[time-nuts] Quadrature Phase Noise Measurement

[Anders Wallin]

>
>
> I am keen to measure close in phase noise 1Hz to 1 MHz offset on 100 MHz
> clocks.
>

We have some preliminary results on 100MHz using an Ettus B210 SDR.
The RF front-end is an AD9361, and if you search on ebay you will find B210
clones at about half the NI/Ettus price (haven't tried those..)

One issue is ch1-to-ch2 isolation, which isn't stellar on the B210.
I'm sure John can enlighten us on the importance of channel isolation for
digital PN and ADEV measurements ;)
The brute-force approach may be to use two B210s in parallel?

gnu-radio is quite good for processing the samples - maybe the digilent or
red pitaya also have gnu-radio drivers?

AW