Sim Data

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Function

The Sim Data panel enables you to add waveforms from the available source data to the active wave plot. It also allows you to obtain measurement information based on the selected waveform and/or use of measurement cursors.

Defining Source Data Waveforms

The Source Data region of the panel contains a list of all available source waveforms that can be used within the active waveform chart. This list includes all waveforms generated as a result of design simulation/signal integrity analysis, as well as any user-defined waveforms that have been manually created.

Click on the Source Data button to access the Source Data dialog:

The dialog contains the same listing of source waveforms as the panel and provides controls for defining this set of waveforms.

• Click the Create button to open the Create New Waveform dialog, from where you can create a new signal waveform, either by entering a set of X and Y data points or by defining the characteristics for a sine or pulse waveform.
• Any of the waveforms can be stored as ASCII text files (WaveformName.wdf), which can be recalled and loaded into the list at any time. A .wdf file stores a waveform as a series of data points, each represented by an XY value pair.
• Any waveform can be deleted permanently from the list. Simply select the required waveform in the list and click on the Delete button. To bring back a waveform that has been deleted, you would either need to recall a stored copy of it (*.wdf file), or rerun the simulation.
• The Edit button allows you to access the Edit Source Waveform dialog for a selected waveform in the list. Only user-defined waveforms are editable.
• Any of the waveforms in the Source Data region of the panel can be added directly to the active wave plot. First ensure that the wave plot to which you wish to add the waveform(s), is made active in the Waveform Analysis window. This is achieved by clicking anywhere within the area of the wave plot. Click on the entry in the list for the waveform you wish to add. Multiple waveforms can be selected using the standard multi-select features (CTRL + Click, SHIFT + Click and click-and-drag). Once the required waveform(s) are selected, click on the Add Wave to Plot button. The waveform(s) will be added to the wave plot accordingly.

Cursor-based Measurements

The Measurement Cursors region of the panel reflects the current and calculated measurements when using one or both of the measurement cursors. For both cursors, the name of the waveform the cursor is currently assigned to is shown, as well as X and Y axis data values, dependent on the cursor's position along the waveform.

The following range of calculated measurements are available, based on the current X-Y values of the two measurement cursors:

• B-A
• Minimum A..B
• Maximum A..B
• Average A..B
• AC RMS A..B
• RMS A..B
• Frequency A..B
  With the exception of the difference calculation, both cursors must be assigned to the same waveform for the data to be available, as illustrated in the image below.

Waveform-based Measurements

The Waveform Measurements region of the panel reflects various general measurements for the selected waveform. Data is calculated from the waveform itself and does not involve the measurement cursors in any way.

The following data is calculated:

• Rise Time - the time taken to rise to the steady state value for the high level of the signal waveform (top line). Measurement data is only available when the selected signal is power-based (mixed-mode simulation) or is a resultant waveform of a signal integrity analysis
• Fall Time - the time taken to fall to the steady state value for the low level of the signal waveform (base line). Measurement data is only available when the selected signal is power-based (mixed-mode simulation) or is a resultant waveform of a signal integrity analysis
• Min - the minimum value reached by the waveform. The X-axis value at which this point occurs is also displayed
• Max - the maximum value reached by the waveform. The X-axis value at which this point occurs is also displayed
• Base Line - the steady state value for the low level of the signal waveform. This value is most noticeable, graphically, for a signal integrity-based analysis waveform, where ringing of the signal occurs about this base line value (undershoot)
• Top Line - the steady state value for the high level of the signal waveform. This value is most noticeable, graphically, for a signal integrity-based analysis waveform, where ringing of the signal occurs about this top line value (overshoot)

Notes

• If the Number of Plots Visible option is set to All in the Document Options dialog (Tools » Document Options), the active wave plot is distinguished by a black solid line around its waveform name section. If the Number of Plots Visible option is set to 1, 2, 3 or 4, the active wave plot is distinguished by a black arrow at the left hand side of its display area.
• A single source data waveform can be added to the active wave plot by double-clicking on its entry in the panel.
• The two measurement cursors (A and B) are available by right-clicking on a waveform's name, in the Waveform Analysis window, and choosing the corresponding command (Cursor A or Cursor B) from the subsequent pop-up menu that appears.
• A waveform is selected by clicking on its name within the Waveform Analysis window (a selected waveform will become bolder in color and have a dot to the left of its name).
• In sections of the panel where multiple columns of data exist, the data may be sorted by any column by clicking on the header for that column. Clicking once will sort in ascending order. Click again to sort by descending order.

See Also