Hi, all, I am using two USRP N210 to estimate the channel impulse response. I sent a 63-PN sequence at 1M sample rate and at 850MHz on one usrp. Another one receives the signal at 850MHz and at 1M sample rate.However, i found the received PN signal has frequency offset which can be seen from the plot of the phase. I have attached the plot of the phase of the received signal. After calculation, I thought the offset would be 397HZ. So i tried to compensate the received signal by a complex signal with a frequency of 397Hz. The workflow is shown in the grc. But this does not eliminate the frequency offset. Anyone has some suggestions? Thanks a lot.
on 2012-10-29 05:33