Hi Derek, If USRPs A & B clocked by an Octoclock, are connected to the same host, I want calibrate the counter values from USRPs A and B. How can I do it? Is this function supported by UHD? If not, could I update the counter values in the FPGA Radio blocks? or I can only keep an calibration table of counter value offsets on my host?
Thanks! Zhongyuan Zhao PhD Candidate, Department of Computer Science & Engineering, University of Nebraska-Lincoln Office Hour: WF 9:30-10:00am, Avery Hall 12, Suite 117, Schorr Center, Lincoln, Nebraska 68588-0115 On Thu, Mar 8, 2018 at 4:42 PM, Derek Kozel <derek.ko...@ettus.com> wrote: > Hello, > > The same commands are available in the GNU Radio environment and I believe > are exposed in the pre-release Python API branch. > > The FPGA radio blocks contain a timekeeper which is a counter which > increments at the same rate as the master_clock_rate which is the effective > ADC/DAC sample rate. This allows for commands to be executed with very fine > temporal precision. > > Regards, > Derek > > On Thu, Mar 8, 2018 at 10:12 PM, Zhongyuan Zhao <zhz...@cse.unl.edu> > wrote: > >> Hi Derek, >> >> I have two questions about the rx timed samples example, >> 1. is there python version for timed command? >> 2. Is the time stamp from the clock on USRP or on the host? >> >> Thanks >> >> Zhongyuan Zhao >> >> PhD Candidate, >> Department of Computer Science & Engineering, >> University of Nebraska-Lincoln >> Office Hour: WF 9:30-10:00am, Avery Hall 12, >> Suite 117, Schorr Center, >> Lincoln, Nebraska 68588-0115 >> >> >> On Thu, Mar 8, 2018 at 3:27 PM, Derek Kozel via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> 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/example >>> s/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 >>>> >>>> >>>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >
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