Joseph Worcester, who developed and sold the SPACE MAGNET ferrite active
antenna, also built a high-performance MW receiver and got a patent on the
circuit which changed the bandwidth as the signal strength changed. I remember
reading the patent and thinking he'd invented AM stereo. Jis radio sold for
$700 in the 70s.
Matt

...got a patent on the circuit which changed the bandwidth as the signal
strength changed.

Automatic regeneration control? I guess that would be shortened to ARC.

On a HW-101 I once had, I added manual regeneration control. Actually, I
modified the stage that had the RF gain control by adding a tickler feedback,
to do just that. To pick out a weaker signal, I would increase the RF gain,
effectively increasing the regeneration which would decrease the band width in
the process.

Bill, K5BY