Hi John,
sounds like excellent work! Just to point you at a nice tool: If you
can build a recent GNU Radio with control port and performance
counters enabled, you can introspect things like buffer fillage with
a GUI, which can be extremely handy in such cases.
Best regards,
Marcus
On 08.08.2015 21:15, John Ackermann
N8UR wrote:
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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