On Sun, 15 Jul 2007 23:49:04 +0200, "Hein ten Horn"
<tenhornRemovE@ThiSraketnet.nl> 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