Could you post scope traces? My guess is that the edges are not crisp enough for the 1PPS input processing.
Sent from my iPhone > On Mar 18, 2021, at 5:00 PM, Richard J. Muri <[email protected]> wrote: > > > Hello, > > I’m using a series of x310 USRPs synchronized together using both an external > 10 MHz reference and a PPS. I have two configurations: in my lab an Octoclock > provides the PPS signal, and in the field configuration I use a GPS > referenced stratum 1 NTP server. > > The lab configuration USRPs blink an LED on the front panel in time with the > PPS. The field configuration does not blink the LEDs at all. Both > configurations light the 10 MHz reference LED. > > I am not fully sure if this is a problem. Occasionally when I run the > application in the field configuration, it works for about a minute and then > appears to drift out of sync, however most of the time everything seems to > operate as intended. It’s very possible my field configuration has other > issues, and my system has not quite reached the maturity to be running > multiple hour/day long test to measure drift on the application > synchronization. > > I examined the PPS connection with a T cable and a scope. Both produce a PPS > pulse with a sharp spike to an initial voltage, followed by a longer > exponential curve up to 5V. The octoclock drives to 2.5V initially, and the > syncserver drives to 4V initial. > > I have tried using shorter cables and a 6dB attenuator on the syncserver > connection to see if I could get the PPS to light, but neither seemed to have > any effect. > > Does anybody have any guidance on how to make sure my x310s in the field > configuration are actually benefitting from the PPS? > > Thank you! > Richard > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected]
_______________________________________________ USRP-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
