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#1
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On Jul 1, 8:53*am, K1TTT wrote:
On Jul 1, 12:37*pm, Cecil Moore wrote: On Jun 30, 11:29*am, Keith Dysart wrote: Check the a0 coefficient in the Fourier transform. This represents the DC component of the signal. And the result is zero EM waves, either forward or reflected, and your argument falls apart. Without this, how would you deal with a signal such as * V(t) = 10 + 2 cos(3t) If the cosine term is zero, there are zero EM waves, either forward or reflected, and your argument falls apart. Incidentally, V(t) = 10, is a perfect way to prove that energy and the time derivitive of energy are not the same thing and your argument falls apart. Alternatively, one can use the standard trick for dealing with non-repetitive waveforms: choose an arbitrary period. 24 hours would probably be suitable for these examples and transform from there. Still, you will have zero frequency component to deal with, but there will be some at higher frequencies (if you choose your function to make it so). Windowing doesn't generate EM waves where none exist in reality and your argument falls apart. -- 73, Cecil, w5dxp.com a better argument is that a constant voltage produces a constant electric field everywhere, since the field is not varying in time or space there is no time or space derivative to create a magnetic field so there can be no propagating em wave. *you could do the same with zero or constant current producing a constant magnetic field. The same question for you... With an infinitely long transmission line excited by a step function, is there an EM wave propagating down the line? If not, what is it that is propagating down the line? Especially at the leading edge? essentially the dc case IS unique in that you must wait forever for it to reach sinusoidal steady state since the lowest frequency component is 0hz You have used similar phrases before. Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? ....Keith |
#2
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On Jul 5, 1:26*am, Keith Dysart wrote:
On Jul 1, 8:53*am, K1TTT wrote: On Jul 1, 12:37*pm, Cecil Moore wrote: On Jun 30, 11:29*am, Keith Dysart wrote: Check the a0 coefficient in the Fourier transform. This represents the DC component of the signal. And the result is zero EM waves, either forward or reflected, and your argument falls apart. Without this, how would you deal with a signal such as * V(t) = 10 + 2 cos(3t) If the cosine term is zero, there are zero EM waves, either forward or reflected, and your argument falls apart. Incidentally, V(t) = 10, is a perfect way to prove that energy and the time derivitive of energy are not the same thing and your argument falls apart. Alternatively, one can use the standard trick for dealing with non-repetitive waveforms: choose an arbitrary period. 24 hours would probably be suitable for these examples and transform from there. Still, you will have zero frequency component to deal with, but there will be some at higher frequencies (if you choose your function to make it so). Windowing doesn't generate EM waves where none exist in reality and your argument falls apart. -- 73, Cecil, w5dxp.com a better argument is that a constant voltage produces a constant electric field everywhere, since the field is not varying in time or space there is no time or space derivative to create a magnetic field so there can be no propagating em wave. *you could do the same with zero or constant current producing a constant magnetic field. The same question for you... With an infinitely long transmission line excited by a step function, is there an EM wave propagating down the line? If not, what is it that is propagating down the line? Especially at the leading edge? essentially the dc case IS unique in that you must wait forever for it to reach sinusoidal steady state since the lowest frequency component is 0hz You have used similar phrases before. Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? ...Keith 'it depends'... in the special case you have concocted where the signal source has no reflections it only takes one round trip. this case is very misleading if you try to extend it to cover other cases. in general it takes infinitely long and you must account for the infinite series of reflections. that is why the approximations used to come up with the sinusoidal steady state solution is so useful, and exactly why it can not be applied to steps and square waves and other non sinusoidal constant sources. and in your infinite line example it never reaches steady state so the step wave propagates forever. |
#3
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On Jul 5, 6:19*am, K1TTT wrote:
