the waveform in Mx. For each memory, choose ENABLED to enable recall to that memory, or DISABLED to disable recall to that memory.

7.45.8 From File

If you enable recall to a memory, the "From File" filename field appears. The options for the recall filename are a directory listing of all filenames on the floppy diskette with numeric extensions. (Waveforms are always stored to files with numeric extensions). The file will not be tested to ensure that it contains a valid waveform until the 'MRECALL'N key is pressed later to initiate the actual recall operation. If Filename Autoincrement is ON, the first

press of the 'MRECALL'N key will recall the chosen file; subsequent presses of the 'MRECALL'N key will recall files with the same base but numerically increasing extensions. If no more files exist with greater extensions,

the same file will be recalled repeatedly.

7.45.9 Read New Floppy Disk

If you want to recall a file from a different floppy disk, change the disk and then press the 'MRead New Floppy Disk'N

softkey. The new floppy's files will then be displayed in the options list.

7.46 Disk Utilities

The Disk Utilities screen allows you to format floppy diskettes and access and maintain files on the internal disk or floppy diskettes. To access the Disk Utilities screen, press the 'MDisk Utilities'N softkey in the Waveform Recall Setup, Waveform Storage Setup, Panel Settings, or Program Setup screens.

7.46.1 Disk Utilites Files

The Disk Utilities fields specify the file(s) to be operated upon. In the Disk Utilities screen, use the 'MMove Box'N detented knob to select a field for modification, and the 'MModify Value'N continuous knob to change the value of the

selected field. The fields follow:

7.46.2 Disk Drive

Choose either FLOPPY or INTERNAL.

Directory

Specify the directory (group of related

files) for disk utility operations on the

internal disk drive by choosing either PANEL

SETUPS or PROGRAM.

7.46.3 Filename

Select either ALL FILES or the individual file for disk utility operations by using the 'MModify Value'N continuous knob to scroll through the list of all files on the specified disk and directory. The time and date of the selected file is

displayed to the right of the filename. If you want to select a file on a different floppy disk, change the disk and then press the 'MRead New Floppy Disk'N softkey. The 7200 will then read the directory listing of all files on the new floppy disk.

7.46.4 Overwrite Existing Files on Copy

For a copy ALL FILES operation, the 'MOverwrite Existing Files on Copy'N field specifies whether existing files should be overwritten, not overwritten, or whether the user should be asked for confirmation. Choose either YES, NO, or CONFIRM.

7.46.5 Disk Utilities Operations

To perform an operation on the specified file(s), press the appropriate Disk Utilities softkey:

7.46.6 Copy Internal to Floppy

When the selected Disk Drive is INTERNAL, the Copy File softkey is labeled 'MCopy

Internal to Floppy.'N Press this softkey to copy the selected file(s) from the internal disk to a floppy disk. If ALL FILES is selected for the Filename, all files on the selected directory on the internal disk will be copied to the floppy. If one of the files to be copied has the same name as a file already existing on the floppy disk, the 7200 will either overwrite the existing file, not overwrite the existing file, or ask for confirmation, as specified by the 'MOverwrite Existing Files on Copy'N field. If an individual file is selected for the Filename, only the selected file will be copied from the internal disk to the floppy. If a file with the same name already exists on the floppy disk, you will be asked whether you want to overwrite the file and prompted to press either the 'MYes'N or 'MNo'N softkey.

7.46.7 Copy Floppy to Internal

When the selected Disk Drive is FLOPPY, the Copy File softkey is labeled 'MCopy Floppy to Internal.'N Press this softkey to copy the selected file(s) from a floppy disk to the internal disk. Panel settings files with the extension .PNL will be copied to the PANEL SETUPS directory on the internal disk. Program files with the extensions .SRC and .APD will be copied to the PROGRAM directory on the internal disk. Files with other extensions will not be copied. If ALL FILES is selected for the Filename, all panel settings and program files on the floppy will be copied to the appropriate

directories on the internal disk. If one of the files to be copied has the same name as a file already existing on the internal disk, the 7200 will either overwrite the existing file, not overwrite the existing file, or ask for confirmation, as specified by the 'MOverwrite Existing Files on Copy'N field. If an individual file is selected for the Filename, only the selected file will be copied from the floppy disk to the internal disk. If the file is not a panel settings or program file, a warning message will be displayed and the copy will be aborted. If a file with the same name already exists on the internal disk, you will be asked whether you want to overwrite the file and prompted to press either the 'MYes'N or 'MNo'N softkey.

7.46.8 Delete File

Press the 'MDelete File'N softkey to delete the specified file(s). If ALL FILES is selected for the Filename, all files on the selected disk and directory will be deleted. Otherwise, only the individual selected file will be deleted. You will be asked "Are you sure?" and prompted to press either the 'MYes'N or 'MNo'N softkey before the file(s) is actually deleted.

7.46.9 Format Floppy Disk

Press the 'MFormat Floppy Disk'N softkey to format a floppy disk. All existing data on the disk will be lost. You will be asked "Are you sure?" and prompted to press either the 'MYes'N or 'MNo'N softkey before the floppy is formatted.

7.47 Hardcopy Setup

The 'MHardcopy'N key allows you to obtain a copy of the 7200's screen on a printer, plotter or floppy disk. Generating the copy does not affect the operation of the LeCroy 7200 Precision Oscilloscope. The hardcopy can be aborted at anytime during the plot by pressing the 'MHARDCOPY'N button again. The Hardcopy Setup lets you change different parameters of the Hardcopy. To configure these features, press 'MMODIFY'N and then 'MHARDCOPY.'N You will then be allowed to change the following parameters:

7.47.1 Port

Specifies which port (GPIB, RS232, Centronics, or Floppy) is used as the output of the hardcopy. If the Hardcopy 'MPORT'N is the same as the 'MRemote Control from'N field in the Communication Setup screen, then the local Hardcopy key is disabled and pressing it sets the User Request bit (URQ) in the Standard Event Status register (*ESR). This is to prevent the hardcopy data from disrupting a Remote Host controller. If you have no Remote Host controller, simply enter the Communications Setup screen via the Configure System softkey and change the 'MRemote Control from'N field to a value that does not conflict with the Hardcopy 'MPORT.'N If you have a Remote Host controller, then it can initiate a remote hardcopy when it is ready.

7.47.2 Filename

When Floppy is selected, the Filename field will appear. To edit the filename, move the box onto the Filename field and press the 'MEdit Text'N softkey. The 'MInsert Character'N and 'MDelete Character'N softkeys will then allow you to edit the filename a character at a time.

7.47.3 Device

Specifies the name of the hardcopy device (printers and plotters). All of the fields (except Port) are device specific, allowing you to set different parameters for different devices and not lose these settings when switching among different devices.

7.47.4 Annotation

Selects whether the 7200 will print/plot the user comment, logo, softkey labels, and acquisition parameters (time and date, timebase, and vertical amplifier settings) with the grid and waveform.

7.47.5 Page Feed

Applies to printers only and causes a Form Feed to follow the printed plot in order to eject the page.

7.47.6 Plot Area

Displays the Page Size or the Paper Size in length x width mmŽ. This field automatically

updates as the paper size changes to tell you the size of the resulting plot/print.

7.47.7 Comment

The Comment is a 40 character field which appears at the top of the plot/print if Annotation is ON. You edit this field by pressing the Edit Text softkey which puts the box around a character in the comment. The Move Box knob moves the box to the next or previous character and the Modify Value continuous knob changes the value in the box to any letter you select. Pressing the Return softkey will save the comment.

7.47.8 Number of Pens

For plotters,enables color plots if multiple pens are present. The 7200 can control up to 8 pens.

7.47.9 Pen Speed

For plotters, selects the plotter's drawing rate.

7.47.10 Paper Size

For plotters, selects the size of the resulting plot. You should decide how large a plot you want, select it, then make sure the plotter has paper in it which is at least as big as the resulting plot or you will get out of limit errors which could ruin your plot.

The 7200 supports three standard sizes and one non-standard size:

PAPER SIZE X ORIGIN Y ORIGIN

---------------- -------- --------

A5 = 5.5" x 8.5" 10 mm 10 mm

A4 = 8.5" x 11" 0 mm 2 mm

A3 = 11" x 17" 10 mm 10 mm

NON STD

7.47.11 Size of Grid Square (mm)

When Non-Standard plot/print is selected, you may select the size of the grid square from 0.0 to 99.9 mm. When there is a single grid, the grid square is the length or width of one box of the grid in millimeters. The size of the grid square will determine the size of the resulting plot/print.

7.47.12 X Position (mm)

Selects the left-most position of the plot. Values range from -999.9 mm to 999.9 mm. Be careful not to position the plot off the page or out of the limits of the plotter.

7.47.13 Y Position (mm)

Selects the bottom-most position of the plot. Values range from -999.9 mm to 999.9 mm. Be careful not to position the plot off the page or out of the limits of the plotter.

7.47.14 Type of Output

For printers, selects the type of output when the Hardcopy key is pressed. The choices are Screen Dump, Waveform, and Program. Screen Dump is similar to plotters except for printers. Selecting Waveform will print waveform data in a formatted table. Selecting Program will print the Program displayed in the "Program Setup" screen.

7.47.15 Graphics Density

For printers, specifies the resolution. The higher the resolution, the finer the prints but also it also takes longer to generate the prints.

7.47.16 Page Size

For printers, specifies the size of the resulting printed plot. The choices are:

A5 = 5.5" x 8.5", left-justified

7.47.17 NON STD

The size you select for output should match the size of the paper in your printer or "out-of-limits" errors could ruin your printed plot. If NON STD is selected, you will be asked to select the size of a Grid Square in millimeters. You may adjust this from 0 to 99.9 mm and this will determine the size of the resulting printed plot. Be careful not to exceed the bounds of your printer or the paper or the printed plot could be ruined.

7.47.18 Trace to Print

For printers, when the Type of Output is Waveform, you must select which trace you want printed. Channels may be printed by having the trace made equal to the channel (ie., T1 = A1).

7.47.19 Waveform Block

For printers, when the Type of Output is Waveform, you must specify which part of the waveform you want printed. Valid choices are: WAVEFORM BLOCK DESCRIPTION

-------------- ----------------------------

DESCRIPTOR: acquisition settings printed

TEXT: user text printed

TIME: time array(s) printed

DATA1: Wave Array 1 printed

DATA2: Wave Array 2 printed

ALL: All above printed

If for some reason there is no data in a

waveform block, there will be no printer

output.

Return

Pressing the Return key will save all the changes in non-volatile memory and exit the menu

Cancel Changes

Pressing the Cancel Changes key cancels all modifications. It exits the menu and restores the original setup.

7.48 Configure System

When this key is pressed, the 7200 displays a summary of the trace equations and of the contents of the memories. The software revision is also displayed. The Configure System screen also provides access via softkeys to screens where you can store and recall panel settings, select screen intensity, set the time and date, select the communication setup (I/O ports), plug-in configuration, examine the system error log, select default settings or reset the system. Each of the softkeys are described in detail below.

7.49 Screen Intensity

After pressing this softkey a half screen grid is shown with any traces which are on. The intensity for "text & traces" and the "grid" may be set independently. They are set as a percentage of full scale from 0 to 100.

