- 15th July 2009, 03:55 #1

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## pss analysis

hi there,

I just begin to do RF circuit design and I have some very fundamental question to ask, please help me if you know the answer. what is periodic or quasi-periodic steady state of a circuit and what is pss analysis and its difference between transient analysis(or DC analysis?) used in analog circuit design? why are the stimulus or stimuli of pss analysis needed to be periodic or co-periodic? thanks in advance!

- 15th July 2009, 03:55

- 16th July 2009, 02:35 #2

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## periodic steady state of a circuit

please help...

- 16th July 2009, 02:35

- 7th December 2010, 14:10 #3

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## Re: question about PSS analysis and periodic steady state

• PSS (Periodic Steady State) analysis: Large Signal Analysis (AC analysis is a small signal analysis). This analysis helps to quickly compute steady state response of a circuit which has a very long time constant, such as oscillators. It sets circuits’ periodic operating point, “After a PSS analysis, the circuit is linearized about a periodic (time varying) operating point with frequency conversion effects included. After the PSS analysis, you can perform one or more of the periodic small-signal analyses. Example circuits where you might use the periodic small-signal analyses include conversion gain in mixers, noise in oscillators, and switched capacitor filters.”

Periodic small signal analyses (pac, pxf etc.)are similar to conventional small signal analysis (AC etc.) but unlike conventional small signal analysis these analyses consider frequency conversion effects. Other periodic small signal analyses use PSS data to start with.

• QPSS (quasi periodic small signal) analysis: Large signal analysis, same as pss but multiple frequencies (hence intermodulation) takes effect. You should select a sinusoidal or pulse as large signal and additional signals must be sinusoid.

You can relate these data to find similarities or dissimilarities among pss, qpss, tran, op and ac analysis. Please read spectreRF analysis theory for more information.

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- 7th December 2010, 14:10

- 7th December 2010, 14:56 #4

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## Re: question about PSS analysis and periodic steady state

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- 7th December 2010, 16:19 #5

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## Re: question about PSS analysis and periodic steady state

I liked the section in the designers' guide doc where it says "Periodic and quasiperiodic analyses can be thought of as RF extensions of SPICE’s DC

analysis." (page#14)

Yes! this would be the simplest answer for what pss and qpss analyses are,

Thanks!!!Last edited by sudip; 7th December 2010 at 21:21.

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- 7th December 2010, 16:43 #6

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## Re: question about PSS analysis and periodic steady state

See my append in input impedance of a passive mixer

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- 7th August 2011, 19:03 #7

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## Re: question about PSS analysis and periodic steady state

thanks for the links and the explanation, I too found it very useful