[Elecraft] KPA1500 TX Sample

[Jim Brown]

On 3/23/2018 11:33 AM, Don Wilhelm wrote:
> I think there will be more information to come about its function. For 
> the time being, it is safe to assume it is not a calibrated output, 
> but simply a tap to observe the output waveform, rather than an 
> amplitude measuring device. 

The most obvious use is as a sampling point to feed NR0V's excellent 
Pure Signal software. Warren received a Technical Excellence award for 
developing it. The software modifies the driving signal by 
"pre-distorting" it so that pre-distortion elements cancel distortion 
within the feedback loop.

This is a fairly old technique -- it was, for example, implemented more 
than 50 years ago in a few professional and consumer power amplifiers, 
and also within "powered" loudspeakers (that is, those with built-in 
power amps) using motional feedback from the transducers.

73, Jim K9YC