7.50 Set Time and Date

This key invokes the Time and Date Setup screen which displays the current system time while allowing you to reprogram the clock. The clock, which is used for time stamping acquisitions, disk files, etc, is battery backed up and need only be set once. Use 'MModify Field'N to select hour, minute, day, date, month, or year and 'MModify Value'N to change it to the appropriate value. When the highlighted time is the time that you want,

press 'MSet New Time & Date'N to set the clock.

7.51 Communication Setup

This key invokes the Communications Menu which is used to set the system's GPIB and RS-232-C Port parameters. The RS-232-C parameters which can be set are Baud Rate, number of Stop Bits, Parity, number of Data Bits, and whether or not to use the Clear to Send/Request to Send handshake.

7.52 Remote Control

Selects the port used to remotely control the 7200. Only the GPIB and RS-232-C ports may be used for remote control. If GPIB is selected for Remote Control, the GPIB address field will appear.

'M Warning: Selecting the same port for both'N

'M Remote Control and Hardcopy will'N

'M disable Remote Control and only'N

'M allow Hardcopy from that port.'N

7.52.1 GPIB Address

If GPIB is selected as the Remote Control port, this field appears to allow you to change the GPIB address of the 7200. Valid GPIB addresses range from 0 to 30 with 0 usually reserved for the Controller.

Baud Rate

Specifies the baud rate for the RS-232-C port. All standard baud rates from 110 through 19200 are supported.

Stop Bits

Specifies whether one or two stop bits are to be added to each character transmitted and expected with each character received by the RS-232-C port.

Parity

Selects whether the RS-232-C port will use EVEN, ODD or no parity (NONE).

Data Bits

Sets the number of data bits to be transmitted and received for each character.

Handshake

This selects either a software handshake (XON-XOFF) or hardware handshake (HARDWIRE).

7.53 Acquisition Setup

The Acquisition Setup screen contains options specific to performing data acquisitions. This screen can be accessed

either thru the Configure System screen or by pressing the 'MMODIFY'N key and then a 'MTRIGGER MODE'N key.

7.54 The Sequence Trigger

Types are Single and Normal. Single Sequence acquiries the requested number of segments and displays a Sequence waveform. To arm the circuit again for another sweep, press 'MTRIGGER MODE'N again to re-select Sequence. Normal Sequence will keep acquiring and displaying Sequence waveforms until the 'MTRIGGER MODE'N key is pressed again to re-select Sequence. The modularity of the 7200 allows different time bases and triggers for each plug-in. For some applications, however, using the same time base, or trigger, or both is necessary. The Acquisition Setup screen allows selection of INDEPENDENT or LOCKED triggers and time bases. If locked is selected, changing a

control, such as 'MTimebase'N on one plug-in effectively changes it on all plug-ins. If set to INDEPENDENT, changing a control on a plug-in, only affects that one. When triggers are locked, there is only one trigger source for all plug-ins. The source may be selected from any plug-in by selecting the desired source with the 'MTrigger Source'N key on the desired plugin.

'MReference Clock'N

The 7200 allows the user to use it's internal reference clock or an externally applied 10 MHz clock. The screen shows whether this 7200 contains the optional HIGH accuracy reference clock or the standard one. If external clock is selected, it must be applied to the back connector of the instrument.

'MHistory Display Update'N

This field selects how often the display is updated while a history function (histograms, averaging, etc.) is accumulating data. To increase the throughput, a longer time between updates should be used.

'MAuto Calibration'N

The 7200 allows the user to enable or disable automatic calibration of the instrument. At power-up, auto-calibration is

turned ON. Automatic calibration enables periodic calibration of both input channels for the current gain, bandwidth, and time-base settings.

The 'MCalibrate All Plug-ins'N key ensures overall vertical, time base, and trigger accuracy by calibrating all plug-ins at it's current setting. Calibration is also performed when the 7200 is powered, when Time base or Vertical Controls are adjusted, and periodically thereafter.

7.55 System Log

The 7200 maintains a log of all system messages. Pressing the 'MSystem Log'N sofkey displays this log. If there are more messages in the log than can be displayed, the continuous knob is labeled 'MNext Line'N and lets you scroll through the entire log. A softkey, 'MErase Log'N clears the system log.

7.56 Panel Settings

'MPanel Settings'N displays a screen which is used to store and recall front panel settings to and from either the 7200's

internal disk or MSDOS formatted 3.5" floppy diskettes. When 'MPanel Settings'N is selected in the Configure System screen, the following fields and softkeys appear:

Disk Drive

Choose either INTERNAL or FLOPPY disk for panel settings store and recall operations.

Store Filename

To specify the name of the file in which to store panel settings, move the box onto the "Store Filename" field. The 'MEdit Text'N softkey will appear in the upper left corner of the screen. Press it to edit the filename letter-by-letter using the 'MInsert Character'N and 'MDelete Character'N softkeys which will appear. When you are finished editing the filename, press the 'MReturn'N softkey to save the changes and regain access to other fields and softkeys in the Panel Settings screen. If the changes are not desired, press the 'MCancel Changes'N softkey to restore the original filename.

Recall Filename

Choose the file from which panel settings will be recalled. The available choices are all the panel settings files on the selected disk.

Read New Floppy Disk

If the selected Disk Drive is FLOPPY and you wish to recall from a different diskette, insert the new diskette and press the 'MRead New Floppy Disk'N softkey. The new floppy's files will be displayed in the options list.

Store Panel Settings

Press the 'MStore Panel Settings'N softkey to store the current front panel settings to the selected disk and filename.

Recall Panel Settings

Press the 'MRecall Panel Settings'N softkey to recall front panel settings from the selected disk and filename. After the softkey is pressed, the following warning prompt will appear in the message area: 'MRECALL PANEL SETTINGS? (PRESS YES OR NO)'N and the 'MYES'N and 'MNO'N softkeys will appear. Press the 'MYES'N softkey to recall panel settings or press the 'MNO'N softkey to cancel the recall operation.

Default Settings

Pressing this softkey resets all control settings to their default values and restarts the 7200.

Reset System

Pressing this softkey causes the 7200 to restart. It does NOT affect any of the current control settings. It can be used to install software upgrades by first placing the floppy disks in the drive and then pressing this key.

7.57 Trace Setup

A trace can represent unprocessed acquired data, or can be the result of processing acquired data and/or other traces. For the default setup, each trace represents acquired data from one channel. For example, Trace 1 represents data from channel A1, Trace 2 represents data from channel A2. In Trace Setup, channel data can be processed or combined to define trace data. Also, trace combinations can define still other traces. The Trace Setup allows you to use math

equations to combine and process the source data. Note: While in this screen, the 7200 suspends acquisition and processing of all other traces to accelerate updating the displayed trace. To enter the Trace Setup press the 'MMODIFY'N key and then the 'MTRACE'N key for the trace you want to setup.

Editing The Trace Equation

The Trace Setup will display the trace in the upper part of the screen. The line below the grid is the trace equation. This equation indicates the source(s) of data and how it has been processed. Use the 'MMove Box'N detented knob to modify different parts of the equation. The source data for the trace can come from an acquisition channel or from another trace. The 7200 automatically determines which channels or traces can be used as sources and displays them in the options list. An equation may contain at most three sources. Since sources are always associated with a processing function, they are added or deleted with processing functions as needed.

7.57.1 Add Processing Functions

The 7200 performs unary waveform mathematical operations, which require only one source, and binary waveform functions which require two sources. An equation may contain at most two processing functions. Each trace can contain one history function (continuous averaging, summation averaging, FFT, or extrema).

To add a mathematical operation to a trace equation, move the box to the desired source. Then press the 'MAdd Function'N softkey. A new math symbol will appear in the equation, and the box will move onto the symbol.

If you add a binary waveform function, a math symbol followed by a second source is added to the right of the box.

7.57.2 Delete a Processing Function

Deleting a processing function is the reverse of adding a processing function. For binary waveform processing functions, the source to the right of the deleted function is also removed.

7.57.3 Unary Waveform Functions

The Unary waveform functions operate on one source: trace or data from one channel. Functions that operate on dual trace waveforms, such as Extrema, will use only one of the traces (for Extrema, the Roof data is used). Waveforms created by using SEQuence Trigger Mode cannot be processed by some single waveform functions unless expanded to a single segment. If processing cannot be performed, the 7200 displays an error message at the top of the screen. The unary processing functions are:

1/ inverts the source.

ABS the absolute value of the source.

AVGSEQ averages the segments in a sequencewaveform.

differentiates the source.

ERES applies an enhanced resolution filter which increases the number of effective bits while decreasing the bandwidth.

´ integrates the source.

EXP the antilog to the base e of the source; that is, e raised to the power equal to the source. The vertical axis

of the result is dimensionless.

EXP10 like EXP, except the base is 10.

FLOOR generates a display of the floor function of the source; that is, the minima of the source from all acquisitions. If the source is an

EXTREMA waveform, the lower part is selected. Otherwise, the EXTREMA is computed with AXSWEEPS=100000, and the lower part is selected.

LIMIT generates an EXTREMA waveform for use in GO-NO-GO testing. See also the section "Limit Function".

LOG performs a log of a dimensionless source to the base e. Values less than or equal to zero are set to underflow.

LOG10 like LOG, except the base is 10.

NEG negates the values in the source.

ROOF generates a display of the roof function of the source; that is, the maxima of the source from all acquisitions. If the source is an EXTREMA waveform, the upper part is selected. Otherwise, the EXTREMA is computed with AXSWEEPS=100000, and the upper part is selected.

SIGN compares the source waveform with zero. Points which are less than zero are set to -1. Points which are equal to zero are set to zero. Points which are greater than zero are set to +1. The vertical axis of the result is dimensionless.

SINX performs 10-to-1 interpolation using a sin(x)/x filter.

Á ‹performs a 1-point moving average.

 ‹performs a 3-point moving average.

à ‹performs a 5-point moving average.

Ä ‹performs a 7-point moving average.

Å ‹performs a 9-point moving average.

SQR squares the source.

... takes the square root of the absolute value of the source.

Limit Function

The GO-NO-GO test procedure compares its input waveform with an EXTREMA waveform stored in M2. The LIMIT function generates such a waveform by "fattening" its input by an amount you specify in both the horizontal and

vertical directions.

Width

The amount of fattening in the horizontal direction, specified in divisions.

Height

The amount of fattening in the vertical direction, specified in divisions.

Binary Waveform Functions

Binary waveform functions operate on two sources which can be either channels or traces. The 7200 automatically compensates for any differences in the vertical gains and offsets of the two sources. The result's vertical range is corrected to fit onto the grid. However, if the source waveforms are acquired with different plug-ins, both source waveforms must have time bases with the same time base settings and compatible units. The trigger point of the sources may be different, but this usually gives results that are difficult to interpret. Binary waveform functions cannot be applied to sequence waveforms unless they are expanded to a single segment. The 7200 can perform the following

processing on 2 waveforms:

adds a second source to the existing source.

subtracts a second source from the existing source.

multiplies a second source to the existing source.

/ divides the existing source by a second source.

