Hi Mark, Unfortunately you're up against the limits of the included examples. There are no UHD only examples which store multiple channels of samples to a file. The rx_multi_samples shows the steps involved in setting up the channels, but doesn't implement the functionality shown in rx_samples_to_file to write to a file.
Yes, uhd_fft can be used to view multiple channels. GNU Radio's framework makes it easy to implement the more advanced application layer features. The arguments will be almost the same as for rx_multi_samples to file. Check out the help message for uhd_fft to see all the options. Simply supplying the frequency of interest and the same --channels 0,1 should show you plots of both channel's spectrum and time series data. To save data from both channels you will need to construct a flowgraph in GNU Radio. There are some examples supplied with gr-uhd which demonstrate the basics of connecting and configuring the USRP source. If you have trouble let us know here or on the GNU Radio mailing list. Regards, Derek On Tue, Aug 1, 2017 at 3:14 PM, Mark Koenig < mark.koe...@iubelttechnologies.com> wrote: > Thanks Derek. > > > > I was setting up rx_multi_samples the following way: > > > > ./rx_samples –args=”addr=192.168.40.2” –nsamps=10000000 –rate=100e6 > –sync=now –subdev=”A:0 B:0” –channels=”0,1” > > > > I see a lot of verbose output, like: > > > > Received Packet: 1996 samples, 1 full secs, 0.500000 frac secs > > > > But, I don’t get any file outputs or anything else. The collection ends > and I am left wondering what just happened. Can I use uhd_fft to look at > the MIMO stream? > > > > Also, there is no place to enter a frequency to collect, should there be? > > > > Mark > > > > *From: *Derek Kozel <derek.ko...@ettus.com> > *Date: *Tuesday, August 1, 2017 at 10:08 AM > *To: *Mark Koenig <mark.koe...@iubelttechnologies.com> > *Cc: *"usrp-users@lists.ettus.com" <usrp-users@lists.ettus.com> > *Subject: *Re: [USRP-users] Trying to verify Rx MIMO operation of x310 > > > > Hello Mark, > > rx_samples_to_file will only receive a single channel. It is a minimal > example. > > Try: > > rx_multi_samples --channels 0,1 > > This will receive two channels, a pair of UBXs only has one RX channel per > daughterboard so UHD can infer the sub device specification. The default > sample rate is 100 MS/s so both channels will fit into a single 10 GigE > connection. Make sure to follow the advice of any warnings printed to > improve the throughput of your network interface card. > > If you have an external 1PPS source you can add `--sync pps --secs 0.1` to > the above parameters to synchronize the two channels. The example currently > forces an external source when synchronizing. If you remove/comment out > line 98 and recompile it will use the internal source. > > Regards, > > Derek > > > > > > > On Tue, Aug 1, 2017 at 2:46 PM, Mark Koenig via USRP-users < > usrp-users@lists.ettus.com> wrote: > > I currently have an x310 with a ubx-40 in each of slots A and B. I have > one 10Gig Ethernet connection hooked up, and would like to receive on both > channels A and B. > > > > I tried using the “rx_multi_samples” function, but I didn’t get a good > feeling I was collecting on both channels. I tried using the > “rx_samples_to_file” function, but didn’t see a coherent collection on A > and B, when setting the subdev to “A:0 B:0”. > > Finally, I tried the “uhd_fft”, and saw collection in channel A, but > nothing from channel B, while setting subdev=”A:0 B:0”. > > > > Am I doing something incorrectly, or is there another function I should > try? > > > > Thanks > > > > Mark > > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > >
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