Re: [SI-LIST] : Waveform comparison metrics

Pat Zabinski (zabinski.patrick@mayo.edu)
Mon, 2 Aug 1999 14:52:30 -0500

Is there any value in looking at a frequency-domain comparison?

More to the point, a simple "substraction" at a logic transition edge
does not provide any insight to the edge rate difference, where
a frequency domain comparison would.

At Mayo, we often deal with components and systems operating well
above 10 Gbps serial data rates, and we find it difficult to make
useful comparisons based simply on time domain measurements. For
one thing, if we're trying to compare simulated vs measured waveforms,
it's quite often that we run up against oscilloscope bandwidth limitations
where our measured waveform is "smoothed out".

Using some form of frequency domain comparison would allow us to
determine how much of the difference is real and how much is
scope-induced.

Comments?

Pat Zabinski

> Your final question gets back to my original inquiry. What is a
> resonable metric (or set of metrics) for defining the level of correlation.
> Certainly there are plenty of effects require us to use an "enveloping"
> method in our simluation of an imperfect environment. What I would really
> like to discuss are the ways to quantify our wavefrom matchup, assuming
> we're have a reasonalbly high confidence in our simulations (i.e. we've
> characterized the laboratory system well enough to understand where our
> potential errors may come from, or in the case of simulator-to-simulator
> comparisons, we've established that our models have been properly
> translated
> by looking at the piece-parts).

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