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Design >> Mixed-Signal Design >> Relationship between phase noise and output
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Message started by analog2000 on Jun 15^th, 2007, 9:53am

Title: Relationship between phase noise and output
Post by analog2000 on Jun 15^th, 2007, 9:53am

Hello,
Would anyone please clarify the difference between the phase noise or jitter calcualted by Spectre RF (pnoise) and the output noise summary (in volts) also calcuated by the pnoise analysis ?
thanks a million
analog2000

Title: Re: Relationship between phase noise and out
Post by didac on Jun 15^th, 2007, 1:23pm

Hi analog2000,
You are mixing two different concepts, phase noise and jitter are effects related to innacuracies of frequency in oscillators(jitter for digital circuits, phase noise in analog oscillators usually). Output noise(in V/sqrt(Hz) or V^2/Hz) is the measurement of thermal,flicker,shot,popcorn noise whetever applies in your case. In other words the first relates more to synchronization(in jitter case for digital systems) or undesired mixing(for rf front-end for phase noise,caused by the fact that you didn't have a true dirac delta in an oscillator) and output noise relates to the sensitivity of the system(which also causes that engineers have work, if noise didn't exist i communications systems will be more easy to design).
Hope it helps this explanation

Title: Re: Relationship between phase noise and output
Post by analog2000 on Jun 17^th, 2007, 12:58pm

Thanks didac for your response.
In Spectre RF you can simulate both phase noise/jitter and output noise using the print summary statements. This is if you do a pnoise simulation. I am just trying to correlate the results of both results i.e. print summary output which allows one to integrate the noise in a given bandwidth and phase noise which allows one to simulate jitter also in a certain bandwidth
thanks
analog2000

Title: Re: Relationship between phase noise and out
Post by didac on Jun 17^th, 2007, 1:01pm

Hi,
I usually use the GUI of spectreRF,plot the waveform and open the calculator, with the calculator you can select the waveform and use the integration function(integ if I don't remember bad,I don't have Cadence opened right now)