Re: [Discuss-gnuradio] ATSC demod tips
On Mon, Sep 22, 2008 at 12:23:20PM -0700, Ben Green wrote: > > > > Eric Blossom wrote: > > > > > > If you are trying to capture continuous data, there is no substitute > > for a disk subsystem that can sustain the required throughput. > > > > For capturing short segments (<500 MB raw data) is a ram disk not > sufficient? If that's enough for your purposes, then sure, it'll work. Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] ATSC demod tips
Eric Blossom wrote: > > > If you are trying to capture continuous data, there is no substitute > for a disk subsystem that can sustain the required throughput. > > For capturing short segments (<500 MB raw data) is a ram disk not sufficient? -- View this message in context: http://www.nabble.com/ATSC-demod-tips-tp19446876p19614781.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] ATSC demod tips
On Mon, Sep 22, 2008 at 09:05:56AM -0700, Ben Green wrote: > > > Wuest Brandon-WTVR47 wrote: > > > > > >> I got a few underruns during the "usrp_rx_cfile". > >> About 10 in 10 seconds. The raw data file is 446 meg. > > > > Underruns are bad. > > > > Try capturing the data to a ram disk instead of your hard drive if you > > do not have a faster hard drive setup available (i.e. RAID). I used the > > ATSC demodulator a few months back and was never able to successfully > > store that data down to my hard drive, so I allocated a 512 MB ramdisk > > and used that which worked great. > > > I am having the same issue. When using a ramdisk I get no usrp overruns but > still the output file is empty. When putting the output of each py file in > its own file, I found btl-fsd.py outputs nothing. Are there any obvious > reasons why this would be happening? Is there anything I can do to narrow > down the problem? If you are trying to capture continuous data, there is no substitute for a disk subsystem that can sustain the required throughput. In general we've had better luck using ext2 file systems rather than ext3 file systems. (You can mount an ext3 as an ext2.) Posting the ext3 journal was causing a problem last time I looked at this in detail (> 2 years ago). Eric ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
RE: [Discuss-gnuradio] ATSC demod tips
Wuest Brandon-WTVR47 wrote: > > >> I got a few underruns during the "usrp_rx_cfile". >> About 10 in 10 seconds. The raw data file is 446 meg. > > Underruns are bad. > > Try capturing the data to a ram disk instead of your hard drive if you > do not have a faster hard drive setup available (i.e. RAID). I used the > ATSC demodulator a few months back and was never able to successfully > store that data down to my hard drive, so I allocated a 512 MB ramdisk > and used that which worked great. > I am having the same issue. When using a ramdisk I get no usrp overruns but still the output file is empty. When putting the output of each py file in its own file, I found btl-fsd.py outputs nothing. Are there any obvious reasons why this would be happening? Is there anything I can do to narrow down the problem? -- View this message in context: http://www.nabble.com/ATSC-demod-tips-tp19446876p19611184.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
RE: [Discuss-gnuradio] ATSC demod tips
> I got a few underruns during the "usrp_rx_cfile". > About 10 in 10 seconds. The raw data file is 446 meg. Underruns are bad. Try capturing the data to a ram disk instead of your hard drive if you do not have a faster hard drive setup available (i.e. RAID). I used the ATSC demodulator a few months back and was never able to successfully store that data down to my hard drive, so I allocated a 512 MB ramdisk and used that which worked great. Thanks, Brandon ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] ATSC demod tips
I just got a USRP, and I'm learning how it works. I'm having trouble getting the ATSC demod to work. The WFM demod works OK, so I know the antenna, etc works. I know I'm tuning the right frequency (KQED with a center frequency of 569MHz), because I can see the signal with usrp_fft. I got a few underruns during the "usrp_rx_cfile". About 10 in 10 seconds. The raw data file is 446 meg. I get an empty output file and a file named "taps.txt", which is also empty. I tried both the Gnuradio v3.1.2 (in Fedora 9) and the Gnuradio from SVN. I get a few output strings, like ">>> gr_fir_fff: using SSE" from btl-fsd and ">>> gr_fir_fff: using SSE Setting initial_freq: 3065000.00" from fpll Do you have any tips on finding the problem? Thanks. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
