Owen Duffy wrote:
"Richard stated "It produces no significant harmonics, so the system is
linear." It is that with which I disagree."

A clear statement. Congratulations. Too bad it is wrong.

Terman wrote:
"Amplitude distortion exists when the modulation envelope contains
frequency components not present in the modulating signal."

It is also true that absence of of harmonics is proof of linearity, as
in my microwave monitoring system alarm. No alarm, a linear system. An
alarm, a nonlinear system. I agree with Terman.

I challenge you to prove a mistake in Terman`s writings.

Best regards, Richard Harrison, KB5WZI