Topband: Rig Comparisons

[Richard (Rick) Karlquist]

On 8/2/2014 4:06 PM, James Wolf wrote:
> It really doesn't matter how much power the amplifier is outputting.   A
> simple explanation is that a sample of the output is inversely fed back and
> combined with the input.   As was mentioned before, this method has been
> around for a long time.  When you fly into an airport, the FAA radios that

What you described is "negative feedback".
What PureSignal claims to do is described as "predistortion".
Those are two different technologies, and along with
a third technology, "feedforward", are neither new
nor panaceas.

I read the technical report on "Pure Signal" and it
sounds like what we used to call a "hero experiment"
in the research lab where I worked, consisting of a
few impressive results, but with many disclaimers,
and nothing you could productize.  What is supposed
to be new is the adaptive part, but it depends
on the amplifier being "well behaved".  Currently,
merely getting a radio to interact with an amplifier
via ALC is a debacle, so it is really hard to imagine
radio manufacturers and amplifier manufacturers ever
getting on the same page regarding predistortion.

Rick N6RK