I'm trying to "carve off" about 250Khz of bandwidth around 38.5MHz, (actually any frequency between about 25MHz and 40MHz) using a Basic_RX and a USRP2.
In GRC, I created a simple flow-graph with a USRP2 source, and an FFT sink. I set the tuning parameter of the source to 38.5MHz, and what I get on the FFT is a flat-line at -410dB! Now, granted, I don't have the inputs connected to anything yet, but I would expect there to be *some* noise, and -410dB seems, well, like bad physics :-) Cribbing from hfx2.py in gnuradio/*examples*/python/apps it seems that this should "just work". Am I missing something? I thought that the FPGA would "do the right thing" in the case of the Basic_RX, and use the DDC to pull the "target" frequency down around DC, etc, etc. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
