Icom IC-746PRO Manual page 135

• The AGC (auto gain control)
controls receiver gain to produce a
constant audio output level even
when the received signal strength is
varied by fading, etc.
– The transceiver has 3 AGC
characteristics (time constant; fast,
mid, slow) for non-FM mode.
– The FM mode AGC time constant is
fixed as 'FAST' (0.1 sec.) and AGC
time constant cannot be selected.
– "AGC OFF" appears when AGC time
constant OFF is set with one of FAST,
MID or SLOW setting in AGC set mode.
AGC Set Mode