Hi Damon, Transmitting at 200 MS/s is very challenging. I'm assuming that you are using two X310s with only 1 channel active on each X310 because it is not possible to transmit 2 channels @ 200 MS/s with a single X310 using cpu-to-host streaming. Is this correct?
Is it possible for your transmission to be implemented in the FPGA using either a fixed length arbitrary waveform (such as with the Replay block) or with a on-the-fly calculated waveform (such as with SigGen block or perhaps your own custom block)? Or does your transmission require continuously updated calculations on the CPU? Rob On Tue, Aug 25, 2020 at 12:36 PM Damon qiu <[email protected]> wrote: > Hi Rob, > > Thank you very much for your reply.I just read through your discussion > with Andreas about this issue. However, your temporary solution is not > suitable for my case. I need to transmit signals in two channels with > 200Msps sample rate for each channel. I can only wait for the Ettus > engineers to fix this bug. It's not sure whether Ettus engineers are > already investigating the bug, as there are no official replies to two > threads about this bug. > > Best regards, > Damon > > On Tue, 25 Aug 2020 at 03:35, Rob Kossler <[email protected]> wrote: > >> 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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