There must be something with my record, because my 20 seconds of running only produces about a 180MB file. I am not seeing any indications of dropped data, though. I am recording to a RAMDisk, but I get the same results recording to my HDD.
Does anyone have recommendations for how to ensure I get my data recorded? I really think that if I cam record the data, playback will be more what I am looking for. Paul B. Huter On Dec 4, 2013 1:20 AM, "Marcus Müller" <mar...@hostalia.de> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi Paul! > > I'm gonna go ahead and rearrange parts of your message for the ease of > reply: > > My datafile was recorded for about 20 seconds at a sample rate of > > 50Msps through a low-pass filter to only capture 0-30MHz. > 50Msps * 20s = 1Gs (you're sure your file is 8GB in size?) should be > plenty enough, so my guess was totally astray. > > > Looking at the configuration for my FFT, and changing 'Refresh > > Rate' from the default '15' to '1M' gives me some extra playback. > what gui toolkit are you using? wx or qt? > However, a refresh rate of one million frames per second... doesn't > even remotely make sense. Since there is no way that your file source > can supply 1024Msps for the GUI sink, even without throttling, I don't > know what the (wx or qt or whatever) FFT sink does in that case. I'd > have to read the source code... > > > I like the way the waterfall looks, but I'm having the same issue > > as the FFT. > > Ok, this is confusing. The waterfall sink should basically be able to > have one pixel of display per sample going in. And with 1 billion > samples going in, there shouldn't really be repitions visible, unless > your data is repetitive. > > > Is there some correlation between data rate on the record and FFT > > refresh rate? > No. Refresh rate is just the display refresh rate, i.e. the speed at > which the GUI updates its visualization. > > > How is 'FFT Size' used (right now I have that at '1024')? > Um this is kinda awkward - it's the size of the FFT; how the samples > are internally processed prior to being transformed depends on the > actual FFT sink implementation. > > > On a related note - is there a way to get the FFT to start out in > > 'Autoscale', or do I need to hit the button every time? > > No. "Autoscale" is (as far as I know and can remember right now) not a > /mode/ for the qt nor the wx gui fft sink, but scales the display to > fit the data that is display /the moment the button is clicked/. So, > since data can only be available at run time, you can't do that before > running the flow graph. However, at least for the qt implementation, > you can set y max/y min, if you know it beforehand. > > So: Verify your data is really about 1 billion samples long and not > only a few thousand; if your waterfall looks periodic, your recorded > signal is periodic. > > Greetings, > Marcus > > On 03.12.2013 22:45, Paul B. Huter wrote: > > > > Is there some correlation between data rate on the record and FFT > > refresh rate? How is 'FFT Size' used (right now I have that at > > '1024')? On a related note - is there a way to get the FFT to start > > out in 'Autoscale', or do I need to hit the button every time? > > > > Thanks! > > > > > > On Tue, Dec 3, 2013 at 3:01 PM, Marcus Müller <mar...@hostalia.de> > > wrote: > > > > Most probably your data is simply to short in relation to the fft > > length and the amount of samples your specific graphical FFT > > amplitude sink drops for display. Please review you fft length, > > update rate, and try out different fft GUIs (qt/wx). > > > > You could zeropad your data generously to notice the repitition. > > However, I think with what you're describing you might be better > > off with a waterfall graph; try them, they're fun :) > > > > Greetings, Marcus > > > > On 03.12.2013 21:45, Paul B. Huter wrote: > >>>> When I play my data file back through a throttle and > >>>> frequency translating FIR filter to an FFT sink with repeat > >>>> OFF, it seems to just show a static plot. However, with > >>>> repeat ON, I get playback, but I can't tell when data ends > >>>> and starts back over. Is there a way for me to know when it > >>>> repeats? Or, is there a way to get playback with repeat > >>>> turned off? > >>>> > >>>> Thanks. > >>>> > >>>> Paul B. Huter > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org > >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >>>> > >> > >> _______________________________________________ Discuss-gnuradio > >> mailing list Discuss-gnuradio@gnu.org > >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >> > > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.15 (GNU/Linux) > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQEcBAEBAgAGBQJSntfEAAoJEAFxB7BbsDrL+3YIAKiTgWXVabYuQas6MeKTm7U0 > QSMRLevun7u5tx8o9Th7321BJcrm1WQ+lFCeaFrx3ug58q9gXmCU76KBB3IbYpoc > FdNwBq7ZtzHaQIVaPYBnC3GB4UdIxDpzFuvkFcUP0VHj09w27/k9sWKbm0Bc4zpK > 7CQvLpTOqsd/mRFxCdrUlv2N3mQS6rhNrqAcA4VONRJVlLjLm9Bf1WDoCo4/ea8F > 0Vb2CmWb9mo9UtaxzYKZuJs5ReZGzeBWHUeCpD6JlMLn+3oA3HblWKavgX99RzL7 > lo3D8MGTqM5vCgULwq+r9aM7BvLNpb7NrgLrOZ19Ft/o09NWlJJpSMp4LK+wYF0= > =kAQK > -----END PGP SIGNATURE----- >
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