Hi Matt, That would be a possibility, but the Real signal was decaying and the power was not shifting to the Imaginary leg. In other words, the phase was not rotating. My "decaying" signal was post-synchronization, so there was no frequency offset.
I was able to demonstrate that the effect was being caused by the DC offset correction within the USRP. Thanks for your reply. - Martin On Fri, May 25, 2018 at 2:49 PM, Radio User via USRP-users < usrp-users@lists.ettus.com> wrote: > Could the "decay" you are seeing actually be the phase changing due to > offsets in the carrier frequency? Unless you are doing some kind of > phase-locking > on the RX signal to correct for frequency differences between the > transmitter > and receiver, the apparent phase will drift a bit. Especially over a > 200microsecond > step. > > (Consider that you're symbol time is about 0.8 mSec... Now assume that the > accuracy > of your carrier is 100 ppb. That says you could be off by 200Hz or so. In > 1 mS you > will have drifted (seen a phase shift) of 0.4pi radians. > > Does that make sense? > > matt >
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