How to get envelope from AM signal without phase shift
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From: WWalker on 28 Mar 2010 14:40 Eric, I am sorry to insist, but it does not matter what the reason is. If I have a communication link that allows me to transmit a pulse over a distance faster than a light propagated pulse, then the pulse propagates faster than light. If I use the pulse to denonate a bomb located a distance away, the bomb will explode sooner than if the pulse propagated at the speed of light. This is absolutly true and cannot be argued. The only question is if the dipole simulation demonstrates that a pulse can be detected over a distance faster than light. I think it has. The Andor circuit is only phase shifting the signal so that it appears the signal outputs before it is sent. The proof is that you can not use the circuit to turn itself off before the message was sent, thereby preventing the message from being sent in the first place. This is clearly shown in Fig. 7. Also note that in my dipole system the pulse always arrives after it is sent, not before as in Andor's circuit. Figure 2 in the Sten paper is showing the propagation of a pulse in the nearfield using the transverse electric field, where I and talking about the magnetic field component and my signals always arrive at the detector after they are sent, not before. Note the transverse electric field pulse in Fig 2b arrives before the signal was sent. This is because the transverse field is being created 1/4 wavelength outside the source and propagates both back toward the dipole and away from the source. At distances larger than the 1/4 wavelength the pulse is seen to propagate away from the dipole. If you plot Stens group speed Eq. 18 you can clearly see this. Refer my paper Eq. 72, and plot Fig.14. An animation showing this is shown in Fig. 20, 21, 23 William >On 3/28/2010 4:24 AM, WWalker wrote: >> Eric, >> >> I think you are missing the point. Refering to the Low Pass Filtered Pulse >> simulation I posted, the simulation clearly shows that if I transmit a >> pulse, the pulse edge arrives sooner than if it had propagated faster than >> light. If my detector at the receiving end is threshold detector which is >> set to look for anything above the noise level, it will fire earlier than >> if the pulse had propagated at light speed. In other words, it shows that >> if I push a button launching the narrowband pulse signal and propagate it >> via a dipole to a nearfield receiver with the threshold detector, the >> pressed button will be detected sooner than a light propagated signal. This >> clearly shows that an action (informaton) in this nearfield dipole system >> can be detected faster than light. If this is true than I have proven my >> point that information propagtes faster than light in the nearfield of a >> dipole. >> >> William > >I get the impression that you either haven't read or haven't understood >any of our previous dialogue. > >What you are seeing appears consistent with a phase advance of a >bandlimited signal, not accelerated propagation. The same sort of >bandlimited pulse is shown, and I'm sure everybody is getting weary of >me citing these same references over and over again, with apparent >acceleration in Andor's blog (Figures 4 and 5) and in Sten's paper (Fig. >2.a). > >Both show apparent arrival of the output pulse before the input, but it >is only a small phase advance of the signal due to the nature of the >medium (i.e., an unusual group delay). Both authors acknowledge this. > You do not. Andor demonstrated, pretty clearly, that the system is, >in fact, causal, by turning off the input signal and observing the >output signal end in Fig. 7. This is why people here have been trying >to get you to do something similar, because otherwise the logical >explanation is that there's just a slight phase advance in the signal. > > >-- >Eric Jacobsen >Minister of Algorithms >Abineau Communications >http://www.abineau.com >
From: Eric Jacobsen on 28 Mar 2010 16:13 On 3/28/2010 11:40 AM, WWalker wrote: > Eric, > > I am sorry to insist, but it does not matter what the reason is. If I have > a communication link that allows me to transmit a pulse over a distance > faster than a light propagated pulse, then the pulse propagates faster than > light. I suppose you can argue semantics here about what defines the "pulse", but understand that "information" is not propagating faster than light in any of the examples, and neither is energy. This seems to be the key point that must be understood. A simple small phase advance of a signal is NOT indicative of information exceeding the speed of light. If you just want to claim that the signal has phase advanced and appears to arrive earlier than expected, that's fine, I don't think anyone will argue with you there. That's what has led to discussion and study on this topic in many places. > If I use the pulse to denonate a bomb located a distance away, the > bomb will explode sooner than if the pulse propagated at the speed of > light. This is absolutly true and cannot be argued. The only question is if > the dipole simulation demonstrates that a pulse can be detected over a > distance faster than light. I think it has. If you want to wave your hands about the definition of the pulse, sure. If you want to claim that actual information has been accelerated, then, no. You've demonstrated something that's been known for a long time, that bandlimited signals have a predictable quality than can be exploited. That's not new. > The Andor circuit is only phase shifting the signal so that it appears the > signal outputs before it is sent. The proof is that you can not use the > circuit to turn itself off before the message was sent, thereby preventing > the message from being sent in the first place. This is clearly shown in > Fig. 7. Also note that in my dipole system the pulse always arrives after > it is sent, not before as in Andor's circuit. The relevant part of the argument is that the signal arrives before expected. Whether the acceleration is due to negative group delay or phase velocity or some other mathematical arrangement, the point is that a bandlimited signal can appear to be predicted by fairly simple