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. |
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