Lynn Richardson wrote:

Ok, we have a terminology problem then. AGC (Automatic Gain Control) is found in
AM receivers to control the gain of the RF amp stage and one or two IF amplifier
stages.

FM receivers almost never use any gain control (some designs that have to work
under very high signal strength conditions may use a simple AGC to keep the
impedance constant at the IF filter), depending instead on the IF limiter(s) to
produce a constant output. They may have an RSS (Relative Signal Strength)
output to drive S-meters. It is usually derived from current changes in the
limiter/last IF stages as the signal input rises. Any signal that falls within
the IF filter passband can make this rise, be it spark/arcing noise from car
ignition, broadband noise from computers, or spill over from nearby tranmitters.

SNIPPED

Lynn, sorry for my direct response to this thread. I posted it before I read
your response.

We are both making the same point. AGC is a negative feedback subsystem in a
receiver to maintain a constant output. I was wondering how the term was/is
being used.

/s/ DD