History Functions

The history functions use the most recent waveforms and one or more previously acquired sets of data to make up a trace. For example, the averaging functions sum sucessive acquisitions together. Since this data must be kept from sweep to sweep only one history function is allowed per trace. Also, when a history function is selected, no other

function can be selected at the same time. When a history function is defined, the 'MClear Display'N softkey appears in the Main Screen . Pressing it sets all the data back to zero. In addition, changing any of the plug-in acquisition parameters, (such as timebase), or any of the the parameters defining the operation of the history function (such as Max Points), resets the history data. In general, the history functions require additional fields to define their operations. When other fields are necessary, the 7200 automatically displays them below the equation. The following fields are common to several history functions:

7.58 Max Sweeps

sets the number of sweeps to accumulate before pausing. Unlike other parameters, changing this parameter does not affect the history data.

Artifact Reject

When enabled, any waveform with an underflow or overflow value is not included in the computation. If Artifact Reject is turned OFF, any overflows are set to the maximum possible value of the ADC and any underflows to the minimum value. The waveform is then processed. The history functions, and their associated parameters are described below:

AVGC Continuous Averaging can be used to remove random noise from a signal and present a better picture of the actual waveform. The Continuous average uses an indefinite number of acquisitions and enables you to see the effects of more recent changes to the signal.

When Contiuous averaging is selected, you can also specify:

Weight specifies the weighting factors, which determine the speed at which the continuous average follows changes in the source waveform. As the value of the weight decreases, the average follows changes in the signal more closely.

AVGS Summed Average also improves the signal to noise ratio and increases the dynamic range by several bits. When this function is selected, the Max Sweeps and Artifact Reject parameters may be adjusted. When the source of

AVGS is an acquisition channel, the averaging will be performed at a high rate (dependent on the plugin) if the following conditions are true:

1) Record Traces is off.

2) The acquisition record length is <= 20K points. (This restriction is specific to the 7242 plugin and may be different for other plugins.)

3) Acquisition type is not RIS or sequence. 4) Each enabled trace which uses a channel must use a unique channel, and must consist of either no processing (eg. T1=A1) or an AVGS function with no decimation (Max # Of Points >= acquisition record length). For example, if T1=AVGS(A1) and T2=A2, averaging will be fast. However, if T1=AVGS(A1) and T2=A1, averaging will not be fast because the same channel is used for both an average and display.

When these conditions are met, the 'MFAVGS'N icon will be displayed at the bottom of the screen.

Extrema The Extrema function generates two waveforms which represent the minimum and maximum values of the source (i.e., the roof and floor functions displayed simultaneously). These waveforms are generated by repeated comparison of acquisitions of the source waveform with the current Extrema waveform. Whenever a point of the new waveform exceeds (either positively or negatively) the corresponding data point of the accumulated Extrema waveform, it replaces the former value in the Extrema waveform.

FFT Averages Fast Fourier Transform Averages are used to average the result of previously computed FFTs. The following FFT average functions are available:

AVGMAG magnitude

AVGPWS power spectrum

AVGPWD power density spectrum

Upon selecting FFT averaging, the Max Sweeps and Artifact Reject parameters may be adjusted.

Fast Fourier Transforms

FFT Fast Fourier Transforms provide spectral analysis of waveforms. The FFT calculation always produces a complex result and is saved for further processing to generate the desired data. Only one FFT may be defined per trace. The following single waveform functions derived from the FFT can be used to further process the results.

FFTMAG magnitude

FFTPHA phase

FFTPWS power spectrum

FFTPWD power density spectrum

FFTRE real part

FFTIM imaginary part

FFTRI real and imaginary parts

Upon selecting FFT processing, theseparameters can be adjusted:

Window Type

Several windowing functions are provided to minimize leakage and maximize spectral resolution of

single shot events. Choices are:

Rectangular, Von Han (Hanning),

Hamming, Blackman-Harris or Flattop.

DC Suppression selects whether or not to remove the DC component.

Histogram and Trend

The 7200 can produce continuously updating histograms of waveform parameter values. Once the histogram has accumulated the specified maximum number of values, it maintains only the most recent values; when a new value is

added to the histogram, the oldest one is subtracted out. 'MHIST'N is reset when the 'MClear Display'N softkey is pressed or its source waveform acquisition parameters change. The 'MHIST'N function produces a waveform

consisting of one point for each histogram bin, where the value of each point is equal to the number of parameter values which fall into the corresponding bin. Parameter values which fall outside the histogram limits as specified by 'MCenter'N and 'MWidth'N are not included in any of the histogram bins, but do count as events for purposes of reaching Max Events.

Max # Of Bins

The number of bins in the histogram which equals the number of points in the waveform.

Parameter

The parameter of the source waveform whose value is to be histogrammed. The parameter is computed on the section

of the waveform delineated by the parameter cursors. If the cursors are turned off, their last position is used. Some parameters require 1 or 2 arguments which appear if needed.

Max Events

The maximum number of parameter value events to maintain in the continuous histogram.

Center

The midpoint of the central bin of the histogram. The softkey "Find Center And Width" can find the center auto-

matically.

Width

The Width is 1/10 of the total width of the histogram. The histogram is displayed with the horizontal scale

per division equal to the selected Width/div. The softkey "Find Center And Width" can be used to find the

width automatically. The Width is split into mantissa and exponent which can be set independently or

the mantissa can be set alone and the exponent will follow its changes.

Vertical

The Vertical field allows you to change the vertical scaling of the displayed histogram. Choices are:

LIN

The vertical axis is linear and the histogram will grow towards the top.

MAX

The maximum value of the histogram is always at the top of the screen.

LOG

A logarithmic display of the histogram is shown. Events Per Waveform This field is present for parameters

whose source waveform sweep can contain multiple events, each of which generates a parameter value. Choices:

FIRST

The parameter value for the first event in the waveform sweep contributes to the histogram.

ALL

The parameter value for all events in the waveform sweep individually contribute to the histogram.

AVERAGE

The parameter value for all events in the waveform sweep are averaged together to produce a single value.

Parameter Arguments

These fields only appear if the selected parameter requires arguments.

Center On Max Softkey

Moves the histogram Center to the mode of the current histogram and keeps the Width the same.

Find Center And Width Softkey

Automatically chooses the histogram Center and Width to encompass the Max Events most recent accumulated events. Trend The 7200 can produce rolling trends of the most recent waveform parameter values. 'MTREND'N is reset when the 'MClear Display'N key is pressed or its source waveform acquisition parameters change.The 'MTREND'N

function produces a waveform consisting of one point for each parameter value trended, where the value of each point is equal to the value of the parameter. 'MTREND'N waveforms always roll from right to left across the screen.

Max # Of Points

The maximum number of parameter values to maintain in the rolling trend which equals the maximum number of points in the trend waveform.

Parameter

The parameter of the source waveform whose value is to be trended. The parameter is computed on the section

of the waveform delineated by the parameter cursors. If the cursors are turned off, their last position is used. Some parameters require 1 or 2 arguments which appear if needed.

Center

The center of the range of parameter values to be included in the trend. The softkey "Find Center and Height"

can be used to automatically set the center.

Height

The Height is 1/8 of the total range of parameter values to be included in the trend. The trend is vertically scaled for display so each division equals Height/div. The "Find Center and Height" softkey automatically sets the Height.

Horizontal

This allows you to set the horizontal time interval. If EVENTS is selected, then whenever an event is received,

it will be accumulated in the trend.

Events Per Waveform

This field is present for parameters whose source waveform sweep can contain multiple events, each of which generates a parameter value. Choices:

FIRST

The parameter value for the first event in the waveform sweep contributes to the trend.

ALL

The parameter value for all events in the waveform sweep individually contribute to the trend.

AVERAGE

The parameter value for all events in the waveform sweep are averaged together to produce a single value used in the trend.

Parameter Arguments

These fields only appear if the selected parameter requires arguments.

Find Center And Height Softkey

Automatically chooses the trend Center and Height to best display the trend of the Max # Of Points most

recent events.

7.59 Time Of Flight Functions

Several functions are provided to assist in analyzing time of flight data. The 'MTOFAN'N function is used to convert an analog time of flight waveform into a histogram. 'MTOFPC'N is a history function which locates and counts pulses in a waveform and builds a time of flight histogram from them. The 'MWINHIST'N function is used to collect data from specific regions in a time of flight histogram. The purpose of the 'MTOFAN'N and 'MTOFPC'N functions is to generate a histogram in which the vertical axis is proportional to the number of ions arriving at the detector. The horizontal axis can be the arrival time or may be converted to the ion mass in atomic mass units (AMUs). The input waveform of 'MTOFAN'N is assumed to be an analog representation of the number of ions as a function of time. The function converts this directly to a histogram by changing the vertical axis from its original units (typically Volts) to histogram events. For this reason, it is usually necessary to apply a large multiplicative constant to the source. An additive constant may be used to provide a lower cutoff for the data. If averaging is required to reduce noise, it should be applied to the source of the 'MTOFAN'N function using one of the averaging functions. The input of 'MTOFPC'N is a waveform containing pulses. Each pulse represents the arrival of one ion at the detector. 'MTOFPC'N updates its histogram by adding one at the appropriate location for each pulse in the input. Since it is a history function, the 'MClear Display'N key may be used to restart the acquisition. Changing any of the parameters except 'MGain, Offset,'N or 'MMax Events'N will also reset this function. The parameters of 'MTOFAN'N and 'MTOFPC'N are listed below. Most parameters are shared between these two functions. However, the 'MCoupling, Threshold,'N and 'MMax Events'N are only used by the 'MTOFPC'N function.

Slope

This control is used to select the polarity of the input waveform. Choices are:

POS

The waveform is positive. For TOFPC, the time of each event is determined by the positive crossing through the threshold.

NEG

The waveform is negative. For TOFPC, the time of each event is determined by the negative crossing through the threshold.

Coupling

This control, used by TOFPC, is similar to the COUPLING control in the plugin's vertical section. Choices:

AC

The threshold is relative to the average value of the waveform.

DC

The threshold is an absolute value Threshold This control, used by TOFPC, specifies the vertical value of the input which is used to determine the time of a pulse.

Gain and Offset

The gain and offset are used together to convert the horizontal offset of a TOFAN or TOFPC waveform from time to

mass. The conversion formula is:

SQRT(Mass) = Gain * (Time + Offset)

If the Gain parameter is set to zero, the horizontal axis is not converted to mass. Instead, it is the original time axis of the input. Two RCL programs, MASSCAL1 and MASSCAL2, have been provided to assist in setting these parameters.

Max Events

This parameter is used by TOFPC to determine how many pulses should be acquired in the waveform before terminating acquisition. The 'MWINHIST'N function is used to extract data from a histogram generated by 'MTOFAN'N or 'MTOFPC.'N It examines windows in the input having equal size and spacing along the

horizontal axis. This is useful for applications where the ions of interest have a regular spacing, as in 'MDNA Sequencing.'N The output of the 'MWINHIST'N function is actually a table presented in the form of a histogram. The bins along the horizontal axis are numbered 0, 1, 2, etc. The vertical value in each bin is the sum of the counts found in the corresponding window in the input histogram.

Max # Of Bins

This specifies the actual number of bins generated by the WINHIST function. If the value selected is not a 1-2-5 number, the histogram is filled on the right with zeros to the next higher such number.

Center

The center is the location of the leftmost window of the input to examine. It is expressed in the horizontal units of the input.

Width

This specifies the width of each window. It is expressed in the horizontal units of the input.

Spacing

The spacing gives the distance from the center of one window to the center of the next. It is expressed in the

horizontal units of the input.

