Jimmie D wrote:
"Jay in the Mojave" wrote in message
...

Hello Brian:

The Smart Squelch is supposed to be smart, just as its said! That
is the squelch will open or turn on the receiver audio when a
signal is received in the receivers IF. A separate pick off of the
IF RF is sampled and then its supposed to only open the Squelch
when there is a real signal, and is not supposed to work on noise,
bleed over, static and such. The Smart Squelch is supposed to be
able to discern between noises and a real RF signal. And its
advertised as having a very high percentage of success, being able
to only open the receiver with a rf signal and not noise.

I built a Analog Smart Squelch back in the 80's for my Motorola
System 500 Mobile SSB/AM CB Radio. (which all ready had a active
Motorola noise canceling circuit in the IF Section) It worked real
well. It was great driving down the freeway and not hearing motor
noise, like setting at home. The Smart Squelch came from a article
in a magazine, and I bought the kit and put it together.

But this new circuit is supposed to be digital. I haven't seen it
yet.

But I know a lot of guys are using the Heil, Alpha Delta, and
others External Speakers with DSP for extra noise cancelling. I
have a Heil DSP External Speaker, and it works great, just need a
smart squelch to go with it.

Jay in the Mojave

Telstar Electronics wrote:

Jay in the Mojave wrote:


I have a good friend on 40 that is going to send me a custom
circuit that is supposed to do all this, and has a smart
squelch to. We will see.


Smart squelch? Please explain...

www.telstar-electronics.com


I remember something that use a "bucket brigrade" audio delay line in
a sqeich circuit in late 70s or early 80s. The audio was delayed a
few milliseconds so the hardware would have time to analyse the
signal to see if it should be squelched or not. Is this what yu are
talking about. Probably a piece of cake for DSP.

My first experience with DSP was in the Air Force. I was sent to
school on this new modem and endured a month of theory on how modems
worked all built around analog devices. In reality this thing was
just a RISC computer attached to D/A and A/D converters. The only
thing analog about it was a couple of op amps used on the input and
output.. The modem itself was tiny but the cabinet it was in was
huge. I guess it had to be this way for all the human interface that
was needed.



Hello Jimmie D:

Oh really, now thats interesting, the "bucket brigade" type delayed
signal for processing. Yeah I would think so, DSP that is now working at
the IF Frequencies should be able to handle all that.

Yeah I am sure the Modem must be able to account for data from noise or
other unwanted voltages seen. I am no Modem expert but your description
sounds like typical of over done military hardware. Maybe the engineers
wanting it to look like something big as it really didn't need to be.
Trying to sell the hardware, as compared to having to deploy with a
bunch of stuff that takes up too much space on a military transport
aircraft. Thats where the military needs to hire a separate maintenance
consultant group, not looking for a star placed next to their name.

I think we have only seen the tip of the Ice Burg here with DSP (Digital
Signal Processing). My old used Icom 746 Pro HF radio, is a first
generation DSP radio. I am able to adjust the Radio's IF (Intermedent
Frequency) Filters at a snap of a switch. Its noise reduction is
fantastic. Stations on USB can almost be rejected when monitoring LSB.

I would think more new wiz bang stuff is coming for DSP.

Jay in the Mojave


Kreediantials:

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