[time-nuts] Keysight N5511A - phase noise measurements down to theoretical-177 dBm/Hz

[Gerhard Hoffmann]

<      http://www.aholme.co.uk/PhaseNoise/Main.htm      >

I happen to have one of these Xilinx boards, but I don't remember what I 
paid for it.

Now Spartan-6 is no longer leading edge, so they should be available 
cheaply.

Looks interesting and it's open source.


Enrico Rubiola has written both on the 3-cornered head and the noise in 
the Red Pitaya.

Now if he is consequent and merges that... :-)

With 2 Red Pitayas one would have 4 16 bit 115 MSPS ADCs , 2 FPGAs and 
Lots of ARM

processing power.  Syncing them is easy.  Just what is needed.

The new 16 bit version of the RP is < €500 IIRC, it should fit the bill 
just so.

<     https://www.redpitaya.com/     >


I don't think there is a cheaper solution short of building it yourself,

preferably with flea market stuff. But not much cheaper.


pic:

My experimental setup to measure added phase noise. The delay line

brings anything into quadrature from 4 to 200 MHz. A lot of Nexans 3.5 
mm semi rigid

cable, 3 pairs of SP6T SMA relays for coarse, mid and fine,  plus a lot 
of patience soldering

the SMA connectors and checking the delays on the TDR. The 24V supply is 
still missing.

I did severely underestimate the power hunger of the relays.


regards, Gerhard



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