Insert pauses during broadcast interruptions

[ebkraus]

Hello, I am analyzing a FSK-modulated signal from a Claber rain sensor. The broadcast is interrupted at regular intervals by short breaks (6 ms) and one long break (20 ms). The demodulated data only shows one pause during the long break, but not during the short breaks. Is there a way to insert pauses during the short breaks as well? Currently, the short broadcast interruptions are interpreted as zeroes, which is probably incorrect.

[andynoack]

Your pause is possibly too short. Try to increase the samplerate so that URH sees more samples for every pause.

[ebkraus]

Thank you for the reply. Unfortunately, increasing the samplerate doesn't change anything. Perhaps the problem is that the samples/symbol increase with the sampling rate and therefore the number of symbols during the broadcast interruptions remains constant. If I reduce the samples/symbol to an unrealistically small value, the short breaks are marked as pauses.

[andynoack]

Yes, there is an internal threshold to differentiate a pause from a zero sequence. In your case this does not seem to work out very well. Do you have problems with re-generating traffic or just with decoding? In the latter case you could apply a custom decoding to fix it according to your needs, for example with an external python script.

[ebkraus]

I am having trouble with decoding so far. Wouldn't it be possible to distinguish a pause from a zero sequence by analyzing signal-to-noise-ratio? During the broadcast interruptions the signal is always below the noise threshold.
My workaround at the moment is to generate piecewise new signals from the broadcast blocks and to analyze them seperately.

[andynoack]

This would work for your case, but is not a generic solution, because there are plenty of very fancy signals. Maybe this is a point where a slider might help, but i am not sure if @jopohl has time to implement that and whether it makes sense for the majority of people.