signal theory


Disabled Account
2002-07-08 8:42 am
Know your components

with "components" I mean every
piece of material a signal have to pass in signal path.

it may be Cu copper
it may be Si silicon
it may be Pb lead
it may be Sn

wires, solder points, caps, resistors
all is out of materials

All materials have their own way to react
or not react to , what we call a signal
Signal are electrons, moving
or small packages of energy,
which have to pass the atomic structure
of the materials.

Not only important is the different materials
single responses, but also when they are joined together
with eachother.
Like a beam of sunlight, bends,
when passing from air to water.

So I say study physics.
Know the elements
which we all are made of and you will know
about very many occurances regarding
energy's way to behave.
Signal Conductivity Theory

Hi Groman,
Your answer is so philosophical orientated rather than technical or scientific that I almost fell off my chair in front of my computer laughing:) It almost reads like a poem. There must be something in the Swedish water or is it in the thin air in Lapland were you live...?
I see you know some symbols for the chemical elements but to tell how these "react" to small packets of energy is long way remote from current theory of conductivity of metals and semiconductors. ;) I absolutely don't see any analogy with a beam of sunlight going from one medium (air) to a other medium (water)
BTW I am a chemist by education, University of Groningen, specialised in synthetic organic chemistry. Had to study a lot of physics as part of obligate exams (including the breaking of light and semiconductors theory) :cool:

Nico6969, (What's in a number? [double Kamasutra??],) I strongly recommed reading the book by Horowitz and Hill, the Art of Electronics, Cambridge University Press.:) :cool:
any analogy with a beam of sunlight going from one medium (air) to a other medium (wa

How about a discontinuity in impedance for a transmission line....
Reflections, change in propagation velocity... I 'll bet there are many analogies that a good EMAG guru could enlighten with. I am just a lowly EE by education.


Depends on what you call signals. Most of us consider them as currents or voltages varying with time. But you can begin to toy with the two main Maxwell's equations, which are apparently so simple and elegant. And split currents into conduction currents and displacement currents. And add the dielectric and magnetic properties of materials, that vary with temperature, frequency, direction, previous conditions (non-linearities) etc... Or consider currents as charge (either electrons or holes) variation with time. Or consider all this stuff from the thermodynamic point of view, as a disturbance in thermodynamic equilibrium. Far too vast to be answered, at least by me :)

But if a signal for you is the variation of "something" with time, start with Fourier analysis, Laplace transforms, convolution, correlation, filters' theory. It should be a nice basis.

hi im back .

ok thank you all guys but your answers are a bit weird for me.
im a 17 yrs old kid whos just startin.
ive already built and know how to calculate class a amps.
but now, besides amplify audio signals i wanna distort em.

so if you could recommend me some books or stuff to read id be grateful .

see ya ´


Disabled Account
2002-07-08 8:42 am

Bias=give them a start current
so they can start working
different bias=how hard you let them work

if you carry your schoolbag, you would walk rather normal
but if you carry home your 70 kilos loudspeakers
you would have a bad walk
so is it with caps, resistors, transistors...
If you put an unsuitable strain unto them,
they will not perform as intended

There is however an optimal strain for
electrical komponents,
That would make them disturb the signal as little as possible

That is a knowledge, I find valuable.
Duo, you made a very good point

How hard you let a circuit work,
will effect the result of that work performed.
We are not slave drivers!
Well, we can buy new slaves,
if a bunch of them scream and die.

Man lives not by bread alone,
neither can you make a lifetime last
only by listening to music.

The good thing with philosophy is,
it can be the tool to try and understand
a variety of things. Not at least signal theory.

needs more beer and less water
Hello Nico,

If you're talking 'bout "signal," there's a bunch of ways to distort/modify it. I assume you are interested to distort it because you are probably a member of a music band... and you're probably the lead guitarists (just kidding), and want to have sound effects.

In that case, you have to dig some popular diy electronic magazine on how to build sound effect (analog circuit).

BUT... if you want to modify the signal DIGITALLY, then it's a bit complicated. Most probably you end up using DSP (Digital Signal Processor). The basic theory is purely mathematics and I think you have to pass calculus class first to understand discrete time signal processing. But if you want to know a bit about DSP theory, you might find a book written by Proakis & Manolakis (Digital Signal Processing) useful. But it's probably very hard to understand.

If you want to know the effect of real world Resistor, caps, cable etc in high frequency, you might find a book written by Ott (ooh, i forgot his full name) useful (the title contains word like "Noise Reduction...").

But, to be exactly, what kind of distortion you want to perform? If you're looking for signal theory... I mean ONLY signal (no schematics), try to read Proakis & Manolakis book. The book explains SIGNAL in time domain & frequency domain.... All Maths and as you wish... no schematics (yucks!)

Okay, I'll stop. Probably you're having a headache right now of what I'm talking. Btw, for 17 years old kid... able to calculate & build class A amp, you're DAMN GOOD! I don't understand how amplifier works, until I take analogue circuit class :)

I say that Swedish beer is good, so therefore Swedish water must be good, so therefore Gromanswe's thoughts are good.
Elso, conduction is not clean DC - there are noise components according to the conductor elements used, and this can be audible.
Dissimilar materials cause a Fermi voltage which puts a bias in conduction paths, and the properties of dielectric/insulation materials can have a profound effect, as can thermal modulation effects (physically large components display less of this), as can internal and external electric and magnetic fields, and as Harry adds these properties can also cause return loss (reflections).

The point is to understand what materials sound good and why - It is all quite elementary really.

Regards, Eric.
Hello Nico...
For analog circuit you might try this book, written by Sedra & Smith:
Microelectronics Circuit (ISBN: 0195116631)

I heard that students at MIT also use this book. This is a VERY good analog circuit book. You'd probably need this book also:

Electric Circuit Analysis (author: David E. Johnson et al., Published by Prentice-Hall).

This book explains the very basic of electric circuit (Resistor, Inductor & Capacitor).