Number of Points to Process

Waveform processing might require appreciable execution time. To reduce this time, you can reduce the number of points to process for a trace by changing the 'MMax # Of Points'N field. You can select this number to be as low as 50 or as high as the number of points acquired. Starting with the first point of a source, the 7200 uses every n-th point,

where n depends on the timebase, the number of points in the source, and the value selected for Max # Of Points.

Constants in Trace Equations

One multiplicative constant and one additive constant are associated with each source. To specify these constants press the 'MAdd Constants'N softkey. The display changes to show the highlighted constants as:

T1 = ('M'BA1'O'N)

Max # Of Points 'M50000'N

£ = 'M1.0000†Œ -'N ¤ = 'M0.0000†Œ'N

The 'MAdd Constants'N softkey is then re-labelled as 'MDelete Constants.'N Pressing the 'MDelete Constants'N softkey will remove the constants from that source and save it in memory. The box may then be moved onto another source and pressing 'MAdd Constants'N will retieve the previously deleted constants. This method may be used to move constants from source to source without re-entering the data. When any of the constants have changed from their reset values, the equation will change to display the greek representations of the constants:

T1 = (£*'MA1'N+¤)

Max # Of Points 'M50000'N

£ = 'M'B1.0001'O†Œ -'N ¤ = 'M0.0000†Œ'N

Additive or Multiplicative Constants are split into a mantissa and an exponent which may be set independently or the mantissa may be set by itself, in which case the exponent will follow it. This allows a wide dynamic range ( ‡�Œ to †�Œ) while also permitting entry of precise mantissa values.

Reset Value

Press the 'MReset Value'N softkey to set the current field to its default value. If non-trivial values are selected, these

constants remain displayed in the trace equation. Since a trace equation may include three sources, three pairs of constants may be specified. Different Greek letters are used for each of the six constants:

T4 = ((£*'MA1'N+¤)+((¥*'MT2'N+¦)+(§*'MT3'N+¨))

£ = 'M1.5000†Œ -'N ¤ = 'M0.1000†Œ'N

¥ = 'M2.5000†Œ -'N ¦ = 'M'B0.2000'O†Œ'N § = 'M3.5000†Œ -'N ¨ = 'M0.3000†Œ'N

Units for the Constants

Pressing 'MEdit Constants'N also allows selection of a unit which will get multiplied by the sources unit. The item next to the multiplicative constant, allows selection of the unit for this source. In the above example, the "-" means that the units are dimensionless. The user may select the following units:

NAME DESCRIPTION NAME DESCRIPTION

Dimensionless s Second

% Percent C Coulomb

dB Decibel F Farad

dBM Decibel Milliwatt ¡ Ohm

dBV Decibel Millivolt V Volt

octave Octave W Watt

ppm Parts per Million H Henry

# Event WB Weber

m Meter N Newton

K Degrees Kelvin J Joule

cyc cycle POISE Poise

A Ampere g Gram

Hz Hertz

Press the 'MReturn'N softkey to save the constants entered. Press the 'MCancel Changes'N softkey to restore the constants to what they were before any changes were made.

Trace Label

A trace label is used by the 7200 to create filenames for storing the trace. If you specify a label other then the default ones (ie. "Trace1", "Trace2", etc), it is printed on the screen next to the key corresponding to that trace. To assign a label other than the default, move the box onto the Trace Label Field and press the 'MEdit Text'N softkey. When the default label is chosen, the trace equation will overwrite the label for this trace. When the label is different than the

default label, trace label will overwrite the label for this trace. This is useful if you want informative data to appear in the trace label for hardcopies.

Annotate Trace

You can annotate up to 10 different points of interest on a trace. The annotation is associated with a trace and moves along with the trace as it is repositioned on the screen. The text is saved with the trace if it is stored to disk or read out of the 7200 via a remote port. It is also useful for generating hardcopy reports. To display the Trace Annotation Setup screen, press the 'MAnnotate Trace'N softkey in the Trace Setup screen. In this screen, there are two fields for each of the 10 strings you can associate with a trace. The first field selects whether or not the string should be displayed. The second field is the text for the string. When you move the box onto the text field, the 'MEdit Text'N softkey will appear. When it is pressed, the box will move on individual characters in the string to allow you to modify the annotation. Pressing the 'MReturn'N softkey will save the annotation string. To reposition the text anywhere within the

grid, press the 'MMove Annotation'N softkey. A horizontal and vertical cursor appear on the grid. The detented knob under the center of the screen is used to select which cursor to move. The center continuous knob is used to move the selected cursor around on the screen. The beginning of the selected text will be placed at the intersection of the two cursors. When you have positioned the text where you want it, press the 'MReturn'N key to save the changes and return to the Trace Annotation Setup screen or 'MCancel Changes'N to restore it to its previous position. To exit the Trace Annotation Setup screen, press the 'MReturn'N softkey to save the annotation entered. Press the 'MCancel

Changes'N softkey to restore the annotation to what it was before any changes were made.

7.60 Display Trig Times

The 'MDisplay Trig Times'N softkey will display the time(s) at which the trigger(s) occurred. For Sequence trigger mode, the first and last trigger times (or Duration) are displayed along with the trigger time for each segment. When there are more segment trig times than can fit on the screen, the 'MNext Line'N continuous knob will allow scrolling up and down the list of trig times. The 'MShow Absolute/Relative Times'N softkey will switch between the display of trig times from the time at which trigger occurred(Absolute) and the time from first trigger(Relative). The 'MReturn'N softkey when pressed will exit the trig times screen and return to the 'MTrace Setup'N screen.

8 7242 Introduction

The 7242 plug-in front panel controls allow changing the timebase, the trigger conditions, the signal amplifiers, and the display of a summary of control settings on the mainframe display. Whenever a plug-in control is changed, the plug-in's vertical and timebase settings are briefly displayed on the screen. The display indicates the settings to be used for the next acquisition. The labels displayed next to the `MTRACE 1`N through `MTRACE 8`N keys indicate the name or label of the displayed trace and the acquisition parameters used when the waveform was acquired and are updated with every waveform acquisition. Note that changes to the control settings will not be reflected in the displayed waveform until the 7242 has acquired new data, since changing the plug-in acquisition settings has no effect on previously acquired waveforms. Therefore, the settings indicated when controls are changed may differ from those displayed next to the trace keys when the 7200 is in the Single or Sequence Trigger Mode and has finished acquiring data.

8.1 Display of Acquisition Parameters

There are several displays which provide parameter acquisition information.

8.2 Plug-in Status

The Plug-in Status screen displays all 7242 control settings. The acquisition parameters which do not have a dedicated control on the front panel are changed from within this screen. Pressing the `MDISPLAY`N key or pressing the `MMODIFY`N key (on the mainframe) and the the `MDISPLAY`N key brings up the Plug-in Status screen. The acquisition parameters which do not have a dedicated control on the front panel can be changed from within this menu. To select the parameter to change, rotate the `MModify Field`N soft knob until the box moves to the item to be changed. To change the item's value, rotate the `MModify Value`N soft knob until your choice appears within the box. The list of choices are shown in the lower right corner of the menu, with the current choice in the center of the list of options. The screen is divided into three main sections: Trigger Controls, Timebase Controls, and Vertical Controls.

8.3 Vertical Status Screen

The Vertical Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Vertical Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the vertical section on the plug-in's front panel or when selected from inside the Trigger or Timebase status screens.

8.4 Trigger Status Screen

The Trigger Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Trigger Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the trigger section on the plug-in's front panel or when selected from inside the Timebase or Vertical status screens.

8.5 Timebase Status Screen

The Timebase Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Timebase Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the timebase section on the plug-in's front panel or when selected from inside the Vertical or Trigger status screens.

8.6 Plug-in Controls

The following sections will describe all the controls available to the user.

8.7 Vertical Controls

The Vertical controls adjust signal amplification for each plug-in channel. These adjustments are made either with dedicated front panel controls or from within the Plug-in or Timebase Status screens. The `MCH1`N or `MCH2`N keys select which channel the Vertical controls will modify. For example, when CH1 is pressed, adjusting a Vertical control will affect CH1 signal input. CH2 settings remain unchanged. The channels LED next to the key is lit to indicate the

selected channel. The `MSelect All Channels`N softkey is located in the Plug-in and Vertical status screens and is used to set all the vertical control settings for every channel of the plug-in to be the same as the vertical control settings for the channel indicated to the right of the "Vertical Controls" label. Both the CH1 and CH2 led's will be lit and

modifiying any vertical controls will affect CH1 and CH2's signal input. The `MV/DIV`N (Volts/Division) knob selects the vertical sensitivity factor in multiples of 1, 2, and 5. The sensitivity range is 5 mV to 1 V/div at both 1 M¡ and 50 ¡ input impedances with the variable sensitivity (as described later) set to unity. The `MVariable Gain`N Knob provides a

variable vertical sensitivity within the V\DIV knob settings. The variable setting knob increases the vertical range up to 2.5 times the V\DIV knob setting. The VAR led is lit next to the knob when the sensitivity is between fixed settings.

Pressing the `MVAR`N key toggles between 1.0 times the V\DIV knob setting and the currently selected Variable Gain setting. An LED next to the `MVAR`N key is lit to indicate that the Variable Gain is selected. The Combined

Volts/div and Variable Gain settings for CH 1 and CH 2 are displayed in the Status Message Field for about ten seconds while any control is adjusted. `MProbe Attenuation`N indicates the probe attenuation factor included in the vertical sensitivity indicators. If attenuation-coded probes are used, the probe contact rings surrounding the CH1 and CH2 BNC connectors recognize the attenuation factors of the probes. If this type of probe is not used, the probe attenuation can be selected in the Plug-in Status screen or the Vertical Status screen. The choices are x1 to x1000.

8.8 Total V/Div

Total V/Div indicates the current setting of the front panel Vertical Sensitivity control multiplied by the variable sensitivity and the probe attenuation. Variable sensitivity is adjusted (up to x2.5 of the V/Div setting) with the `MVAR`N knob inside of the `MV/Div`N knob.

8.9 Probes

Two Model 7200-P12 passive probes are supplied with the 7242. These probes have 1 M¡ input impedance and approximately 15 pF capacitance. The system bandwidth with 7200-P12 probes is DC to 250 MHz (typical)

with 1M¡ DC coupling, and less than 10 Hz to 250 MHz in AC coupling.

8.10 Probe Calibration

To calibrate the 7200-P12 Probe, connect it to the BNC connector labeled CH 1 or CH 2. Connect the probe's grounding alligator clip to the front panel ground lug of the oscilloscope and connect the tip to the signal lug. Use the `MAuto Setup`N key to obtain a signal. If over or undershooting of the displayed signal occurs, it is possible to

adjust the 7200-P12 Probe by inserting the small screwdriver supplied with the probe package into the trimmer on the probe's barrel. Turn the screwdriver either clockwise or counter-clockwise to achieve the optimal square wave contour.

8.11 Input

BNC type connectors are used for both CH 1 and CH 2 signal inputs, and the external trigger connector marked EXT TRIG. The maximum permissible input voltage is 250 V (DC + peak AC) in 1 M¡. The `MCOUPLING`N keys select the method used to couple the signal to the vertical amplifier input. Sequentially press key to select one of four types of input coupling. LED's to the left of the `MCOUPLING`N keys indicate the selection. Possible selections are as follows:

AC with 1 M¡ input impedance

DC with 1 M¡ input impedance,

GND (appears open, as seen from the input connector), and

DC with 50 ¡ impedance.

