[BC] AM Fidelity vs FM fidelity

[Jim Tonne]

Mr. Meuser is pointing out the simple fact (as I did a day ago) that in 
both cases,
AM and FM, the receiver enters into the picture. Very few people watch a
transmitter on an oscilloscope or a modulation monitor, or as a plot in 
a SPICE
simulation.   Most people use a receiver.

That receiver, and all the junk (including path problems such as noise) 
between it
and the transmitter, clearly enters into the picture in the real world.

Mr. Johnson's posted stuff is quite irrelevant in the case where the 
receiver is in
the picture, as it generally is. His simplistic displays - seemingly 
correct as far as
they go -  ignore the path and they ignore both selectivity and 
nonlinearities in
the receiver.   The receiver will invariably alter the sideband 
structure and it will
also introduce nonlineaities in the demodulation process itself.   His 
posted stuff,
while quite colorful and pretty, ignores those two critical items. His 
simulations
taught me absolutely nothing.

This is a real world, not a fantasy, and AM and FM must be considered as
systems, not just as transmitters by themselves.

- JimT