Russell Shaw wrote:
Kevin Aylward wrote:
gwhite wrote:

The simple fact is you are wrong in thinking you can all of the
sudden make up your own definition of linearity, or carry forward
without challenge the mistaken definition of others.

Absolute crap. Show me one respectable math reference that says if
y=exp(x), that y is a linear function of x.

You were right about one

Show me one real practical example that does not use a device with a
functional relation between input and output voltage/current that is
linear, as I defined above. As did note as an after thought, it may
be possible in principle, for example, maybe one could construct a
true, linear with voltage, voltage controlled resistor. However, I
am not aware of such magic devices.

The physical reality is that it is not possible. Produce one and I
will retract my claim.

A light dependant resistor. One input drives a LED via a linearizer
to compensate for LDR non-linearity. The LDR resistance is unaffected
by the voltage across it. Therefore, the resulting current
Io=f(V1,V2)= k.V1*V2 (4-quadrant multiplier or compensated gilbert
cell)


I have already pointed out the light dependant resistor in another post
in this thread, so I did already do a retraction and a qualification on
this point. This was a minor oversight. The distinction is whether or
not the controlling elements output terminals are connected to its
controlling terminals. If the controlling terminals, are connected to
the controlled terminals then we have a non-linear resister de-facto. A
resister can only be linear if its resistance does not depend on the
current through it, or the voltage across it.

In the case of the transistor, the gain is set by its small signal
resistance re=1/gm. However, the control of the value of gm is by its
own bias current, therefore it has to be non-linear.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Russell Shaw wrote:
Kevin Aylward wrote:
gwhite wrote:

The simple fact is you are wrong in thinking you can all of the
sudden make up your own definition of linearity, or carry forward
without challenge the mistaken definition of others.

Absolute crap. Show me one respectable math reference that says if
y=exp(x), that y is a linear function of x.

You were right about one

Show me one real practical example that does not use a device with a
functional relation between input and output voltage/current that is
linear, as I defined above. As did note as an after thought, it may
be possible in principle, for example, maybe one could construct a
true, linear with voltage, voltage controlled resistor. However, I
am not aware of such magic devices.

The physical reality is that it is not possible. Produce one and I
will retract my claim.

A light dependant resistor. One input drives a LED via a linearizer
to compensate for LDR non-linearity. The LDR resistance is unaffected
by the voltage across it. Therefore, the resulting current
Io=f(V1,V2)= k.V1*V2 (4-quadrant multiplier or compensated gilbert
cell)


I have already pointed out the light dependant resistor in another post
in this thread, so I did already do a retraction and a qualification on
this point. This was a minor oversight. The distinction is whether or
not the controlling elements output terminals are connected to its
controlling terminals. If the controlling terminals, are connected to
the controlled terminals then we have a non-linear resister de-facto. A
resister can only be linear if its resistance does not depend on the
current through it, or the voltage across it.

In the case of the transistor, the gain is set by its small signal
resistance re=1/gm. However, the control of the value of gm is by its
own bias current, therefore it has to be non-linear.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

On Wed, 10 Sep 2003 10:25:49 +0100, "Kevin Aylward"
wrote:


That is, to achieve linear multiplication by this transistor gm method,
it necessarily requires a non-linear relation between I and V for the
transistors gm characteristics. This forms a proof of my statement that
the class A modulator achieves such modulation by a non-linear process.

gwhite:

Please do not respond if you are going to past masses of waffle text
that you don't understand. Provide a *mathematical* *explicit* disproof
of my mathematics or present your retraction.

Well this is compelling stuff, I must say. I'd hoped to be able to
disappear on holiday for a week and return refreshed, but it looks
like I'm going to have to seek out cybercafes to keep up to date on
these exchanges instead. :-( Still no outright winner so far...


--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

On Wed, 10 Sep 2003 10:25:49 +0100, "Kevin Aylward"
wrote:


That is, to achieve linear multiplication by this transistor gm method,
it necessarily requires a non-linear relation between I and V for the
transistors gm characteristics. This forms a proof of my statement that
the class A modulator achieves such modulation by a non-linear process.

gwhite:

Please do not respond if you are going to past masses of waffle text
that you don't understand. Provide a *mathematical* *explicit* disproof
of my mathematics or present your retraction.

