I'm using 500 kHz sampling rate. Wouldn't a lower rate effect my ToF accuracy? My understanding is that with 500 kHz sample rate my best ToF accuracy would be 2 us. My next question is why is the ToF shifting by less than 2 us (1/500e3)? My master clock is 16MHz so maybe the ToF shifts by multiples of 1/16e9?
Devin On Wed, Dec 19, 2018 at 2:01 PM Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 12/19/2018 01:56 PM, Devin Kelly via USRP-users wrote: > > Hello, > > > > I have an X310 transmitting packets to an E310, the E310 can > > successfully demodulate the packet and estimate the time of flight. > > I'm sending one packet per second for about half an hour and the ToF > > estimate is very consistent, except for when I have an overflow on the > > E310. I get an overflow once every 15-20 minutes or so. > > > > When I get an overflow my ToF estimate increases permanently by a > > small amount, enough to affect my application. For example, I might > > get 500 packets in a row with a ToF of 100 us each, then I get an > > overflow and all my remaining packets have a ToF of 101.6 us. All the > > USRPs are wired together so my channel isn't changing. I tried to > > figure out if I could compensate for the difference but I couldn't > > figure it out. I also tried to reset the PPS on the E310, which > > didn't work. > > > > I know it's on the receive side because I have multiple receivers and > > I can match each overflow to each ToF change. On the E310 I'm using > > UHD 3.9.2. Can anyone help me figure this out? > > > > Also, is there a newer image I should be using for the E310? Or, a > > newer UHD? It doesn't look like the E310 is supported much anymore, > > or is there something I'm not seeing? > > > > Thanks, > > Devin > > > What sample rate are you using on the E310? Can you operate with a > lower rate? > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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