"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/