Re: [Discuss-gnuradio] "D" errors after flowgraph runs for some time

[John Ackermann N8UR]

I think I may have found the problem.  The NBFM output rate was 25ksps 
while the audio sink was 24ksps.  So there was a slow accumulation of 
excess samples.  That also explains some gaps I saw in the channel 
output waterfall.

Adding a rational resampler to the NBFM block output seems to have 
cleaned things up.  Revised .grc file attached.

John
----

On 08/08/2015 02:56 PM, John Ackermann N8UR wrote:
> I am playing with a slightly modified version of Chris Kuethe's
> channelizer example for NOAA radio stations (my version attached).  I'm
> using 3.7.6.1.
>
> The program runs just fine for the first 20-30 minutes on my I7-4710HQ
> laptop.  System monitor shows typically one core running at about 50%
> with the others ranging from idling to 30%.  Only a fraction of system
> memory is used.  The laptop is wired to a USRP2/WBX via GigE switch, and
> is showing about 5MIB/s of incoming data when the flowgraph is running.
>
> But after 20-30 minutes I start to get a string of "D"s on the console,
> and while the program keeps decoding audio, the signal strength drops by
> 40dB or more.
>
> When I first started playing with Chris' example, I also had a string of
> "D"s immediately upon startup which I cured by turning on realtime
> scheduling.  It appears that just moved the problem off into the future.
>
> I am guessing this is some sort of buffer exhaustion or similar problem.
>   Any suggestions on how to address is?
>
> Thanks,
> John
>
>
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noaa_demo.grc
Description: application/gnuradio-grc