[Elecraft] P3 as a phase noise measurement tool

[jerry]

....and I have an Ebay special GPSDO, which is ridiculously accurate.  
But I
don't know how pure it is.

                  - Jerry KF6VB

On 2022-06-07 17:14, Wes wrote:
> Sure, but how do you quantify the "relatively pure" source if you
> build one?  Typically you want it to be 10 dB better than what you are
> measuring (or the measuring instrument).
> 
> The other option is a commercial source with published specs.  For
> example I have an ebay special Morion MV89 10 MHz OCXO that is
> specified at -150 dBc/Hz at 1 kHz offset, which is way better than you
> could measure with a spectrum analyzer technique.
> 
> Wes  N7WS
> 
> 
> 
> On 6/7/2022 2:12 PM, jerry wrote:
>> On 2022-06-07 13:56, Wes wrote:
>>  *plus* the phase
>>> fluctuations in the measurement system's oscillators and/or sampling
>>> clock jitter.  This is the K3/P3.
>> 
>> *** I wonder if the noise of the K3/P3 could be measured using a 
>> relatively pure
>> signal source - then once that's known, you would subtract the K3/P3's 
>> noise from the
>> total noise measured from the DUT.
>> 
>>    I had a book somewhere with plans for a really clean 
>> single-frequency signal source.  It used several
>> identical crystals;  one as an oscillator and then some more as a 
>> filter to clean it up.
>> 
>>                   - Jerry KF6VB