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Measurements >> Phase Noise and Jitter Measurements >> jitter vs center frequency
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Message started by iVenky on Jan 17th, 2018, 7:50am

Title: jitter vs center frequency
Post by iVenky on Jan 17th, 2018, 7:50am

Hi,

I am trying to measure the jitter of a clock signal by sending through a transmitter using 11001100 pattern (fclk/2) and 1010 pattern (fclk).  First, the absolute RJ should be the same on both cases, right? Also, if I integrate the phase noise over a certain bandwidth, it should be the same in both the cases, right?

Also, I am seeing a mismatch in the jitter obtained from a scope (through histogram) and integrated jitter from spectrum analyzer. Is that possible?

Title: Re: jitter vs center frequency
Post by deba on Jan 21st, 2018, 8:49pm

The phase noise will scale with the centre frequency. If you double the frequency, phase noise goes up by 2. This is to maintain the same timing jitter.

Can you share your setting in scope and spectrum analyzer?

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