I’ve been working on a flow-graph for meteor-burst detection on VHF
(more specifically using the NAVSPASUR “space fence” as a signal
source).
Part of the flow-graph involves probes that run at several-Hz rate and
decide whether to start recording signal-power data, based on
triggering criteria. This works just fine. The
trigger-detection/recording function also returns a filename (either
/dev/null if not
triggered, or a dynamically-generated filename otherwise). The
intention of this is to provide the filename for a gr_file_sink to use
to record downsampled baseband data during triggering. The problem,
of course, is that if this variable is handed to gr_file_sink,
it’ll be re-opening files (either /dev/null or the “real” file) at a
many-Hz rate, which is not the desired semantic. So I modified
gr_file_sink
to check for a change in filename in the open() method, and only
proceed with a re-open if the filename has changed. This isn’t really
clean and elegant.
GRC doesn’t lend itself particularly well to this type of processing.
I suppose I could run the baseband streams into a vector sink, and have
my
poll function unload those vectors whenever the poll function is
called. Any hints on how to do that?
–
Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium