Does the 6674T also forwards the 2nd (3rd, etc) pulse?

[joaorob]

Hey,

I’m running a single USRP test where I transmit from one RF (say RF0) and received on the other RF. Timing synchronization of transmission/acquisition is performed though software by sending a PPS signal and starting transmission/acquisition when receiving this pulse. If I have a single USRP and cable the PPS with PPS out, the test works fine: I can trigger different acquisitions at different times with no problem.

If instead I connect the PPS output to the 6674T and back to the PPS inout, it seems that only the first acquisition works fine, but after there is Rx FIFO overflows (71) error. Does the 6674T also forwards the 2nd (3rd, etc) pulse?

Thank you in advance

Joao

PS - No ... I didn't forget to initialize the timming/synch module 🙂

[joaorob]

I did some more measuring using one USRP, and it seems that the 6674T is fowarding all the PPS pulses.

What I don't understand now, is why does the synchonization using multiple pulses work if we directly wire the PPS in to the PPS out of one USRP, and does not work if the the PPS out goes to the 6674T and back to the PPS in. Should the 6674T act as a transparent switch? There will be some sort of latency introduced (perhaps on the ns level), but still I don't know why it does not work. Any ideas?

Joao