sheldon
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Schehrazi,
Some additional comments, there are simulation challenges that the Fourier Analyzer is uniquely suited to analyze. For example, when characterizing circuits DACs, Spectre's Fourier Analyzer is better. In the process of sampling you lose information about waveform. So while it is difficult to analyze the effect of glitch impulse on the re-constructed waveform using an FFT, it is simple to perform this analysis with the Fourier Analyzer.
Some comments on run time:
1) The analysis time is a function of the number of frequency components and the number of transient time points.
2) For a typical for a Pipeline ADC, equivalent to a 256-point FFT , the overhead is not a big issue. The overall run time is on the order of the time to run the FFT.
3) For a Sigma-Delta Modulator, the overhead can be significant, ~10-100x (or more) the time to run the FFT. Simulating a Sigma-Delta requires many time points, for example 8192 points, and high accuracy. So even though the number of frequency components is low, the znalysis time is long.
Best Regards,
Sheldon
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