Metadata recording behaviour when changing the frequency parameter during Program execution.

[KishanJ29]

I have source installed digital_RF blocks main 3.8 branch using following commands,

git checkout maint-3.8
git submodule update --init --recursive
mkdir build
cd build/
cmake ../
make
sudo make install

I would like to know what happens if we suddenly change frequency during running of program and how is it notified in metadata.

I have set the variable "Frequency" value to QR GUI range gnu radio block. So during running of program when the RF and metadata is being recorded if I change the slider value of frequency. Will the corresponding changed frequency value will be reflected in the metadata and RF recording.

Thanks in advance!

[ryanvolz]

Hi @KishanJ29! Currently, changing the frequency is not reflected in the metadata. This would be a nice feature, and probably more work needs to happen to improve metadata handling in GNU Radio flowraphs in general.

You can try modifying https://github.com/MITHaystack/digital_rf/blob/master/python/gr_digital_rf/digital_rf_sink.py#L376 (in this case, just uncomment that line) to enable the ability to process stream tags other than "metadata". In that part that was commented out, it used to process "rx_freq" stream tags like you might want, but we encountered various issues that made it easier to disable. You might have better luck now, but I don't know if changing the frequency with the QT GUI Range block will create the appropriate "rx_freq" tag or if there's more that would need to be done.