Re: [Discuss-gnuradio] Flipping problem

[Matt Ettus]

isaacgerg wrote:
> I am sending a known sequence of samples from one USRP to another using the
> Basix RX/TX d'boards setting the frequency to 24e6.
>
> When I rx the sequence, the correlation of it keeps flipping, but not in a
> way that suggests residual carrier.  It seems as if I am experiencing an
> instantaneous flip.
>
> My gain on both the RX and TX is set to 500. The signal amplitude I rx is
> ~1200. When I run the GRC model, the Rx says I have no residual carrier,
> invert is set to false, the dxc frequency is set to -24e6 and the baseband
> to zero.  On the TX side, I have these same values with the exception of the
> dxc freq, it is not set to 24e6. Why the flip??   What do all these things
> mean???
>
> Is 24e6 a bad freq to use with the basic TX/Rx?
>
> Thanks in advance!
>   

I believe what you are seeing here is that the two USRPs are on two 
different frequencies.  This is not a fault of the USRP.  No two 
oscillators will be on exactly the same frequency, and so in any 
practical receiver you must synchronize. 

Matt