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Design >> RF Design >> Question about phase noise simulation
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Message started by applecore on Jun 18^th, 2007, 12:03pm

Title: Question about phase noise simulation
Post by applecore on Jun 18^th, 2007, 12:03pm

I am confused by some of my recently study. Please help ~

The cadence document "SpectreRF Simulation Option User Guide 5.1.41"page 388 suggests use "source" as noise type, which, in my understanding, is time-average PSD. However, in your online document "An Introduction to Cyclostationary Noise", when both cyclostantionary and stantionary noise present (the case of VCO), the noise in side bands are correlated. Should I use "modulated" or "source" as noise type in this case?

I ran some simulation of a simple LC VCO using both source and modulated noise type. I found the Pnoise from source simulation is same as upper side band ("USB") noise from modulated noise. Can I say they are equivalent? "LSB" noise is smaller than "USB", why does that happen? Should I regard "PM" noise as phase noise, and making more sense to system performance?

Thanks and happy father's day~

Ji

Title: Re: Question about phase noise simulation
Post by Ken Kundert on Jun 18^th, 2007, 5:45pm

For background information on AM, PM, USB and LSB noise, see Section 6.1.2 of http://www.designers-guide.org/Analysis/rf-sim.pdf.

-Ken