[Discuss-gnuradio] Multiple inputs on LFRX - phase difference and zero-crossings detection

Hello,
I now have a project with the following specifications:
I need to send 2 input-signals parallel over USRP, then find out the
zero-crossings (time) of each signal so I can calculate the phase difference
of them.
The 1st signal S1 is up to 1MHz
The 2st signal S2 is about 50 Hz

1. Sending 2 input signals parallel to USRP:
My idea is:
- Sending these 2 Signals in 2 separate daughter-boards LFRX
- (Or) Put them two on only one LFRX through the 2 SMA connectors.
- How about using digital I/O pins ?
- What is the maximum voltage can I feed the daughter-board through SMA ?
- Will the inputs be synchronously sent and sampled ?

Zero-crossings detection:
- How can I find out the zero-crossing time, esp. of the signal S2 ?

Thanks in advance for your reply.

--
View this message in context: http://old.nabble.com/Multiple-inputs-on-LFRX---phase-difference-and-zero-crossings-detection-tp29300504p29300504.html
Sent from the GnuRadio mailing list archive at Nabble.com.

_______________________________________________
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
http://lists.gnu.org/mailman/listinfo/discuss-gnuradio