On 10/06/2017 03:47 PM, Piotr Krysik via USRP-users wrote:
W dniu 06.10.2017 o 21:33, Piotr Krysik via USRP-users pisze:
Hello everyone,
I synchronized two USRPs B210 with use of Octoclock-G and the attached
gnuradio-companion flowgraph.
I've connected signal generator generating sinusoid to both devices (it
was on frequency 694.5MHz while USRPs were tuned to 694.3MHz, signal
power was about -40dBm). What I would expect is to see constant phase
offset between signals received by both USRPs (perhaps changing slightly
with temperature etc.). However what I see is constant changes of phase
that corresponds to frequency offset between two devices. Moreover this
frequency offset changes significantly from one execution of a flowgraph
to another (look at the image):
relative phase of two B210's
Missing image of phase offsets in the attachment.
Best Regards,
Piotr Krysik
Try disabling automatic DC-offset and I/Q correction. I've run into
this before--since the DC offset and I/Q correction logic is somewhat
stochastic, you would
expect precise phase-measurements between two devices to wander
around a bit with respect to one another.
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