I doubt you've missed something basic! I don't know what I'm doing! I followed Brian's suggestions - but then also changed to 24khz audio out to see if that would help. So a decimate by 2 and then 20, so 960khz / 40 = 24khz.
I should also mention that I have poor reliability with limesdr. It lasts for 5 minutes at most before needing a restart, and needs constant firmware reflashing. So this could also be an issue. Matt On 6 March 2018 at 17:20, Adrian Musceac <kanto...@gmail.com> wrote: > Hi Matt, > > Perhaps I'm missing something very basic, but I fail to see how you > reached the numbers for the sample rates. They look wrong to me. 1 > Msps -> decimation by 4 -> 960 Ksps? > > Regarding performance, I'd say some optimization is required for > better performance. I was able to demodulate WFM with gnuradio on a > 1.2 GHz ARM mobile phone with plenty of CPU to spare (50% or more). > I can give you a flowgraph if you want, but it's C++ code not GRC. > > Regards, > Adrian > > On 3/6/18, matthew venn <m...@mattvenn.net> wrote: > > Hi Brian and Adrian, thanks for the help. > > > > we've finally gotten around to having another go with gnuradio. > > Brian, I tried your settings and we have the same situation. Things work > > fine until we adjust the tuning, then something happens. There is still > > some crackling from the speakers, but > > we can never get the sound back, even if we retune to exactly where we > > started. > > > > Attached is the new patch, and the errors that get printed when we tune. > > One thing that has changed is there is no aU errors anymore. > > > > > > > > Regarding hardware, it's the LimeSDR. My PC is 6 core 3ghz FX6100 with > 8gb > > ram. It hits 50% on one core with gnuradio companion running. When > tuning I > > don't notice a difference. > > Thanks! > > Matt > > > > > > On 16 February 2018 at 22:42, Adrian Musceac <kanto...@gmail.com> wrote: > > > >> Hi, > >> Based on your graph, the filter seems to be running at the same sample > >> rate as the source, even though you have a decimator block ahead of it. > >> I suggest to correct that and then try again. > >> > >> Cheers, > >> Adrian > >> > >> On February 16, 2018 8:42:13 PM UTC, matthew venn <m...@mattvenn.net> > >> wrote: > >>> > >>> Hi all, > >>> I've got a limesdr that I'm using to learn about SDR. I started with > the > >>> AM tutorial from the website and have now moved on to something that I > >>> can > >>> pickup with an antenna. > >>> > >>> The flow works, until I tune it. Then I get aU on the log, and the > audio > >>> changes (it still makes noise), but I can never get the audio back even > >>> if > >>> I retune to exactly where it was. > >>> > >>> I can use the waterfall to find a new frequency, then stop the flow, > >>> type > >>> that new number as the default tuning and then start and hear audio > >>> again. > >>> Until I tune... > >>> > >>> Any idea why it breaks the audio when I tune it? > >>> > >>> Thanks, > >>> Matt > >>> > >> > > > > > > -- > > Matthew Venn > > web mattvenn.net twitter @matthewvenn <https://twitter.com/matthewvenn> > > > -- Matthew Venn web mattvenn.net twitter @matthewvenn <https://twitter.com/matthewvenn>
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