processes. The circuit in Andor's example isn't very complicated. The mechanisms by which the dispersion or phase response is affected in the near field of an antenna doesn't appear to be out of that realm at all. The key point is that there is a straightforward explanation that doesn't involve non-causality or propagation faster than light. So when somebody comes along and shows the exact same sort of small phase advance associated with bandlimited prediction and says, "this proves propagation faster than c!", it cannot be taken as true by anyone who knows of the more likely explanation. There is a very large burden of proof that goes with such a claim, and I haven't seen anything that would indicate to me a single step past the ordinary explanation. > Figure 2 in the Sten paper is showing the propagation of a pulse in the > nearfield using the transverse electric field, where I and talking about > the magnetic field component and my signals always arrive at the detector > after they are sent, not before. Note the transverse electric field pulse > in Fig 2b arrives before the signal was sent. This is because the > transverse field is being created 1/4 wavelength outside the source and > propagates both back toward the dipole and away from the source. At > distances larger than the 1/4 wavelength the pulse is seen to propagate > away from the dipole. If you plot Stens group speed Eq. 18 you can clearly > see this. Refer my paper Eq. 72, and plot Fig.14. An animation showing this > is shown in Fig. 20, 21, 23 Perhaps what you think you're demonstrating is the mechanism by which the system achieves the same sort of bandlimited prediction experienced in a negative group delay filter. Again, that's far, far more believable than propagation faster than c, especially when it's a known and understood phenomenon. Yet again let me point out that a discontinuity like that shown in Andor's analysis might be able to be measured through your system. It's clear you're not trying to show causality, but propagation. So why not demonstrate the discontinuity propagating faster than c? I'd think it'd be a good experiment and might reveal something useful about the system. I think until you can demonstrate something like that the more likely explanation of bandlimited prediction would be expected to prevail. -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com
From: glen herrmannsfeldt on 28 Mar 2010 16:31 WWalker <william.walker(a)n_o_s_p_a_m.imtek.de> wrote: > I am sorry to insist, but it does not matter what the reason is. If I have > a communication link that allows me to transmit a pulse over a distance > faster than a light propagated pulse, then the pulse propagates faster than > light. If I use the pulse to denonate a bomb located a distance away, the > bomb will explode sooner than if the pulse propagated at the speed of > light. This is absolutly true and cannot be argued. The only question is if > the dipole simulation demonstrates that a pulse can be detected over a > distance faster than light. I think it has. No it doesn't. A narrow band pulse has to build up slowly. If it has a sudden edge then it necessarily has a wide bandwidth. A common case is a wave packet with a Gaussian envelope. With such a pulse, there is some signal long before the main part of the pulse, and that can be detected. There are materials that can amplify the leading edge of a pulse, and attenuate the rest. The result is a new pulse that seems to have gone faster than c. If you try to use it for information transmission, though, you will find that it does not violate special relativity. -- glen
From: Jerry Avins on 28 Mar 2010 21:12 Eric Jacobsen wrote: ... > I think until you can demonstrate something like that the more likely > explanation of bandlimited prediction would be expected to prevail. Even allowing the unlikely possibility that the 6-degree phase advance *in the near field* represents a real speed increase, and that the "pulse" in the far field is expected to show no advance at all, What practical use can this have? Jerry -- Discovery consists of seeing what everybody has seen, and thinking what nobody has thought. .. Albert Szent-Gyorgi �����������������������������������������������������������������������
From: steveu on 28 Mar 2010 22:58
>On 3/28/2010 11:40 AM, WWalker wrote: >> Eric, >> >> I am sorry to insist, but it does not matter what the reason is. If I have >> a communication link that allows me to transmit a pulse over a distance >> faster than a light propagated pulse, then the pulse propagates faster than >> light. > >I suppose you can argue semantics here about what defines the "pulse", >but understand that "information" is not propagating faster than light >in any of the examples, and neither is energy. This seems to be the key >point that must be understood. A simple small phase advance of a >signal is NOT indicative of information exceeding the speed of light. > >If you just want to claim that the signal has phase advanced and appears >to arrive earlier than expected, that's fine, I don't think anyone will >argue with you there. That's what has led to discussion and study on >this topic in many places. Now you're getting to the crux. Information is energy. Real physical energy. Not virtual photons, and other smoke and mirrors. Its real physical energy of the kind that gets water hot. Show energy flow faster than light and you've shown information flow faster than light. Fail, and you haven't. >> If I use the pulse to denonate a bomb located a distance away, the >> bomb will explode sooner than if the pulse propagated at the speed of >> light. This is absolutly true and cannot be argued. The only question is if >> the dipole simulation demonstrates that a pulse can be detected over a >> distance faster than light. I think it has. Bombs dissipate real physical energy. This is why nobody disputes the carriage of information - typically the news that someone is seriously pissed off. Until the energy starts to dissipate, the information has not arrived (although side channel information, like seeing the bomb fly over, may well arrive earlier). Demonstrate an energy flow faster than light, and we'll all be amazed, and you'll be rich. Steve |