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Simulators >> RF Simulators >> Jitter of a VCO+DELAY LINE with SpectreRF
https://designers-guide.org/forum/YaBB.pl?num=1443633937

Message started by federico.butti on Sep 30^th, 2015, 10:25am

Title: Jitter of a VCO+DELAY LINE with SpectreRF
Post by federico.butti on Sep 30^th, 2015, 10:25am

Hello,

I would like to ask to experts what is the best practice to quantify the jitter of a VCO driving a squarer and an inverter delay line.
When I simulate a VCO, I usually calculate phase noise, and calculate the square root of 2 times the integral up to fosc/2, then I divide the results by 2PIfosc. This is the absolute jitter as defined by most literature.

When I simulate an inverter delay line, I usually use the PNOISE JITTER simulation, given that it computes the noise sampled at a given threshold, and then the integrated result is divided by the slope at the threshold.
If I perform the phase noise calculation on the same driven circuits, results are not the same.
I am not sure why.

Here comes the question: what is the best practice when I simulate an autonomous circuit (VCO) loaded with a delay line (driven circuit)?
Phase noise integral or PNOISE jitter at the delay line output?
Or simulating each one and then summing up jitter variances quadratically?

Thanks for the replies!