The stream command object has a field for a time spec of when to start streaming and a boolean flag for whether to make use of that time spec. http://files.ettus.com/manual/structuhd_1_1stream__cmd__t.html
Here we can see it used in an rx example. https://github.com/EttusResearch/uhd/blob/maint/host/examples/rx_timed_samples.cpp#L92-L93 Usually it is most practical to make a call to get_time_now() and then add an offset from that time which is returned. The minimum offset would be the roundtrip command time, usually a few milliseconds. Regards, Derek On Thu, Mar 8, 2018 at 9:03 PM, Andrew Thommesen <andrewjoh...@outlook.com> wrote: > No, how do you do that? > > > Sent from Outlook <http://aka.ms/weboutlook> > ------------------------------ > *From:* Derek Kozel <derek.ko...@ettus.com> > *Sent:* 08 March 2018 20:58:38 > *To:* Andrew Thommesen > *Cc:* usrp-users > *Subject:* Re: [USRP-users] TwinRx Channel Alignment > > Hello Andrew, > > Are you starting the streaming with timed commands? > > Regards, > Derek > > On Mar 8, 2018 7:32 PM, "Andrew Thommesen via USRP-users" < > usrp-users@lists.ettus.com> wrote: > > Hi all, > > > I have an x310 with a twinRx and would like to process coherent, > time aligned data within the FPGA. However, the data is not currently time > aligned and there is an offset of ~400 samples between the two channels. > > > The RFNoC radio block is configured to receive data on both channels, with > the LO of channel 1 set to companion. The output of the radio block then > passes through the RFNoC DDC block that decimates from 100MSPS to 50MSPS. > The decimated data then passes to a custom RFNoC block that strips out the > timestamps (for loopback). It is within this custom block that the the > offset is detected at the output of the AXI wrapper before any processing > has taken place. > > > Any ideas? > > > Andy > > > > > Sent from Outlook <http://aka.ms/weboutlook> > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > >
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