Re: [Discuss-gnuradio] Clock Sync Problems + Timestamp question

[Matt Ettus]

Tim Pearce wrote:
> Hi,
>
> I've been trying to get two USRP2's with their clocks both synced to a 
> 10MHz reference (for now the same reference from the back of some test 
> equipment) - to do this I'm using the following code:
>
>         in_pipe1=usrp2.source_32fc('eth0')
>         in_pipe2=usrp2.source_32fc('eth2')
>        
>         in_pipe1.config_mimo(usrp2.MC_WE_LOCK_TO_SMA)
>         in_pipe2.config_mimo(usrp2.MC_WE_LOCK_TO_SMA)
>
> As a quick test I then connected each usrp2 to a complex oscilloscope 
> (i.e scopesink2.scope_sink_c)
>
> This sort of works -- checking on the test clock pins on each USRP2 the 
> 100MHz clocks are locked.
>
> Unfortunately putting in a sine wave from a lab sig gen garbage is seen 
> -- a constant DC signal on the BasicRX and what looks like modulated 
> noise on the DBSRX (testing at different frequencies on both boards) -- 
> the signal looks as expected if the config_mimo line is commented (and 
> the usrp2's restarted).
>
> Am I missing something obvious?


There is no frequency which can be received by both the BasicRX and the 
DBSRX.  What frequency are you putting in?  What frequency are you 
telling the USRP2s to tune to?

Matt