I was trying to implement a TDD system using UHD time stamp feature. I used the UHD API directly (not gr_uhd) to test it first. The transmit path sends bursts periodically, and the receive path captures all the time. For comparison, I have also recorded the signal from another USRP N200
receiver. The first problem I observed was that few bursts following the FIRST burst are always lost. Pictures below are snapshots of received signals by the receive path (a) and the separate receiver (b) (a).
(b)
The second problem is that the receive path does not capture the transmitted signal (c) unless the USRP box is power restarted. Flushing the receive buffer with the following command
did not fix the problem.