[time-nuts] OCXO Phase Noise Measurement in Primitive Conditions

Bob Camp kb8tq at n1k.org
Tue Sep 2 21:13:13 EDT 2014


Hi

The gotcha of using a telecom  Rb is that it (probably) has a worse ADEV than a good GPSDO out to somewhere in the 100 second range. It also (probably) isn’t going to do much good in the > 20,000 seconds range either. 

Much easier to just build two or three GPSDO’s…. at least then you can compare out to their loop bandwidth. 

Bob
 
On Sep 2, 2014, at 4:46 PM, Bob Stewart <bob at evoria.net> wrote:

> Hi Magnus,
> 
> I knew I was missing something!  I'll warm up the Rb and test against that again.
> 
> Thanks!
> 
> 
> Bob
> 
> 
> 
> ________________________________
> From: Magnus Danielson <magnus at rubidium.dyndns.org>
> To: time-nuts at febo.com 
> Sent: Tuesday, September 2, 2014 3:27 PM
> Subject: Re: [time-nuts] OCXO Phase Noise Measurement in Primitive Conditions
> 
> 
> Well, in that case you do measure a form of noise-floor rather than 
> measuring the OCXO performance, as OCXO performance is being corrected 
> out in the PPS position (and sawtooth-correction).
> 
> If you want to measure that OCXO performance, you need to do that 
> against an independent PPS.
> 
> Cheers,
> Magnus
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