In the AC position, signals are coupled capacitively, thus blocking the input signal's DC component and limiting the signal frequencies to more than 10 Hz. The maximum dissipation into 50 ¡ is 0.5 W, and signals will automatically be disconnected whenever this level is exceeded. A warning LED (OVLD) lights up indicating when an overload condition has been detected. The input coupling is simultaneously switched to GND. The overload condition is reset by removing the signal from the input and re-selecting the desired input impedance again. The `MOFFSET`N knob adjusts the voltage offset used to position the signal within the amplifier's input range. The maximum offset is > 12 times the fixed sensitivity setting and is manually adjustable (or programmable) in 0.02 division increments. A pair of upward- or downward-pointing arrows (Ü or Ý) on the grid's upper or lower edge indicate when the trace has been positioned outside of the grid. The `MZero Offset`N key toggles between zero offset and the currently selected offset value. An LED next to the key lights "ZERO" to indicate zero offset.

The `MBandwidth Limit`N field in the Plug-in or Vertical Status screen can be used to reduce the bandwidth from 400 MHz (500 MHz for 7242A) to 95 MHz in 50 ¡ and from 250 MHz to 95 MHz in 1 M¡. This reduction in bandwidth is achieved with an analog hardware lowpass filter, before the digitizer, and is useful in reducing system noise in cases where the signal frequency components are below 95 MHz. The filter rolls off at about -18dB per octave (3-pole).

The `MEnhanced Res`N field in the Plug-in and Vertical Status screens allows the user to select the amount of digital filtering for enhancing resolution. By reducing the system bandwidth, both noise and signal above the cutoff are effectively removed from the resulting waveform. If the signal components of interest are below the cutoff, then the

effective resolution can be improved beyond the ADC's ideal resolution. Selecting greater values of this parameter, results in progressively lower system bandwidths. Since the ADC's each have 8 bits, selecting the lowest value (8.0) removes the filter. Indicated next to the number of bits is the effective system bandwidth (calculated from the theoretical filter bandwidth and the unfiltered analog bandwidth. Because extra samples before and after the resulting

waveform record are required to do the digital filtering, Enhanced Res cannot be used when the trigger mode is Sequence.

The `MOpt Pulse Resp`N field in the Plug-in and Vertical Status screens allows the user to select the type of low-pass filter applied to data that was digitized at 2GS/s. Optimal pulse response is achieved with a filter that rolls of slowly from the maximum analog bandwidth to 1GHz. When this field is set to "NO" a filter with much steeper roll-off is

applied to the data providing better effective bit performance.

Timebase Controls

Timebase controls allows the user to select the horizontal parameters used to acquire data. These parameters are Timebase, Random Interleaved Sampling, Max Memory, Sampling, Clock (source), and if in sequence trigger

mode the Number of Segments.

The `MTIMEBASE`N knob is used to select the amount of time each horizontal division represents. The Timebase setting, the Max Memory, and if in sequence mode, the number of segments determines the sampling frequency and the number of sample points displayed per division. The detented knob selects the Timebase in a 1-2-5 sequence from 200 ps/DIV to 10,000 sec/DIV. The number of Point/div and the Time/point is dispalyed in the Plug-in status or Timebase Status screens. Depending on the timebase setting, the following three sampling modes are selectable: Random Interleaved Sampling (RIS), Single Shot, and Sequence.

The `MRandom Interleaved Sampling (RIS)`N key turns on or off RIS acquisition mode depending on the timebase setting. For the 7242, the RIS acquisition consists of many single-shot acquisitions at 200 MS/s, each with about 1/100th of the final Memory size. For each acquisition the time between the actual trigger signal and the next sampling clock is recorded, and used to associate the single-shot acquisition with one of 100 "leaves". When there is an acquisition for each of 100 "leaves", the single-shot waveforms are "interleaved" to form a RIS waveform, with effectively 100 times the single-shot sampling rate, or in this case 20 GS/s. Because the triggers are randomly

associated with the sampling process (uncorrelatd with the sampling clock), the word random is used in Random

Interleaved Sampling. This method requires repetitive signal source, a stable trigger and a rep-rate not correlated with the 200MS/s sample clock. It is interesting to note that considerably more than 100 randomly correlated triggers are required to fully populate the 100 RIS leaves. Based on statistical arguments, the nominal factor is between 5 and 6 times for 100 leaves (i.e. 500 to 600 triggers), but as many as 10 times is not impossible. Since the trigger times are random, even though a 50 picosecond spacing between leaves is used, each individual leaf could have an error as large

as +- 25 picoseconds. The 7242 uses the "best" 100 acquisitions to form a RIS record (i.e. if a newly acquired trigger has a smaller error than the previously acquired trigger for that leaf, the acquisition with the smallest error is used. No averaging is done; nominally 80% of the acquisitions are discarded.

At timebase settings from 200 ps/DIV to 5 nsec/div, the 7242 automatically uses the RIS mode for signal acquisition. When selected, an "ON" led on the 7242 front-panel will be lit, otherwise, the "ON" led is not lit and single-shot acquisitions are used. If the Max Memory is set to 2K, RIS or single-shot may be selected in the range 5nsec/div and

10nsec/div. If the memory size is set to 20K, RIS or single shot may be selected in the range 5nsec/div and .1 ¢sec/div. If the memory size is set to 50K, RIS or single shot may be selected in the range 5nsec/div and .1 ¢sec/div. The 7242 can record waveforms in a single-shot acquisition for timebase settings between 5 nsec and 200 msec/div.

Sampling rates up to 1 gigasamples/sec are possible in the single-shot mode. Two `MSampling`N options are available in RIS mode, RANDOM and INTERPOLATED. RIS data has inherently non-uniform sampling intervals. Because RIS waveforms are generally highly oversampled (i.e. the effective sample rate is many times higher than the signal bandwidth) the non-uniformity of sample spacing has subtle implications. The INTERPOLATED Sampling option uses a linear interpolation algorithm and the nearest neighboring samples to create a RIS record with uniform sampling intervals. The RANDOM option does not perform this interpolation. INTERPOLATED is generally the

most useful choice, however in cases where the fundamental assumptions of RIS sampling are in question (not truly repetitive signal), RANDOM Sampling is preferred. For example, if Persistence Display is to be used to analyse

varying timing, and the timebase selection is such that RIS is required, then RANDOM Sampling should be used. Eye Diagram analyses are inherently non-repetitive, and care must be taken in attempting this kind of analysis with RIS acquisition.

`MNumber of Segments`N is a selectable field in the Plug-in and Timebase Status screens when the trigger mode is Sequence. The Number of segments indicates the number of segments in a sweep. The number of segments, the timebase setting, and the acquisition memory size determine the number of data points per segment and the time per point which is displayed in the Plug-in and Timebase status screens. Number of segments can be selected from 2 to 200 segments.

The `MMax Memory`N field appears in the Plug-in and Timebase Status screens and allows the user to specify the maximum number of points to represent each waveform. Together with the timebase setting (and if in Sequence mode, the number of segments), it determines the the segment length and the time per point. The choices are 1K, 2K, 5K, ..., 50K points. Acquire 1,000 samples to achieve maximum waveform throughput. Obtaining 50,000 points, provides a greater window of the signal, requiring more time to process the additional points.

Points/div

Indicates the number of samples in each division of the display grid, provided the waveform is not decimated or expanded.

Time/point

Indicates the sample rate or the time between digitized sample points for the corresponding timebase setting.

The `MClock`N field appears in the Plug-in and Timebase Status screens and allows the user to specify whether to used the Plug-in's internal clock or an external clock which is applied to the 7200's rear panel. With an external clock, the suggested clock rate is specified. The maximum sample rate is 1 gigasample.

Trigger Controls

The 7242 offers two independent triggering methods: Standard and Smart Trigger. Standard trigger provides basic trigger functions which can be controlled from the front panel. Smart Trigger adds additional qualifications to the trigger source(s). The Smart Trigger key on the plug-in front panel toggles between selecting either method. The LED indicates when Smart Trigger is selected. Smart Trigger options can be adjusted either with dedicated front panel controls or from within the Plug-in or Trigger Status screens.

The pair of `MSOURCE`N keys enable trigger source selection as follows:

CH 1 Selects Channel 1 as the trigger source, i.e., the signal connected to the Channel 1 BNC input connector.

CH 2 Selects Channel 2 as the trigger source, i.e., the signal connected to the Channel 2 BNC input connector.

Ext With the Trigger source set to EXT, a signal applied to the BNC connector labeled "EXT TRIG" is used to trigger the scope within a range of ‚ 2 V.

Ext/10 With the Trigger source set to EXT/10, a signal applied to the BNC connector labeled "EXT TRIG" is used to trigger the scope within a range of ‚ 20 V.

Line Selects the line voltage which powers the oscilloscope to provide a stable display of signals synchronous with

the power line.

When EXT or EXT/10 is selected as the trigger source, a signal applied to the BNC connector labelled EXT TRIG can be used to trigger the scope when the signal is between ‚ 2 V. This BNC input accepts an external trigger signal bias of up to ‚ 250 VDC. Input impedance is 1 M¡ in parallel with <<30 pF.

The `MCOUPLING`N keys select the type of signal coupling at the input of each trigger circuit. Note that the trigger coupling can be adjusted independently for each trigger source. Therefore, a change of the trigger source may also result in a change of the trigger coupling LEDs since the coupling associated with the newly selected source is

remembered. The types of coupling are as follows:

AC

Signals are capacitively coupled; DC Levels are rejected and frequencies below 8 Hz are attenuated.

LF REJ

Signals are DC coupled to the trigger circuit and a low-pass filter network attenuates frequencies above 50 kHz. The LF trigger mode is used to trigger on low frequency signals.

HF REJ

Signals are coupled via a capacitive high-pass filter network. DC is rejected and signal frequencies below 50 kHz are attenuated. The HF trigger mode is used to reject high frequency signals.

DC

All of the signal's frequency components are coupled to the trigger circuit.

The `MDELAY`N field is used to select the function of the delay knob. The choices are TIME and PERCENT. When delay is set as a function of TIME, the delay knob adjusts the amount of time the signal is recorded before(pre_trigger) or after(post trigger) the trigger occurs. When delay unit is set to PERCENT, the trigger delay can be positioned

any where on the screen and will remain constant as the time per division is changed. The `MDELAY`N knob is used to select the Trigger Delay. `MDELAY`N adjusts the amount of signal recorded before(pre-trigger) or after(post-trigger) the trigger occurs. The pre-trigger amount depends on the Timebase, memory size, and if in Sequence trigger mode, the number of segments. The delay can be adjusted in time or as a percentage of the screen. The maximum limit is 10,000 record lengths. The arrow under the grid indicates the trigger point of the displayed trace. Trigger delay is locked to other plug-ins when the timebase controls are locked. The `MZero Delay`N key toggles between the

selected delay setting and a trigger delay of 0.0 sec or 50 %, which would put the trigger at the center of the grid. An LED next to the key lights "ZERO" to indicate zero trigger delay. Trigger delay is locked to other plug-ins when the timebase controls are locked.

