Will it be enough to clock USRP from the external 10 MHz signal generator? When I run the flowgraph I cannot see the information that is using the external clock. Here is the output from GNU Radio: [INFO] [UHD] linux; GNU C++ version 9.4.0; Boost_107100; UHD_3.15.0.HEAD-0-gaea0e2de [INFO] [B200] Detected Device: B200 [INFO] [B200] Operating over USB 2. [INFO] [B200] Initialize CODEC control... [INFO] [B200] Initialize Radio control... [INFO] [B200] Performing register loopback test... [INFO] [B200] Register loopback test passed [INFO] [B200] Setting master clock rate selection to 'automatic'. [INFO] [B200] Asking for clock rate 16.000000 MHz... [INFO] [B200] Actually got clock rate 16.000000 MHz. [INFO] [B200] Asking for clock rate 51.200000 MHz... [INFO] [B200] Actually got clock rate 51.200000 MHz. [INFO] [MULTI_USRP] 1) catch time transition at pps edge [INFO] [MULTI_USRP] 2) set times next pps (synchronously) [INFO] [B200] Asking for clock rate 51.200000 MHz... [INFO] [B200] OK [INFO] [B200] Asking for clock rate 51.200000 MHz... [INFO] [B200] OK [WARNING] [AD936X] Selected Tx sample rate (0.2 MHz) is less than analog frontend filter bandwidth (0.2 MHz).
[image: image.png] śr., 11 maj 2022 o 15:24 Marcus D. Leech <patchvonbr...@gmail.com> napisał(a): > On 2022-05-11 09:18, Marcin Puchlik wrote: > > Marcus, > Thank you very much for the answer. Does it mean that 1 PPS signal is > optional? Can I only provide an external 10 MHz clock without 1 PPS? > *Z poważaniem * > *Marcin Puchlik* > > > > > > > > > > *Yes, absolutely. If timestamp synchronization is not important to you, > then you can just provide a 10MHz reference when you want better > frequency accuracy and drift characteristics than are offered by the > on-board clock and/or you want some type of phase-synchronization but > don't care much about mutual phase offsets.... * > > > > śr., 11 maj 2022 o 14:24 Marcus D. Leech <patchvonbr...@gmail.com> > napisał(a): > >> On 2022-05-11 06:17, Marcin Puchlik wrote: >> >> Hello Community, >> Like in the topic, I know that a stable 10 MHz source is needed as a >> clock signal but why do we need 1 PPS signal? How is it used by the USRP >> hardware? Can someone explain that to me? >> Thanks >> Marcin >> >> _______________________________________________ >> USRP-users mailing list -- usrp-users@lists.ettus.com >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com >> >> 1PPS is used to provide timestamp-clock synchronization across multiple >> devices, typically. This is important when your application requires this, >> such as in MIMO or >> multi-receiver TDOA schemes, etc. >> >> Basically, when you have multiple devices you use set_time_unknown_pps() >> or set_time_next_pps() to signal to all devices in your multi_usrp object >> that at the next >> 1PPS, to set the timestamp clock to the value given in the the API call. >> >> This turns out to be useful even in single devices that are "bicameral", >> such as B210 and X310, where there are (for historic and architectural >> reasons) >> TWO timestamp clocks. Use the 1PPS synchronization primitives causes >> the internal timestamp clocks to become synchronized. >> >> >> _______________________________________________ >> USRP-users mailing list -- usrp-users@lists.ettus.com >> To unsubscribe send an email to usrp-users-le...@lists.ettus.com >> > >
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