On Tue, 10 Jul 2007 05:28:56 +0100, " Peter"
wrote:

+++"james" wrote...
+++
+++ Let me be sure that I understand what you are saying.
+++
+++
+++If you are having trouble with my English, try these...
+++ (Full book titles, authors and ISBN numbers at bottom)
+++
+++
+++quote ref=Electronics For Engineers, page 11
+++ Amplification This essential process involves an increase
+++ in the amplitude or size of a signal without any change
+++ to the waveform.
+++/quote
+++
+++
+++quote ref=Electronics 2, page 114
+++ the input and output will have the same waveshape.
+++/quote
+++
+++
+++quote ref=Electronics Servicing Vol2, page 61
+++ we ideally require the output signal to be a faithful but
+++ magnified replica of the input signal.
+++quote
+++
+++
+++ If that is your position then that is utter bovine, canine, feline and
+++ any other *ine excrement you wish to use.
+++
+++Tell it to the authors of those books, but you had best consider
+++their qualifications and experience first.
+++
+++
+++ The only way the output waveform is equal to the input waveform is
+++ when the stage is at unity gain
+++
+++I have the choice of accepting the word of several well qualified
+++and experienced lecturers and engineers, or someone on a CB newsgroup.
+++Tough call... can I think about it?
+++
+++ period.
+++
+++ 1/f
+++
+++ A waveform of any continuous time varying signal is defined
+++ as a set of intantaineous points versus time that represent
+++ that signal.
+++
+++At the input of an amplifier, you have a single frequency signal...
+++ 10mV @ 1Khz
+++The waveform is...
+++ sin 2pi f t
+++
+++The signal at the output is amplified...
+++ 100mV @1KHz
+++The waveform should now be
+++ sin 2pi f t
+++
+++That is assuming a perfectly linear amplifier. We both
+++agree that perfection doesn't exists in this world.
+++Transistors are not perfectly linear but, with good design,
+++an amplifier can get pretty damn close.
+++
*********************

Partially correct in your formulae.

Consider this and reflect with your noted lecturers and writers.

let the input signal of an amplifier be:
f(t) = Ai * sin(2*PI*f*t)

Where Ai is the input signal amplitude.

Now let the scalar value of the transfer function of the amplifier be
a real number greater than one and represented by the constant K. This
becomes essentially a distorionless amplifier and does not consider
internal noise generated in the amplifier.

The output signal from the amplifier:
g(t) = Ai * K *sin(2*PI*f*t)

Now if you can prove that g(t) is equal to f(t) when K greater than
one I will be glad to nominate you for a Noble prize for mathematics.

The frequency component of the function, sin(2*PI*f*t),remains the
same in both equation. The amplitude does not. Therefore the two
functions are not equal. They will have similar waveshapes in that
they will be mathematical multiples of each other. To state that they
are the same is ludicrous. Now I can believe the mathematics that I
have been taught or accept your hypothesis.

Hmmm. Let me get back to you on that.



james

"james" wrote...

Partially correct in your formulae.

It is printed as I gave it on pages 147 & 148 in...

Electrical principles and measurements Level 2
By I. McKenzie Smith
(B.Sc., Dip.A.Ed., C. Eng., M.I.E.E., M.I.E.R.E., F.I.T.E)
Head of the Department of Electrical Engineering,
Stow Colledge, Glasgow.

The words of the noted lecturers, one of whom also worked
for the Ministry of Defence, are incredibly clear... the
waveform does not change.

So I think that what we have here is a perception issue. Try this...

You say that the waveform changes so tell me:
If you amplify a sinusoidal waveform, what waveform does it become?
At what level does a sinusoidal waveform become some other waveform?
Or, at what level is it a sinusoidal waveform?

Can you see where I am going with this?
To say that a large sinewave is not still a sinewave is like saying
a large circle is no longer a circle.

With pure amplification, the signal may have altered in amplitude,
but a sinusoidal waveform will still be a sinusoidal waveform on
the output. The sine, angular frequency and phase shift are
all unchanged.

I am not saying that the signal is unaltered, but that the
waveform is still whatever waveform was put in.
Now I don't like to disagree with you but, if you really believe
that an amplified sinewave is not a sinewave, then I really
must stick with the named lecturers and Heads of Departments.
Nothing personal, you understand, but they do have a sh1tload
of letters after their names :~)


BTW: Sometimes I may take a while to reply to messages,
it's just that I have other things to do and just fit this
and other groups in where possible.


Regards,
Peter.
http://www.citizensband.radiouk.com/

On Thu, 12 Jul 2007 05:23:51 +0100, " Peter"
wrote:

+++With pure amplification, the signal may have altered in amplitude,
+++but a sinusoidal waveform will still be a sinusoidal waveform on
+++the output. The sine, angular frequency and phase shift are
+++all unchanged.
*************

Wrong

Depending on how the amplifier is configured there is a phase shift.
In a Common emmiter configured transistor amp there is a 180 degree
shift in the pahse. So the waveform is altered by phase.

Only the emitter(source) follower in a semiconductor amplifier will
not cause a phase shift.

Correct that the angular frequency is not changed and that a sine wave
is a sine wave, but still the amplitude has changed. Therefore they
are not identical weaveforms. Therefore they do change, if only in
amplitude.

james

On Thu, 12 Jul 2007 17:39:01 GMT, james wrote
in :

On Thu, 12 Jul 2007 05:23:51 +0100, " Peter"
wrote:

+++With pure amplification, the signal may have altered in amplitude,
+++but a sinusoidal waveform will still be a sinusoidal waveform on
+++the output. The sine, angular frequency and phase shift are
+++all unchanged.
*************

Wrong

Depending on how the amplifier is configured there is a phase shift.
In a Common emmiter configured transistor amp there is a 180 degree
shift in the pahse. So the waveform is altered by phase.

Only the emitter(source) follower in a semiconductor amplifier will
not cause a phase shift.

Correct that the angular frequency is not changed and that a sine wave
is a sine wave, but still the amplitude has changed. Therefore they
are not identical weaveforms. Therefore they do change, if only in
amplitude.


I think the key word here is 'waveform', where 'form' is the issue and
scale or phase are not. Because ANY device, active or passive, will
introduce some phase delay and amplitude variation to the signal. So
be practical or be a purist, but you're both really just saying the
same thing.

Now if you wanted to take this to a philosophical level, no two
signals can EVER be identical for the simple reason that they can
always be differentiated, if not by amplitude or phase then by
temporal location (one is the input, the other is the output) or by
physical location (you measure this one here and that one there). But
by the same rule of identity I guess that means no two opinions will
ever be identical either, so argue away.....

On Thu, 12 Jul 2007 12:18:59 -0700, Frank Gilliland
wrote:

+++On Thu, 12 Jul 2007 17:39:01 GMT, james wrote
+++in :
+++
+++On Thu, 12 Jul 2007 05:23:51 +0100, " Peter"
+++wrote:
+++
++++++With pure amplification, the signal may have altered in amplitude,
++++++but a sinusoidal waveform will still be a sinusoidal waveform on
++++++the output. The sine, angular frequency and phase shift are
++++++all unchanged.
+++*************
+++
+++Wrong
+++
+++Depending on how the amplifier is configured there is a phase shift.
+++In a Common emmiter configured transistor amp there is a 180 degree
+++shift in the pahse. So the waveform is altered by phase.
+++
+++Only the emitter(source) follower in a semiconductor amplifier will
+++not cause a phase shift.
+++
+++Correct that the angular frequency is not changed and that a sine wave
+++is a sine wave, but still the amplitude has changed. Therefore they
+++are not identical weaveforms. Therefore they do change, if only in
+++amplitude.
+++
+++
+++I think the key word here is 'waveform', where 'form' is the issue and
+++scale or phase are not. Because ANY device, active or passive, will
+++introduce some phase delay and amplitude variation to the signal. So
+++be practical or be a purist, but you're both really just saying the
+++same thing.
+++
+++Now if you wanted to take this to a philosophical level, no two
+++signals can EVER be identical for the simple reason that they can
+++always be differentiated, if not by amplitude or phase then by
+++temporal location (one is the input, the other is the output) or by
+++physical location (you measure this one here and that one there). But
+++by the same rule of identity I guess that means no two opinions will
+++ever be identical either, so argue away.....
+++
*********

