The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Mixed-Signal Design >> Simulating DAC with qpss
https://designers-guide.org/forum/YaBB.pl?num=1116960471

Message started by ml on May 24^th, 2005, 11:47am

Title: Simulating DAC with qpss
Post by ml on May 24^th, 2005, 11:47am

I have a multi-bit D/A where the input signal is fed from pwl sources. The D/A is a switched capacitor structure. Would appreciate if somebody can help me run distortion analysis. How does the simulator know about the input tone. Thanks.

Title: Re: Simulating DAC with qpss
Post by sheldon on Jun 1^st, 2005, 8:44pm

ml,

Why not just synthesize a sine wave and run an FFT? Use
a sine source and the ideal ADC in the ADE ahdlLib to generate
the digital codes for the D/A Converter. Depending on your
application, the Spectre fourier analysis maybe also be appropriate.
NOTE: the analogLib four component does not support the
full features of the fourier analysis so you may need
to do some manual editing.

BTW, an FFT uniformly samples the D/A converter output so it will ignore
the effect glitch impulse on the output response. In some applications, this
effect can not be ignored, in particular, waveform synthesis in
communications systems. Spectre's fourier analysis uses the Fourier
Integral and inegrates over the entire waveform so it will include the
effect of glitch impulse, see Ken's book for more details.

Best Regards,

Sheldon