How to get envelope from AM signal without phase shift
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From: WWalker on 26 Mar 2010 09:46 Eric, I am not sure adding two signals is deterministic independant of the time span it is viewed. The signal only repeats after the modulation time 2/(f2-f1). One needs to sample the signal over this entire time period to be sure what the equation the signal corresponds to enabling one to say it is deterministic. If one only views the signal over a portion of the modulation peroid, one cannot be sure whether it is predictable because it could easily change from predictability when viewed over a larger time period. This is what the autocorrolation experiment of the this signal shows. Only after a modulation period does one see significant sidelobes in the triangular autocorrolation signal. I think an important question to resolve is if the dipole system is a filter or not. Filters can only phase shift signals, whereas a dipole generates a true time delay due to wave propagation. It is clear that this is true in the farfield. Why should it be different in the nearfield? With my last simulation I obtained the same superluminal results using a filtered an extremly nondeterministic random signal. If the dipole system is not a filter, how could the modulation envelope arrive sooner than a light propagated signal? Your last comment regarding the effects of noise are very impotant. As I mentioned at the very start of this discussion (thread), in order to prove information propagates faster than light in the nearfield of a dipole, one has to measure the time delay of the modulation (tp) and also show that it is possible to extract the information in a fraction of a carrier cycle (td). This is because the superluminal phenomina only occurs over a fraction of a carrier period and v=d/(tp+td. I am very certain that in a nearfield dipole system, the modulations of narrow band AM signals can be observed to arrive earlier in time than a light speed propagated signal. What I am not sure is wheather the modulations can be extracted in a fraction of a carrier cycle with real AM signals which noise. This is why I have contacted this group. From my investigations, the usual signal processing techniques do not work. Simple diode/mixer low pass filtering cannot be used because the filter requires more than a fraction of a carrier cycle to extract the modulation. FFT has the same problem. William >On 3/25/2010 8:45 AM, WWalker wrote: >> Eric, >> >> A narrow band AM signal propagates undistorted and faster than light in the >> nearfield and reduces to the speed of light as it goes into the farfield. A >> pulse distorts in the nearfield and and realigns as it goes into the >> farfield. When the pulse is distorted, one cannot say anything about the >> speed of the pulse. To transmit information faster than light one must use >> narrowband signals like AM and transmitt and receive them in the nearfield >> of the carrier. >> >> It is true that a real dipole anntena has filter characteristics. The >> simulation I presented is an idealized dipole like an oscillating electron >> which does not have filter characteristics. In an experiment with real >> antennas one would have to subtract out the phase shifts due to the >> antennas filter characteristics so that one only sees the time delay >> behavior of the propagating fields. >> >> The signals I used in my simulation are a changing modulation over the time >> window of analysis. The changing modulation does not repeat over this >> window. It is true that they are created from deterministic signals. >> Bassically I generated a beat frequency modulation which has a carrier and >> a modulation frequency. Provided the window of analysis is smaller than a >> modulation time period, the modulation pattern does not repeat. After a >> modulation period the patern repeats again. I chose this type of signal >> because it is a changing pattern which eventually repeats, enabling me to >> trigger it in a real experient and also enabling me to do time averaging >> which will help a lot with improving the SNR if a experimental signal. > >The period of the signal isn't necessarily consequential, the fact that >it is not random is. The point being that the signal you are using is >not suitable for measuring propagation at the resolution you're >interested in because it is a deterministic signal. Even when there's >a component that is randomly changing with time it is easy to get fooled >by the nature of narrowband signals, and that was pretty much a big >point of Andor's paper. I'm beginning to see why he chose the title >that he did. > >> When perform an autocorrelation of the modulation I used in my simulation, >> I see a triangular signal with a peak at the time of the analysis time >> window, indicating that the signal has no obserable repetition pattern of >> the this time. Only after I increase the analysis time window greater than >> the modulation period do I get significant sidelobes in the autocorrelation >> signal, indicating that the pattern repeats after each multiple of a >> modulation cycle. > >Again, how many periods you observe isn't what matters when the signal >is completely deterministic. You're just observing the same, >informationally-static signal over different periods of time. That >tells you little to nothing about the propagation of information. > > >> Of course I can create a random narrowband signal as was done in the OpAmp >> resonator paper: http://www.dsprelated.com/showarticle/54.php >> modulate it with a carrier and pass it through a dipole system, and finally >> extract the modulation, and compare it to a light propagated signal. If >> this is done you get exactly the same answer as I showed in my simulation. >> But if this technique is used than I can not use time averagiing to improve >> SNR which is need for detection of the modulation in real experimental >> signals. I have perfomed this random modulation simulation using Agilent >> Vee Pro software which is not possible to show here in text format. But I >> can try to describe it. I took a 100V random generator and sent the signal >> through a 50 MHz cutoff (fc), 6th order LPF with the following transfer >> function [1/(j(f/fc)+1)^6]. Then I multiplied it with a 500MHz carrier and >> sent it though a light speed propagating transfer function [e^(ikr)] and >> though the magnetic component of a electric dipole transfer function >> [e^(ikr)*(-kr-i)]. Finally I extracted the modulation envelopes of the >> tranmitted signal, light speed signal, and the dipole signal. To extract >> the envelopes I used squared the signal and then passed it through a 300MHz >> cutoff (fc), 12th order LPF with the following transfer function >> [1/(j(f/fc)+1)^12]. > >Again, be careful even when there is a random component, as the narrow >band predictability of the signal can easily appear to be accelerated >propagation, as Andor demonstrated. He hit it spot-on, IMHO, by >showing a pulse appear to arrive before the stimulus, but then >demonstrated that interrupting the source proved that the signal was, in >fact, causal after all. A train of such pulses can be modulated with a >random component, but if one isn't extremely careful I'd think it'd be >pretty easy to make an incorrect conclusion about what was propagation >and what was just typical band-limited predictability. > >This is why I suggested interrupting your transmit signal at some point, >perhaps even at a zero crossing, because