On Wed, Jan 14, 2015 at 12:53 PM, Marcus D. Leech <mle...@ripnet.com> wrote:
> On 01/14/2015 12:44 PM, Chris Hallinan wrote: > > Greetings, I'm a first time user of gnuradio. Kudos to the developers, it > only took me about a day to build gnuradio + gr-osmosdr (for my el-cheapo > rtl2832 dongle) from source, including getting a basic FM broadcast > receiver sort-of running. Host Ubuntu 14.04 on a very fast Dell > 8-core server platform. > > I've prototyped an FM receiver as described in the tutorial at the > bottom of this page: > > http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_Hardware_Considerations > > However, when I run it, and set the center frequency to a close-by FM > station, although I can hear actual broadcast audio snippets, meaning that > it's actually receiving a coherent signal, it is very choppy, with audio > snippets being played in a very choppy, almost rhythmic fashion. The > console window on gnuradio-companion shows a continuous series of aUaUaU, > etc. > > I'm guessing this might be an underrun situation somewhere, but that is > speculation. I'm using parameters provided by the tutorial including a > sample rate 250K. I've tried moving the sample rate around, but without > much improvement. Dropping it down significantly destroys all hints of > intelligence in the signal ;) Am I overtaxing the capabilities of this > rtl-sdr dongle? > > I have a reasonable (and growing) understand of the core concepts, but > could use some help on the learning curve. > > Any advice appreciated. > > -Chris > > > > -- > Life is like Linux - it never stands still. > > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > You almost certainly have a sample-rate mismatch somewhere in the > flow--likely, your audio sink is configured for a sample-rate other than > what > the hardware (or PulseAudio) can support. Sometimes also, PulseAudio > gets into trouble and gets all under-runny. I'd go with Alsa direct if it > were my problem, and skip Pulse entirely. > > > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortiumhttp://www.sbrac.org > > The manual gives you a few hints for different possible device names you can try: http://gnuradio.org/doc/doxygen/classgr_1_1audio_1_1sink.html Unlike Marcus, I've always had better luck with pulse that direct alsa. But we have very different systems and use different Linux versions, so ymmv. Tom
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