[Orion] new AGC system

[ke5c]

> Added AGC Rise control to the DSP and CPU code.

> The includes a new AGC slope feature that provides a varying audio level
in relation to the received signal when the DSP AGC system is active.
Stronger signals will appear to be louder and weak signals will appear to be
weaker. The AGC Slope function can be adjusted for OFF, 1dB slope or 2dB
slope. The 1 or 2 dB slopes refer to the amount of audio rise for each 10dB
of signal rise.

> 73,  Bill  W4ZV

Why???  One of the nicest things about the Orion was not having to adjust
audio levels every time I dialed across a new station.  I used an IC-7800 in
the NA Sprint on Saturday evening, and I really missed the "level" audio of
the Orion - now that's going away?  For whatever reason???