[Amps] Pre-Distortion Linearizer

[Paul Christensen]

Not exactly Motorola transistor related but the subject reminded me of this: 
AC2IQ has developed an interesting pre-distortion "linearizer."

http://www.qrz.com/db/AC2IQ

Linearizers have been used in the cell phone industry to more efficiently 
pack more digitally-modulated channels into licensed spectrum.  Broadcasters 
have been using this technology for the last decade.  Swiss ADAT was the 
first amateur manufacturer to use the technology in their ADT-200A 
transceiver.  In fact, it works so well that within limits, the ADAT will 
sample the output of a non-linear amp, and correct for the amp's 
non-linearity back in the transceiver.

Apparently, AC2IQ is using an analog, rather than a digital method to 
achieve extreme linearity from his SD2931x16  MOSFET amp.  Not sure what 
class the amp is biased.  Scroll down to the middle of the page and you can 
see the result of his work.  This isn't just lab performance.  Folks have 
observed his 75m signal with no IMD "wings" on their SDR receivers.

I'm aware of digital adaptive pre-distortion techniques, but I've not seen 
this done using analog components.  Anyone familiar with this type of 
circuit?

Paul, W9AC

----- Original Message ----- 
From: "Paul" <w8aef at q.com>
To: "Amps" <amps at contesting.com>
Sent: Tuesday, April 30, 2013 7:12 PM
Subject: [Amps] Motorola transistors


>
>
> From: Paul
> Sent: Tuesday, April 30, 2013 4:11 PM
> To: ScQRPions
> Subject: Motorola transistors
>
> Advanced Semiconductor continues to make most Motorola, Philips, and SGS 
> Thompson RF transistors.
>
> http://www.advancedsemiconductor.com/index.html
>
> de Paul, W8AEF
>
> ZF2JI/ZF2TA 8Q7AA FO8DX/FO0PLA XZ0A VU7RG/VU3PYM TX5A A52PP
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