On Mon, Dec 11, 2006 at 08:30:25PM -0800, Shyamnath wrote: > > hi, > I am new to gnuradio architecture and am trying to learn about it. I was > using the usrp_siggen,py sample code provided with different interpolation > rates (4, 8,12,16,64) since it has to be a multiple of 4. the observations > are as follows (which cannot explain) > > 1) For interpolation rates set to 4,8,12, at the sender, what I observe on > the receiver (directly connecting the usrp_source to a file_sink), is just > noise. > > 2) For a interpolation rate set to 64, I almost get the required sinuosoidal > at the required frequence(100khz), with the difference that the frequency of > the signal at the receiver for nearly 200 samples at the beginning is > nearly 7KHZs. To understand this better, I just send a constant signal on > the sender (using usrp_siggen.py) and received a sinousoidal at the receiver > with a frequency of 7Khz (which I presume is because of the frequency > offset). Although I think the above two observations are related I could not > explain them. > > 3) Another interesting case is when the interpolation rate is set to 16. the > output at the reciver is a signal which has a sinousoidal with the required > frequency(100khz) spaced with sinousoidals with a frequency of 7khzs. This > observation is something I cannot understand. > > Kindly help me out with this. > > Thanks > Shyam
You didn't mention which daughterboard you are using, but assuming it's a Basic Tx, be sure to set the -f <freq> option to something like 10M. Neither the Basic Tx nor Basic Rx will pass signals under about 100kHz. Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
