> I guess I'm confused about what -f, -c and -i really do in > usrp_siggen.py?
There are 3 different "frequencies" here. First, -f refers to the frequency of the waveform which software is generating and sending over the USB bus think of this as a first (low) IF. The -c refers to the digital upconverter frequency (DUC). This is the frequency which the USRP hardware translates the first signal to. Lastly, you have -i which controls the USRP interpolation rate. USRP output samples are at 128 MS/s, so this is the factor by which your data is upsampled in the USRP hardware. If you use 128, it means that your PC must send 1 MS/s across the bus so that the USRP can upsample by 128 to make 128 MS/s. This number must be a multiple of 4. > Also, what does the scrolling > text UuUuUuUuUuUu mean? Seems to work even if the text does not appear. The "u" stands for USRP, and the "U" for "underrun" meaning your PC is not generating data fast enough to keep the USRP running. Sometimes you may also see uO, meaning USRP overrun. This happens on receive applications, where your PC is not reading out the data FROM the USRP fast enough, and you end up dropping data because your buffers aren't big enough. The same things apply with aU and aO, but for audio devices. Every time you see uU the USRP has nothing to transmit when it needs data, so it sends zeros. Matt _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
