[GreenKeys] Experimental DSP TU

[Harold Hallikainen]

If anyone is interested in my adventures building a DSP-based terminal
unit, my notes are at https://w6iwi.org/rtty/DspTU/ .

Additional notes are at:

https://w6iwi.org/rtty/TuComparison

https://w6iwi.org/rtty/TuNotes

https://w6iwi.org/rtty/TuReferences.html

Next steps are:

Add code to determine what percentage of the time the CPU is executing the
code versus just looping.

Add code to drive a display as a tuning scope.

Add code for dynamic threshold control.

Add mark hold on loss of signal.

Implement loop current sampling (H11AA1)

Finish FSK generation (keying to LPF to DDS)

Add PTT control.

Harold
https://w6iwi.org