-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Lisa Creer wrote: > On 8/20/07, Eric Blossom <[EMAIL PROTECTED]> wrote: >> On Mon, Aug 20, 2007 at 11:15:36PM -0400, Lisa Creer wrote: >>> I'm testing the -8 option in various example programs, and haven't been >>> successful in receiving valid data. The following test resulted in a >> very >>> brief, flat line being displayed, then absolutely no data showed on the >>> graph, but the program continued to run. >>> >>> ./usrp_fft.py -f 100M -d 4 -8 >>> format = 0x288 >>> set_format = True >> Have you tried increasing the gain? > > > Yes, to no avail. > > What daughterboard are you using? > > > Basic Rx. > > Do you have an antenna connected? If so, what kind? > > > Yes. My antenna ignorance will become apparent here, it's what I'd call a > basic antenna (non-telescoping), vertical antenna 14 inches tall with a > strong magnet on the bottom.
This sounds like it's the wrong length to pick up FM stations. >> I decided to try decimating by 4 without specifying the 8-bit option, and >> I >>> received the 'uO' indicating that samples were dropped from the USRP to >>> host, but data was displayed on the graph, and it was 16MHz >> wide. What's >>> going on? >>> >>> ./usrp_fft.py -f 92.7M -d 4 >>> uOuOuOuOuOuOuOuOuOu >> 64 MS/s / 4 * 4 bytes/S = 64MB/s. This won't fit across the USB, >> hence the continuous overruns. > > > Wait, I thought the -8 option provided 8-bit I and 8-bit Q across the USB. > It sounds like you're saying the samples are still 4 bytes total (2 byte > each I and Q). So the samples are converted to shorts AFTER they get to the > host? Then how can we decimate by 4 when using the -8 option? How can we > cram more data through the USB if it can only handle 32 MB/s? This calculation is in reference to your immediately preceding run without -8. With -8, the samples are indeed 2 bytes total, not 4. - -Dan -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGy4/cy9GYuuMoUJ4RAkTCAKCGmZ841O0bj9nsY8mUm6gDVsFJvQCfeWrM sNFi25ix/mZKSmUrhrGX4Mc= =D3MK -----END PGP SIGNATURE----- _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
