Request for comments: alternative squelch implementation

[13RF7373]

Dear all,

I am currently experimenting with an alternative squelch implementation and would like to kindly ask you for your feedback, before I send a pull request to Steven:

https://github.com/cborss/frontend/tree/main

This fork contains the following changes to the frontend:

1) The "SQ" button no longer enables/disables the squelch but sets it slightly above the current noise floor. This reproduces the behavior of the OpenWebRX squelch button, that I like so much that I don't want to miss it.

2) I replaced the first order auto-regressive smoothing filter by a short maximum (rank order) filter, that results in constant opening/closing times of the squelch. In the current implementation, the exponential smoothing results in longer closing times with longer noise tails for stronger stations. Since I prefer a shorter closing time that is independent from the signal level, I simply use the maximum value of the last N power values.

What do you think? Do we need different time constants (filter lengths) for different demodulators (short for FM, long for AM/SSB/CW)?


Best regards,
Christian (13RF7373)

[Bas ON5HB]

Link to test it?

[13RF7373]

Sorry, I do not have a publicly reachable server. I am running it locally.