The `MLEVEL`N knob adjusts the voltage level at which trigger will occur. When the trigger level is increased, the trigger circuit will respond at a higher voltage level. If vertical sensitivity is adjusted such that the previously selected trigger level exceeds the sensitivity range, then the trigger level is automatically reduced to fit the new range. The range of trigger levels is as follows:

Trigger Source Trigger Range

CH 1 or 2 +-5 screen divisions * total gain

LINE none (zero-crossing is used)

EXT +-2 Volts

EXT/10 +-20 Volts

The `MZero Level`N key toggles between the selected trigger level and a trigger level of 0.0 Volts. An LED next to the key lights "ZERO" to indicate zero trigger level. The `MSLOPE`N key selects the signal edge used to activate the trigger circuit. The slope of the trigger can be adjusted for each individual trigger source and is indicated by LEDs above the `MSLOPE`N key.

POS Triggers on a positive-going edge.

NEG Triggers on a negative-going edge.

The Trigger Slope setting is not used if the trigger source is Line.

A READY LED on each plug-in indicates that the trigger circuit has been armed and the plug-in is currently acquiring input signals. The TRIG'D LED is lit whenever the time base is stopped (normally after a valid trigger).

The `MSmart Trigger`N key toggles between selecting the Standard Trigger and the Smart Trigger. Smart Trigger is setup from within the Plug-in and Trigger status screens. An LED next to the key will light "ON" to indicate Smart Trigger is selected. Smart Trigger offers a variety of trigger qualifications based on the ability of the 7242 to :

- To count a specified number of events(1 to 15,000,000)

- To measure time intervals(1 nsec up to 680 sec)

- To recognize a pattern input to the selected trigger sources. When Smart Trigger is selected one of five triggering methods can be selected:

`MSingle Source`N - Trigger on the selected source when the trigger conditions and one of the following qualifications are met:

- Holdoff for 30 nsec up to 680 sec.

- Holdoff for 1 to 15,000,000 events.

- Interval < 30 nsec up to 680 sec.

- Interval > 30 nsec up to 680 sec.

- Pulse < 1 nsec up to 680 sec.

- Pulse > 1 nsec up to 680 sec.

`MPattern`N Trigger whenever the selected combination of signals occurs and one of the following qualifications are met:

- Holdoff for 30 nsec up to 680 sec.

- Holdoff for 1 to 15,000,000 events.

- Interval < 30 nsec up to 680 sec.

- Interval > 30 nsec up to 680 sec.

- Time between patterns < trigger on entering(1 nsec up to 680 sec).

- Time between patterns > trigger on entering(1 nsec up to 680 sec).

- Pattern width < trigger on exiting (1 nsec up to 680 sec).

- Pattern width > trigger on exiting (1 nsec up to 680 sec).

`MState Qualified`N - Trigger whenever the trigger source meets its trigger condition during the selected pattern and one of the following qualifications are met:

- Wait for 10 nsec up to 680 sec.

- And Before 10 nsec up to 680 sec.

- Trigger on 1 to 15,000,000 events.

`MTime Qualified`N - Trigger whenever the trigger source meets its trigger condition after the selected combination and one of the following qualifications are met:

- Wait for 10 nsec up to 680 sec.

- And Before 10 nsec up to 680 sec.

- Trigger on 1 to 15,000,000 events.

`MTV`N - Trigger on the selected horizontal scan line of the composite sync signal connected to the EXT trigger input. The following qualifications can be selected:

- Select the horizontal scan line from 10 to 2500 to trigger on

- Select the frame the line is selected from. The choices are `MEVEN FRAME`N , `MODD FRAME`N , or `MBOTH FRAMES`N .

- Select the horizontal scan rate. The choices are 15 to 20 Khz, 20 to 30 KHz, or 30 to 63 KHz.

The `MHF Sync`N field appears in the Plug-in and Trigger Status screens and allows the user to turn on and off the Hi Freq Sync. When HF Sync is ON, the trigger source has its frequency rate divided. Select ON to allow stable triggering for sources greater than 200 MHz. When HF Sync is ON, the trigger slope is always positive regardless of what was previously selected. HF Sync can not be used with Smart Trigger.

Calibrate

The `MCalibrate`N key ensures overall vertical, timebase, and trigger accuracy by calibrating the plugin at it's cuurent

setting. Calibration is also performed when the 7200 is powered, when Timebase or Vertical Controls are adjusted, and periodically thereafter. There is a calibrate softkey located in all Status screens. The 7291 adapter can be calibrated by pressing the modify key before pressing the calibrate softkey whenever a 7291 adapter is attached.

10 7242B Introduction

The 7242B plug-in front panel controls allow changing the timebase, the trigger conditions, the signal amplifiers, and the display of a summary of control settings on the mainframe display. Whenever a plug-in control is changed, the plug-in's vertical and timebase settings are briefly displayed on the screen. The display indicates the settings to be used for the next acquisition. The labels displayed next to the `MTRACE 1`N through `MTRACE 8`N keys indicate the name or label of the displayed trace and the acquisition parameters used when the waveform was acquired and are

updated with every waveform acquisition. Note that changes to the control settings will not be reflected in the displayed waveform until the 7242B has acquired new data, since changing the plug-in acquisition settings has no effect on previously acquired waveforms. Therefore, the settings indicated when controls are changed may differ from

those displayed next to the trace keys when the 7200 is in the Single or Sequence Trigger Mode and has finished acquiring data.

10.1 Display of Acquisition Parameters

There are several displays which provide parameter acquisition information.

10.2 Plug-in Status

The Plug-in Status screen displays all 7242B control settings. The acquisition parameters which do not have a dedicated control on the front panel are changed from within this screen. Pressing the `MDISPLAY`N key or

pressing the `MMODIFY`N key (on the mainframe) and the the `MDISPLAY`N key brings up the Plug-in Status screen. The acquisition parameters which do not have a dedicated control on the front panel can be changed from within this menu. To select the parameter to change, rotate the `MModify Field`N soft knob until the box moves to the

item to be changed. To change the item's value, rotate the `MModify Value`N soft knob until your choice appears within the box. The list of choices are shown in the lower right corner of the menu, with the current choice in the center of the list of options. The screen is divided into three main sections: Trigger Controls, Timebase Controls, and Vertical Controls.

10.3 Vertical Status Screen

The Vertical Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Vertical Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the vertical section on the plug-in's front panel or when selected from inside the Trigger or Timebase status screens.

10.4 Trigger Status Screen

The Trigger Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Trigger Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the trigger section on the plug-in's front panel or when selected from inside the Timebase or Vertical status screens.

10.5 Timebase Status Screen

The Timebase Status screen contains a sub-set of the control settings shown in the Plug-in Status display so that the waveforms can be viewed while the acquisition controls are being changed. The Timebase Status screen appears when you press the `MMODIFY`N key and then press any key or rotate any knob in the timebase section on the plug-in's front panel or when selected from inside the Vertical or Trigger status screens.

10.6 Plug-in Controls

The following sections will describe all the controls available to the user.

10.6.1 Vertical Controls

The Vertical controls adjust signal amplification for each plug-in channel. These adjustments are made either with dedicated front panel controls or from within the Plug-in or Timebase Status screens. The `MCH1`N or `MCH2`N keys select which channel the Vertical controls will modify. For example, when CH1 is pressed, adjusting a Vertical control will affect CH1 signal input. CH2 settings remain unchanged. The channels LED next to the key is lit to indicate the

selected channel. The `MSelect All Channels`N softkey is located in the Plug-in and Vertical status screens and is used to set all the vertical control settings for every channel of the plug-in to be the same as the vertical control settings for the channel indicated to the right of the "Vertical Controls" label. Both the CH1 and CH2 led's will be lit and modifiying any vertical controls will affect CH1 and CH2's signal input. The `MV/DIV`N (Volts/Division) knob selects the vertical sensitivity factor in multiples of 1, 2, and 5. The sensitivity range is 5 mV to 1 V/div at both 1 M¡ and 50 ¡ input impedances with the variable sensitivity (as described later) set to unity. The `MVariable Gain`N Knob provides a

variable vertical sensitivity within the V\DIV knob settings. The variable setting knob increases the vertical range up to 2.5 times the V\DIV knob setting. The VAR led is lit next to the knob when the sensitivity is between fixed settings.

Pressing the `MVAR`N key toggles between 1.0 times the V\DIV knob setting and the currently selected Variable Gain setting. An LED next to the `MVAR`N key is lit to indicate that the Variable Gain is selected. The Combined Volts/div and Variable Gain settings for CH 1 and CH 2 are displayed in the Status Message Field for about ten seconds while any control is adjusted. `MProbe Attenuation`N indicates the probe attenuation factor included in the vertical

sensitivity indicators. If attenuation-coded probes are used, the probe contact rings surrounding the CH1 and CH2 BNC connectors recognize the attenuation factors of the probes. If this type of probe is not used, the probe attenuation can be selected in the Plug-in Status screen or the Vertical Status screen. The choices are x1 to x1000.

10.7 Total V/Div

Total V/Div indicates the current setting of the front panel Vertical Sensitivity control multiplied by the variable sensitivity and the probe attenuation. Variable sensitivity is adjusted (up to x2.5 of the V/Div setting) with the `MVAR`N knob inside of the `MV/Div`N knob.

10.8 Probes

Two Model 7200-P12 passive probes are supplied with the 7242B. These probes have 1 M¡ input impedance and approximately 15 pF capacitance. The system bandwidth with 7200-P12 probes is DC to 250 MHz (typical)

with 1M¡ DC coupling, and less than 10 Hz to 250 MHz in AC coupling.

10.9 Probe Calibration

To calibrate the 7200-P12 Probe, connect it to the BNC connector labeled CH 1 or CH 2. Connect the probe's grounding alligator clip to the front panel ground lug of the oscilloscope and connect the tip to the signal lug. Use the `MAuto Setup`N key to obtain a signal. If over- or undershooting of the displayed signal occurs, it is possible to

adjust the 7200-P12 Probe by inserting the small screwdriver supplied with the probe package into the trimmer on the probe's barrel. Turn the screwdriver either clockwise or counter-clockwise to achieve the optimal square wave contour.

10.10 Input

BNC type connectors are used for both CH 1 and CH 2 signal inputs, and the external trigger connector marked EXT TRIG. The maximum permissible input voltage is 250 V (DC + peak AC) in 1 M¡.

The `MCOUPLING`N keys select the method used to couple the signal to the vertical amplifier input. Sequentially press key to select one of four types of input coupling. LED's to the left of the `MCOUPLING`N keys indicate the

selection. Possible selections are as follows: AC with 1 M¡ input impedance DC with 1 M¡ input impedance, GND (appears open, as seen from the input connector), and DC with 50 ¡ impedance. In the AC position, signals are coupled

capacitively, thus blocking the input signal's DC component and limiting the signal frequencies to more than 10 Hz.