Well this is compelling stuff, I must say. I'd hoped to be able to
disappear on holiday for a week and return refreshed, but it looks
like I'm going to have to seek out cybercafes to keep up to date on
these exchanges instead. :-( Still no outright winner so far...


--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

"Kevin Aylward" wrote in message ...
Frank Raffaeli wrote:
"Kevin Aylward" wrote in message
...

[snipped much voluminous banter]

Whilst, I do agree that Win is very knowledgeable and an expert, I am
also an expert. I have been doing this rather a long time as well you
know. The fact that I am not an academic is not relevant. In all
honesty, there is not much I don't know about general analogue
design, although, obviously, I don't claim to know it all. Does Win
know more than me? Unlikely. Or do I know more than Win. Unlikely.
However, we may well know different things.

[snipped more banter]

Does the above pose a question, or is it mere rhetoric? Could the
scientific method be applied with gusto? Are Win and Kev evenly
matched?

I don't know. How tall is he, I'm only 5'8"

All talk, then. Pity, I would have enjoyed the sport of a contest. It
seems this issue has been smothered with words. If one could apply the
"science" to "design", the words would have more meaning.

Frank Raffaeli
http://www.aomwireless.com/

"Kevin Aylward" wrote in message ...
Frank Raffaeli wrote:
"Kevin Aylward" wrote in message
...

[snipped much voluminous banter]

Whilst, I do agree that Win is very knowledgeable and an expert, I am
also an expert. I have been doing this rather a long time as well you
know. The fact that I am not an academic is not relevant. In all
honesty, there is not much I don't know about general analogue
design, although, obviously, I don't claim to know it all. Does Win
know more than me? Unlikely. Or do I know more than Win. Unlikely.
However, we may well know different things.

[snipped more banter]

Does the above pose a question, or is it mere rhetoric? Could the
scientific method be applied with gusto? Are Win and Kev evenly
matched?

I don't know. How tall is he, I'm only 5'8"

All talk, then. Pity, I would have enjoyed the sport of a contest. It
seems this issue has been smothered with words. If one could apply the
"science" to "design", the words would have more meaning.

Frank Raffaeli
http://www.aomwireless.com/

Paul Burridge wrote:
On Wed, 10 Sep 2003 10:25:49 +0100, "Kevin Aylward"
wrote:


That is, to achieve linear multiplication by this transistor gm
method, it necessarily requires a non-linear relation between I and
V for the transistors gm characteristics. This forms a proof of my
statement that the class A modulator achieves such modulation by a
non-linear process.

gwhite:

Please do not respond if you are going to past masses of waffle text
that you don't understand. Provide a *mathematical* *explicit*
disproof of my mathematics or present your retraction.

Well this is compelling stuff, I must say. I'd hoped to be able to
disappear on holiday for a week and return refreshed, but it looks
like I'm going to have to seek out cybercafes to keep up to date on
these exchanges instead. :-( Still no outright winner so far...

Not to me aint. The case is closed.

The problem with gwhite, is that his arguments are all based on "an
appeal to authority", and we all know that is not the way science is
done. He pastes reams of stuff without the slightest idea of what the
documents are talking about. The assumption being that such documents
back him up. They don't. He hasn't presented one, not even one
derivation of his claim, only end results. This is typical of all
vacuous claims. It says so in the bible, so it must be true sort of
thing.

On the otherhand, he does have a very valid point that one, could in
principle, make a modulator that does not depend on an inherent
non-linearity, he just happened to pick the wrong examples, and the
wrong person to debate with. He obviously learnt the basic concept from
a coarse he took, but never understood
enough to know when and how to apply it. For the active bipolar or fet
case, the gain setting is gm based, and this gm is electrically
controlled by the value of its
own current, hence, as a I proved, must have a non-linear V/I curve.
However, for example, in a passive case, things are different. If one
used a fet as a passive voltage controlled resister, the resistance is a
function of the gate source voltage, but the control voltage is not
connected accross the controlled resistance, and the resistance
variation is not implied to be a function of its own current, therefore
a non-linear resistance is not implied. Indeed, this technique is used
in guitar phaser pedals to produce a swept notch filter, and I designed
and built my
first one of those around 25 years ago, based on this concept. To make
the fet even more linear, as qwhite correctly suggested, I used, as is
well known standard practice, a series gate resister and feedback
resistor from drain to gate. Unfortunately, I made a mistake...in my
"there is only a world market for 5 computers" statement, I forgot what
I already knew:-)

