[time-nuts] Producing jitter with Phase Modulation

[Pete]

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