[Elecraft] KPA-500 "Output for Input" schedule?

[Cortland Richmond]

The INTERESTING thing about the article is that it is ANALOG predistortion.
Even a few dB would be an improvement, if 10 to 20 dB proves beyond reach
for such a broad (16:1) spectrum as HF.

 

Cortland

KA5S

____________________________________________________________________________
________________
Date: Thu, 12 May 2011 13:43:51 -0400
From: Jack Smith <jack.smith at cliftonlaboratories.com>
Subject: Re: [Elecraft] KPA-500 "Output for Input" schedule?
To: elecraft at mailman.qth.net
Message-ID: <4DCC1C56.5050703 at cliftonlaboratories.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Geoff & list readers ...

There's an article in the current Electronics Design News, as a matter
of fact, on pre-distortion.

http://www.edn.com/article/518070-RF_predistortion_straightens_out_your_sign
als.php

Although aimed at cellular radio digital modulation, the concepts apply
to analog SSB as well.

Jack


On 5/12/2011 12:44 PM, Geoffrey Mackenzie-Kennedy wrote:
> Hello Guy,
>
> The short answer to the first part of your question is yes, and the
generic
> term for such a scheme is Predistortion. A term that has been used to
> identify a Predistortion scheme which employ digital techniques is a
> "Digital Predistortion Linearizer" (DPL), and its use can bring about a
> significant reduction in the level of IMD being transmitted compared to a
> classic class AB design. Unfortunately the relevant data that I have is
> packed ready to leave for Luxembourg.
>
> I don't know how easy or difficult DPL would be to implement in the K3, or
> in any other "already designed" rig which employs DSP, but I suspect that
> somebody else reading this could tell you.
>
> 73,
> Geoff
> GM4ESD
>
>