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Paul Burridge wrote:
On Wed, 10 Sep 2003 10:25:49 +0100, "Kevin Aylward"
wrote:


That is, to achieve linear multiplication by this transistor gm
method, it necessarily requires a non-linear relation between I and
V for the transistors gm characteristics. This forms a proof of my
statement that the class A modulator achieves such modulation by a
non-linear process.

gwhite:

Please do not respond if you are going to past masses of waffle text
that you don't understand. Provide a *mathematical* *explicit*
disproof of my mathematics or present your retraction.

Well this is compelling stuff, I must say. I'd hoped to be able to
disappear on holiday for a week and return refreshed, but it looks
like I'm going to have to seek out cybercafes to keep up to date on
these exchanges instead. :-( Still no outright winner so far...

Not to me aint. The case is closed.

The problem with gwhite, is that his arguments are all based on "an
appeal to authority", and we all know that is not the way science is
done. He pastes reams of stuff without the slightest idea of what the
documents are talking about. The assumption being that such documents
back him up. They don't. He hasn't presented one, not even one
derivation of his claim, only end results. This is typical of all
vacuous claims. It says so in the bible, so it must be true sort of
thing.

On the otherhand, he does have a very valid point that one, could in
principle, make a modulator that does not depend on an inherent
non-linearity, he just happened to pick the wrong examples, and the
wrong person to debate with. He obviously learnt the basic concept from
a coarse he took, but never understood
enough to know when and how to apply it. For the active bipolar or fet
case, the gain setting is gm based, and this gm is electrically
controlled by the value of its
own current, hence, as a I proved, must have a non-linear V/I curve.
However, for example, in a passive case, things are different. If one
used a fet as a passive voltage controlled resister, the resistance is a
function of the gate source voltage, but the control voltage is not
connected accross the controlled resistance, and the resistance
variation is not implied to be a function of its own current, therefore
a non-linear resistance is not implied. Indeed, this technique is used
in guitar phaser pedals to produce a swept notch filter, and I designed
and built my
first one of those around 25 years ago, based on this concept. To make
the fet even more linear, as qwhite correctly suggested, I used, as is
well known standard practice, a series gate resister and feedback
resistor from drain to gate. Unfortunately, I made a mistake...in my
"there is only a world market for 5 computers" statement, I forgot what
I already knew:-)

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Paul Burridge wrote:
On Mon, 08 Sep 2003 10:23:36 -0700, gwhite wrote:

That is clever -- you want me to "declare" something is true that
I've made no reference to. You are quite the inventor. Face it:
you had an incorrect notion about linearity. All the rest of your
words are twisting, squirming, and turning to try to save face after
you acted condescending (and still do) about a very simple matter.
That's all.

I have to say I've been wrestling with this attitude problem of kev's
as well. Earlier this evening I postulated to myself that the reason
for all these contradictory posts

What contradictory posts?

As far as attitude goes, I think we can all get rather exasperated when
someone else uses very strong rhetoric against ones own competence, when
it is trivially obvious that such claims are completely without any
merit whatsoever.

and arguments over semantics might
possibly be due to Kev's impared usage of English.

See below.

If the guy's
dyslexic or has some other comprehension problem, he might very well
be an electronics genius but we'd find it hard to tell because this
veil between he and us muddies the water both ways.

This makes little sense. Most of my posts are very clear, although not
necessarily pristine in all aspects of their structure. Any lack of
comprehension of them, is often a problem with the reader.

You view as
expressed above is a very much more cynical one, but I'm forming the
view that one or t'other must explain it. But Kev has admitted to
English not being his strong suit elsewhere on the group

My fundamental problem with English is that I have a very poor memory,
in conjunction with the fact that I am a two fingered typist. This
results in an inability to spell or type accurately. I usually function
by understanding and deriving results from basic concepts, rather than
by remembering millions of facts. Unfortunately I don't always check the
spell checked version that well. For instance, "simplely" might come out
as "simple" instead of "simply", making the statement "Its that simply",
grammatically wrong.

and if that's
the case and he really *does* know what he's talking about then

Of course I do.

