[Eeyore]

Don Pearce wrote:

Kevin Aylward wrote:
JosephKK wrote:
On Thu, 18 Sep 2008 18:26:25 -0000, "Jorden Verwer"
wrote:

Eeyore wrote:
given that you've apparently never heard of the term
offset.
Offset is IRRELEVANT to output devices you complete MORON !
I know that, and I never claimed otherwise. Offset is a form of
noise, in a sense. And like noise, it is caused almost completely by
the input transistors. I'm well aware of all that.

Do do you know what a 'closed loop' means ?
Yes.

Offset is a form of noise???? This is the first time i have ever
heard that.

Not for me. Its very common interpretation.

There is no engineering reason to look at it that way.

There is to me, and to many others.

is fundamentally a different property with different physics.

Offset is an error. Noise is an error. For example, the standard method of
analysing Sigma-Delta converters is to treat what is, technically, an error
in coding a signal from its actual value, as an additional *noise* source,
that is considered to be unrelated to the signal, when in fact, it is!

I don't see that it matters much where the error comes from, it can be
handled in the same general way.

It can be handled the same way, but doesn't need to be. Noise must be
handled by filtering, with with a specific inline filter or effective
filtering by means of a control loop. DC will also be handled that way,
but for DC there is always the option of trimming it away with either an
adjustable or an SOT. You can't do that with noise, which makes them
fundamentally different things.

And offset in an audio power amp is commonly corrected by not making it DC
coupled. A filter of sorts I suppose.

Graham