On Fri, Apr 6, 2012 at 2:04 AM, guelord ingala <gueloring...@yahoo.fr>wrote:
> Hi all, > I need to multiply 2 signals (800 MHz and 820 MHz) from external signal > generators. I used the usrp-1 and DBSRX daughter-boards to detect the 2 > signals. I attached the grc file that I created for this application. I can > detect signal from the output of the usrp source. > > When I multiply, I expect to have 2 components (sum and difference) at 20 > MHz and 1.620 GHz. To visualize these 2 components, I need to set the > FFT-sink to display a wide range. This means the FFT sink sample rate must > be high i.e 3.4 G. With this value, the FFT doesn't display the plot. I > used a Rational Resampler to match the usrp source sample rate with the FFT > sample rate. But it's still not working. > It is working, but you have a misunderstanding of how the USRP and Gnuradio work. The DBSRXs downconvert the 800 and 820MHz signals to baseband (0Hz) and then the USRP digitizes them and brings them to Gnuradio. You are effectively multiplying two 0Hz signals. You cannot mix RF signals in Gnuradio, only baseband signals. In the same way, a sample rate of 3.4Gsps does not make sense. --n > > Can anyone tell me how to fix this. Your help will be appreciated. > Dominique > Regards. > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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