I feel
sorry for him. It must be pretty ****ty and exceedingly frustrating
for anyone in that position. I know; I've met a few and it's ruined
their lives.

My life is quite fine thank you. I have wrote volumes of decent
technical reports, with no complaints.

I usually write quite accurately, expressing exactly what I want to say
in order to cover my arse. I do this explicitly, deliberately and
seriously as a general rule, with the method of "Yes Minister" TV series
speak. Often, it is a joy to watch other people fail to understand what
was actually said. For example, suppose the Minister had read a paper
indicating that a proposal of his would generate 500 redundancies. In
the House of Commons, he would say "No person informed me that there
would be any redundancies from my proposal". If you actually go back and
check my posts, you might be well surprised how subtle some of the
points are. Of course, at times I have made what might have been
inaccurate statements, but this is often simply because I have
temporally forgot something that I know well, or I have made an
assumption, that the obvious exceptions, are being deliberately ignored
for the purposes of the discussion. The issue here, is that the novice,
interprets this as a lack of understanding on my part. It just gets too
cumbersome addressing all the details, when only the general picture is
required.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

Paul Burridge wrote:
On Mon, 08 Sep 2003 10:23:36 -0700, gwhite wrote:

That is clever -- you want me to "declare" something is true that
I've made no reference to. You are quite the inventor. Face it:
you had an incorrect notion about linearity. All the rest of your
words are twisting, squirming, and turning to try to save face after
you acted condescending (and still do) about a very simple matter.
That's all.

I have to say I've been wrestling with this attitude problem of kev's
as well. Earlier this evening I postulated to myself that the reason
for all these contradictory posts

What contradictory posts?

As far as attitude goes, I think we can all get rather exasperated when
someone else uses very strong rhetoric against ones own competence, when
it is trivially obvious that such claims are completely without any
merit whatsoever.

and arguments over semantics might
possibly be due to Kev's impared usage of English.

See below.

If the guy's
dyslexic or has some other comprehension problem, he might very well
be an electronics genius but we'd find it hard to tell because this
veil between he and us muddies the water both ways.

This makes little sense. Most of my posts are very clear, although not
necessarily pristine in all aspects of their structure. Any lack of
comprehension of them, is often a problem with the reader.

You view as
expressed above is a very much more cynical one, but I'm forming the
view that one or t'other must explain it. But Kev has admitted to
English not being his strong suit elsewhere on the group

My fundamental problem with English is that I have a very poor memory,
in conjunction with the fact that I am a two fingered typist. This
results in an inability to spell or type accurately. I usually function
by understanding and deriving results from basic concepts, rather than
by remembering millions of facts. Unfortunately I don't always check the
spell checked version that well. For instance, "simplely" might come out
as "simple" instead of "simply", making the statement "Its that simply",
grammatically wrong.

and if that's
the case and he really *does* know what he's talking about then

Of course I do.

I feel
sorry for him. It must be pretty ****ty and exceedingly frustrating
for anyone in that position. I know; I've met a few and it's ruined
their lives.

My life is quite fine thank you. I have wrote volumes of decent
technical reports, with no complaints.

I usually write quite accurately, expressing exactly what I want to say
in order to cover my arse. I do this explicitly, deliberately and
seriously as a general rule, with the method of "Yes Minister" TV series
speak. Often, it is a joy to watch other people fail to understand what
was actually said. For example, suppose the Minister had read a paper
indicating that a proposal of his would generate 500 redundancies. In
the House of Commons, he would say "No person informed me that there
would be any redundancies from my proposal". If you actually go back and
check my posts, you might be well surprised how subtle some of the
points are. Of course, at times I have made what might have been
inaccurate statements, but this is often simply because I have
temporally forgot something that I know well, or I have made an
assumption, that the obvious exceptions, are being deliberately ignored
for the purposes of the discussion. The issue here, is that the novice,
interprets this as a lack of understanding on my part. It just gets too
cumbersome addressing all the details, when only the general picture is
required.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.