In a way this could be considered nit picking. I agree that the
overall form is a sinusoid. I just don't like the implication that all
sinusiods are unchanged by amplification, positve or negative. Granted
the amplitude of the form is alterd and little on none of the rest of
the function is not. Yet the amplitude is a partt of a sinusoidal
waveform.

again it is a minor point.

james

On Sat, 14 Jul 2007 20:06:09 GMT, james wrote
in :

snip
In a way this could be considered nit picking. I agree that the
overall form is a sinusoid. I just don't like the implication that all
sinusiods are unchanged by amplification, positve or negative. Granted
the amplitude of the form is alterd and little on none of the rest of
the function is not. Yet the amplitude is a partt of a sinusoidal
waveform.

again it is a minor point.


True, and your point is perfectly valid. You are technically correct
that amplification, inversion and phase shift are types of distortion.
But for the purpose of -this- discussion (audio distortion caused by
Brian's noise-board), it seems you are trying to sand the table-top
before cutting down the tree. Now if this were carried over to a new
thread it might be fun....

"james" wrote...

I just don't like the implication that all sinusiods are
unchanged by amplification,

I neither stated or implied that they are "all sinusiods
are unchanged". You have clearly assumed that from a
simple statement.

Let's be clear about what I stated, which is what several well
qualified people have also stated in their books... that the
waveform is unchanged by amplification.

That is the position of the named engineers, lecturers and heads,
and I am not about to call them stupid by saying it is not as they
state in their books.

Before arguing further, that these people are all wrong and
their employers really should have given you the job, please
look at my other replies. Maybe it will clear up why you
believe these people wrong.


again it is a minor point.

For a minor point, you certainly are willing to spend time
claiming the authors to be "wrong" or "incorrect".
Not something I would do on a "minor point", and without
some damn good references or better qualifications than
all those authors.


Regards,
Peter.
http://www.citizensband.radiouk.com/

"Frank Gilliland" wrote...

I think the key word here is 'waveform', where 'form' is the issue and
scale or phase are not. Because ANY device, active or passive, will
introduce some phase delay and amplitude variation to the signal. So
be practical or be a purist, but you're both really just saying the
same thing.

What's up with you, playing peace-maker?

The difference of opinion here appears to be whether waveform
is defined by the absolute value at the peak, rather than
relative changes throughout a cycle.

In the noted references, signal amplitude does not affect
the waveform of the signal.

Considering the qualifications of these chaps, and the fact
that they each have said the same, I am somewhat reluctant
to consider their words, math and diagrams to be incorrect.


Now if you wanted to take this to a philosophical level, no two
signals can EVER be identical for the simple reason that they can
always be differentiated,

Ah, signals... fine. The term "signal" can cover everything, the
slightest change of anything (including amplitude) could be taken
as a change in the signal.

I would not argue that a larger version of a sinewave may not
be considered an identical *signal* to the smaller version, but
I would argue that the waveform property of the signal has
not changed.


if not by amplitude or phase then by
temporal location (one is the input, the other is the output) or by
physical location (you measure this one here and that one there). But
by the same rule of identity I guess that means no two opinions will
ever be identical either, so argue away.....

You act as peace-maker, then encourage us to argue?


Regards,
Peter.
http://www.citizensband.radiouk.com/

"james" wrote in message
...
On Thu, 12 Jul 2007 05:23:51 +0100, " Peter"
wrote:

+++With pure amplification, the signal may have altered in amplitude,
+++but a sinusoidal waveform will still be a sinusoidal waveform on
+++the output. The sine, angular frequency and phase shift are
+++all unchanged.
*************

Wrong

No, you are confusing issues with stuff like...

