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Measurements >> Phase Noise and Jitter Measurements >> Instrument inteference in jitter measurement
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Message started by ywguo on Aug 17^th, 2004, 5:29am

Title: Instrument inteference in jitter measurement
Post by ywguo on Aug 17^th, 2004, 5:29am

Hi,

I measured the jitter of the output of Agilent 33250A function/arbitrary waveform generator. Its peak-to-peak jitter is about 120ps when the output is 80MHz.

To my surprise, it increased to about 160ps when I turned on a HP 3234A DC power supply. Then it increased to 400ps when I turned on a HP 16500C logic analysis system. Those two instruments were put in half a meter near the Agilent 33250A. :(

Obviously, the instruments had prominent interference on the output of Agilent 33250A. ??? Do you have any method to avoid or reduce the interference?

Thanks
Yawei

Title: Re: Instrument inteference in jitter measurement
Post by Paul on Aug 26^th, 2004, 6:01am

Yawei,

maybe you should try to find out whether interference is due to power supply (220V or whatever) or due to EMI. In the first case you could try to use seperate power nodes. Typically you have 3 phases of power supply (at least over here in Europe) and you could use seperate ones.

But I expect it to be EMI, so that wouldn't help. In that case, I don't know... Maybe go ask Agilent, all equipment comes from them...

Good luck, and please keep us updated.

Paul