gwhite wrote:
"Eric C. Weaver" wrote:

This discussion happens all the time on comp.dsp, between primarily
computer-science folks approaching DSP and EE types approaching it.

EE folks' definition of "linear" implicitly includes time invariance;


Interesting thought since a Signals and Systems course, or a Linear
Systems course, or a Communications course is often required to get an
EE degree. After all, these courses explicitly distinguish the
linearity property and the time-invariance property. And I've never
seen the "af(t) = f(at)" so-called "definition" until a few days ago.

Your a liar. Its that simple. I clearly stated that it was *not* a
definition. It was simply trying to illustrate the concept of constant
gain. You expanding on some trivial minor point to avoid answering the
main issue, to wit, you have failed to disprove my claim on your class A
amplifier.



DSP
people have to see it stated explicitly (as "LTI": Linear Time
Invariant) lest they think "linear" just means having no
second-or-higher-order terms.

It is not a deficiency on either party's part, just a difference of
definition in each's respective discipline (is that enough
alliteration?).

Therefore, I advise each to bend this much: Use the full phrase
"Linear Time-Invariant" when this miscommunication is suspected, so
both know what the hell the other is talking about.

Absolute crap. The notion that y=x^2 is a non-linear equation is
universally accepted by anyone who has done even the slightest bit of
theory on basic algebraic equations. It does not require any
qualification in the slightest.


Now go and sin
no more.

I've met folks before who think that linearity means freqs cumzoutas
must only equal freqs gozintas. But they don't usually put up such a
fuss when actually presented with the widely available and consistant
literature or reasonable arguments. This is more about fuss than
facts.

Indeed. So why *are* you putting up such a fuss about notions that are
widely held in the literature. Show me one, and I mean just one, that
declares y=x^2 a linear equation.


Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
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