Unfortunately I don’t have any screenshots. It could be awhile before I have access to the equipment again; I can try to post a trace sometime next week.
From: Marcus D Leech <[email protected]> Sent: Thursday, March 18, 2021 5:09 PM To: Richard J. Muri <[email protected]> Cc: [email protected] Subject: Re: [USRP-users] x310 PPS issues 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]<mailto:[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<https://www.microsemi.com/product-directory/gps-instruments/4135-syncserver-s650>. 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]<mailto:[email protected]> To unsubscribe send an email to [email protected]<mailto:[email protected]>
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