The maximum dissipation into 50 ¡ is 0.5 W, and signals will automatically be disconnected whenever this level is exceeded. A warning LED (OVLD) lights up indicating when an overload condition has been detected. The input

coupling is simultaneously switched to GND. The overload condition is reset by removing the signal from the input and re-selecting the desired input impedance again. The `MOFFSET`N knob adjusts the voltage offset used to position the signal within the amplifier's input range. The maximum offset is > 12 times the fixed sensitivity setting and is manually adjustable (or programmable) in 0.02 division increments. A pair of upward- or downward-pointing arrows (Ü or Ý) on the grid's upper or lower edge indicate when the trace has been positioned outside of the grid. The `MZero Offset`N key toggles between zero offset and the currently selected offset value. An LED next to the key lights "ZERO" to indicate zero offset. The `MBandwidth Limit`N field in the Plug-in or Vertical Status screen can be used to reduce the bandwidth from 500 MHz to 95 MHz in 50 ¡ and from 250 MHz to 95 MHz in 1 M¡. This reduction in bandwidth is achieved with an analog hardware lowpass filter, before the digitizer, and is useful in reducing system noise in cases where the signal frequency components are below 95 MHz. The filter rolls off at about -18dB per octave (3-pole).

The `MEnhanced Res`N field in the Plug-in and Vertical Status screens allows the user to select the amount of digital filtering for enhancing resolution. By reducing the system bandwidth, both noise and signal above the cutoff are effectively removed from the resulting waveform. If the signal components of interest are below the cutoff, then the

effective resolution can be improved beyond the ADC's ideal resolution. Selecting greater values of this parameter, results in progressively lower system bandwidths. Since the ADC's each have 8 bits, selecting the lowest value (8.0) removes the filter. Indicated next to the number of bits is the effective system bandwidth (calculated from

the theoretical filter bandwidth and the unfiltered analog bandwidth. Because extra samples before and after the resulting waveform record are required to do the digital filtering, Enhanced Res cannot be used when the trigger mode is Sequence. The `MOpt Pulse Resp`N field in the Plug-in and Vertical Status screens (when a 7291 is present) allows the user to select the type of low-pass filter applied to data that was digitized at 2GS/s. Optimal pulse response is achieved with a filter that rolls of slowly from the maximum analog bandwidth to 1GHz. When this field is set to "NO" a filter with much steeper roll-off is applied to the data providing better effective bit performance.

10.11 Timebase Controls

Timebase controls allows the user to select the horizontal parameters used to acquire data. These parameters are Timebase, Random Interleaved Sampling, Max Memory, Sampling, Clock (source), and if in sequence trigger

mode the Number of Segments. The `MTIMEBASE`N knob is used to select the amount of time each horizontal division represents. The Timebase setting, the Max Memory, and if in sequence mode, the number of segments determines the sampling frequency and the number of sample points displayed per division. The detented knob selects the Timebase in a 1-2-5 sequence from 200 ps/DIV to 10,000 sec/DIV. The number of Point/div and the Time/point is dispalyed in the Plug-in status or Timebase Status screens. Depending on the timebase setting, the following three

sampling modes are selectable: Random Interleaved Sampling (RIS), Single Shot, and Sequence.

The `MRandom Interleaved Sampling (RIS)`N key turns on or off RIS acquisition mode depending on the timebase setting. For the 7242B, the RIS acquisition consists of many single-shot acquisitions at 200 MS/s, each with about 1/100th of the final Memory size. For each acquisition the time between the actual trigger signal and the next sampling

clock is recorded, and used to associate the single-shot acquisition with one of 100 "leaves". When there is an acquisition for each of 100 "leaves", the single-shot waveforms are "interleaved" to form a RIS waveform, with effectively 100 times the single-shot sampling rate, or in this case 20 GS/s. Because the triggers are randomly

associated with the sampling process (uncorrelatd with the sampling clock), the word random is used in Random Interleaved Sampling. This method requires repetitive signal source, a stable trigger and a rep-rate not correlated with the 200MS/s sample clock. It is interesting to note that considerably more than 100 randomly correlated triggers are required to fully populate the 100 RIS leaves. Based on statistical arguments, the nominal factor is between 5 and 6 times for 100 leaves (i.e. 500 to 600 triggers), but as many as 10 times is not impossible. Since the trigger times are random, even though a 50 picosecond spacing between leaves is used, each individual leaf could have an error as large

as +- 25 picoseconds. The 7242B uses the "best" 100 acquisitions to form a RIS record (i.e. if a newly acquired trigger has a smaller error than the previously acquired trigger for that leaf, the acquisition with the smallest error is used. No averaging is done; nominally 80% of the acquisitions are discarded.

At timebase settings from 200 ps/div to 1 nsec/div, the 7242B automatically uses the RIS mode for signal acquisition. When selected, an "ON" led on the 7242B front-panel will be lit, otherwise, the "ON" led is not lit and single-shot acquisitions are used. When the timebase is set between 2 ns/div and 1 ¢sec/div RIS or single shot may be selected

depending upon the memory size currently selected. Please refer to the operator's manual for more details. The 7242B can record waveforms in a single-shot acquisition for timebase settings between 2 nsec and 200 msec/div. Sampling rates up to 1 gigasamples/sec are possible in the single-shot mode.

Two `MSampling`N options are available in RIS mode, RANDOM and INTERPOLATED. RIS data has inherently non-uniform sampling intervals. Because RIS waveforms are generally highly oversampled (i.e. the effective sample rate is many times higher than the signal bandwidth) the non-uniformity of sample spacing has subtle implications. The INTERPOLATED Sampling option uses a linear interpolation algorithm and the nearest neighboring samples to create a RIS record with uniform sampling intervals. The RANDOM option does not perform this interpolation.

INTERPOLATED is generally the most useful choice, however in cases where the fundamental assumptions of RIS sampling are in question (not truly repetitive signal), RANDOM Sampling is preferred. For example, if Persistence Display is to be used to analyse varying timing, and the timebase selection is such that RIS is required, then RANDOM

Sampling should be used. Eye Diagram analyses are inherently non-repetitive, and care must be taken in attempting this kind of analysis with RIS acquisition. When the trigger mode is Sequence, there are two possible acquisition modes: sequential and synchronous averaging.

10.12 Sequential acquires

multiple segments and displays each individually. Synchronous averaging acquires multiple segments and averages them all together, displaying one waveform. When sequential is the current acquisition mode, the `MSelect Sync Avg`N softkey changes the acquisition mode to synchronous averaging which also includes alternate synchronous

averaging. When synchronous averaging is the current acquisition mode, the `MSelect Sequential`N softkey changes the acquisition mode to sequential.

`MSequence Trigger Rate`N is a selectable field in the Plug-in and Timebase Status screens when the trigger mode is Sequence. This field selection will determine the method in which segments get acquired. The two methods are to mazimize Trigger Rate vs. Points Per Segment. Selection of maximize trigger rate will tradeoff the number of segments and segment size for a greater trigger rate (the time from one trigger to the next). This method can acquire a maximum of 1000 (4000 with L1 option) segments between screen updates due to the limitations in acquisition memory.

Selection of maximize points per segment will maximize the number of segments and points per segment. This method

processes each segment as it is acquired. This method can acquire a maximium of 4000 segments between screen updates because it is not limited by acquisition memory, but by processing memory. The trigger rate will vary with the length of each segment and the number of channels acquiring data. When in Sequence Mode, the approximate trigger rate is displayed in the Plug-in and Timebase Status screens. `MNumber of Segments`N is a selectable field in the Plug-in and Timebase Status screens when the trigger mode is Sequence. The Number of segments indicates the number of segments in a sweep. The number of segments, the timebase setting, the acquisition memory size, the number of channels acquiring data, and the sequence acquisition method determine the number of data points per segment and the time per point which is displayed in the Plug-in and Timebase status screens. Number of segments can be selected from 1 to 1000 (4000) segments when maximize trigger rate is selected and 1 to 4000 segments when maximize points per segment is selected. The table below shows the relationship between maximum memory size, number of channels acquiring data, and maximum number of segments for each of the Sequence Maximize Options. Memory Max # 0f Segs Max # of Segs Length with Max Trig with Max PntsRate Per Seg

Standard Opt L1

1K 50 50 4000

2K 100 100 4000

5K 200 200 4000

10K 500 500 4000

20K 1000 1000 4000

50K 1000 2000 4000

>100K 1000 4000 4000

The `MMax Memory`N field appears in the Plug-in and Timebase Status screens and allows the user to specify the maximum number of points to represent each waveform. Together with the timebase setting (and if in Sequence mode, the number of segments), it determines the the segment length and the time per point. The choices are 1K, 2K, 5K, ..., 200K (1M with L1 option) points. Acquire 1,000 samples to achieve maximum waveform throughput. Obtaining 200,000 (1,000,000) points, provides a greater window of the signal, requiring more time to process the additional points.

10.13 Points/div

Indicates the number of samples in each division of the display grid, provided the waveform is not decimated or expanded.

10.14 Time/point

Indicates the sample rate or the time between digitized sample points for the corresponding timebase setting. The `MClock`N field appears in the Plug-in and Timebase Status screens and allows the user to specify whether to used the Plug-in's internal clock or an external clock which is applied to the 7200's rear panel. With an external clock, the suggested clock rate is specified. The maximum sample rate is 1 gigasample.

The `MAverage mode`N field appears in the Plug-in and Timebase Status screens and allows the user to select between synchronous averaging `M(STANDARD)`N or alternate synchronous averaging `M(ALTERNATE).`N Synchronous averaging acquires multiple acquisitions and averages them together. There is no history associated with this averaging

so that after the number of sweeps have been acquired, averaged and displayed, re-arming the plug-in will acquire an entirely new set of sweeps. Synchronous averaging differs from fast averaging in that the trigger rate is guarranteed. Since no display updates occur during the acquisition, the only dead time between sweeps is due to reading and summing the waveform data which is fixed based on the points/sweep and the timebase setting. In fast averaging, considerable time is lost between sweeps when the waveform is updated on the screen.

Alternate synchronous averaging is similar to synchronous averaging except that every other sweep is acquired with the complement of the currently selected trigger slope. This is most commonly used to subtract background noise. Alternate synchronous averaging produces a dual waveform. The ROOF function can be used to isolate the averaged waveform acquired on the selected trigger slope. The FLOOR function can be used to isolate the averaged waveform acquired on the opposite trigger slope. In alternate synchronous averaging only Channel 1 acquires data and

Channel 2 may be used as a trigger source. The `MNum Sweeps`N field appears on the Plug-in and Timebase Status screens and allows the user to select the number of sweeps which will contribute to the average. Points/sweep

Indicates the number of samples acquired in each sweep which also equals the number of samples in the final averaged waveform. The `MTurn ON Art Reject`N softkey appears on the Plug-in and Timebase Status screens and allows the user to turn on artifact rejection during sychronous averaging and alternate synchronous averaging. When enabled, any

waveform with an underflow or overflow value is not included in the computation. If Artifact Reject is turned OFF, any overflows are set to the maximum possible value of the ADC and any underflows to the minimum value.

10.15 Trigger Controls

The 7242B offers two independent triggering methods: Standard and Smart Trigger. Standard trigger provides basic trigger functions which can be controlled from the front panel. Smart Trigger adds additional qualifications to the trigger source(s). The Smart Trigger key on the plug-in front panel toggles between selecting either method. The LED indicates when Smart Trigger is selected. Smart Trigger options can be adjusted either with dedicated front panel controls or from within the Plug-in or Trigger Status screens. The pair of `MSOURCE`N keys enable trigger

source selection as follows:

CH 1 Selects Channel 1 as the trigger source, i.e., the signal connected to the Channel 1 BNC input connector.

