Re: [Discuss-gnuradio] Re garding uhd_fft.grc

[Ryan Connelly]

My guess is it's a DC component resulting from the way the XCVR
downmixes from carrier frequency (direct conversion). I have that
problem too with an SBX daughterboard. There is a way to offset the LO
in the mixing stage to do low-IF instead of direct conversion and that
apparently removes the DC although I haven't tried that personally.

Also worth mentioning, it gets worse if you set the gain too high.

On Thu, Jul 12, 2012 at 6:23 AM, golisandeep <address@hidden> wrote:
>
> Hi,
> Yesterday i ran uhd_fft.grc  using gnuradio companion.I tried to sense the
> spectrum from 2.4 to 2.5 GHZ.In the graph that i got, i could see a sharp
> vertical  line  at center frequency,even if i change the frequency also i am
> getting same graph .I am not understanding why i am getting this sharp
> vertical line at center.
>
> I attached screen shots of the graphs.
> I am using gnuradio with USRP2 - XCVR daughter board.
>
> Thanks & Regards,
> Sandeep. http://old.nabble.com/file/p34149475/graph.jpg
> http://old.nabble.com/file/p34149475/graph2.jpg
> http://old.nabble.com/file/p34149475/graph3.jpg
> --
> View this message in context: 
> http://old.nabble.com/Regarding-uhd_fft.grc-tp34149475p34149475.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio