On Sun, 15 Jul 2007 23:49:04 +0200, "Hein ten Horn"
wrote:

John Fields wrote:

And what does it look like, then?

Roughly like the ones in your Excel(lent) plots.

---
I've posted nothing like that, so if you have graphics which support
your position I'm sure we'd all be happy to see them.
--

Mathematical terms like linear, logarithmic, etc. are familiar
to me, but the guys here use linear and nonlinear in another
sense.

Where is "here"?

In this thread.

I'm writing from sci.electronics.basics

Subscribing to that group would be a good
thing to do, I suspect.

and, classically, a device
with a linear response will provide an output signal change over its
linear dynamic range which varies as a function of an input signal
amplitude change and some system constants and is described by:


Y = mx+b


Where Y is the output of the system, and is the distance traversed
by the output signal along the ordinate of a Cartesian plot,

m is a constant describing the slope (gain) of the system,

x is the input to the system, is the distance traversed by
the input signal along the abscissa of a Cartesian plot, and

b is the DC offset of the output, plotted on the ordinate.

In the context of this thread, then, if a couple of AC signals are
injected into a linear system, which adds them, what will emerge
from the output will be an AC signal which will be the instantaneous
arithmetic sum of the amplitudes of both signals, as time goes by.

In general: that sum times a constant factor.
Perhaps the factor being one is usually tacitly assumed.

---
That's not right.

The output of the system will be the input signal multiplied by the
gain of the system, with the offset added to that product.
---

As nature would have it, if the system was perfectly linear, the
spectrum of the output would contain only the lines occupied by the
two inputs.

Kinda like if we listened to some perfectly recorded and played back
music...

If the system is non-linear, however, what will appear on the output
will be the AC signals input to the system as well as some new
companions.

Those companions will be new, real frequencies which will be located
spectrally at the sum of the frequencies of the two AC signals and
also at their difference.

From physics (and my good old radio hobby)
I'm familiar with the phenomenon. The meanwhile
cleared using of the word non-linear in a narrower
sense made me sometimes too careful, I guess.

---
OK, I guess...
---

Something to do with harmonics or so? Anyway,
that's why the hint isn't working here.

Harmonics _and_ heterodynes.

If the hint isn't working then you must confess ignorance, yes?

The continuous thread was clear to me.

Thanks.

---
:-)


--
JF