Hi Florian, The device arguments are "clock_source" and "time_source". I noticed in your command you had them as "clock_src" and "time_src". That may be the source of the problem.
Regards, Michael On Mon, Dec 10, 2018 at 11:33 AM Florian Kaltenberger via USRP-users < usrp-users@lists.ettus.com> wrote: > Dear Nate, > > no it says something like this is not supported with the N310 and I should > pass it using the args options. Sorry, I don't have access to the N310 > right now, so I can't give you the exact message, but I have tried that. > > Florian. > On 10/12/2018 19:00, Nate Temple wrote: > > Hi Florian, > > If you pass the arg "--ref external" to tx_waveforms, does it resolve > this frequency offset? > > > https://github.com/EttusResearch/uhd/blob/master/host/examples/tx_waveforms.cpp#L62 > > Regards, > Nate Temple > > On Thu, Dec 6, 2018 at 12:22 AM Florian Kaltenberger via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Hi Marcus, >> >> I have measured this with a spectrum analyzer simply by setting markers >> to the peak of the sinusoid (one marker per measured USRP) and then taking >> the delta. >> >> Could it be that the USRP is ignoring the external reference when used >> alone? Remember, I am doing the test with one USRP at a time, as the test >> using multiple USRP simultaneously does not work. >> >> Florian. >> On 06/12/2018 00:29, Marcus Müller wrote: >> >> oh! That means 341 ppb frequency error, which *really* shouldn't be >> happening. >> >> I'd like to get some statistics of that error, how are you measuring >> it? >> >> Best regards, >> Marcus >> >> On Wed, 2018-12-05 at 12:55 +0100, Florian Kaltenberger wrote: >> >> Sorry typo. I did use a frequency of 3.51GHz. >> >> >> On 5 Dec 2018, at 12:54, Marcus Müller <marcus.muel...@ettus.com> >> <marcus.muel...@ettus.com> >> wrote: >> >> Hi Florian, >> >> trying to get my head to understand the order of problems here: >> Could you try to use a higher frequency (say, --freq 2e9 instead of >> 3.5e6)? >> I'd thing 3.51 MHz is out of range for the N310, anyway? >> >> Best regards, >> Marcus >> >> On Wed, 2018-12-05 at 11:49 +0100, Florian Kaltenberger via USRP- >> users >> wrote: >> >> So I can confirm that there is a frequency offset between the two >> USRP N310s when using only an octoclock (10MHz + PPS) to >> synchronize. >> I have measured with the tx_waveforms program >> ./tx_waveforms --args >> "addr=192.168.x.2,time_src=external,clock_src=external,master_clo >> ck_r >> ate=122.88e6" --rate 122.88e6 --freq 3.51e6 --wave-type SINE -- >> wave- >> freq 10e6 --gain 100 >> on the first USRP N310 (x=10) and then on the other (x=20). There >> is >> an offset of 1200Hz between the peaks of the sinusoids between >> the >> two measurements. >> Using an external LO didn't change anything either. Unless I need >> to >> provide any other arguments in that case? >> I also tried to do a test where I use both USRPs simultaneously >> ./tx_waveforms --args >> "addr0=192.168.10.2,addr1=192.168.20.2,time_src=external,clock_sr >> c=ex >> ternal,master_clock_rate=122.88e6" --rate 122.88e6 --freq 3.51e6 >> -- >> wave-type SINE --wave-freq 10e6 --gain 100--channels "0,4" >> but unfortunately that does not work at all at my testbench >> (program >> hangs and no signal transmitted). >> My UHD version is 3.13.0.2 (UHD_3.13.0.HEAD-0-g0ddc19e5) >> Any help appreciated. >> Thanks! >> Florian. >> >> >> On 04/12/2018 21:29, Florian Kaltenberger via USRP-users wrote: >> Hi Marcus and Robin, >> thanks for your answers, this is helpful information. I should >> add, >> that I actually tried the synchronization with an octoclock >> (10MHz >> + PPS), but it did not give me the expected results, i.e., I >> saw >> some residual frequency offsets. But maybe I screwed up at some >> point. Let me do some more measurements and get back to you on >> this. >> Florian. >> >> >> On 04/12/2018 18:57, Marcus D. Leech via USRP-users wrote: >> On 12/04/2018 10:14 AM, Florian Kaltenberger via USRP-users >> wrote: >> >> Hi there, >> I just discovered that in addition to the external 10MHz >> reference in, the USRP N310 also has external local >> oscilator >> inputs, one for each daughterboard and each TX/RX. So does >> that >> mean that in order to synchronize multiple N310 in >> frequency, >> phase, and time, it is no longer sufficient to use an >> octoclock >> to provide a 10MHz reference and PPS? If so, at what >> frequency >> do you have to drive the external LOs and at what power? >> Florian. >> >> >> In addition to what Robin posted, I'll observe that the >> external >> LO port is an *additional feature* of this device. >> >> You should still be able to use the external 10MHz and 1PPS >> ports >> the same way you would with a B210 or E310, since the AD9371 >> front-end chip is similar to the AD9361 chip used in the >> B210 >> and E310. >> >> The thing about synchronizing multiple independent PLL >> synthesizers, though, compared to a strictly-shared-LO, is >> that >> the former will >> experience both phase ambiguities, and have a higher mutual >> phase-noise than the latter, which is why you might decide to >> choose >> the latter. >> >> >> >> >> _______________________________________________ >> USRP-users mailing >> listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> -- >> Follow us on Google+, LinkedIn, or Twitter! >> >> >> _______________________________________________ >> USRP-users mailing >> listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> -- >> Follow us on Google+, LinkedIn, or Twitter! >> _______________________________________________ >> USRP-users mailing >> listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> -- >> Follow us on Google+ <https://plus.google.com/+OpenairinterfaceOrg>, >> LinkedIn <https://www.linkedin.com/company/openairinterface>, or Twitter >> <https://twitter.com/osalliance5g>! >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> > -- > Follow us on Google+ <https://plus.google.com/+OpenairinterfaceOrg>, > LinkedIn <https://www.linkedin.com/company/openairinterface>, or Twitter > <https://twitter.com/osalliance5g>! > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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