Using the external reference clock "REF CLOCK"

GNU Radio
1

Hello:

I am trying to sync up the clocks on two USRP2 boards. How do I use the
external reference clock “REF CLOCK” input on the USRP2 board? What does
this input take? My understanding is that it takes a 10 MHz sine wave, 1
volt peak-to-peak.

And how do I enable this input? Do I need to set anything in my
flowgraph?

Thanks.

Steve McMahon