The waveform window is able to display analog simulation output. This simulation output comes from external simulators (such as Spice). When the system is asked to display the results of an external simulation, it reads the simulation output and shows it.
The analog waveform window looks like the picture below. Note that there is a side bar with a cell explorer in the window, just like in all windows, but the explorer has a "SIGNALS" section that lists the signals found in the simulation (and optionally a "SWEEPS" section if swept data was found).
The waveform window contains a set of panels, each with one or more signals and waveforms. In a panel, signal names are shown on the left, and their waveform on the right. Above the signal names in each panel are 5 names and controls:
You can rearrange the order of the signals by dragging their names to their desired location. You can change the color of a signal by right-clicking on its name.
You can add a signal to the list by double-clicking on its name in the "SIGNALS" area
(or by dragging that name to the waveform part on the right).
The signal will be added to the highlighted panel (the one with the bold vertical axis).
You can create a new panel, with no signals in it, by clicking on the button in the upper-left of the waveform window
(looks like: a panel-with-waveform icon being dropped down).
If the simulation had sweeps, those values are shown in the cell explorer in the "SWEEPS" area. You can right-click on a sweep and choose to include or exclude it from the display. You can also request that a sweep signal be highlighted. Right-clicking on the "SWEEPS" icon lets you include or exclude all of them.
If the layout or schematics cell that produced the simulation is being displayed in another window, and the currently selected network in that window is found in the simulation output, then that output can be added to the waveform window with the Add to Waveform in New Panel command (in menu Edit / Selection). The command Add to Waveform in Current Panel overlays the signal on top of others in the currently selected waveform panel.
The order of signals in the waveform window is saved in the original cell
so that subsequent simulations will show the same signals.
Two vertical cursors appear in the window, called "main" and "extension" (the extension cursor is dotted). Their time values and their difference are shown at the top of the window. You can click over the cursors and drag them to different time locations. You can also use the "Center" buttons to bring these cursors to the center of the display.
The time axis of the simulation window can be controlled with the appropriate Window menu commands. Use Zoom Out and Zoom In to scale the time axis by a factor of two. Use Focus on Highlighted to display the range between the main and extension cursors.
![]() | Besides controlling time with menu commands, you can also use the Pan and Zoom tools of the toolbar. | ![]() |
The pan tool lets you smoothly shift time when you click and drag. In the zoom tool, you zoom into an area by clicking and dragging out that area. To zoom out, hold the shift key and click in the center of the desired area.
You can control the horizontal and vertical range precisely by double-clicking in the vertical scale area. The dialog lets you type exact values into the ranges. | ![]() |
The different panels in the waveform window are locked in time: they all show the same range of time,
as shown at the top of the waveform window.
If you click on the "time lock" button at the top of the waveform window
(looks like a lock with the time on it: )
then time is unlocked, and each panel has its own time scale.
Now individual panels can show a different range of time than the rest.
A set of VCR buttons is available to animate the main time cursor. The play rate can be controlled by the "F" and "S" buttons which make it go faster or slower. As the time cursor sweeps across the waveform window, the original circuit can be seen to change levels.
These window functions apply to the analog simulation windows:
At the top of the waveform window, above the signal names, are many useful controls. Those relating to time have already been discussed. Here are the remaining buttons: