Re: [Discuss-gnuradio] LFTX Rev 2.2 Compatibility Issue with USRP2

[Josh Blum]

On 06/20/2012 05:08 PM, juancolon wrote:
> 
> Hi,
> 
> We have a USRP2 with a LFTX Rev 2.2 daughterboard. When I run a GRC program,
> I try to look at the signal with a spectrum analyzer and the signal is not
> there. There is no error at all, everything seems to be up and running. The
> system is recognizing the USRP2, daughterboard and I have also played around
> with the subdev's but everything is correct.
> 
> To make sure there is nothing wrong with the LFTX, I pulled it out from the
> USRP2 and installed it on a USRP N210. In the N210 I re-run the same exact
> GRC program and finally see the signal at the spectrum analyzer. To confirm
> that the USRP2 transmit side is working, I've installed a RFX1800 and re-run
> the same GRC program and this also works perfect. 
> 

LFTX and RFX1800 have very different frequency ranges. Perhaps you are
not looking in the right frequency range for your signal? LFTX is just a
direct line from the DAC, so +/- 30 or so MHz centered about DC.

I suggest putting a known signal into the usrp sink and put a scope on
the output of the LFTX. If RFX is working, the DAC output should
definitely be there.

-josh