You might want to take a look at http://www.designers-guide.org/Analysis/rf-sim.pdf. And for information on phase noise, read the material on cyclostationary noise at http://www.designers-guide.org/Theory/.

-Ken

Thanks Ken and Loose for the information. Just print out these docs, will read in details.

Ken, I have another question.

I am doing divider design. Following your papers on cyclostatioanary noise, I do pnoise analysis with noise type time-domain. In this form, I need to fill in Noise Skip Count or Number of Points. What does this mean? which one I should tick and commonly what is number I should put in?

Thank you very much..

There is no sense in including the VCO if you are only interested in the divider noise. To see how to simulate the noise of dividers, take a look at http://www.designers-guide.org/Analysis/PLLnoise+jitter.pdf.

The Artist interface is designed to allow you to plot the noise as it evolves over a cycle. In the extreme case, it would perform a noise analysis for every time point the simulator used during a cycle. This would take a long time, so it allows you to skip steps. The Noise Skip Count is used to specify how many time points it should skip between noise analyses. Since you only want the noise analysis to be performed at one time point, you should set this value arbitrarily high. Then the interface allows you to specify specific points you want the noise for. You would enter 1 for the Number of Points, then specify the particular point you wanted. You would use the time where the output crosses the threshold value for the circuit it would be expected to drive.

I believe the newer versions of SpectreRF allow you to simply specify the threshold voltage and direction, and it takes it from there.

-Ken