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Re: [TenTec] RF speech processors

To: <ken.d.brown@hawaiiantel.net>, "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Subject: Re: [TenTec] RF speech processors
From: "pfizenmayer" <pfizenmayer@qwest.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 3 Feb 2009 10:09:19 -0700
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
That is exactly how the Drake SP75 speech processor works - Hank K7HP 


> You connect your microphone audio to a little AM or DSB generator, 
> working at some frequency such as 455 kHz. Then you compress or even 
> clip that signal to increase the average power output. Probably goes 
> though some bandwidth limiting filters. After that it gets demodulated 
> back to audio, and feeds the microphone input of the SSB rig. Since the 
> compression/clipping/whatever is done at some "intermediate frequency" 
> and then demodulated back down to audio, the IMD "splatter" and 
> harmonics that are generated, don't get transmitted. Only bandwidth 
> limited audio goes to the microphone input of the SSB transmitter, and 
> the SSB transmitter audio stages and RF stages are never driven into 
> non-linearity. The transmitted signal bandwidth is limited by the usual 
> crystal or mechanical filters. You get a really dense high average power 
> signal.
> 

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