Hi Damon, See my other post today regarding "skip_dram=1". I believe there is a bug. But, if you can skip the Dma FIFO (if your sample rate is low enough), you can get around the bug. Rob
On Mon, Aug 24, 2020 at 3:31 PM Damon qiu via USRP-users < [email protected]> wrote: > Hi all, > > After repeated tests, we feel that two of the four channels of two devices > will be randomly selected, and the probability of choosing the correct > channel is very low. It must be a bug. > > Hi Macus, > > > try: > > > > stream_args.channels.push_back(0); > > stream_args.channels.push_back(1): > > > > Instead of your: > > > > stream_args.channels = {0,1}; > > > I think these should be equivalent, but my C++ fluency is low... > > Thank you for your reply, but your suggestion didn't work. Please don't > forget to cc it to me next time. > > Best regards, > Damon > > > > On Fri, 7 Aug 2020 at 01:32, Damon qiu <[email protected]> wrote: > >> Hi all, >> >> I am using two USRP X310s to transmit signals on 2 channels. The two USRP >> are synchronized through a octoclock-g. >> >> A multi_usrp object is used to control those two USRP, device address is >> set to addr0=192.168.40.2,addr1=192.168.60.2. I want to set two USRP >> transmitting signal at RFA at the same time. I tried two ways to set up the >> tx channel and subdev spec: >> >> Method 1: The TX frontend specification is set to A:0 for both two mboard. >> d_dev->set_tx_subdev_spec("A:0"); >> or >> d_dev->set_tx_subdev_spec("A:0", 0); >> d_dev->set_tx_subdev_spec("A:0", 1); >> >> uhd::stream_args_t stream_args(tx_cpu, tx_otw); >> stream_args.channels = {0, 1}; >> uhd::tx_streamer::sptr tx_stream = d_dev->get_tx_stream(stream_args); >> >> Method 2: The TX frontend specification is set to "A:0 B:0"for both two >> mboard. >> d_dev->set_tx_subdev_spec("A:0 B:0"); >> or >> d_dev->set_tx_subdev_spec("A:0 B:0", 0); >> d_dev->set_tx_subdev_spec("A:0 B:0", 1); >> >> uhd::stream_args_t stream_args(tx_cpu, tx_otw); >> stream_args.channels = {0, 2}; >> uhd::tx_streamer::sptr tx_stream = d_dev->get_tx_stream(stream_args); >> >> In the above two methods, there is a certain probability (about 10% to >> 30%) that the two transmission channels are on the same motherboard. I >> guess this is a bug of UHD. >> >> OS: Ubuntu 18.04 >> UHD: UHD-3.15.LTS >> >> Please CC me as I can only receive the daily digest of the mailing list. >> >> Best regards, >> Damon >> > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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