FWIW, I got the aforementioned "fm101.8_1Msps.cfile" to demodulate once I tried using the more generic FM demod block rather than the WBFM receive block. I was using the rational resampler block in both cases to match the audio sink rate (48 kHz) and I did have the 'Ok to block' option turned off in the audio sink there too. I do have to go to some trouble to configure the audio for the ArchLinux VM I am using but it does work once I remember to crank up the volume.
So the only change I made was to switch to using the FM demod block and then I could hear the demodulated fm sample file. I note that the FM demod block includes a LPF setting but I assumed that was present in the WBFM receive block? Anyway I was able to use the WBFM receive block successfully to 'listen to' FM radio received and streamed by a B200. Just a bit puzzled as to why it didn't work with the streamed data file. Regards Jacqueline From: Discuss-gnuradio [mailto:discuss-gnuradio-bounces+jacqueline.walker=ul...@gnu.org] On Behalf Of Jacqueline.Walker Sent: 29 June 2017 20:44 To: discuss-gnuradio@gnu.org Subject: [Discuss-gnuradio] Fwd: query about fm example file in github tutorials repository Sent from my HTC ----- Forwarded message ----- From: "Jacqueline.Walker" <jacqueline.wal...@ul.ie<mailto:jacqueline.wal...@ul.ie>> To: "Marcus Müller" <marcus.muel...@ettus.com<mailto:marcus.muel...@ettus.com>> Subject: [Discuss-gnuradio] query about fm example file in github tutorials repository Date: Thu, Jun 29, 2017 8:40 P.M. OMG, silly me ...it was staring me in the face as I was laboriously typing out the filename!! Thanks will try that Regards Jacqueline Sent from my HTC ----- Reply message ----- From: "Marcus Müller" <marcus.muel...@ettus.com<mailto:marcus.muel...@ettus.com>> To: "discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org>" <discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org>> Subject: [Discuss-gnuradio] query about fm example file in github tutorials repository Date: Thu, Jun 29, 2017 6:43 P.M. Hi Jacqueline, judging from the file name (_1Msps), the sampling rate is 1 MS/s. When it comes to signal bandwidth - a complex 1MS/s stream can contain up to 1 MHz of bandwidth, but FM broadcast radio stations typically use something like 75 kHz of bandwidth for their FM signal. Best regards, Marcus On 06/29/2017 04:39 PM, Jacqueline.Walker wrote: Hi, I downloaded the file fm101.8MHz_1Msps.cfile (from gr-tutorials/examples/tutorial6/ ) to use for trying out demodulation flowgraphs in gnuradio. It was recommended here: https://wiki.gnuradio.org/index.php/Guided_Tutorial_Hardware_Considerations But I can't find any details about the file - it says on the tutorial page - 'an actual recording from a radio (USRP I presume) with nothing done to the data, so I presume it is just a binary stream such as one would receive from a USRP and that the centre frequency is 101.8MHz. What is the sample rate output by the USRP that recorded the file - is it 250k as given on the tutorial page? What is the signal bandwidth expected? I ask this because I don't see that much on the FFT? Thanks Jacqueline _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org<mailto:Discuss-gnuradio@gnu.org> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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