Nick: I tried downsampling the 25MHz to 10, but still was not recording the whole time I ran (about 10 seconds, with only a couple seconds of playback). That was when I tried using a RAM disk, albeit at 50 downsampled to 30. I am using the following for my disk:
mount -o size=1G -t tmpfs none /mnt/tmpfs I then store my data file to /mnt/tmpfs Am I doing that wrong? Or is there some other explanation for not storing data (other than storage size)? Again, all feedback and help is appreciated. Nick Foster <bistrom...@gmail.com> wrote: Paul, 30MHz is a big chunk of data to be streaming to anything. A 4GB ramdisk will be full in 30 seconds at this rate. Do you really not know *a priori* where in the whole 0-30MHz spectrum your signal will be? I notice now in your first post that you're streaming 25Msps with a low-pass filter to 10MHz -- if this is the case, why use a 25Msps rate in the first place? You can make the USRP work for you by asking for 10Msps (or less, if you know you need less bandwidth) -- it'll handle the downsampling and filtering. --n On Mon, Dec 2, 2013 at 1:32 PM, Paul B. Huter <paul.b.hu...@gmail.com>wrote: > I finally got around to trying writing to RAM, and the result is worse - > my replay FFT is static. > > I am trying to record a chunk of spectrum (in this case the shortwave > chunk, 0-30MHz) and then go back and look at small pieces to find my > specific data. If someone can provide insight into how to do this, I would > appreciate it. > > Thank you all for all the assistance to date. > > Paul B. Huter > On Nov 25, 2013 9:38 AM, "West, Nathan" <n...@ostatemail.okstate.edu> > wrote: > >> I agree with Nick: that VOLK stuff is all expected behavior. If you're >> trying to write to a file at high rates you should look in to using a >> ramdisk/tmpfs. You'll be limited by how much RAM you have rather than >> IO speed. >> >> However, based on your other threads I wonder if you've taken Tom's >> recent suggestion to just lower your input sampling rate? If you're >> only interested in ~1MHz bandwidth you shouldn't be sampling at 50 >> MHz. >> >> -nathan >> >> On Mon, Nov 25, 2013 at 12:08 AM, Nick Foster <bistrom...@gmail.com> >> wrote: >> > Your file sink only records a few seconds of data because your hard >> drive >> > can't keep up, not because of any problem with Volk. The Volk machine >> being >> > used does not indicate which particular architecture is used for each >> kernel >> > -- that isn't printed at runtime. >> > >> > --n >> > >> > On Nov 24, 2013 9:58 PM, "Paul B. Huter" <paul.b.hu...@gmail.com> >> wrote: >> >> >> >> When running with a USRP source at 25M and a low pass filter down to >> >> 10MHz, I get something saying "Using Volk machine: sse4_a_64", and my >> file >> >> sink only records a couple seconds of data. I ran the volk_profile >> script, >> >> but still get the same result. The script returned something other than >> >> "sse4_a_64" as the best volk to use. My GNU Radio seems to have trouble >> >> reading configuration files, so is there a way to manually point to >> the volk >> >> parameter to use when I load GNU Radio? >> >> >> >> Paul B. Huter >> >> >> >
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
