[time-nuts] Re: DIY Low offset Phase Noise Analyzer (Erik Kaashoek)

[Erik Kaashoek]

Not something I want to implement on short notice but maybe for the future.
The biggest limitation in this DIY PNA is the phase noise of the 
reference OCXO and the noise of the opamp amplifying the output of the 
mixer.
So I was wondering if it would make sense to do the following
1: Split the output of the DUT into two completely separate PNA's
2: Feed the output of the two PNA's into the PC left/right audio inputs 
where the noise of both ADC's gets added.
3: Do a cross correlation of the two inputs.
This should (as far as I have understood the feedback) eliminate both 
the phase noise of the two independent OCXO's used as reference and 
eliminate the noise of the opamps in the two PNA's and the ADC's, given 
enough time to do the correlation.
Erik.