[time-nuts] Producing jitter with Phase Modulation

[Bilal Amin]

Pete,
Thanks for your valuable information. You have explained exactly what is 
happening and I have got it finally. I have a digi. oscilloscope with a 
jitter measurement option, but it is only for square waveforms. 
Unfortunately the Sig. Gen. I am using has no option for square wave. I 
think I have to use a comparator to get the square wave form and then 
measure jitter with oscilloscope.

Cheers
Bilal
----- Original Message ----- 
From: "Pete" <peterawson at earthlink.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, March 20, 2007 2:42 AM
Subject: Re: [time-nuts] Producing jitter with Phase Modulation


> Bilal,
>
> The GR noise generators were specified for total noise voltage in a
> specified bandwidth. With the HP signal generator input limited to 10KHz,
> your observation of increasing noise as the GR source bandwidth is reduced
> is as expected. You are simply applying more of the GR's output to the HP
> signal generator by better matching the source bandwidth to the "load".
>
> An oscilloscope is a difficult tool for the measurement you propose. If
> that's what you must use, then get a storage 'scope or an equivalent 
> digital
> 'scope which will allow you to integrate up the jittering waveform. This 
> is
> essentially what folks do to create an "eye" diagram for estimating high
> speed data link jitter. The difficulty with this approach is that the
> probability observing maximum jitter is quite low & the 'scope waveform
> tends to have very low intensity for these "rare" events, so it's tough to
> know where the outer edges of the jitter are. The digital "scopes are
> superior for this application, but rather expensive.
>
> Regards,
> Pete Rawson
>
>
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