it may help to see what's >really going on. > >Your burden of proof is large, and it appears to me that you're not at >all very far down the road of sufficiency if you're not addressing these >issues head on. Your continued use of a completely deterministic signal >for propagation measurements suggests to me that you've not been >measuring what you think you have been. > >I think you want a signal with enough entropy to justify your claims. >The signals you're using are nearly entropy-free. I suspect there's a >relationship between signal entropy and the sort of resolution or >confidence you can have in a propagation measurement, but I don't know >what it might be off the top of my head. If you had such a >demonstrated relationship you may then be able to show whether or not >you were really measuring propagation rather than prediction. >Otherwise folks like me (and I'm guessing some of the others here who've >spoken up and plenty of others like them) are going to continue to point >to the known prediction mechanisms as the far more likely explanation of >your results rather than grandiose claims of exceeding c. > > > > > > >> William >> >> >>> On 3/24/2010 4:56 PM, WWalker wrote: >>>> Eric, >>>> >>>> The dicontinuity of a pulse from a dipole source propagates at light >> speed, >>>> but the pulse distorts in the nearfield because it is wideband and the >>>> dispersion is not linear over the bandwidth of the signal. In the >> farfield >>>> the pulse realigns and propagates with out distortion at the speed of >>>> light. Group speed only has meaning if the signal does not distort as >> it >>>> propagates. So in the nearfield one can not say anything about the >>>> propagation speed of a pulse, but in the farfield the pulse clearly >>>> propagates undistorted at the speed of light. >>> >>> In previous posts you seemed to be claiming that the signal was >>> propagating faster than c in the near field. Now you are saying "in >>> the nearfield one can not say anything about the propagation speed of a >>> pulse". Can you clear up my confusion? Are you claiming that there is >>> a region over which the signal propagates at a speed faster than c? >>> >>>> Only a narrowband signal propagates without distortion in both the >>>> nearfield and farfield from a dipole source. This is because the >> dispersion >>>> is not very nonlinear and can approximately linear over the bandwidth of >> a >>>> narrow band signal. Since the signal does not distort as it propagates >> then >>>> the group speed can be clearly observed. >>> >>>> The dipole system is not a filter. Wave propagation from a dipole >> source >>>> occurs in free space. There is not a medium which can filter out or >> change >>>> frequency components in a signal. The transfer functions of a dipole >> source >>>> simply decribes how the field components propagate. >>> >>> Dipoles are actually bandpass filters with a center frequency determined >>> by the length of the dipole as related to the wavelength of the carrier. >>> Efficiency drops off significantly as the wavelength changes >>> substantially from the resonant length of the dipole. >>> >>>> Clearly simple narrowband AM radio transmission contains information. >> Just >>>> turn on an AM radio and listen. The information is known to be the >>>> modulation envelope of the AM signal. My simmulation simply shows that >> in >>>> the nearfield, the modulation envelope arrives earlier in time (dt) than >> a >>>> light speed propagated modulation (dt=0.08/fc), where fc is the carrier >>>> frequency. >>> >>> You seem to be unclear on the definition of "information" in this >>> context, and I think it's a big part of what's tripping you up. The AM >>> radio broadcast signals you like to cite contain "information" because >>> they're modulated with a significant degree of random components. As >>> has been pointed out previously, you may not have an adequate grasp on >>> what "random" means in this context, either. So not getting >>> "information" and "random" right in this context may be the root of >>> what's led you astray. >>> >>> I shall point out again, as have others, that if you introduce some >>> genuine randomness (i.e., information) into your test signals you will >>> be able to demonstrate whether your claims of propagation faster than c >>> are true (if you are, in fact, still claiming that) or not. Until then >>> I will again point out that your current test signals are NOT adequate >>> for that purpose. Jerry pointed out long ago that your signals are >>> completely deterministic, and, therefore, not random. Anybody with the >>> most basic knowledge of trigonometry can predict the exact value of the >>> signal at ANY point in the future given the initial parameters. In >>> fact, your simulation can do that, too! And it is! That proves >>> absolutely nothing and does not support the claims that you have been >>> making of propagation faster than the speed of light. >>> >>> The same can not be said of a typical AM radio broadcast signal because >>> those do, in fact, have random components due to the changing nature of >>> the modulating signals. The parameters of your modulating signals, the >>> amplitudes and relative phases of the initial input sinusoids, do not >>> change and therefore carry no information beyond those initial >>> parameters. This means that a short window of observation is all that >>> is needed to extract what little information there is in the signal, >>> because there isn't any additional information added beyond that. >>> After that, no information is carried in the signal other than "no >>> change", and there certainly aren't any random components by which to >>> measure information propagation. >>> >>> A static '1' has minimal information, and observing it's state past >>> reliable detection of the initial transition into that state will reveal >>> no additional information by which propagation speed can be measured. >>> This is the case with your test signals as well. The relative phases of >>> the signals are NOT indicative of propagation velocity. You need to add >>> a perturbation of some sort, i.e., new modulating information, and >>> detect the propagation velocity of that new modulated information. >>> Until you do that it appears to me that you have no basis on which to >>> make claims of any unexpected phenomena. >>> >>> >>> >>>> >>>> William >>>> >>>> >>>>> On 3/24/2010 8:04 AM, WWalker wrote: >>>>>> Eric, >>>>>> >>>>>> There is fundamental difference between a phase shift caused by a >>>> filter >>>>>> and a time delay caused by wave propagation across a region of space. >>>> The >>>>>> Op Amp filter circuit is simply phase shifting the harmonic >> components >>>> of >>>>>> the signal such that the overall signal appears like it has arrived >>>> before >>>>>> it was transmitted. The circuit is not really predicting the signal >> it >>>> is >>>>>> only phase shifting it. >>>>> >>>>> Yes, this is fundamental. Still, of note, is that the way to >>>>> distinguish between such a phase shift and an increase in propagation >>>>> velocity is to introduce a perturbation, as Andor did, so that it can >> be >>>>> seen whether the prediction is due to negative group delay or >>>>> accelerated propagation. Andor's experiment is revealing in that it >>>>> offers a method to demonstrate that what appears to be accelerated >>>>> propagation is really narrow-band prediction. As far as I can tell >> you >>>>> have not yet done the same, and are instead claiming the