On Sat, 30 Jun 2007 10:30:53 -0700, Jim Thompson wrote:

I have a specification for an amplifier design that says "0.25%
linearity".

I can't seem to lay my hands on a precise definition of what that
means.

Likewise... How to calculate?

...Jim Thompson

When I teach classes and seminars one of my hobby horses is the
definitions of words. Some things have a pretty well defined meaning, but
there are a whole bunch of words and phrases (% linearity, for instance),
that have no consistent across-the-board meaning. I try to target 80 or
90% comprehension, which means that I get about 50% of the class rolling
their eyes at me.

Were it me, I'd ask my customer to define what _they_ mean by it; if I
think they know enough to be dangerous and no more, I may even preface my
questions by saying "y'know, different segments of the market define this
differently...".

I suspect they mean "linearity" in the same sense that "integral linearity"
is defined in an op-amp -- but even there I bet the definition varies with
the vendor.

Further, if you deliver an amplifier to them that's perfectly linear
except for a crossover distortion that's 0.25% of full scale output
they'll be unhappy with your "0.25% linearity".

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html