Andrew Beckett
Senior Fellow
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Life, don't talk to me about Life...
Posts: 1742
Bracknell, UK
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Note that you can also sweep one of the frequencies (say the LO or the RF) using the sweep on the PSS form - and the other using the parametric analysis form.
For the beat frequency, put some nominal value (it doesn't really matter - just do auto-calculate, perhaps).
Then in the Options form, down the bottom, there is a field labeled "Additional Parameters". Enter "autofund=yes" in that field.
You need to be using at least IC5141 USR2 or later for the additional parameters field to be present. And you need to be using spectre from MMSIM60 or later for pss to support autofund. This tells pss to calculate the pss fundamental from the sources in the circuit, rather than using a specified fundamental frequency. The one place this won't work is if you have a divider in the circuit - if you do, then add a dummy source in the circuit at the divided down frequency.
Regards,
Andrew.
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