CH 2 Selects Channel 2 as the trigger source, i.e., the signal connected to the Channel 2 BNC input connector.

Ext With the Trigger source set to EXT, a signal applied to the BNC connector labeled "EXT TRIG" is used to trigger

the scope within a range of ‚ 2 V.

Ext/10 With the Trigger source set to EXT/10, a signal applied to the BNC connector labeled "EXT TRIG" is used to trigger the scope within a range of ‚ 20 V.

Line Selects the line voltage which powers the oscilloscope to provide a stable display of signals synchronous with

the power line.

When EXT or EXT/10 is selected as the trigger source, a signal applied to the BNC connector labelled EXT TRIG can be used to trigger the scope when the signal is between ‚ 2 V. This BNC input accepts an external trigger signal bias of up to ‚ 250 VDC. Input impedance is 1 M¡ in parallel with <<30 pF. The `MCOUPLING`N keys select the type of

signal coupling at the input of each trigger circuit. Note that the trigger coupling can be adjusted independently for each trigger source. Therefore, a change of the trigger source may also result in a change of the trigger coupling LEDs since the coupling associated with the newly selected source is remembered. The types of coupling are as follows:

AC

Signals are capacitively coupled; DC Levels are rejected and frequencies below 8 Hz are attenuated.

LF REJ

Signals are DC coupled to the trigger circuit and a low-pass filter network attenuates frequencies above 50 kHz. The LF trigger mode is used to trigger on low frequency signals.

HF REJ

Signals are coupled via a capacitive high-pass filter network. DC is rejected and signal frequencies below 50 kHz are attenuated. The HF trigger mode is used to reject high frequency signals.

DC

All of the signal's frequency components are coupled to the trigger circuit.

The `MDELAY`N field is used to select the function of the delay knob. The choices are TIME and PERCENT. When delay is set as a function of TIME, the delay knob adjusts the amount of time the signal is recorded before(pre_trigger) or after(post trigger) the trigger occurs. When delay unit is set to PERCENT, the trigger delay can be positioned any where on the screen and will remain constant as the time per division is changed. The `MDELAY`N knob is used to select the Trigger Delay. `MDELAY`N adjusts the amount of signal recorded before(pre-trigger) or

after(post-trigger) the trigger occurs. The pre-trigger amount depends on the Timebase, memory size, and if in Sequence trigger mode, the number of segments. The delay can be adjusted in time or as a percentage of the

screen. The maximum limit is 10,000 record lengths. The arrow under the grid indicates the trigger point of the displayed trace. Trigger delay is locked to other plug-ins when the timebase controls are locked. The `MZero Delay`N key toggles between the selected delay setting and a trigger delay of 0.0 sec or 50 %, which would put the trigger

at the center of the grid. An LED next to the key lights "ZERO" to indicate zero trigger delay. Trigger delay is locked to other plug-ins when the timebase controls are locked. The `MLEVEL`N knob adjusts the voltage level at which trigger will occur. When the trigger level is increased, the trigger circuit will respond at a higher voltage level. If vertical sensitivity is adjusted such that the previously selected trigger level exceeds the sensitivity range, then the trigger level is automatically reduced to fit the new range. The range of trigger levels is as follows:

Trigger Source Trigger Range

CH 1 or 2 +-5 screen divisions * total gain

LINE none (zero-crossing is used)

EXT +-2 Volts

EXT/10 +-20 Volts

The `MZero Level`N key toggles between the selected trigger level and a trigger level of 0.0 Volts. An LED next to the key lights "ZERO" to indicate zero trigger level.

The `MSLOPE`N key selects the signal edge used to activate the trigger circuit. The slope of the trigger can be adjusted for each individual trigger source and is indicated by LEDs above the `MSLOPE`N key.

POS Triggers on a positive-going edge.

NEG Triggers on a negative-going edge.

The Trigger Slope setting is not used if the trigger source is Line. A READY LED on each plug-in indicates that

the trigger circuit has been armed and the plug-in is currently acquiring input signals. The TRIG'D LED is lit whenever the time base is stopped (normally after a valid trigger). The `MSmart Trigger`N key toggles between selecting the Standard Trigger and the Smart Trigger. Smart Trigger is setup from within the Plug-in and Trigger status screens. An LED next to the key will light "ON" to indicate Smart Trigger is selected. Smart Trigger offers a variety of trigger qualifications based on the ability of the 7242B to :

- To count a specified number of events(1 to 15,000,000)

- To measure time intervals(1 nsec up to 680 sec)

- To recognize a pattern input to the selected trigger sources. When Smart Trigger is selected one of five triggering methods can be selected:

`MSingle Source`N - Trigger on the selected source when the trigger conditions and one of the following qualifications are met:

- Holdoff for 30 nsec up to 680 sec.

- Holdoff for 1 to 15,000,000 events.

- Interval < 30 nsec up to 680 sec.

- Interval > 30 nsec up to 680 sec.

- Pulse < 1 nsec up to 680 sec.

- Pulse > 1 nsec up to 680 sec.

'MPattern`N

- Trigger whenever the selected combination of signals occurs and one of the following

qualifications are met:

- Holdoff for 30 nsec up to 680 sec.

- Holdoff for 1 to 15,000,000 events.

- Interval < 30 nsec up to 680 sec.

- Interval > 30 nsec up to 680 sec.

- Time between patterns < trigger on entering(1 nsec up to 680 sec).

- Time between patterns > trigger on entering(1 nsec up to 680 sec).

- Pattern width < trigger on exiting (1 nsec up to 680 sec).

- Pattern width > trigger on exiting (1 nsec up to 680 sec).

`MState Qualified`N - Trigger whenever the trigger source meets its trigger condition during the selected pattern and one of the following qualifications are met:

- Wait for 10 nsec up to 680 sec.

- And Before 10 nsec up to 680 sec.

- Trigger on 1 to 15,000,000 events.

`MTime Qualified`N - Trigger whenever the trigger source meets its trigger condition after the selected combination and one of the following qualifications are met:

- Wait for 10 nsec up to 680 sec.

- And Before 10 nsec up to 680 sec.

- Trigger on 1 to 15,000,000 events.

`MTV`N - Trigger on the selected horizontal scan line of the composite sync signal connected to the EXT trigger input. The following qualifications can be selected:

- Select the horizontal scan line from 10 to 2500 to trigger on

- Select the frame the line is selected from. The choices are `MEVEN FRAME`N , `MODD FRAME`N , or `MBOTH FRAMES`N .

- Select the horizontal scan rate. The choices are 15 to 20 Khz, 20 to 30 KHz, or 30 to 63 KHz.

The `MHF Sync`N field appears in the Plug-in and Trigger Status screens and allows the user to turn on and off the Hi Freq Sync. When HF Sync is ON, the trigger source has its frequency rate divided. Select ON to allow stable triggering for sources greater than 200 MHz. When HF Sync is ON, the trigger slope is always positive regardless of what was

previously selected. HF Sync can not be used with Smart Trigger.

10.16 Calibrate

The `MCalibrate`N key ensures overall vertical, timebase, and trigger accuracy by calibrating the plugin at it's cuurent

setting. Calibration is also performed when the 7200 is powered, when Timebase or Vertical Controls are adjusted, and periodically thereafter. There is a calibrate softkey located in all Status screens. The 7291 adapter can be calibrated by pressing the modify key before pressing the calibrate softkey whenever a 7291 adapter is attached.

11 Support Software

Supplied with the LeCroy 7200 Precision Digital Oscilloscope is a Utilities Diskette containing support programs which can be executed on any MSDOS IBM-compatible PC. The programs are described below.

11.1 COMPILE.EXE

Compile.exe is the compiler for 7200 RCL programs. It translates RCL programs written on a PC into a form the 7200 can understand. To translate a program in the file filename.src, type COMPILE FILENAME. The file filename.apd will be created and will contain a translated version of the program which can then be loaded into the 7200 via 3.5" floppy disk or the TRANSFER_FILE remote command. See Section 7 of the 7200 Remote Programmer's Manual.

11.2 RCLUTIL.EXE

RCLUTIL, is a PC utility program which allows you to edit, compile and transfer RCL programs to and from the 7200 from a single, integrated environment. For instance, when you compile a program and if an error is found, the editor is automatically invoked and the line containing the error is displayed. Another feature is that either GPIB or RS-232-C can be used to transfer programs to and from the 7200.

11.3 7200TALK.EXE

7200talk.exe is a GPIB communication program. It is self-prompting and contains built-in help.

7200talk is compatible with the National Instruments PCII, PCIIA, and PCIII GPIB cards and uses the National Instruments device driver gpib.com.

11.4 WAVETRAN.EXE

Wavetran.exe translates a waveform file created by a LeCroy digital oscilloscope and generates ASCII (readable text) output. Type WAVETRAN -h for a help message.

To print the data values in the waveform file trace1.000, type WAVETRAN TRACE1.000. The data values will be printed to the screen. To direct the output to the file data, type WAVETRAN -oDATA TRACE1.000. To print the acquisition control settings and other information associated with the waveform, type WAVETRAN -d TRACE1.000. The acquisition information will be printed to the screen. To direct the output to the file info, type WAVETRAN -d -oINFO TRACE1.000.

Wavetran uses another file, called the template file, to interpret the waveform. The template file describes the

structure of the waveform produced by the oscilloscope. The file 7200.tpl on the Utilities Diskette contains the template for waveforms produced by the 7200 oscilloscope. Wavetran uses the template file named 7200.tpl by default. To translate waveforms produced by another LeCroy oscilloscope, a different template file may be specified as described in the help message. (The template may be read out of the 7200 via GPIB or RS-232C with the TEMPLATE? remote query, but is provided on the Utilities Diskette in the file 7200.tpl for convenience.)

IMPORTANT: If wavetran is copied onto another disk, it will not work unless the file 7200.tpl is also copied into the same directory.

See Section 3 of the 7200 Remote Programmer's Manual for a description of the 7200 waveform format and the template.

The information and data can be printed in different formats by specifying a print format file, as WAVETRAN -fFORMAT.FMT TRACE1.000. The file all.fmt on the Utilities Diskette is a sample format file that prints all

parts of a waveform, including sequence trigger times.

Each line of the format file is either a command or the name of a variable (containing acqusition information - eg. VERTICAL_GAIN) to be printed. Lines starting with '$' are commands. The commands are:

$PRINT WAVEFORM

prints the entire waveform

$PRINT BLOCK <block name> DEFAULT

prints the specified block in default order

$PRINT BLOCK <block name> SPECIFIED

prints the variables in the block which appear on subsequent lines of the format file

$PRINT ARRAY <array name> <start point> <end point>

prints the specified data or time array from start point to end point

end point = -1 means print to the end

$COLS <num columns>

specifies number of columns for output format

$LINES <num lines>

specifies number of lines to skip between each line of output

$LABELS <ON or OFF>

specifies whether or not to label the parts of the waveform

$SKIP <num lines>

skip the specified number of lines

$TITLE <title string>

print the specified title string

11.5 graph.exe

Graph.exe graphs a list of up to 500 numbers on the screen of a PC. Type GRAPH -h for a help message.

To graph the data points in a file called data (which may have been created by using wavetran to translate a 7200 waveform), type GRAPH DATA.