The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Apr 18th, 2024, 7:44am
Pages: 1
Send Topic Print
maxacfreq parameter in PSS analysis in SpectreRF (Read 1545 times)
ULPAnalog
Community Member
***
Offline



Posts: 97

maxacfreq parameter in PSS analysis in SpectreRF
Mar 16th, 2016, 8:14pm
 
Dear experts

This is regarding the maxacfreq parameter in PSS options in spectreRF. I am running a simulation with the following settings/parameters to understand how some of the parameters are being chosen by simulator. In a test circuit with clock frequency 2kHz, PSS analysis is performed with 25 output harmonics requested followed by PAC analysis with maxsidebands = 25 and fstop = 1G. With such a large fstop, I expected simulator to give a warning about sweep being truncated, which it does. However, it says that sweep has been truncated to 208.93kHz, with a suggestion to set maxacfreq = 1.00005 GHz.
Based on the spectreRF documentation, my understanding is that the the simulator sets maxacfreq to max(4*largest harmonic request, 40*fundamental). Since 25th harmonic is the largest requested, I would expect the sweep to be truncated in such a way that no input frequency produces an output greater than 200kHz. Is my understanding correct? If so, how can 208.93kHz be a valid input frequency?

The suggestion of setting maxacfreq to 1.00005GHz makes sense given that this number is 1G+2k*25.

Thanks and regards
Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2024 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.