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Measurements >> Phase Noise and Jitter Measurements >> pnoise result from Ken's verilog-A vco model?
https://designers-guide.org/forum/YaBB.pl?num=1155157976

Message started by jvbws on Aug 9^th, 2006, 2:12pm

Title: pnoise result from Ken's verilog-A vco model?
Post by jvbws on Aug 9^th, 2006, 2:12pm

Hi,

I've used verilog-A models for VCOs before. Typically they provide a sinusoidal output. I model the phase noise by providing thermal noise at the vco tuning port. A resistor sized appropriately for the desired noise @ a particular offset can accomplish this. I simulate using PSS and PNOISE, and get the desired phase noise profile at the vco output.

But when I use the verilog-A VCO model proposed in "Modeling Jitter in PLL-based Frequency Synthesizers", the same trick doesn't seem to work for me and I'm wondering if someone can offer an explanation as to why? The output of this model is a square wave as opposed to the sine wave model I'm accustomed to using, but shouldn't the effect of the noise at the VCO input on the square wave zero-crossing be captured in a PSS/PNOISE solution?

Thanks,
Jeff