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

[Paul Christensen]

> I would like to know if some kind of feedback (maybe complicated)
> could bring about a quantum leap in linearity, like sampling the
> output of the amp and feeding that back to the K3 to digitally
> pre-alter the audio to cancel the distortion going out.

That's exactly the function of adaptive pre-distortion.and is used in the 
ADAT ADT-200A.  Scarce as that rig is, it works well.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.123.2357&rep=rep1&type=pdf

See the section entitled "The Predistortion Concept."  The adaptive part of 
predistortion comes from the use of a dynamic algorithm like LMS -- the 
same, or nearly the same algorithm used in the K3's denoiser DSP function.

Paul, W9AC