Re: [Discuss-gnuradio] uhd_fft.py and USRP N210

[Marcus D. Leech]

On 06/02/2011 03:06 AM, rahul sol wrote:

Hi,

first of all thanks very much for the quick reply. Now, I used XCVR2450 with USRP N210 to receive signals transmitted from network analyzer. The peak of fft exactly followed change in frequency of network analyzer.

Additionally, I used TVRX2 with USRP N210 but I got weird results. As shown in attached pic "1", 510 MHz is center frequency and 514.4 MHz is the frequency at which network analyzer is transmitting. However, I got peak at other frequencies, which didn't happen with XCVR.

Moreover, SBX is also giving weird results. Although the network analyzer is transmitting at 952 MHz, I got peaks at 948 & 952 MHz. It's like mirror image around the center frequency. I tried in all possible band, in both TVRX2 & SBX but the results are same.

Thank you,

Rahul

Rahul:

Your TVRX2 plot looks very much like you're driving it into the clipping region, which will produce
  massive amounts of harmonic content.  Try turning down the gain, and reducing the output of your
  signal generator.

For the SBX, I'm not sure what might be going on there, but again, you may be running into a clipping
  issue.

-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org