Re: [Discuss-gnuradio] WBFM decoding flowgraph: Audio terminates when tuning

[matthew venn]

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  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  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  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 
> >> 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 
> >
>



-- 
Matthew Venn
web mattvenn.net twitter @matthewvenn 
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Re: [Discuss-gnuradio] WBFM decoding flowgraph: Audio terminates when tuning

[Adrian Musceac]

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  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  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 
>> 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 
>

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Re: [Discuss-gnuradio] WBFM decoding flowgraph: Audio terminates when tuning

[Adrian Musceac]

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  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 
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