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/