On Jul 5, 1:26*am, Keith Dysart wrote: On Jul 1, 8:53*am, K1TTT wrote: On Jul 1, 12:37*pm, Cecil Moore wrote: On Jun 30, 11:29*am, Keith Dysart wrote: Check the a0 coefficient in the Fourier transform. This represents the DC component of the signal. And the result is zero EM waves, either forward or reflected, and your argument falls apart. Without this, how would you deal with a signal such as * V(t) = 10 + 2 cos(3t) If the cosine term is zero, there are zero EM waves, either forward or reflected, and your argument falls apart. Incidentally, V(t) = 10, is a perfect way to prove that energy and the time derivitive of energy are not the same thing and your argument falls apart. Alternatively, one can use the standard trick for dealing with non-repetitive waveforms: choose an arbitrary period. 24 hours would probably be suitable for these examples and transform from there. Still, you will have zero frequency component to deal with, but there will be some at higher frequencies (if you choose your function to make it so). Windowing doesn't generate EM waves where none exist in reality and your argument falls apart. -- 73, Cecil, w5dxp.com a better argument is that a constant voltage produces a constant electric field everywhere, since the field is not varying in time or space there is no time or space derivative to create a magnetic field so there can be no propagating em wave. *you could do the same with zero or constant current producing a constant magnetic field. The same question for you... With an infinitely long transmission line excited by a step function, is there an EM wave propagating down the line? If not, what is it that is propagating down the line? Especially at the leading edge? essentially the dc case IS unique in that you must wait forever for it to reach sinusoidal steady state since the lowest frequency component is 0hz You have used similar phrases before. Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? ...Keith 'it depends'... in the special case you have concocted where the 'Concocted has such perjorative ring to it. Much better would be 'appropriately selected to illustrate a point'! signal source has no reflections it only takes one round trip. * Excellent. Some agreement. this case is very misleading if you try to extend it to cover other cases. in general it takes infinitely long and you must account for the infinite series of reflections. * Of course. But this illustrates one of the benefits of "appropriately selecting" examples. One can choose examples that do not take forever to settle and therefore can be analyzed in finite time. that is why the approximations To which approximations do you refer? used to come up with the sinusoidal steady state solution is so useful, and exactly why it can not be applied to steps and square waves and other non sinusoidal constant sources. Are you suggesting that it is inappropriate to use the reflection coefficient computed at an impedance discontinuity to predict the behaviour of a transmission line excited with a 'step, square wave or other non sinusoidal constant sources"? and in your infinite line example it never reaches steady state so the step wave propagates forever So is this 'step wave' an EM wave, according to your definition of an EM wave? If not, what would you call it? ....Keith |
#4
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On Jul 6, 12:17*am, Keith Dysart wrote:
On Jul 5, 6:19*am, K1TTT wrote: On Jul 5, 1:26*am, Keith Dysart wrote: On Jul 1, 8:53*am, K1TTT wrote: On Jul 1, 12:37*pm, Cecil Moore wrote: On Jun 30, 11:29*am, Keith Dysart wrote: Check the a0 coefficient in the Fourier transform. This represents the DC component of the signal. And the result is zero EM waves, either forward or reflected, and your argument falls apart. Without this, how would you deal with a signal such as * V(t) = 10 + 2 cos(3t) If the cosine term is zero, there are zero EM waves, either forward or reflected, and your argument falls apart. Incidentally, V(t) = 10, is a perfect way to prove that energy and the time derivitive of energy are not the same thing and your argument falls apart. Alternatively, one can use the standard trick for dealing with non-repetitive waveforms: choose an arbitrary period. 24 hours would probably be suitable for these examples and transform from there. Still, you will have zero frequency component to deal with, but there will be some at higher frequencies (if you choose your function to make it so). Windowing doesn't generate EM waves where none exist in reality and your argument falls apart. -- 73, Cecil, w5dxp.com a better argument is that a constant voltage produces a constant electric field everywhere, since the field is not varying in time or space there is no time or space derivative to create a magnetic field so there can be no propagating em wave. *you could do the same with zero or constant current producing a constant magnetic field. The same question for you... With an infinitely long transmission line excited by a step function, is there an EM wave propagating down the line? If not, what is it that is propagating down the line? Especially at the leading edge? essentially the dc case IS unique in that you must wait forever for it to reach sinusoidal steady state since the lowest frequency component is 0hz You have used similar phrases before. Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? ...Keith 'it depends'... in the special case you have concocted where the 'Concocted has such perjorative ring to it. Much better would be 'appropriately selected to illustrate a point'! signal source has no reflections it only takes one round trip. * Excellent. Some agreement. this case is very misleading if you try to extend it to cover other cases. in general it takes infinitely long and you must account for the infinite series of reflections. * Of course. But this illustrates one of the benefits of "appropriately selecting" examples. One can choose examples that do not take forever to settle and therefore can be analyzed in finite time. that is why the approximations To which approximations do you refer? used to come up with the sinusoidal steady state solution is so useful, and exactly why it can not be applied to steps and square waves and other non sinusoidal constant sources. Are you suggesting that it is inappropriate to use the reflection coefficient computed at an impedance discontinuity to predict the behaviour of a transmission line excited with a 'step, square wave or other non sinusoidal constant sources"? and in your infinite line example it never reaches steady state so the step wave propagates forever So is this 'step wave' an EM wave, according to your definition of an EM wave? If not, what would you call it? ...Keith correct, the 'step wave' is not AN EM wave, it is an infinite summation of EM waves. |
#5
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On Jul 6, 6:01*pm, K1TTT wrote:
On Jul 6, 12:17*am, Keith Dysart wrote: On Jul 5, 6:19*am, K1TTT wrote: On Jul 5, 1:26*am, Keith Dysart wrote: On Jul 1, 8:53*am, K1TTT wrote: On Jul 1, 12:37*pm, Cecil Moore wrote: On Jun 30, 11:29*am, Keith Dysart wrote: Check the a0 coefficient in the Fourier transform. This represents the DC component of the signal. And the result is zero EM waves, either forward or reflected, and your argument falls apart. Without this, how would you deal with a signal such as * V(t) = 10 + 2 cos(3t) If the cosine term is zero, there are zero EM waves, either forward or reflected, and your argument falls apart. Incidentally, V(t) = 10, is a perfect way to prove that energy and the time derivitive of energy are not the same thing and your argument falls apart. Alternatively, one can use the standard trick for dealing with non-repetitive waveforms: choose an arbitrary period. 24 hours would probably be suitable for these examples and transform from there. Still, you will have zero frequency component to deal with, but there will be some at higher frequencies (if you choose your function to make it so). Windowing doesn't generate EM waves where none exist in reality and your argument falls apart. -- 73, Cecil, w5dxp.com a better argument is that a constant voltage produces a constant electric field everywhere, since the field is not varying in time or space there is no time or space derivative to create a magnetic field so there can be no propagating em wave. *you could do the same with zero or constant current producing a constant magnetic field. The same question for you... With an infinitely long transmission line excited by a step function, is there an EM wave propagating down the line? If not, what is it that is propagating down the line? Especially at the leading edge? essentially the dc case IS unique in that you must wait forever for it to reach sinusoidal steady state since the lowest frequency component is 0hz You have used similar phrases before. Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? ...Keith 'it depends'... in the special case you have concocted where the 'Concocted has such perjorative ring to it. Much better would be 'appropriately selected to illustrate a point'! signal source has no reflections it only takes one round trip. * Excellent. Some agreement. this case is very misleading if you try to extend it to cover other cases. in general it takes infinitely long and you must account for the infinite series of reflections. * Of course. But this illustrates one of the benefits of "appropriately selecting" examples. One can choose examples that do not take forever to settle and therefore can be analyzed in finite time. that is why the approximations To which approximations do you refer? used to come up with the sinusoidal steady state solution is so useful, and exactly why it can not be applied to steps and square waves and other non sinusoidal constant sources. Are you suggesting that it is inappropriate to use the reflection coefficient computed at an impedance discontinuity to predict the behaviour of a transmission line excited with a 'step, square wave or other non sinusoidal constant sources"? and in your infinite line example it never reaches steady state so the step wave propagates forever So is this 'step wave' an EM wave, according to your definition of an EM wave? If not, what would you call it? ...Keith correct, the 'step wave' is not AN EM wave, it is an infinite summation of EM waves Well at least there is no attempt at diversion here. What is the shape of these EM waves of which there is an infinite number which sum to a step? ....Keith |
#6
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On Jul 4, 8:26*pm, Keith Dysart wrote:
Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? Your infinitely long open-circuited transmission line example certainly takes infinitely long to reach steady-state so the leading- edge EM wave continues forever with zero reflected EM waves and your argument involving reflected waves falls apart. Your finite open-circuited transmission line example reaches DC steady- state where EM waves cease to exist so your argument involving forward and reflected waves falls apart. -- 73, Cecil, w5dxp.com |
#7
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On Jul 5, 1:16*pm, Cecil Moore wrote:
On Jul 4, 8:26*pm, Keith Dysart wrote: Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? Your infinitely long open-circuited transmission line example certainly takes infinitely long to reach steady-state so the leading- edge EM wave continues forever with zero reflected EM waves and your argument involving reflected waves falls apart. Your finite open-circuited transmission line example reaches DC steady- state where EM waves cease to exist so your argument involving forward and reflected waves falls apart. -- 73, Cecil, w5dxp.com 'dc steady state' is an oxymoron... |
#8
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On Jul 5, 8:38*am, K1TTT wrote:
'dc steady state' is an oxymoron... Webster's says an "oxymoron" is self-contradictory. "DC transient state" would be an oxymoron. "DC steady-state" is merely redundant. :-) -- 73, Cecil, w5dxp.com |
#9
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On 5 jul, 10:16, Cecil Moore wrote:
On Jul 4, 8:26*pm, Keith Dysart wrote: Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? Your infinitely long open-circuited transmission line example certainly takes infinitely long to reach steady-state so the leading- edge EM wave continues forever with zero reflected EM waves and your argument involving reflected waves falls apart. Your finite open-circuited transmission line example reaches DC steady- state where EM waves cease to exist so your argument involving forward and reflected waves falls apart. -- 73, Cecil, w5dxp.com Hi Richard, good day: Again you give me another rethoric answer... Please, tell us how to measure to distinguish Osc. A from Osc. B, having Osc. A 4*10^28 quanta and Osc. B 4*10^28 +1 quanta, having each 80 m quantum 2.3 * 10^-19 J. Your answers are making me remember = "It was the only explicit answer you will ever get" or "Superman's cataracts with his xray vision. This is probably going to be your only direct answer." (Please do not go upsetting, I am joking). You dislike my examples, you dislike R & H & K classic and obviously really good peer reviewed book reference (and examples), you dislike university notes, you dislike analogies, you dislike Sagan... Today I know all things you dislike, what I do not know is how measure A and B oscillator to distinguish each other... :D Remember, you are rebutting things stated in standard university physics book, does not reverse the burden of proof. Please be a good boy, be plain and do not resort to old tricks such as posting esoteric rocket science hiper-specialized incomprehensible answers :) 73 Miguel Ghezzi - LU6ETJ |
#10
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On 5 jul, 14:20, lu6etj wrote:
On 5 jul, 10:16, Cecil Moore wrote: On Jul 4, 8:26*pm, Keith Dysart wrote: Are you suggesting that an open circuited transmission line excited with a step function takes infinitely long to read steady state? Your infinitely long open-circuited transmission line example certainly takes infinitely long to reach steady-state so the leading- edge EM wave continues forever with zero reflected EM waves and your argument involving reflected waves falls apart. Your finite open-circuited transmission line example reaches DC steady- state where EM waves cease to exist so your argument involving forward and reflected waves falls apart. -- 73, Cecil, w5dxp.com Hi Richard, good day: Again you give me another rethoric answer... Please, tell us how to measure to distinguish Osc. A *from *Osc. B, having Osc. A 4*10^28 quanta and Osc. B 4*10^28 +1 quanta, having each 80 m quantum 2.3 * 10^-19 J. Your answers are making me remember = "It was the only explicit answer you will ever get" or "Superman's cataracts with his xray vision. *This is probably going to be your only direct answer." (Please do not go upsetting, I am joking). You dislike my examples, you dislike R & H & K classic and obviously really good peer reviewed book reference (and examples), you dislike university notes, you dislike analogies, you dislike Sagan... Today I know all things you dislike, what I do not know is how measure A and B oscillator to distinguish each other... :D Remember, you are rebutting things stated in standard university physics book, does not reverse the burden of proof. Please be a good boy, be plain and do not resort to old tricks such as posting esoteric rocket science hiper-specialized incomprehensible answers :) 73 Miguel Ghezzi - LU6ETJ- Ocultar texto de la cita - - Mostrar texto de la cita - SRI, I ommited to say the example of the University of New Mexico link it is similar to the one given in "Physics for scientists and engineers" (Serway & Beichner, my copy is in spanish). They say the same about it. Humoroues note: Richard Feynman do not share your dislike for analogies he compare corks in water with charged objects fields :) |
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