Thank you Paul, I had inspectrum but didn't use it much. I see that people extract samples by adding Plots in Inspectrum, but it never worked for me.
Here is screenshot of my file in Inspectrum: http://imgur.com/a/kh6GG Can you tell me what you see here and what information you can extract from this view? Like can you guess it's modulation? Can you guess/figure out symbol rate here? This is a single burst transmitted from the device. Please advise. Thanks once again. On Thu, Dec 1, 2016 at 5:16 PM, Garver, Paul W <[email protected]> wrote: > No, I think the data is fine I’m just telling you it isn’t normalized to > +/- 1 as the USRP does when you record fc32 format versus sc16. No big > deal, just a constant scale factor throughout the record. > > I don’t really know what you are looking for, so I can’t really tell you > if it looks good or not. You may be interested in inspectrum [1] for signal > analysis. > > [1] https://github.com/miek/inspectrum > > > On Dec 1, 2016, at 2:20 PM, AndroidT Tester <[email protected]> > wrote: > > Paul, > This is indeen NI-USRP capture. So you think the Cfile that I've created > using gr_fileman and gr_mkheader isn't correct? I can see lots of good data > by loading the cfile in Gqrx. I think it's working, am I wrong? > > Also I had another question, I converted my file to Wav file after > demodulation (GMSK). > Here is audio file loaded in Audacity: http://imgur.com/a/CllLI > > I can't properly figure out what's symbol rate here, can't clearly > distinguish 0 and 1s to count, then diff the time and find out symbol rate. > I would really appreciate any help/hint/advise. > > Thank you! > > On Thu, Dec 1, 2016 at 4:16 PM, Garver, Paul W <[email protected]> wrote: > >> Cheers, and thanks for finding the error. Also, you should note that the >> USRP scales fc32 format to +\- 1, but the sc16 format is ADC levels. >> gr_fileman doesn't scale during the conversion, so .sc16 converted to .fc32 >> will be scaled differently than straight out of the USRP. >> >> Paul Garver >> >> >> On Dec 1, 2016, at 2:08 PM, AndroidT Tester <[email protected]> >> wrote: >> >> Hello Paul, >> >> Indeed it's working now :) I successfully converted my 16-bit IQ sample >> file to a Cfile :) Thanks for all your help!! >> >> On Thu, Dec 1, 2016 at 4:04 PM, Garver, Paul W <[email protected]> >> wrote: >> >>> I think you found an error in gr_mkheader! In truth, it isn’t >>> particularly well tested so I’m glad you are using it. I just pushed a >>> commit to fix this to github. git pull the changes, rebuild, and try again. >>> Let me know if it solves the issue for you. >>> >>> PWG >>> >>> On Dec 1, 2016, at 11:46 AM, AndroidT Tester <[email protected]> >>> wrote: >>> >>> Thank you once again Paul. >>> >>> ls -la >>> drwx------ 1 Username Username 4096 Dec 1 13:40 . >>> drwx------ 1 Username Username 12288 Nov 30 16:21 .. >>> -rwx------ 1 Username Username 7683964928 Nov 20 18:23 Sample-408MHz >>> >>> gr_mkheader -r 1.8e6 -t sc16 -f 408e6 -l 1920991232 Sample-408MHz >>> >>> >>> Now I have Sample-408MHz.hdr: >>> gr_read_file_metadata Sample-408MHz.hdr -D >>> HEADER 0 >>> Version Number: 0 >>> Sample Rate: 1800000.00 sps >>> Seconds: 0.000000 >>> Item size: 4 >>> Data Type: short (1) >>> ..... >>> ..... >>> .... >>> >>> >>> etc. >>> >>> Now when I do >>> >>> gr_fileman Sample-408MHz Sample.cfile -o fc32 >>> >>> I get >>> sample_cnt_end=500000,final_index=1920991232 >>> Empty Header, quitting. >>> >>> >>> >>> >>> On Thu, Dec 1, 2016 at 1:35 PM, Garver, Paul W <[email protected]> >>> wrote: >>> >>>> It probably can’t find the header. The command >>>> >>>> # gr_mkheader -r 1.8e6 -t sc16 -f 408e6 -l 1920991232 Sample-408MHz >>>> >>>> should produce the file "Sample-408MHz.hdr" >>>> >>>> Check that the file Sample-408MHz.hdr is produced. You can read it with >>>> >>>> # gr_read_file_metadata Sample-408MHz.hdr -D >>>> >>>> Then, >>>> >>>> # gr_fileman Sample-408MHz Sample-408MHz.cfile -o fc32 >>>> >>>> Sample-408MHz should be the raw data, and Sample-408MHz.hdr the >>>> metadata produced with gr_mkheader. This should produce >>>> Sample-408MHz.cfile and Sample-408MHz.cfile.hdr. >>>> >>>> On your copied command it appears you didn’t add the -o fc32 to specify >>>> you want a file type conversion. >>>> >>>> PWG >>>> >>>> >>>> >>>> >>>> On Dec 1, 2016, at 11:20 AM, AndroidT Tester < >>>> [email protected]> wrote: >>>> >>>> Thank you Paul, >>>> >>>> I got this; >>>> sample_cnt_end=500000,final_index=1920991232 >>>> Empty Header, quitting. >>>> >>>> I followed all your instructions and double checked all parameters. I >>>> did filesize / 4 for sample count. >>>> I did this first: >>>> >>>> gr_mkheader -r 1.8e6 -t sc16 -f 408e6 -l 1920991232 Sample-408MHz >>>> >>>> >>>> Then when I try to do: >>>> >>>> gr_fileman Sample-408MHz Sample.cfile >>>> >>>> I got the error above, what am I missing? >>>> >>>> On Thu, Dec 1, 2016 at 12:07 PM, Garver, Paul W <[email protected]> >>>> wrote: >>>> >>>>> There are two different metadata types: >>>>> 1) Inline >>>>> 2) Detached >>>>> >>>>> Here, you are using the detached headers. With detached, the raw >>>>> samples are in a file, say myfile.sc16, and the metadata in >>>>> myfile.sc16.hdr. See [1] for more information on GNURadio metadata. >>>>> So suppose you have myfile.sc16 as your raw sample file. Then you >>>>> generate headers for it, since you didn’t record it with any. You also >>>>> need >>>>> to give gr_mkheader -l num_samps so it knows how long the file is. For >>>>> sc16 >>>>> you just do file_size_bytes/4 to get # of samples in a file. >>>>> >>>>> # gr_mkheader -r 1.8e6 -t sc16 -f 408e6 myfile.sc16 >>>>> >>>>> This generates the file: myfile.sc16.hdr containing the file type, >>>>> center frequency, sample rate, etc. This is simply my convention, but the >>>>> metadata is “linked” to the raw samples by the filename >>>>> raw data: myfile.sc16, where sc16 specifies the file format. >>>>> metadata: myfile.sc16.hdr >>>>> >>>>> Then, you can give this to gr_fileman to convert the type: >>>>> >>>>> # gr_fileman myfile.sc16 myfile.fc32 -o fc32 >>>>> >>>>> gr_fileman looks for filename.hdr for the detached header info. So in >>>>> this case, it files myfile.sc16.hdr, and should happily convert for you. >>>>> >>>>> PWG >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> [1] http://gnuradio.org/doc/doxygen/page_metadata.html >>>>> >>>>> On Dec 1, 2016, at 9:45 AM, AndroidT Tester < >>>>> [email protected]> wrote: >>>>> >>>>> Thank you Paul, I never heard of gr-analysis before. >>>>> So I tried this: >>>>> >>>>> gr_mkheader -r 1.8e6 -t sc16 -f 408e6 myheader >>>>> >>>>> This only created myheader.hdr file. How can I link this to my actual >>>>> recording sample which is 16-bit IQ pair and then convert it to CFile? >>>>> Do I concatenate the files? put myheader.hdr at top of my recording? >>>>> Sorry again for these newbie questions >>>>> >>>>> >>>>> >>>>> On Thu, Dec 1, 2016 at 11:32 AM, Garver, Paul W <[email protected]> >>>>> wrote: >>>>> >>>>>> Please copy the list next time so other folks can respond besides me. >>>>>> >>>>>> Just attach a file sink to the ishort to complex block. There’s also >>>>>> a command-line tool called gr_fileman in gr-analysis [1] which will do >>>>>> this, but the file needs headers. If you don’t have them, you can >>>>>> generate >>>>>> with gr_mkheader in gr-analysis. >>>>>> >>>>>> [1] https://github.com/garverp/gr-analysis >>>>>> >>>>>> Hope this helps, >>>>>> PWG >>>>>> >>>>>> On Dec 1, 2016, at 9:22 AM, AndroidT Tester < >>>>>> [email protected]> wrote: >>>>>> >>>>>> Now, how can I convert this to a CFILE format where I can play it in >>>>>> Gqrx? Thank you >>>>>> >>>>>> On Wed, Nov 30, 2016 at 11:34 AM, AndroidT Tester < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Thank you very much! It worked :) >>>>>>> >>>>>>> On Wed, Nov 30, 2016 at 11:04 AM, Garver, Paul W <[email protected] >>>>>>> > wrote: >>>>>>> >>>>>>>> Use a file source block with “short” type into an “Ishort to >>>>>>>> Complex” block. The Ishort to Complex block will de-interleave the >>>>>>>> shorts >>>>>>>> into complex samples. >>>>>>>> >>>>>>>> PWG >>>>>>>> > On Nov 30, 2016, at 8:55 AM, AndroidT Tester < >>>>>>>> [email protected]> wrote: >>>>>>>> > >>>>>>>> > Hey guys, >>>>>>>> > >>>>>>>> > I have a sample file with IQ pairs, each I and Q is 16-bits, I >>>>>>>> want to load this in GNURadio companion using File source sink, but >>>>>>>> I'm not >>>>>>>> sure how can I specify 16-bit format for I and 16-bit for Q in Gnuradio >>>>>>>> companion and then connect it to lets say FFT or Waterfall widget. Can >>>>>>>> someone advise a bit? >>>>>>>> > >>>>>>>> > Thank you! >>>>>>>> > _______________________________________________ >>>>>>>> > Discuss-gnuradio mailing list >>>>>>>> > [email protected] >>>>>>>> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>> >>> >> > >
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