Depending on how the amplifier is configured there is a phase shift.

Now, read my part again, carefully. I did not mention amplification
with phase shift or specific amplifier circuits. You are several
steps ahead of yourself, considering specific circuits before
considering the required function...
Amplification.

If I asked what was the purpose of a light bulb, would you start
talking about heat and fingers getting burned changing them when
they have been on a few minutes?

With that in mind, what is the purpose of an amplifier and what
is amplifictation? I'll give you a clue... heat, distortion, phase
shift, specific components and negative feedback do not come
in at this stage.

To design something, first you must consider the purpose. Otherwise,
you can end up with a big, empty, useless dome and the whole world
laughing at you.
Believe me, us Brits know all about that one.


In a Common emmiter configured transistor amp
there is a 180 degree shift in the pahse.

Only the emitter(source) follower in a semiconductor amplifier
will not cause a phase shift.


As you should have worked out from the above, phase shift
is not amplification, and it is not the basic function of
an amplifier.


Correct that the angular frequency is not changed and that
a sine wave is a sine wave, but still the amplitude has changed.

Nobody said it hasn't.

The difference of opinion here appears to be whether waveform
is defined by the value of the amplitude at the peak.
Acccording to the noted and extremely well qualified gentlemen,
the form is not dependent upon the peak value.

You appear to be confusing the words signal and waveform.

Although a change to any of the properties of a signal will
be a change in that signal, you can change any one of it's
properties without changing the others.
So, changing the signal amplitude does not change it's
waveform.

The signal amplitude is absolute and measured in volts or
amps. When assessing the waveform of the signal, waveform
amplitude is relative to the signal amplitude and so has a
maximum value of 1.

No matter how accurate your mathematics, if you do not
correctly identify the problem at hand then you may be
working on the wrong problem and your result will be
not be the required solution.


Regards,
Peter.
http://www.citizensband.radiouk.com/

"james" wrote...


First of all, I should point out that I have not seen any messages
posted since my last reply, they will be downloaded as this is sent...


When your mathematics appear to disagree with so many well
qualified engineers, lecturers, heads of educational departments
and technical authors, it's time to check for some little
error... something that can slip through or seem insignificant.


The frequency component of the function, sin(2*PI*f*t),remains the
same in both equation.

It will always appear constant, it is not an absolute value...
f*t
Through a complete cycle, the maximum result will be 1, regardless
of the actual frequency.


The amplitude does not.


Of course not, *you* are using an absolute value.

The waveform is the relationship between changes in amplitude
and time. By putting in an absolute value, peak voltage, you
are now comparing signal levels rather than waveform.

The amplitude should have a maximum value of 1...

quote ref=1
The maximum voltage of a sine is 1, thus Vm is the
maximum or peak value of the alternating voltage.
/quote

Diagrams in the book show exactly that. But, as you may
not have the book collection that I have, check out the
diagram here...
http://upload.wikimedia.org/wikipedi...ine_Cosine_Gra
ph.png/300px-Sine_Cosine_Graph.png

(NOTE: URL wrapped to two lines)

Now,
v = Vm sin 2pi*f*t
= sin 2pi*f*t

So, as said before...

quote ref=2
Amplification This essential process involves an increase
in the amplitude or size of a signal without any change
to the waveform.
/quote


Now I can believe the mathematics that I
have been taught or accept your hypothesis.


Those are the words of well respected and qualified engineers,
lecturers, heads of educational departments and technical
authors.



Regards,
Peter.
http://www.citizensband.radiouk.com/

ref1: Electrical and electronic principles Level 2
I. McKenzie Smith.
(pages 144 - 148)

ref2: Electronics For Engineers.
R. J. Maddock (Former principle lecturer,
Southampton Institute of Higher Education)
D. M. Calcutt (Senior Lecturer, School of Systems
Engineering, University of Portsmouth).
(page 11)