Power Squelch

This will either pass the input unchanged, or block it, depending on whether its envelope is over a certain threshold. The envelope is calculated by taking the squared magnitude of the signal and lowpassing it with a single pole IIR filter (with the specified alpha).

The ramp parameter specifies the attack / release time, in samples. A sinusodial ramp is used to progressively mute / unmute the input. If ramp is set to 0, input is muted / unmuted without a ramp.

If the gate parameter is true no output will be produced when in muted state, instead of producing zeros (the default).

Parameters

(R): Run-time adjustable

Threshold (R)

Threshold (in dB) for power squelch

Alpha (R)

Gain of averaging filter. Defaults to 0.0001.

Ramp

Attack/release time in samples; a sinusodial ramp is used. Set to 0 to disable.

Gate

If true, no output if no squelch tone. if false, output 0's if no squelch tone.

Example Flowgraph

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

Source Files

C++ files

TODO

Header files

TODO

Public header files

TODO

Block definition

TODO