AM modulation

bbruhns at bbruhns at
Tue Feb 16 18:37:16 CST 2010

That's right, that high-efficiency linear with the combiner that got increased power from the carrier tube on modulation peaks was the Doherty amp, and it was not designed by Terman as I misrecalled, but only described by him.

Communications engineers are also thinking about these amplification and modulation techniques today because radio systems are using methods that involve variable power, and in some cases also rapidly varying amplitude, and the old efficiency issue is still with us.  The simple method of reducing drive to reduce the output of an FM power amp results in poor efficiency, and that means higher power consumption, shorter battery life, more heat, etc. 

   Bob, WA3WDR
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: rabruner at
Date: Tue, 16 Feb 2010 19:08:20 
To: <tacos at>
Subject: Re: AM modulation

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