rather >>>>> grandiose explanation of virtual photons (which cannot be used in the >>>>> context of information transfer) and propagation faster than the speed >>>>> of light. >>>>> >>>>> It could be cleared up pretty easily by demonstrating actual >> information >>>>> transmission, but it seems to me that you resort to hand waving >> instead. >>>>> >>>>>> In my system, the time delay of the signal is completely due to wave >>>>>> propagation across space. It is not a filter. >>>>> >>>>> You have not yet demonstrated that. >>>>> >>>>>> The simulation I presented simply shows the time delay of the >> modulation >>>> of >>>>>> an AM signal transmission between two nearfield dipole antennas. If >> you >>>>>> zoom in one can see that the modulations arrive earlier than a light >>>>>> propagated signal. >>>>> >>>>> Except that with the signals you're using the propagation cannot be >>>>> distinguished from a phase shift. Again, the point of Andor's paper >> is >>>>> that there's a simple way to distinguish the difference. Until you >> do >>>>> so you should not expect much respect of your grandiose claims when >>>>> there's a much simpler explanation. >>>>> >>>>>> This is not phase velocity, this is group velocity i.e. time delay of >>>> the >>>>>> envelope. >>>>>> >>>>>> William >>>>> >>>>> It doesn't matter which it is or whether the conditions are linear so >>>>> that they're the same, you haven't demonstrated that the propagation >> has >>>>> accelerated. Either demonstrate some actual information transmission >>>>> or expect people to keep pushing back on you. You have a high burden >> of >>>>> proof to make the claims that you're making, but you don't seem to >> want >>>>> to offer anything substantial. >>>>> >>>>> >>>>>> >>>>>> >>>>>> >>>>>>> On 3/23/2010 6:06 PM, WWalker wrote: >>>>>>>> Eric, >>>>>>>> >>>>>>>> Interesting article, but I don't see how it applies to my system. >> The >>>>>>>> system described in the paper is a bandpass filter in a feedback >>>> loop, >>>>>>>> where the bandpass filter phase function is altered by the >> feedback. >>>>>> The >>>>>>>> feedback forces the endpoints of the phase to zero, creating >> regions >>>> of >>>>>>>> possitive slope, which yield negative group delays for narrow band >>>>>> signals. >>>>>>>> This causes narrow band signals at the output of the circuit appear >>>> to >>>>>>>> arrive earlier than signals at the input of the circuit. Because >> the >>>>>>>> information in the signals is slightly redundant, the circuit is >> able >>>>>> to >>>>>>>> reconstruct future parts of the signal from the present part of the >>>>>>>> signal. >>>>>>> >>>>>>> Snipped context to allow bottom-posting. >>>>>>> >>>>>>> Feedback is not necessary to produce negative group delay. Here's >>>>>>> another example with a passive notch filter that exhibits negative >>>> group >>>>>>> delay. >>>>>>> >>>>>>> http://www.radiolab.com.au/DesignFile/DN004.pdf >>>>>>> >>>>>>> It doesn't matter what's inside a black box if it has a negative >> group >>>>>>> delay characteristic if the transfer function is LTI. Whether >>>> there's >>>>>>> feedback or not in the implementation is inconsequential. Consider >>>>>>> that the passive notch filter could also be implemented as an active >>>>>>> circuit with feedback, and if the transfer functions are equivalent >>>> they >>>>>>> are functionally equivalent. This is fundamental. I don't think >> the >>>>>>> feedback has anything to do with it. >>>>>>> >>>>>>> You're argument on the redundancy, though, is spot-on. Note that, >> as >>>>>>> others have already pointed out multiple times, the signals you're >>>> using >>>>>>> in your experiment are HIGHLY redundant, so much so that they carry >>>>>>> almost no information. These signals are therefore not suitable >> for >>>>>>> proving anything about information propagation. >>>>>>> >>>>>>> >>>>>>>> First of all, this is a circuit which alters the phase function >> with >>>>>>>> respect to time and not space, as it is in my system. The phase >>>> function >>>>>> in >>>>>>>> the circuit is not due to wave propagaton, where mine is. >>>>>>> >>>>>>> As far as I've been able to tell, your evidence is based on a >>>>>>> simulation, in which case dimensionalities are abstractions. You >> are >>>>>>> not performing anything in either time or space, you're performing a >>>>>>> numerical simulation. Space-time transforms are not at all unusual >>>> and >>>>>>> it is likely that a substitution is easily performed. Nothing has >>>>>>> propagated in your simulation in either time or space. >>>>>>> >>>>>>>> Secondly,unlike the circuit, my system is causal. The recieved >> signal >>>> in >>>>>> my >>>>>>>> system arrives after the signal is transmitted. It just travels >>>> faster >>>>>> than >>>>>>>> light. >>>>>>> >>>>>>> Uh, the circuit is causal. That was the point. >>>>>>> >>>>>>> You have not demonstrated that your system is causal or not causal. >>>>>>> That cannot be concluded using the waveforms you show in your paper >>>> due >>>>>>> to the high determinism and narrow band characteristics. >>>>>>> >>>>>>>> Thirdly, the negative group delay in the circuit was accomplished >> by >>>>>> using >>>>>>>> feedback which does not exist in my system. >>>>>>> >>>>>>> As I stated above, this is inconsequential. >>>>>>> >>>>>>> >>>>>>>> Information (modulations) are clearly transmitted using narrowband >> AM >>>>>> radio >>>>>>>> communication, just listen to an AM radio. The simulation I >> presented >>>>>>>> simply shows that random AM modulations arrive undistorted across >>>> space, >>>>>> in >>>>>>>> the nearfield, earlier than a light speed propagated signal. >>>>>>> >>>>>>> Your simulation does not demonstrate that. Turn the signal off, >> even >>>> at >>>>>>> a zero crossing if you want to minimize perturbations, and see what >>>>>> happens. >>>>>>> >>>>>>>> Signal purturbations can not be used to measure the signal >>>> propagation >>>>>> in >>>>>>>> the nearfield because they distort in the nearfield, and group >> speed >>>> has >>>>>> no >>>>>>>> meaning if the signal distorts as it propagates. >>>>>>>> >>>>>>>> William >>>>>>> >>>>>>> If you cannot use a perturbation (i.e., information transmission) to >>>>>>> measure signal propagation then you cannot demonstrate the speed of >>>>>>> information propagation. Until you can actually demonstrate >>>> something >>>>>>> other than phase velocity (which is NOT information transmission and >>>>>>> many here have acknowledged can be faster than c, as do I), then you >>>>>>> cannot make the conclusions that you are claiming. >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Eric Jacobsen >>>>>>> Minister of Algorithms >>>>>>> Abineau Communications >>>>>>> http://www.abineau.com >>>>>>> >>>>> >>>>> >>>>> -- >>>>> Eric Jacobsen >>>>> Minister of Algorithms >>>>> Abineau Communications >>>>> http://www.abineau.com >>>>> >>> >>> >>> -- >>> Eric Jacobsen >>> Minister of Algorithms >>> Abineau Communications >>> http://www.abineau.com >>> > > >-- >Eric Jacobsen >Minister of Algorithms >Abineau Communications >http://www.abineau.com >
