What are the primary differences between the usage or definitions of the terms “AGC”, “compressor”, “limiter”, and dynamics processor? They all seem to be forms of playing with gain knobs.
one category has a protection property and has a very fast response to large amplitude transients.
another category attempts to maximize sensitivity.
another group tries to put the receiver in a predictable “sweet spot” or operating point.
some can be “slow” and others are “fast”.
none of these are mutually exclusive.
advances in converter bit resolution (dynamic range) moves these techniques along.
One might consider schemes that adapt to be related.