[time-nuts] GNURadio USRP for Allan/Phase-noise measurement
John Ackermann N8UR
jra at febo.com
Wed Jun 22 15:17:45 EDT 2005
Poul-Henning Kamp wrote:
> Has anybody considered using the GNURadio USRP to measure Allan
> variation and phase-noise of signals ?
> It can sample two input signals at high resolution and speed
> so it should be almost ideal for our purposes...
I've *considered* it, but haven't done anything about it yet :-).
I do have one of the USRP units, and it is a highly cool piece of
hardware. The whole system (including the four ADCs, each
64msample/sec, 14 bit) is clocked from a single 64MHz oscillator, and
provision is made to replace the on-board oscillator with an SMA jack.
My plans are to use a Reflock II
(http://w3ref.cfn.ist.utl.pt/cupido/reflock.html, and to be available
from TAPR within the next couple of months) to control a 64MHz VCXO that
feeds into that SMA...
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