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Re: DSP noise reduction--now I'm confused



on 2/20/03 7:57 AM, Robert McGwier at rwmcgwier@comcast.net wrote:

> The Widrow algorithm has
> no method for distinguishing between good tones and bad tones.
> The time constant or gain might make it work in Morse mode but it
> will nevertheless depress the power in the Morse tone.  The
> slower the Morse, the deeper the depression given a fixed adaptation
> constant.

That might be correct.  However, not knowing the software of the ClearSpeech
unit and how it works, I can't comment on it's algorithms.  This I do know:

1.) For normal CW, there is NO depression or at least none that is
recognizable.

2.) In order for the tone to start being suppressed, the tone must be there
for several seconds.  I've never counted how long before it starts notching
it out, but it is much longer than what is used in even 5 wpm CW.  It's a
notch designed to filter out tuner-uppers and carriers and heterodynes and
it works well.

Unless someone is sending extremely slow CW where the length of a dash is
several seconds there is no degradation.

When I get time and a good sat pass, I am going to make some recordings of
all this and put them up on my web site.

73,

Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Citizen of the People's Democratic Republik of Illinois

Life Member: ARRL, NRA
Member:  AMSAT, DXCC

http://www.qsl.net/na9d   <- Updated on 1/22/03!!!

"A life lived in fear is a life half lived."


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