From: Jerry Avins on 26 Mar 2010 11:24 WWalker wrote: > Eric, > > I am not sure adding two signals is deterministic independant of the time > span it is viewed. The signal only repeats after the modulation time > 2/(f2-f1). One needs to sample the signal over this entire time period to > be sure what the equation the signal corresponds to enabling one to say it > is deterministic. If one only views the signal over a portion of the > modulation peroid, one cannot be sure whether it is predictable because it > could easily change from predictability when viewed over a larger time > period. This is what the autocorrolation experiment of the this signal > shows. Only after a modulation period does one see significant sidelobes in > the triangular autocorrolation signal. > > I think an important question to resolve is if the dipole system is a > filter or not. Filters can only phase shift signals, whereas a dipole > generates a true time delay due to wave propagation. It is clear that this > is true in the farfield. Why should it be different in the nearfield? > > With my last simulation I obtained the same superluminal results using a > filtered an extremly nondeterministic random signal. If the dipole system > is not a filter, how could the modulation envelope arrive sooner than a > light propagated signal? > > Your last comment regarding the effects of noise are very impotant. As I > mentioned at the very start of this discussion (thread), in order to prove > information propagates faster than light in the nearfield of a dipole, one > has to measure the time delay of the modulation (tp) and also show that it > is possible to extract the information in a fraction of a carrier cycle > (td). This is because the superluminal phenomina only occurs over a > fraction of a carrier period and v=d/(tp+td. I am very certain that in a > nearfield dipole system, the modulations of narrow band AM signals can be > observed to arrive earlier in time than a light speed propagated signal. > What I am not sure is wheather the modulations can be extracted in a > fraction of a carrier cycle with real AM signals which noise. This is why I > have contacted this group. From my investigations, the usual signal > processing techniques do not work. Simple diode/mixer low pass filtering > cannot be used because the filter requires more than a fraction of a > carrier cycle to extract the modulation. FFT has the same problem. > > William > > >> On 3/25/2010 8:45 AM, WWalker wrote: >>> Eric, >>> >>> A narrow band AM signal propagates undistorted and faster than light in > the >>> nearfield and reduces to the speed of light as it goes into the > farfield. A >>> pulse distorts in the nearfield and and realigns as it goes into the >>> farfield. When the pulse is distorted, one cannot say anything about > the >>> speed of the pulse. To transmit information faster than light one must > use >>> narrowband signals like AM and transmitt and receive them in the > nearfield >>> of the carrier. >>> >>> It is true that a real dipole anntena has filter characteristics. The >>> simulation I presented is an idealized dipole like an oscillating > electron >>> which does not have filter characteristics. In an experiment with real >>> antennas one would have to subtract out the phase shifts due to the >>> antennas filter characteristics so that one only sees the time delay >>> behavior of the propagating fields. >>> >>> The signals I used in my simulation are a changing modulation over the > time >>> window of analysis. The changing modulation does not repeat over this >>> window. It is true that they are created from deterministic signals. >>> Bassically I generated a beat frequency modulation which has a carrier > and >>> a modulation frequency. Provided the window of analysis is smaller than > a >>> modulation time period, the modulation pattern does not repeat. After a >>> modulation period the patern repeats again. I chose this type of signal >>> because it is a changing pattern which eventually repeats, enabling me > to >>> trigger it in a real experient and also enabling me to do time > averaging >>> which will help a lot with improving the SNR if a experimental signal. >> The period of the signal isn't necessarily consequential, the fact that >> it is not random is. The point being that the signal you are using is >> not suitable for measuring propagation at the resolution you're >> interested in because it is a deterministic signal. Even when there's >> a component that is randomly changing with time it is easy to get fooled >> by the nature of narrowband signals, and that was pretty much a big >> point of Andor's paper. I'm beginning to see why he chose the title >> that he did. >> >>> When perform an autocorrelation of the modulation I used in my > simulation, >>> I see a triangular signal with a peak at the time of the analysis time >>> window, indicating that the signal has no obserable repetition pattern > of >>> the this time. Only after I increase the analysis time window greater > than >>> the modulation period do I get significant sidelobes in the > autocorrelation >>> signal, indicating that the pattern repeats after each multiple of a >>> modulation cycle. >> Again, how many periods you observe isn't what matters when the signal >> is completely deterministic. You're just observing the same, >> informationally-static signal over different periods of time. That >> tells you little to nothing about the propagation of information. >> >> >>> Of course I can create a random narrowband signal as was done in the > OpAmp >>> resonator paper: http://www.dsprelated.com/showarticle/54.php >>> modulate it with a carrier and pass it through a dipole system, and > finally >>> extract the modulation, and compare it to a light propagated signal. If >>> this is done you get exactly the same answer as I showed in my > simulation. >>> But if this technique is used than I can not use time averagiing to > improve >>> SNR which is need for detection of the modulation in real experimental >>> signals. I have perfomed this random modulation simulation using > Agilent >>> Vee Pro software which is not possible to show here in text format. But > I >>> can try to describe it. I took a 100V random generator and sent the > signal >>> through a 50 MHz cutoff (fc), 6th order LPF with the following transfer >>> function [1/(j(f/fc)+1)^6]. Then I multiplied it with a 500MHz carrier > and >>> sent it though a light speed propagating transfer function [e^(ikr)] > and >>> though the magnetic component of a electric dipole transfer function >>> [e^(ikr)*(-kr-i)]. Finally I extracted the modulation envelopes of the >>> tranmitted signal, light speed signal, and the dipole signal. To > extract >>> the envelopes I used squared the signal and then passed it through a > 300MHz >>> cutoff (fc), 12th order LPF with the following transfer function >>> [1/(j(f/fc)+1)^12]. >> Again, be careful even when there is a random component, as the narrow >> band predictability of the signal can easily appear to be accelerated >> propagation, as Andor demonstrated. He hit it spot-on, IMHO, by >> showing a pulse appear to arrive before the stimulus, but then >> demonstrated that interrupting the source proved that the signal was, in >> fact, causal after all. A train of such pulses can be modulated with a >> random component, but if one isn't extremely careful I'd think it'd be >> pretty easy to make an incorrect conclusion about what was propagation >> and what was just typical band-limited predictability. >> >> This is why I suggested interrupting your transmit signal at some point, >> perhaps even at a zero crossing, because it may help to see what's >> really going on. >> >> Your burden of proof is large, and it appears to me that you're not at >> all very far down the road of sufficiency if you're not addressing these >> issues head on. Your continued use of a completely deterministic signal >> for propagation measurements suggests to me that you've not been >> measuring what you think you have been. >> >> I think you want a signal with enough entropy to justify your claims. >> The signals you're using are nearly entropy-free. I suspect there's a >> relationship between signal entropy and the sort of resolution or >> confidence you can have in a propagation measurement, but I don't know >> what it might be off the top of my head. If you had such a >> demonstrated relationship you may then be able to show whether or not >> you were really measuring propagation rather than prediction. >> Otherwise folks like me (and I'm guessing some of the others here who've >> spoken up and plenty of others like them) are going to continue to point >> to the known prediction mechanisms as the far more likely explanation of >> your results rather than grandiose claims of exceeding c. >> >> >> >> >> >> >>> William >>> >>> >>>> On 3/24/2010 4:56 PM, WWalker wrote: >>>>> Eric, >>>>> >>>>> The dicontinuity of a pulse from a dipole source propagates at light >>> speed, >>>>> but the pulse distorts in the nearfield because it is wideband and > the >>>>> dispersion is not linear over the bandwidth of the signal. In the >>> farfield >>>>> the pulse realigns and propagates with out distortion at the speed of >>>>> light. Group speed only has meaning if the signal does not distort as >>> it >>>>> propagates. So in the nearfield one can not say anything about the >>>>> propagation speed of a pulse, but in the farfield the pulse clearly >>>>> propagates undistorted at the speed of light. >>>> In previous posts you seemed to be claiming that the signal was >>>> propagating faster than c in the near field. Now you are saying "in >>>> the nearfield one can not say anything about the propagation speed of > a >>>> pulse". Can you clear up my confusion? Are you claiming that there > is >>>> a region over which the signal propagates at a speed faster than c? >>>> >>>>> Only a narrowband signal propagates without distortion in both the >>>>> nearfield and farfield from a dipole source. This is because the >>> dispersion >>>>> is not very nonlinear and can approximately linear over the bandwidth > of >>> a >>>>> narrow band signal. Since the signal does not distort as it > propagates >>> then >>>>> the group speed can be clearly observed. >>>>> The dipole system is not a filter. Wave propagation from a dipole >>> source >>>>> occurs in free space. There is not a medium which can filter out or >>> change >>>>> frequency components in a signal. The transfer functions of a dipole >>> source >>>>> simply decribes how the field components propagate. >>>> Dipoles are actually bandpass filters with a center frequency > determined >>>> by the length of the dipole as related to the wavelength of the > carrier. >>>> Efficiency drops off significantly as the wavelength changes >>>> substantially from the resonant length of the dipole. >>>> >>>>> Clearly simple narrowband AM radio transmission contains information. >>> Just >>>>> turn on an AM radio and listen. The information is known to be the >>>>> modulation envelope of the AM signal. My simmulation simply shows > that >>> in >>>>> the nearfield, the modulation envelope arrives earlier in time (dt) > than >>> a >>>>> light speed propagated modulation (dt=0.08/fc), where fc is the > carrier >>>>> frequency. >>>> You seem to be unclear on the definition of "information" in this >>>> context, and I think it's a big part of what's tripping you up. The > AM >>>> radio broadcast signals you like to cite contain "information" because >>>> they're modulated with a significant degree of random components. As >>>> has been pointed out previously, you may not have an adequate grasp on >>>> what "random" means in this context, either. So not getting >>>> "information" and "random" right in this context may be the root of >>>> what's led you astray. >>>> >>>> I shall point out again, as have others, that if you introduce some >>>> genuine randomness (i.e., information) into your test signals you will >>>> be able to demonstrate whether your claims of propagation faster than > c >>>> are true (if you are, in fact, still claiming that) or not. Until > then >>>> I will again point out that your current test signals are NOT adequate >>>> for that purpose. Jerry pointed out long ago that your signals are >>>> completely deterministic, and, therefore, not random. Anybody with > the >>>> most basic knowledge of trigonometry can predict the exact value of > the >>>> signal at ANY point in the future given the initial parameters. In >>>> fact, your simulation can do that, too! And it is! That proves >>>> absolutely nothing and does not support the claims that you have been >>>> making of propagation faster than the speed of light. >>>> >>>> The same can not be said of a typical AM radio broadcast signal > because >>>> those do, in fact, have random components due to the changing nature > of >>>> the modulating signals. The parameters of your modulating signals, > the >>>> amplitudes and relative phases of the initial input sinusoids, do not >>>> change and therefore carry no information beyond those initial >>>> parameters. This means that a short window of observation is all that >>>> is needed to extract what little information there is in the signal, >>>> because there isn't any additional information added beyond that. >>>> After that, no information is carried in the signal other than "no >>>> change", and there certainly aren't any random components by which to >>>> measure information propagation. >>>> >>>> A static '1' has minimal information, and observing it's state past >>>> reliable detection of the initial transition into that state will > reveal >>>> no additional information by which propagation speed can be measured. >>>> This is the case with your test signals as well. The relative phases > of >>>> the signals are NOT indicative of propagation velocity. You need to > add >>>> a perturbation of some sort, i.e., new modulating information, and >>>> detect the propagation velocity of that new modulated information. >>>> Until you do that it appears to me that you have no basis on which to >>>> make claims of any unexpected phenomena. >>>> >>>> >>>> >>>>> William >>>>> >>>>> >>>>>> On 3/24/2010 8:04 AM, WWalker wrote: >>>>>>> Eric, >>>>>>> >>>>>>> There is fundamental difference between a phase shift caused by a >>>>> filter >>>>>>> and a time delay caused by wave propagation across a region of > space. >>>>> The >>>>>>> Op Amp filter circuit is simply phase shifting the harmonic >>> components >>>>> of >>>>>>> the signal such that the overall signal appears like it has arrived >>>>> before >>>>>>> it was transmitted. The circuit is not really predicting the signal >>> it >>>>> is >>>>>>> only phase shifting it. >>>>>> Yes, this is fundamental. Still, of note, is that the way to >>>>>> distinguish between such a phase shift and an increase in > propagation >>>>>> velocity is to introduce a perturbation, as Andor did, so that it > can >>> be >>>>>> seen whether the prediction is due to negative group delay or >>>>>> accelerated propagation. Andor's experiment is revealing in that > it >>>>>> offers a method to demonstrate that what appears to be accelerated >>>>>> propagation is really narrow-band prediction. As far as I can tell >>> you >>>>>> have not yet done the same, and are instead claiming the rather >>>>>> grandiose explanation of virtual photons (which cannot be used in > the >>>>>> context of information transfer) and propagation faster than the > speed >>>>>> of light. >>>>>> >>>>>> It could be cleared up pretty easily by demonstrating actual >>> information >>>>>> transmission, but it seems to me that you resort to hand waving >>> instead. >>>>>>> In my system, the time delay of the signal is completely due to > wave >>>>>>> propagation across space. It is not a filter. >>>>>> You have not yet demonstrated that. >>>>>> >>>>>>> The simulation I presented simply shows the time delay of the >>> modulation >>>>> of >>>>>>> an AM signal transmission between two nearfield dipole antennas. If >>> you >>>>>>> zoom in one can see that the modulations arrive earlier than a > light >>>>>>> propagated signal. >>>>>> Except that with the signals you're using the propagation cannot be >>>>>> distinguished from a phase shift. Again, the point of Andor's > paper >>> is >>>>>> that there's a simple way to distinguish the difference. Until you >>> do >>>>>> so you should not expect much respect of your grandiose claims when >>>>>> there's a much simpler explanation. >>>>>> >>>>>>> This is not phase velocity, this is group velocity i.e. time delay > of >>>>> the >>>>>>> envelope. >>>>>>> >>>>>>> William >>>>>> It doesn't matter which it is or whether the conditions are linear > so >>>>>> that they're the same, you haven't demonstrated that the propagation >>> has >>>>>> accelerated. Either demonstrate some actual information > transmission >>>>>> or expect people to keep pushing back on you. You have a high > burden >>> of >>>>>> proof to make the claims that you're making, but you don't seem to >>> want >>>>>> to offer anything substantial. >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>>> On 3/23/2010 6:06 PM, WWalker wrote: >>>>>>>>> Eric, >>>>>>>>> >>>>>>>>> Interesting article, but I don't see how it applies to my system. >>> The >>>>>>>>> system described in the paper is a bandpass filter in a feedback >>>>> loop, >>>>>>>>> where the bandpass filter phase function is altered by the >>> feedback. >>>>>>> The >>>>>>>>> feedback forces the endpoints of the phase to zero, creating >>> regions >>>>> of >>>>>>>>> possitive slope, which yield negative group delays for narrow > band >>>>>>> signals. >>>>>>>>> This causes narrow band signals at the output of the circuit > appear >>>>> to >>>>>>>>> arrive earlier than signals at the input of the circuit. Because >>> the >>>>>>>>> information in the signals is slightly redundant, the circuit is >>> able >>>>>>> to >>>>>>>>> reconstruct future parts of the signal from the present part of > the >>>>>>>>> signal. >>>>>>>> Snipped context to allow bottom-posting. >>>>>>>> >>>>>>>> Feedback is not necessary to produce negative group delay. > Here's >>>>>>>> another example with a passive notch filter that exhibits negative >>>>> group >>>>>>>> delay. >>>>>>>> >>>>>>>> http://www.radiolab.com.au/DesignFile/DN004.pdf >>>>>>>> >>>>>>>> It doesn't matter what's inside a black box if it has a negative >>> group >>>>>>>> delay characteristic if the transfer function is LTI. Whether >>>>> there's >>>>>>>> feedback or not in the implementation is inconsequential. > Consider >>>>>>>> that the passive notch filter could also be implemented as an > active >>>>>>>> circuit with feedback, and if the transfer functions are > equivalent >>>>> they >>>>>>>> are functionally equivalent. This is fundamental. I don't think >>> the >>>>>>>> feedback has anything to do with it. >>>>>>>> >>>>>>>> You're argument on the redundancy, though, is spot-on. Note > that, >>> as >>>>>>>> others have already pointed out multiple times, the signals you're >>>>> using >>>>>>>> in your experiment are HIGHLY redundant, so much so that they > carry >>>>>>>> almost no information. These signals are therefore not suitable >>> for >>>>>>>> proving anything about information propagation. >>>>>>>> >>>>>>>> >>>>>>>>> First of all, this is a circuit which alters the phase function >>> with >>>>>>>>> respect to time and not space, as it is in my system. The phase >>>>> function >>>>>>> in >>>>>>>>> the circuit is not due to wave propagaton, where mine is. >>>>>>>> As far as I've been able to tell, your evidence is based on a >>>>>>>> simulation, in which case dimensionalities are abstractions. You >>> are >>>>>>>> not performing anything in either time or space, you're performing > a >>>>>>>> numerical simulation. Space-time transforms are not at all > unusual >>>>> and >>>>>>>> it is likely that a substitution is easily performed. Nothing has >>>>>>>> propagated in your simulation in either time or space. >>>>>>>> >>>>>>>>> Secondly,unlike the circuit, my system is causal. The recieved >>> signal >>>>> in >>>>>>> my >>>>>>>>> system arrives after the signal is transmitted. It just travels >>>>> faster >>>>>>> than >>>>>>>>> light. >>>>>>>> Uh, the circuit is causal. That was the point. >>>>>>>> >>>>>>>> You have not demonstrated that your system is causal or not > causal. >>>>>>>> That cannot be concluded using the waveforms you show in your > paper >>>>> due >>>>>>>> to the high determinism and narrow band characteristics. >>>>>>>> >>>>>>>>> Thirdly, the negative group delay in the circuit was accomplished >>> by >>>>>>> using >>>>>>>>> feedback which does not exist in my system. >>>>>>>> As I stated above, this is inconsequential. >>>>>>>> >>>>>>>> >>>>>>>>> Information (modulations) are clearly transmitted using > narrowband >>> AM >>>>>>> radio >>>>>>>>> communication, just listen to an AM radio. The simulation I >>> presented >>>>>>>>> simply shows that random AM modulations arrive undistorted across >>>>> space, >>>>>>> in >>>>>>>>> the nearfield, earlier than a light speed propagated signal. >>>>>>>> Your simulation does not demonstrate that. Turn the signal off, >>> even >>>>> at >>>>>>>> a zero crossing if you want to minimize perturbations, and see > what >>>>>>> happens. >>>>>>>>> Signal purturbations can not be used to measure the signal >>>>> propagation >>>>>>> in >>>>>>>>> the nearfield because they distort in the nearfield, and group >>> speed >>>>> has >>>>>>> no >>>>>>>>> meaning if the signal distorts as it propagates. >>>>>>>>> >>>>>>>>> William >>>>>>>> If you cannot use a perturbation (i.e., information transmission) > to >>>>>>>> measure signal propagation then you cannot demonstrate the speed > of >>>>>>>> information propagation. Until you can actually demonstrate >>>>> something >>>>>>>> other than phase velocity (which is NOT information transmission > and >>>>>>>> many here have acknowledged can be faster than c, as do I), then > you >>>>>>>> cannot make the conclusions that you are claiming. William, I think there are a few misconceptions that need to be addressed. DETERMINISM. Consider the series 1, 2, 1, 2, 1. It seems pretty straightforward, but it's necessarily. There is no way to make an assured prediction of the next term. We can see a pattern *so far* but we have no guarantee that the pattern will continue. There are circuits that behave well with this sequence and its "expected" sequel is applied, but which become erratic if the next input were to be, say. -20. So while the signal is not predictable, *if we treat it as if it were predictable,* we can get interesting effects. That is what you seem to be doing. DIPOLES AND FILTERS. A physical dipole's response is a function of frequency. As such, it is a filter. It is not true that a filter has no delay. All filters have delay. This is especially easy to see with digital filters because they are constructed of delay elements, but it is true of all filters. Analog filters have phase shift, as you recognize. When that phase shift is proportional to frequency, there is a non-dispersive delay. A properly connected collection of inductors and capacitors provides a very good delay. It can simulate a long transmission line and delay speech. It is used in oscilloscopes to delay the displayed signal, allowing an entire pulse to be displayed even though the sweep is triggered by the pulse's rise. The phenomenon you observe is simple. The near field is in phase with the dipole's excitation and falls off with the cube of distance. It dominates near the radiator. The far field is in quadrature with the dipole's excitation. It exists throughout space, falling off as the square of distance, so eventually it dominates. The phase at any point is due to the sum of these components. The disparate decay rates of the two field components make it appear, based on phase measurements alone, that the wave propagates superluminally. 