and we humans don't process breaks in audio as we do with
visual perceptions.
There is GREAT truth to this statement.
Motorola, back before the era the MICOR radio set was being
developed, invested great time and money in this very issue.
It is my understanding, from talking to the inventor and several
engineers that worked at Motorola during the MICOR era that the
circuitry, which ultimately resulted in the famous M6709/M7716
squelch chip, was originally designed for receivers used in NASA
space missions (moon). Obviously, it is crucial the circuit opened
squelch under the slightest amount of quieting. In addition, it
was discovered that the human brain had a difficult time
understanding words that are broken by silence; it is much easier if
the unintelligent space is filled with noise. For this reason, what
became known as the MICOR squelch was a circuit that accomplished
this task, as well as having the ability to close quickly if the
recovered audio was considerably noiseless.
Seasoned operators can put together enough recovered audio to make
sense out of a broken transmission, and people didn't have to listen
to a squelch burst if the recovered transmission was fairly quiet.
This circuitry and theory can be reviewed in detail by going to the
USPTO and do a patent number search;
3628058