Stand down, I found the stupid mistake. I didn't realize that this X310 has BX-120 daughter cards. So of course tuning to a freq that is WELL below the operating freq range is going to give issues. It would great with the USRP Source. When I switch to RFNoC radio, it would perfect the first time and then can bounce around a little on subsequent re-runs. So if I power cycle between runs it is fine. Not sure what is going on there, but I'll come back to that issue later. --------- Original Message --------- Subject: weirdness with RFNoC RX "walking" From: "Jason Matusiak" <ja...@gardettoengineering.com> Date: 11/27/18 7:48 am To: "Ettus Mail List" <usrp-users@lists.ettus.com>
I am seeing something weird that I am sure is a simple mistake on my side, but I can't quite see what I am doing wrong. I have a test transmitter outputting a signal at 391.5MHz. It is on 10s, and then off 10s. This works fine and runs independently. My flowgraph of interest on the receive side is an RFNoC receiver tuned to 400MHz, gain of 20, sample rate of 200MHz, bandwidth of 56MHz. I take the RX signal, go through a DDC to take it down to a 66.6667MHz sample rate. Then look at the output on a freq sink with a bandwidth of 66.6667MHz. What I see is that the signal pops up where it shouldn't. Sometimes the signal is in the plot, sometimes not. Even when it is in the plot though, it isn't in the right place. I will see it pop up at somewhere like 375MHz (and a weaker copy at 425MHz). I saw it pop up correctly once, but can't repeat that. It just feels like the clock is walking or something, but I can't figure out why it is consistently off, and occasionally not on the screen at all. I am using a default XG bitfile.
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