'Taint so. Jerry -- Discovery consists of seeing what everybody has seen, and thinking what nobody has thought. .. Albert Szent-Gyorgi �����������������������������������������������������������������������
From: Eric Jacobsen on 26 Mar 2010 12:03 On 3/26/2010 6:46 AM, WWalker wrote: > Eric, > > I am not sure adding two signals is deterministic independant of the time > span it is viewed. The signal only repeats after the modulation time > 2/(f2-f1). One needs to sample the signal over this entire time period to > be sure what the equation the signal corresponds to enabling one to say it > is deterministic. If one only views the signal over a portion of the > modulation peroid, one cannot be sure whether it is predictable because it > could easily change from predictability when viewed over a larger time > period. This is what the autocorrolation experiment of the this signal > shows. Only after a modulation period does one see significant sidelobes in > the triangular autocorrolation signal. Tell me if I'm wrong, but my recollection is that you're adding a few sine waves together for your stimulus. All one needs to know is the initial parameters of amplitude and phase for each term and the signal is known, completely, for all future time. This is pretty deterministic. It is also why it conveys no information beyond the initial parameters and therefore is a poor choice for measuring information propagation. The example I gave of a static binary '1' is the same idea; you can't compare the transmitted and received waveform and learn anything about propagation time. From that perspective it doesn't matter at what phase or what fraction of composite period the signal is observed over, as that doesn't change the deterministic nature of the signal or the amount of information it's carrying. See Jerry's response as well. > I think an important question to resolve is if the dipole system is a > filter or not. Filters can only phase shift signals, whereas a dipole > generates a true time delay due to wave propagation. It is clear that this > is true in the farfield. Why should it be different in the nearfield? Yes, a dipole is a filter. The paper by Sten and Hujanen that you cited previously seems to me to be saying and demonstrating exactly the relevant issue; that the phase response of the near field is dispersive so that superluminal propagation seems apparent, but really isn't so. Again, their Figure 2 shows that pretty clearly by my reading. > With my last simulation I obtained the same superluminal results using a > filtered an extremly nondeterministic random signal. If the dipole system > is not a filter, how could the modulation envelope arrive sooner than a > light propagated signal? See, again, Andor's paper on dsprelated. Prediction of a band-limited signal can appear to be time travel or superluminal or whatever you want to call it, but it's not. It's just narrow-band prediction, which is not magic at all. Also see, again, Fig. 2b of the Sten and Hujanen paper. It "appears" that the pulse has advanced in time before the stimulus, but that's due only to the dispersion of the frequency content of the signal by the phase response of the medium. Figures 4, 5, and 6 in Andor's blog show this as well, including Fig 6 which appears to have a fair amount of randomness. This is why it can be easily duplicated in a numerical simulation: it's just a mathematical effect of the non-linear phase response and negative group delay in the transfer function. > Your last comment regarding the effects of noise are very impotant. As I > mentioned at the very start of this discussion (thread), in order to prove > information propagates faster than light in the nearfield of a dipole, one > has to measure the time delay of the modulation (tp) and also show that it > is possible to extract the information in a fraction of a carrier cycle > (td). This is because the superluminal phenomina only occurs over a > fraction of a carrier period and v=d/(tp+td. I am very certain that in a > nearfield dipole system, the modulations of narrow band AM signals can be > observed to arrive earlier in time than a light speed propagated signal. > What I am not sure is wheather the modulations can be extracted in a > fraction of a carrier cycle with real AM signals which noise. This is why I > have contacted this group. From my investigations, the usual signal > processing techniques do not work. Simple diode/mixer low pass filtering > cannot be used because the filter requires more than a fraction of a > carrier cycle to extract the modulation. FFT has the same problem. > > William Fine time resolution can be achieved with a signal with wide bandwidth (which is pretty much what we've been saying for a while regarding information content and randomness). If the AM signal is not synchronous to the carrier phase then time resolution much finer than a carrier period can be achieved. I don't think that's where your problem lies, though. > > >> On 3/25/2010 8:45 AM, WWalker wrote: >>> Eric, >>> >>> A narrow band AM signal propagates undistorted and faster than light in > the >>> nearfield and reduces to the speed of light as it goes into the > farfield. A >>> pulse distorts in the nearfield and and realigns as it goes into the >>> farfield. When the pulse is distorted, one cannot say anything about > the >>> speed of the pulse. To transmit information faster than light one must > use >>> narrowband signals like AM and transmitt and receive them in the > nearfield >>> of the carrier. >>> >>> It is true that a real dipole anntena has filter characteristics. The >>> simulation I presented is an idealized dipole like an oscillating > electron >>> which does not have filter characteristics. In an experiment with real >>> antennas one would have to subtract out the phase shifts due to the >>> antennas filter characteristics so that one only sees the time delay >>> behavior of the propagating fields. >>> >>> The signals I used in my simulation are a changing modulation over the > time >>> window of analysis. The changing modulation does not repeat over this >>> window. It is true that they are created from deterministic signals. >>> Bassically I generated a beat frequency modulation which has a carrier > and >>> a modulation frequency. Provided the window of analysis is smaller than > a >>> modulation time period, the modulation pattern does not repeat. After a >>> modulation period the patern repeats again. I chose this type of