Hello I am trying to time synchronize two USRPs. I have connected reference and PPS trigger out of USRP A to reference and PPS trigger in of USRP B. In USRP A i have set time and clock source to GPSDO and in USRP B I have set time and clock source to external. But I when I try to compare uhd::time_spec for both the boards I see there is a time mismatch. Please help me understanding where I am going wrong. Regards Snehasish

You cannot synchronize USRP devices by using a daisy-chain configuration. The 10 MHz reference and the 1 PPS on both USRP devices must be connected to a common 10 MHz reference and to a common 1 PPS signal. The OctoClock-G device can be used to generate these signals and to distribute them to 8 devices. Then, for each USRP device, in UHD or GNU Radio, set your clocking source and timing source to "external". https://kb.ettus.com/OctoClock_CDA-2990 https://kb.ettus.com/Synchronization_and_MIMO_Capability_with_USRP_Devices --Neel Pandeya On Thu, 16 Jul 2020 at 05:00, Snehasish Kar via USRP-users < usrp-users@lists.ettus.com> wrote: > Hello > > I am trying to time synchronize two USRPs. I have connected reference and > PPS trigger out of USRP A to reference and PPS trigger in of USRP B. In > USRP A i have set time and clock source to GPSDO and in USRP B I have set > time and clock source to external. But I when I try to compare > uhd::time_spec for both the boards I see there is a time mismatch. Please > help me understanding where I am going wrong. > > Regards > Snehasish > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >

Thanks Neel for the clarification! Regards Snehasish ________________________________ From: Neel Pandeya <neel.pandeya@ettus.com> Sent: Thursday, July 16, 2020 3:51 PM To: Snehasish Kar <snehasish.cse@live.com> Cc: usrp-users@lists.ettus.com <usrp-users@lists.ettus.com> Subject: Re: [USRP-users] support for synchronizing two USRPs You cannot synchronize USRP devices by using a daisy-chain configuration. The 10 MHz reference and the 1 PPS on both USRP devices must be connected to a common 10 MHz reference and to a common 1 PPS signal. The OctoClock-G device can be used to generate these signals and to distribute them to 8 devices. Then, for each USRP device, in UHD or GNU Radio, set your clocking source and timing source to "external". https://kb.ettus.com/OctoClock_CDA-2990 https://kb.ettus.com/Synchronization_and_MIMO_Capability_with_USRP_Devices --Neel Pandeya On Thu, 16 Jul 2020 at 05:00, Snehasish Kar via USRP-users <usrp-users@lists.ettus.com<mailto:usrp-users@lists.ettus.com>> wrote: Hello I am trying to time synchronize two USRPs. I have connected reference and PPS trigger out of USRP A to reference and PPS trigger in of USRP B. In USRP A i have set time and clock source to GPSDO and in USRP B I have set time and clock source to external. But I when I try to compare uhd::time_spec for both the boards I see there is a time mismatch. Please help me understanding where I am going wrong. Regards Snehasish _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com<mailto:USRP-users@lists.ettus.com> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com