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Design >> RF Design >> estimation of phase noise contribution of divider
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Message started by arunm on May 1^st, 2007, 12:24pm

Title: estimation of phase noise contribution of divider
Post by arunm on May 1^st, 2007, 12:24pm

Hello,
I have an asynchronous, programmable divider chain in my PLL. I would like to estimate the phase noise contribution of the divider noise to the output.
I am currently doing as follows:
I am driving the divider chain with a frequency source and running a PSS + pnoise analysis. The fundamental frequency was set as the output frequency of the divider. My PLL spec has a noise limit at a frequency 'x' from the carrier. So, what I do now is note down the noise (in dBc/Hz as given by pnoise simulation) at frequency 'x' away from the output frequency of the divider and manually multiply it with the relevant transfer function to the output (it will be a lpf similar to ref noise). Is this procedure ok?
I have a doubt as to how much I should set the maxsidebands value in pnoise. Should it be the divide value?

Thanks in advance,
Arun