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Measurements >> Phase Noise and Jitter Measurements >> How to setup parameters when do pss+pnoise for PFD+CP?
https://designers-guide.org/forum/YaBB.pl?num=1274939997

Message started by easyads on May 26^th, 2010, 10:59pm

Title: How to setup parameters when do pss+pnoise for PFD+CP?
Post by easyads on May 26^th, 2010, 10:59pm

Hi
I am doing pss+pnoise analysis to simulate PFD+CP noise.
The PFD working frequency is 1MHz. The Ton(to eliminate dead zone) of CP 1ns. And I have some problems and need you help.
1. how to choose pss harmonic in pss setup? 10,100 or 1000 for this case?
2. how to choose max sideband in pnoise setup? 10, 100 or 1000 for this case?
3. Can we choose max sideband in pnoise large than pss harmonic in pss? for example, maxsideband=1000, pss harmonic=10
Thanks

Title: Re: How to setup parameters when do pss+pnoise for PFD+CP?
Post by Ken Kundert on May 26^th, 2010, 11:24pm

You chose the harmonics based on how many harmonics you want to see. Often it is set to one because you only need the fundamental. The number of sidebands determines the accuracy of the noise analysis. Start with a reasonable number and then increase it and see how the noise results change. Choose a value that gives you a reasonable trade off between accuracy and speed.

See http://www.designers-guide.org/Analysis/sc-filters.pdf for general information about setting maxsidebands.

harmonics and maxsidebands can be set completely independently of each other.

-Ken

Title: Re: How to setup parameters when do pss+pnoise for PFD+CP?
Post by steff on Jul 29^th, 2010, 3:39am

Hi,
I'm simulating a PFD/CP and I want to get the output noise. As written somewhere in the forum i drive the PFD with a vpulse and then i measure the output current noise.
While setting the simulation parameters in pnoise analysis ( i'm using cadence) i set "Sweeptype" to relative and then i choose the first armonic. Is this setting right? Or i have to set "Sweeptype" to absolute?

thank you.