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https://designers-guide.org/forum/YaBB.pl Simulators >> RF Simulators >> pnoise simulation problem https://designers-guide.org/forum/YaBB.pl?num=1307304226 Message started by harmonic on Jun 5th, 2011, 1:03pm |
Title: pnoise simulation problem Post by harmonic on Jun 5th, 2011, 1:03pm Hi, trying to simulate a chopper amplifier input referred noise. The use of spectre RF seems appropriate enough. For the direct plot which option should I choose SSB noise, DSB noise ect. ? I am using the following pnoise, pss settings: pss pss fund=100k harms=3 errpreset=conservative + annotate=status pnoise ( out 0 ) pnoise sweeptype=relative relharmnum=1 + start=1 stop=50k log=20 maxsideband=20 iprobe=V2 refsideband=0 + annotate=status The direct plot input refered noise does not seems to reduce the flicker noise. have also tried following the chopper opamp with a with a sample and hold and taking the output for pnoise simulation from the sample and hold but this still does not reduce the flicker noise seen on the direct plot when using SSB noise for input refered noise. I've read Ken Kundert's sc-filters.pdf from www.designers-guide.org/Analysis/ . Any ideas where I'm going wrong with the simulation setup and direct plot? Regards, harmonic |
Title: Re: pnoise simulation problem Post by rfcooltools.com on Jun 6th, 2011, 2:21pm harmonic, I don't have the document in front of me, but believe that you should be sweeping the input relative to the 0th harmonic, where the input should reside. http://rfcooltools.com |
Title: Re: pnoise simulation problem Post by Ken Kundert on Jun 7th, 2011, 12:08am Indeed, with relharmnum=1 you are observing the noise at the output of the chopper from 100,001 to 150,000 Hz. That is probably not what you want. You should probably not be using a relative sweep. -Ken |
Title: Re: pnoise simulation problem Post by harmonic on Jun 8th, 2011, 2:47am Thanks Guys, yeap its: rfcooltools.com wrote on Jun 6th, 2011, 2:21pm:
Ken Kundert wrote on Jun 7th, 2011, 12:08am:
Obvious mistake once pointed out. Works fine with relharmnum=0. |
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