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#1
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Keith Dysart wrote:
I then restated your claim as applying only at those particular times and not at other points in the cycle, but you were unhappy with that limitation. There are no limitations. If zero interference exists, then 100% of the reflected energy is dissipated in the source resistor. -- 73, Cecil http://www.w5dxp.com |
#2
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I have consolidated three replies below...
On Mar 20, 12:29*am, Cecil Moore wrote: Keith Dysart wrote: I then restated your claim as applying only at those particular times and not at other points in the cycle, but you were unhappy with that limitation. There are no limitations. If zero interference exists, then 100% of the reflected energy is dissipated in the source resistor. Sentence one says "no limitations". Sentence two specifies a limitation. But your paper did provide that limitation and indicated that circuit (Fig 1-1) with a 45 degree line was an example which satisfied that limitation. But in subsequent discussion you have waffled about whether, for the circuit in Fig 1-1, "100% of the reflected energy is dissipated in the source resistor" is applicable for all time or only for those instances when the source voltage is equal to 0. Could you clarify whether your claim for the circuit of Fig 1-1 applies to all time, or just to those instances when the source voltage is 0. On Mar 20, 12:34 am, Cecil Moore wrote: Keith Dysart wrote: If you wish to have your equalities apply at only selected points within the cycle, that works for me. Not only at selected points within the cycle but also for average values. If zero average interference exists then 100% of the average reflected energy is dissipated in the source resistor which is the subject of my Part 1 article. If the instantaneous interference is zero, 100% of the instantaneous reflected power is dissipated in the source resistor. Perhaps this has clarified. So you are only claiming that reflected energy is dissipated in the source resistor at those instances when the source voltage is zero. Good. Now as to averages: Averaging is a mathematical operation applied to the signal which reduces information. I do agree that the increase in the average dissipation in the source resistor is numerically equal to the average value of the reflected power. But this is just numerical equivalency. It does not prove that the energy in the reflected wave is dissipated in the source resistor. To prove the latter, one must show that the energy in the reflected wave, on an instance by instance basis is dissipated in the source resistor because conservation of energy applies at the instantaneous level. And I have shown in an evaluation of the instantaneous energy flows that the energy dissipated in the source resistor is not the energy from the reflected wave. I repeat: When zero interference exists, 100% of the reflected energy is dissipated in the source resistor. But only at those instances where the source voltage is zero. On Mar 20, 12:50 am, Cecil Moore wrote: Keith Dysart wrote: But I notice that you have not yet indicated which energy equation I may have written that was unbalanced. Why should I waste my time finding your conservation of energy violations? Mostly to prove that my analysis has an error. I repeat: When there exists zero interference, 100% of the reflected energy is dissipated in the source resistor. Since you think you provided an example where that statement is not true, your example violates the conservation of energy principle. But if there is no error in my analysis (and you have not found one), then perhaps you should examine whether the clause "When there exists zero interference, 100% of the reflected energy is dissipated in the source resistor" is in error. Sometimes one has to re-examine one's deeply held beliefs in the light of new evidence. It is the only rational thing to do. ...Keith |
#3
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Keith Dysart wrote:
Sentence one says "no limitations". Sentence two specifies a limitation. Semantic games. There are no limitations within the stated boundary conditions just like any number of other concepts. Could you clarify whether your claim for the circuit of Fig 1-1 applies to all time, or just to those instances when the source voltage is 0. There are no claims regarding instantaneous power in Fig 1-1 or anywhere else in my web article. All the claims in my web article refer to *average* powers and the article states exactly that. For the purpose and subject of the web article, the subject of instantaneous power is just an irrelevant diversion. No other author on the subject has ever mentioned instantaneous power. Given average values, time doesn't even appear in any of their equations. Apparently, those authors agree with Eugene Hecht that instantaneous power is "of limited utility". Here's my claim made in the article: When the *average* interference at the source resistor is zero, the *average* reflected power is 100% dissipated in the source resistor. I gave enough examples to prove that claim to be true. Since the instantaneous interference averages out to zero, this claim about *average* power is valid. When Tom, K7ITM, asserted that the same concepts work for instantaneous power, I took a look and realized that he was right. One can make the same claim about instantaneous power although I do not make that claim in my web article. When the instantaneous interference at the source resistor is zero, the instantaneous reflected power is 100% dissipated in the source resistor. Perhaps this has clarified. So you are only claiming that reflected energy is dissipated in the source resistor at those instances when the source voltage is zero. Good. I am claiming no such thing. Please cease and desist with the mind fornication, Keith. You cannot win the argument by being unethical. Mostly to prove that my analysis has an error. I have pointed out your error multiple times before, Keith, and you simply ignore what I say. Why should I waste any more time on someone who refuses to listen? One more time: Over and over, you use the equation Ptot = P1 + P2 even though every sophomore EE student knows the equation is (usually) invalid. The valid method for adding AC powers is: Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A) The last term is called the interference term which you have completely ignored in your analysis. Therefore, your analysis is obviously in error. When you redo your math to include the interference term, your conceptual blunders will disappear. Until then, you are just blowing smoke. -- 73, Cecil http://www.w5dxp.com |
