Hi, I am using the USRP X310+UBX160 with gnuradio to perform very precicse phase measurements: The TX transmits a CW which is reflected by an object and received by the RX.
The received phase provides an accurate estimate of the distance to the reflected object, once the fixed phase relation (between TX/RX-LO, filters, cables etc.) has been subtracted out. This works nicely so far. However, I need my system to work across power cycles, and more importantly, across different frequencies: The goal is to perform fast frequency hopping and obtain the phase for each frequency. Unfortunately it seems that the phase relationship between TX/RX is lost when I tune the USRP to a different center frequency and back. For example, I have the center frequency set to 900 MHz and the phase I measure (by computing the angle of the I/Q samples) stays constant. But when I set the center frequency to 950 MHz and then back to 900 MHz, the phase has a random value again. Is there any way to avoid this? Or is there any way to lock the LO phase to a particular phase when tuning back to the original frequency? Thanks, Luke _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
