> > Kevin wrote:
> > The human brain is not as good at putting broken words
> > together where the break is a total dead absence. On
> > the contrary, if the broken word is bridged with noise,
> > the brain can fill in the blanks, and a severely broken
> > sentence can make sense.
I suspect the untrained ear (brain) is more distracted by
the transition from audio to silence versus the audio to
noise change. A key issue is the interplay of actual audio
level (quantity) transitions. The DSP brain software in
the untrained ear/head appears to better serial sort choppy
signals because the noise can (and in most cases does) act
as space fillers (timing) or place holders.
Noise can also be very fatiguing...
Motorola also invented a very impressive repeater dual
squelch system, very fast and when properly set removes
much of the fatiguing unintelligible loss of signal noise.
Different from the Micor Squelch Chip, but also very
effective.
> > Motorola did a lot or research on this subject during
> > the Space Program of the late 1960's. The result is
> > the MICOR squelch many try to replicate. If anyone
> > that is interested in this subject would like to learn
> > more about the what the Motorola engineers take on it
> > was, I suggest you get a copy of a MICOR manual and
> > read the theory.
Motorola later incorporated their dual-squelch level system
in the late 1970's, early 1980's. You can find an actual
example of it in the MSR-2000 Repeater Manual(s). The fly
in the soup is how the large majority of MSR-2000 people
fail to read and completely understand the MSR-2K's Squelch
Circuit operation and of course they rarely set control
values for optimal (best) operation. If you remove the MSR
Modules and install your external repeater controller direct
to the back-plane... you of course lose the MSR-2000 squelch
circuit.
Both the Micor and MSR-2000 type of squelch circuits are
excellent in operation.
> Mike wrote:
> Thanks for that explanation... you're spot-on with
> your observation about how difficult it is to understand
> spoken-word chopped up Kendecom style!
But the observation may not be the root/real cause...
> My system is on VHF, but exhibits exactly the behavior
> you describe and it's very difficult if not impossible
> to make any sense out of what is being said. Before
> your explanation, I could not rationalize why, but it
> makes good sense now.
A number of early FM Receiver Squelch Circuits and
the first Doug Hall Voter suffered from "voice talk
off" problems. But a number of us figured out how to
work around or modify the circuit for more reliable
operation.
If you have the time and motivation... we could talk
about fairly simple modifications to the squelch
circuit to supply less voice, more high frequency
noise audio to the (squelch) rectifier section. In
some cases it's just about your installing or modding
that section of the circuit with a simple high or band
pass audio circuit (some capacitors and resistors).
If you're a time restricted or plug and play person
the credit card provides many very practical options.
Sometimes you buy your bait, save and enjoy more time
fishing with friends... and that also makes good sense.
cheers,
s.
