Metafile Sink Execution Time

GNU Radio
1

How long it takes for the Metafile Sink to began recording data?

I have a “No GUI” script that is a simple USRP source, throttle, and
metafile sink. All have a 1M sample rates; the metafile sink has a
relative
rate of change of 1, 1M segment size, and have a detached header.

I start my script up I get the usually GNU Radio feed back (e.g.
“Opening a
USRP2/N-Series device…”), I get the “Press Enter to quit:”, however
post
processing of collected meta data has shown that I can not immediately
start my data collection as it won’t collect the leading edge of the
signal, I need to wait several seconds before proceeding. Why does this
happen and is it possible to get a prompt on when the metafile sink has
started recording?

Thanks,

Jon

2

First thing, get rid of the throttle. It is only needed in
simulations. In graphs with real hardware, everything is “paced” by
the hardware.

On 2014-08-25 15:12, Jonathan F. wrote:

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3

Got rid of it and it sped things up considerably. I think the whole
reason
why I had it there in the first place was to prevent sample overruns.

Thanks for the help.

4

What about delays for a multiple USRP sinks and metafile sinks? I had to
wait 10 seconds before I could start recording when I used a script like
that.

5

On 08/25/2014 04:30 PM, Jonathan F. wrote:

Got rid of it and it sped things up considerably. I think the whole
reason why I had it there in the first place was to prevent sample
overruns.

Thanks for the help.

Putting a throttle in a flow that already has rate-pacing will just make
things worse…