-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 With most hardware interfaces, you get notifications when your driver/interface starts dropping samples -- with UHD you'd see loads of 'O' indicating overflows. If you don't see that, there is something really wrong. How does your data acquisition take place? 50Msps is really a lot for an average PC if you do filtering; I don't know how your low pass filter looks, but I think it's probably causing to much computational load for your computer to process the incoming samples in real time.
Greetings, Marcus On 04.12.2013 12:39, Paul B. Huter wrote: > 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: > > 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/ iQEcBAEBAgAGBQJSnyATAAoJEAFxB7BbsDrLer0H/ikK1c3mNHcWj5NtsWk7e9rD GXPW5aR9KFSp8O6UVu01K9vjXNbksuHVOPdJqT24ysSditqcjaxlBU+WlfjtEKtB 8kWEGINs1RNsG0lgsFdkVNi+83wGjUm5z+Vgo5eiMwbInVUoxRzhVBEjZzZicBQn x0TmcRH3zDpynINZCicqimvk4uZ/eYL4IowS375zLeGhIyn+SOtSI4qemAwJ6lpl 8U1EyJWBMZ1VjPMy68uYSnwSWg37Sv2BrKpOECY2mtCYU8lwD4QhVlbyg12jVB4I JpBNXbxgOU4rowek+y3qmRob79NVnuohHR6yo5eP0T4WYCiKRKTcpX4xW1hEScQ= =wN1n -----END PGP SIGNATURE----- _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
