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Things You Didn't Know About The Rhinovirus and ViVA (Part 3)

Comments(1)Filed under: Custom IC Design, Virtuoso, Virtuoso IC 6.1.3, ViVa-XL, Virtuoso Analog Design Environment, IC 6.1

Okay, so I really have no idea how to tie those 2 things together, but I ran across this little widget the other day and just had to share it (slide the slider until it's about 2/3 of the way across).  I know we've all seen electron microscope images of those transistors we're fiddling with, but do you really have any idea how small they are?  Maybe you do, but I don't think I realized that the length of the gate of that transistor you're about to put in your circuit is the same size as a single rhinovirus (that's the common cold to use layfolks).  Looks like you could fit a whole inverter inside of an influenza virus (would that make it not an influenza virus?).  All I can say is...wow...and don't sneeze on my chip...

Okay, now on to our main topic--the ViVA Results Browser and a few useful features you may not have known were there.

Results Browser (RB)

The RB can be invoked from lots of places--from the Tools menu of the ADE L window or any ViVA graph window, from an icon in an ADE XL window, even from the CIW.  And of course, the RB is your main base of operations if you invoke ViVA stand-alone.  Once you've found it, click on the little icon that looks like a file folder to find a waveform database and open it.  Go ahead, open more than one at a time.  That's one of the real powers of the RB.

Searching through the hierarchy and through multiple databases

The bottom half of the RB has 2 tabs.  If you click on the Search tab, you can enter a search string and find all the signals throughout the hierarchy in all open databases matching that string.  Then you can select (or Ctrl-select) what you're interested in click the right mouse button and plot them.  This is a quick way to compare the same signal from multiple simulations or to find a signal buried deep in the hierarchy.

Sweep Range

One way of sorting through the clutter of a large database, especially the results of a parametric sweep is to use the "Select Sweep Data" feature.  This can be accessed by clicking on the icon at the top of the RB that looks like a set of horizontal lines with a curly bracket next to them (or from the Options->Select Data... menu item).  If you have a parametric sweep database, you can then selectively highlight just the parameter values for the data you want to plot and instead of getting a whole family of curves, you'll only get the ones you want.  If you've just got a single sweep database (like a regular transient run, for example), this features comes in handy to load only a limited slice of a large database.  Just enter the start and end times in the form (use scientific notation for this--for some reason suffix notation doesn't work) and only that section of the waveform will be loaded and plotted.

Y vs. Y

Another feature of the RB that is fairly cryptic to use is the Y vs. Y plot.  If you want to plot 2 signals against each other, here's how to do it.  First click on the signal you want to be on the Y axis.  Then click on the Y vs. Y icon at the top of the RB (looks like one Y with another Y lying down next to it).  Finally click on the signal you want to be on the X axis and voila! the plot appears.  Just remember, Y, then X.

Export

Finally, I wanted to point out some of the powerful data export features in ViVA.  A waveform or trace can be exported from the RB (File->Export... or RMB->Export...) or from the graph window (select trace, then Trace->Save... or RMB->Save...).  One popular application of this is to save the waveform in Spectre format so it can be used as stimulus in a Spectre PWL source.  You also have to option to sample and/or interpolate the data to get specific step sizes

Another useful application is to save one or more waveforms (or time slices of the waveforms) to PSF or SST2 format in order to reduce the size of the database. Data can also be saved in Matlab or CSV format for additional post-processing.

Happy browsing until next time...

Stacy Whiteman

Comments(1)

By deana on June 3, 2010
Stacy -
I can honestly say that your posts are most helpful as well as entertaining. I really need to start visiting this site weekly to make sure I do not miss one of your educational as well as entertaining blogs Stacy. Your blogs are almost as fun as You Tube.........almost.
Thanks for all the information you pass on.
Deana

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