"Arfa Daily" wrote in message
...

"William Sommerwerck" wrote in message
...
"Class D amplifiers can be controlled by either analog or digital
circuits.
The digital control introduces additional distortion called
quantization
error caused by its conversion of the input signal to a digital
value."

I'm sorry, but I consider that to be an ill-informed gobbledy-gook
statement.

It's overly terse, but quite correct (though I would have said "signals"
rather than "circuits").

It is not. We've already agreed that the signal in a class D topology
amplifier, is not converted to any kind of digital value at any point.


No, we didn't. I said that most (if not all) PWM amplifiers are analog. But
you can have a digital PWM amplifier.



I think that you are mis-understanding what the author is trying to convey
in his statement. When he said "controlled by ...... circuits ",
that's
probably exactly what he meant, and was referring to control of volume,
balance etc by use of either a fully analogue pot, or a
digitally-controlled
pot IC.

It's possible, and I agree it's ambiguous, but given the way he states it,
ADC is implied.


However, even if a pot IC is employed, no quantization of the signal takes
place within it, and if for no other reason, he is wrong to suggest
otherwise. A digitally-controlled pot IC is merely a step attenuator,
based
on FET-switched resistors. Thus, for all practical purposes, it is no more
than a conventional resistive pot, and introduces no more or less
distortion
into the signal path, than a conventional resistive pot would.

You're right in principle, but the way this piece is written, ADC is
implied.