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Measurements >> Phase Noise and Jitter Measurements >> Jitter/Phase noise
https://designers-guide.org/forum/YaBB.pl?num=1204473367

Message started by Godfrey on Mar 2^nd, 2008, 7:56am

Title: Jitter/Phase noise
Post by Godfrey on Mar 2^nd, 2008, 7:56am

Sorry if this is basic questions but I am new to jitter and phase noise.

If something is specified with jitter value, then the jitter is the same for any frequency? But if phase noise is specified, then it change with frequency and also quoted offset.

If I have 80dbc/Hz phase noise at 10kHz offset at 1G, if I divide that clock by two to 500M, what happens to the phase noise, is it increase by 3dB? So to find out acceptable phase noise at different frequency, I just scale the figure by the change in frequency?

Also can I work out phase noise at different offset too?

Thanks for helping.

Title: Re: Jitter/Phase noise
Post by Stefan on Mar 3^rd, 2008, 12:38am

Jitter is a measure of timinig uncertainity, typically with a gaussian distribution.
If you calculate the actual frequeny deviation, you will see something similar to the PN plot (although typically only the part due to white noise sources).

You should check the paper section of this website, there are some very good explanations for the other questions in there.

Regards,

Stefan