[time-nuts] Best phase detector / mixer for 100MHz?

[Bruce Griffiths]

Support HpW-Works.com wrote:
> Bruce,
>
>    
>>> There's no evidence of a cross power spectrum function in this suite.
>>> One needs to be able to average at least 10,000 cross power spectra for some
>>> applications.
>>>        
> In the PSD (power density)&  PSP (power spectrum) there are cross power and cross
> power complex average implemented (selectable using the spectrum channel mixer)!
> Additional to this you may apply / add averaging of the resulting spectrum or use
> additional peak hold.
>
> Average of 10'000 cross points is a large count and often seen on 1-4k sample size.
> Better in my opinion is to use a higher sample size 32k-64k and then less averaging
> is required.
>    
The equivalent phase noise (measured in dBc/Hz) is essentially 
independent of the sample size.
So increasing the sample size isnt particularly useful for reducing the 
phase noise floor.
The increased frequency resolution achieved by increasing the sample 
size is only useful for measuring spurs.
In the direct digital method of measuring phase noise a few terasamples 
(a few gigasamples at baseband) need to be processed to achieve a 
sufficiently low instrument noise floor.
However with a sound card plus a mixer a somewhat lower number of 
samples should suffice since there is no carrier.
> Just download the evaluation version with fully feature set.
>
> HpW
>
>
>    
Bruce