#4
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On Mar 20, 10:02*am, Cecil Moore wrote:
Keith Dysart wrote: Sentence one says "no limitations". Sentence two specifies a limitation. Semantic games. The whole question here revolves around the meaning of the limitations on your claim. That is semantics. Not games. And it is key to the discussion. There are no limitations within the stated boundary conditions just like any number of other concepts. But you need to clearly state your limitations and stop flip flopping. Could you clarify whether your claim for the circuit of Fig 1-1 applies to all time, or just to those instances when the source voltage is 0. There are no claims regarding instantaneous power in Fig 1-1 or anywhere else in my web article. All the claims in my web article refer to *average* powers and the article states exactly that. For the purpose and subject of the web article, the subject of instantaneous power is just an irrelevant diversion. No other author on the subject has ever mentioned instantaneous power. I am surprised, this being 2008, that I could actually be offering a new way to study the question, but if you insist, I accept the accolade. Given average values, time doesn't even appear in any of their equations. Apparently, those authors agree with Eugene Hecht that instantaneous power is "of limited utility". Here's my claim made in the article: When the *average* interference at the source resistor is zero, the *average* reflected power is 100% dissipated in the source resistor. I gave enough examples to prove that claim to be true. Since the instantaneous interference averages out to zero, this claim about *average* power is valid. Without prejudice to the accuracy of the above, let us explore a bit. We know that conservation of energy requires that the energy flows balance at all times, which means that at any instance, the flows must account for all the energy. Analysis has shown that when examined with fine granularity, that for the circuit of Fig 1-1, the energy in the reflected wave is not always dissipated in the source resistor. For example, some of the time it is absorbed in the source. Now when the instantaneous flows are averaged, it is true that the increase in dissipation is numerically equal to the average power for the reflected wave. But this does not mean that the energy in the reflecte wave is dissipated in the source resistor, merely that the averages are equal. Now you qualify your claim with the term "*average* power". You say "the *average* reflected power is 100% dissipated in the source resistor." But the actual energy in the reflected wave is not dissipated in the source resistor. So what does it mean to say that the *average* is? When Tom, K7ITM, asserted that the same concepts work for instantaneous power, I took a look and realized that he was right. One can make the same claim about instantaneous power although I do not make that claim in my web article. When the instantaneous interference at the source resistor is zero, the instantaneous reflected power is 100% dissipated in the source resistor. Perhaps this has clarified. So you are only claiming that reflected energy is dissipated in the source resistor at those instances when the source voltage is zero. Good. I am claiming no such thing. Please cease and desist with the mind fornication, Keith. You cannot win the argument by being unethical. Unfortunately you struck the sentence which I paraphrased and then failed to explain which parts of it I may have misinterpreted. That does not help. It would have been more valuable for you to rewrite the original sentence to increase its clarity. Mostly to prove that my analysis has an error. I have pointed out your error multiple times before, Keith, and you simply ignore what I say. Why should I waste any more time on someone who refuses to listen? One more time: Over and over, I only have two expression involving power. you use the equation Ptot = P1 + P2 even though every sophomore EE student knows the equation is (usually) invalid. The valid method for adding AC powers is: Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A) Which of the two needs the 'cos' term? Ps(t) = Prs(t) + Pg(t) or Pg(t) = Pf.g(t) + Pr.g(t) In fact neither do. They both stand quite well on their own. Both are so correct, that they apply for any voltage function provided by the source. What would you propose to use for cos(A) when the source voltage function is aperiodic pulses? Fortunately, the 'cos' term is not needed so the question is completely moot. Non-the-less do feel free to offer corrected expression that include the 'cos(A)' term. The last term is called the interference term which you have completely ignored in your analysis. Therefore, your analysis is obviously in error. When you redo your math to include the interference term, your conceptual blunders will disappear. Until then, you are just blowing smoke. The math holds as it is. But I invite you to offer an alternative analysis that includes cos(A) terms. We can see how it holds up. If you can't, then you should definitely reconsider who is 'blowing smoke'. ...Keith |
#5
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Keith Dysart wrote:
But you need to clearly state your limitations and stop flip flopping. What you are calling "flip flopping" is me correcting my errors. Once I correct an error, I don't flip-flop back. My error was in assuming that the power-density (irradiance) equation only works on average powers. K7ITM convinced me that it works on instantaneous powers also. I am surprised, this being 2008, that I could actually be offering a new way to study the question, but if you insist, I accept the accolade. I'm sure you are not the first, just the first to think there is anything valid to be learned by considering instantaneous power to be important. Everyone except you discarded that notion a long time ago. Analysis has shown that when examined with fine granularity, that for the circuit of Fig 1-1, the energy in the reflected wave is not always dissipated in the source resistor. Yes, yes, yes, now you are starting to get it. When interference is present, the energy in the reflected wave is NOT dissipated in the source resistor. Those facts will be covered in Part 2 & 3 of my web article. Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A) Which of the two needs the 'cos' term? Ps(t) = Prs(t) + Pg(t) or Pg(t) = Pf.g(t) + Pr.g(t) In fact neither do. For instantaneous values of voltage, the phase angle is either 0 or 180 degrees so the cosine term is either +1 or -1. The math is perfectly consistent. That you don't recognize the sign of the instantaneous interference term as the cosine of 0 or 180 is amazing. Non-the-less do feel free to offer corrected expression that include the 'cos(A)' term. I did and you ignored it. There is no negative sign in the power equation yet you come up with negative signs. That you don't recognize your negative sign as cos(180) is unbelievable. The math holds as it is. But I invite you to offer an alternative analysis that includes cos(A) terms. We can see how it holds up. It it unfortunate that you don't comprehend that the cos(0) is +1 and the cos(180) is -1. The sign of the instantaneous interference term is the cosine term. The math certainly does hold as it is - you are just ignorant of the "is" part. -- 73, Cecil http://www.w5dxp.com |
#6
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On Mar 21, 12:37*pm, Cecil Moore wrote:
Keith Dysart wrote: But you need to clearly state your limitations and stop flip flopping. What you are calling "flip flopping" is me correcting my errors. Once I correct an error, I don't flip-flop back. Actually the flip-flopping I was referring to was the constant changes in your view of the limitations that apply to your claim. I am surprised, this being 2008, that I could actually be offering a new way to study the question, but if you insist, I accept the accolade. I'm sure you are not the first, just the first to think there is anything valid to be learned by considering instantaneous power to be important. Everyone except you discarded that notion a long time ago. Analysis has shown that when examined with fine granularity, that for the circuit of Fig 1-1, the energy in the reflected wave is not always dissipated in the source resistor. Yes, yes, yes, now you are starting to get it. Is this a flop or a flip? Are you now agreeing that the energy in the reflected wave is only dissipated in the source resistor for those instances when Vs is 0? When interference is present, the energy in the reflected wave is NOT dissipated in the source resistor. Those facts will be covered in Part 2 & 3 of my web article. Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A) Which of the two needs the 'cos' term? Ps(t) = Prs(t) + Pg(t) or Pg(t) = Pf.g(t) + Pr.g(t) In fact neither do. For instantaneous values of voltage, the phase angle is either 0 or 180 degrees so the cosine term is either +1 or -1. The math is perfectly consistent. [gratuitous insult snipped] Non-the-less do feel free to offer corrected expression that include the 'cos(A)' term. I did and you ignored it. I could not find them in the archive. Could you kindly provide them again, showing where the 'cos(A)' term fits in the equations: Ps(t) = Prs(t) + Pg(t) and Pg(t) = Pf.g(t) + Pr.g(t) There is no negative sign in the power equation yet you come up with negative signs. [gratuitous insult snipped] Negative signs also arise when one rearranges equations. The math holds as it is. But I invite you to offer an alternative analysis that includes cos(A) terms. We can see how it holds up. [gratuitous insult snipped] ...Keith |
#7
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Keith Dysart wrote:
Actually the flip-flopping I was referring to was the constant changes in your view of the limitations that apply to your claim. As I said, I corrected an error in my thinking. You are free to consider that to be a flip-flop, I consider it to be a step forward. Are you now agreeing that the energy in the reflected wave is only dissipated in the source resistor for those instances when Vs is 0? Yes, for instantaneous reflected energy exactly as I previously stated, but not true for average reflected energy. 100% of the average reflected energy is dissipated in the source resistor when the transmission line is 45 degrees long. That intra-cycle interference exists, thus delaying the dissipation by 90 degrees, is irrelevant to where the net energy winds up going. Your conservation of power principle would have you demanding that the power sourced by a battery charger must be instantaneously dissipated. Everyone except you seems to realize that is an invalid concept. The dissipation of energy can be delayed by a battery or a reactance. In the present example, the dissipation of the instantaneous reflected energy is delayed by 90 degrees by the reactance. I could not find them in the archive. Could you kindly provide them again, showing where the 'cos(A)' term fits in the equations: Go back and read the part where I said cos(0)=+1 and cos(180)=-1. There is no such thing as conservation of power. Your equations assume a conservation of power principle that doesn't exist in reality. The forward power is positive power. The reflected power is positive power. The only negative power is destructive interference which must be offset by an equal magnitude of constructive interference. When the instantaneous interference power is negative, the two voltages are 180 degrees out of phase and that is your cos(180)=-1. When the instantaneous interference power is positive, the two voltages are in phase and that is your cos(0)=+1. Why don't you already know all this elementary stuff? -- 73, Cecil http://www.w5dxp.com |
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