Hi Marcus,
> Von: "Marcus D. Leech" <[email protected]> > [...] > > > You're using the MANUAL policy for BOTH DSP and RF. Let the automatic > "stuff" do its thing, with the only difference being integer-N tuning. Wow, this is all so black magic. After a long time I figured out that I also have to supply int_n_step (I use int_n_step=100e3), as I randomly stumbled across in http://www.radio-science.net/2017/12/adventures-in-usrp-tuning.html. The documentation does not even mention the existence of this parameter. tune_req_tx = uhd.tune_request(target_freq=fcenter) tune_req_rx = uhd.tune_request(target_freq=2*fcenter) tune_req_rx.args=uhd.device_addr(','.join(["mode_n=integer", "int_n_step=100e3",])) tune_req_tx.args=uhd.device_addr(','.join(["mode_n=integer", "int_n_step=100e3",])) now = self.uhd_usrp_sink_0.get_time_now() self.uhd_usrp_sink_0.set_command_time( now + uhd.time_spec(1)) self.uhd_usrp_source_0.set_command_time(now + uhd.time_spec(1)) self.uhd_usrp_sink_0.set_center_freq( tune_req_tx, 0) self.uhd_usrp_source_0.set_center_freq(tune_req_rx, 0) self.uhd_usrp_source_0.set_center_freq(tune_req_rx, 1) self.uhd_usrp_source_0.clear_command_time() self.uhd_usrp_sink_0.clear_command_time() So now my RX/TX tune again (i.e., I get a signal other than noise). Unfortunately I run into the same issue that I had already some time at the beginning: My signal is frequency offset (*) - by an odd 2.5 kHz. I set my clock explicitely to 200 MHz. A step size of 100kHz should be able to synthesize my even numbers (900 MHz) without issues. On the other hand, the frequency offset stays at 2.5kHz for different values of int_n_step... Thanks, Luke (*) What I mean by that: I send a signal at "f+fif" and downconvert "2*(f+fif)". In gnuradio I multiply with exp(i*2*pi*fif*t). I expect my signal to be a DC signal (which it is in absence of the mode_n=integer). With frequency shift I mean that I see a frequency of 2.5 kHz instead of 0Hz. _______________________________________________ USRP-users mailing list [email protected] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
