Hi Jason, A few questions: - why do you want to avoid using PPS? - are you using a common 10 MHz ref? - what is the level of "synchronous" you are looking for? Are you hoping to have simultaneous sampling across all channels? Rob
On Wed, Dec 8, 2021 at 3:15 PM Jason Merlo <merlo...@egr.msu.edu> wrote: > Hi All, > > I’m currently working to synchronize multiple X310’s clocks without a PPS > input, however right now the best method I can find to update the clock > from a host PC (using the C++ API) is to query the current time from the > USRP device (using usrp::multi_usrp::get_time_now), add a time delta to > the current time, then send back the new clock time to the USRP device > (using usrp::multi_usrp::set_time_now). Unfortunately, this method > introduces large timing errors due to the nondeterministic nature of packet > processing on both he CPU and network stack. > > I’m wondering if anyone knows of any other techniques for an "in-place" > time update. I.e., is there a method for the host PC to send a time delta > to the USRP which would be added to the clock register in a single > operation? > > I see there are other get/set_time_now functions in the rfnoc::mb_control > and rfnoc::radio_control classes, but I’m not sure if these would allow > me to accomplish this using only the C++ API. I can’t seem to find much > documentation on this aside from the examples in the > “uhd/host/examples/rfnoc*” folder. > > If it’s not possible to accomplish this using a purely C++ approach, is it > possible to do this through a custom RFNoC block? I don’t have experience > with RFNoC at the moment and I’m not sure if that register is exposed to > user blocks, or if so, if the register update would be deterministic in > time, but if there’s motivation I would be willing go down the RFNoC path. > > Thanks in advance, > Jason > _______________________________________________ > 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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