signal >>> because it is a changing pattern which eventually repeats, enabling me > to >>> trigger it in a real experient and also enabling me to do time > averaging >>> which will help a lot with improving the SNR if a experimental signal. >> >> The period of the signal isn't necessarily consequential, the fact that >> it is not random is. The point being that the signal you are using is >> not suitable for measuring propagation at the resolution you're >> interested in because it is a deterministic signal. Even when there's >> a component that is randomly changing with time it is easy to get fooled >> by the nature of narrowband signals, and that was pretty much a big >> point of Andor's paper. I'm beginning to see why he chose the title >> that he did. >> >>> When perform an autocorrelation of the modulation I used in my > simulation, >>> I see a triangular signal with a peak at the time of the analysis time >>> window, indicating that the signal has no obserable repetition pattern > of >>> the this time. Only after I increase the analysis time window greater > than >>> the modulation period do I get significant sidelobes in the > autocorrelation >>> signal, indicating that the pattern repeats after each multiple of a >>> modulation cycle. >> >> Again, how many periods you observe isn't what matters when the signal >> is completely deterministic. You're just observing the same, >> informationally-static signal over different periods of time. That >> tells you little to nothing about the propagation of information. >> >> >>> Of course I can create a random narrowband signal as was done in the > OpAmp >>> resonator paper: http://www.dsprelated.com/showarticle/54.php >>> modulate it with a carrier and pass it through a dipole system, and > finally >>> extract the modulation, and compare it to a light propagated signal. If >>> this is done you get exactly the same answer as I showed in my > simulation. >>> But if this technique is used than I can not use time averagiing to > improve >>> SNR which is need for detection of the modulation in real experimental >>> signals. I have perfomed this random modulation simulation using > Agilent >>> Vee Pro software which is not possible to show here in text format. But > I >>> can try to describe it. I took a 100V random generator and sent the > signal >>> through a 50 MHz cutoff (fc), 6th order LPF with the following transfer >>> function [1/(j(f/fc)+1)^6]. Then I multiplied it with a 500MHz carrier > and >>> sent it though a light speed propagating transfer function [e^(ikr)] > and >>> though the magnetic component of a electric dipole transfer function >>> [e^(ikr)*(-kr-i)]. Finally I extracted the modulation envelopes of the >>> tranmitted signal, light speed signal, and the dipole signal. To > extract >>> the envelopes I used squared the signal and then passed it through a > 300MHz >>> cutoff (fc), 12th order LPF with the following transfer function >>> [1/(j(f/fc)+1)^12]. >> >> Again, be careful even when there is a random component, as the narrow >> band predictability of the signal can easily appear to be accelerated >> propagation, as Andor demonstrated. He hit it spot-on, IMHO, by >> showing a pulse appear to arrive before the stimulus, but then >> demonstrated that interrupting the source proved that the signal was, in >> fact, causal after all. A train of such pulses can be modulated with a >> random component, but if one isn't extremely careful I'd think it'd be >> pretty easy to make an incorrect conclusion about what was propagation >> and what was just typical band-limited predictability. >> >> This is why I suggested interrupting your transmit signal at some point, >> perhaps even at a zero crossing, because it may help to see what's >> really going on. >> >> Your burden of proof is large, and it appears to me that you're not at >> all very far down the road of sufficiency if you're not addressing these >> issues head on. Your continued use of a completely deterministic signal >> for propagation measurements suggests to me that you've not been >> measuring what you think you have been. >> >> I think you want a signal with enough entropy to justify your claims. >> The signals you're using are nearly entropy-free. I suspect there's a >> relationship between signal entropy and the sort of resolution or >> confidence you can have in a propagation measurement, but I don't know >> what it might be off the top of my head. If you had such a >> demonstrated relationship you may then be able to show whether or not >> you were really measuring propagation rather than prediction. >> Otherwise folks like me (and I'm guessing some of the others here who've >> spoken up and plenty of others like them) are going to continue to point >> to the known prediction mechanisms as the far more likely explanation of >> your results rather than grandiose claims of exceeding c. >> >> >> >> >> >> >>> William >>> >>> >>>> On 3/24/2010 4:56 PM, WWalker wrote: >>>>> Eric, >>>>> >>>>> The dicontinuity of a pulse from a dipole source propagates at light >>> speed, >>>>> but the pulse distorts in the nearfield because it is wideband and > the >>>>> dispersion is not linear over the bandwidth of the signal. In the >>> farfield >>>>> the pulse realigns and propagates with out distortion at the speed of >>>>> light. Group speed only has meaning if the signal does not distort as >>> it >>>>> propagates. So in the nearfield one can not say anything about the >>>>> propagation speed of a pulse, but in the farfield the pulse clearly >>>>> propagates undistorted at the speed of light. >>>> >>>> In previous posts you seemed to be claiming that the signal was >>>> propagating faster than c in the near field. Now you are saying "in >>>> the nearfield one can not say anything about the propagation speed of > a >>>> pulse". Can you clear up my confusion? Are you claiming that there > is >>>> a region over which the signal propagates at a speed faster than c? >>>> >>>>> Only a narrowband signal propagates without distortion in both the >>>>> nearfield and farfield from a dipole source. This is because the >>> dispersion >>>>> is not very nonlinear and can approximately linear over the bandwidth > of >>> a >>>>> narrow band signal. Since the signal does not distort as it > propagates >>> then >>>>> the group speed can be clearly observed. >>>> >>>>> The dipole system is not a filter. Wave propagation from a dipole >>> source >>>>> occurs in free space. There is not a medium which can filter out or >>> change >>>>> frequency components in a signal. The transfer functions of a dipole >>> source >>>>> simply decribes how the field components propagate. >>>> >>>> Dipoles are actually bandpass filters with a center frequency > determined >>>> by the length of the dipole as related to the wavelength of the > carrier. >>>> Efficiency drops off significantly as the wavelength changes >>>> substantially from the resonant length of the dipole. >>>> >>>>> Clearly simple narrowband AM radio transmission contains information. >>> Just >>>>> turn on an AM radio and listen. The information is known to be the >>>>> modulation envelope of the AM signal. My simmulation simply shows > that >>> in >>>>> the nearfield, the modulation envelope arrives earlier in time (dt) > than >>> a >>>>> light speed propagated modulation (dt=0.08/fc), where fc is the > carrier >>>>> frequency. >>>> >>>> You seem to be unclear on the definition of "information" in this >>>> context, and I think it's a big part of what's tripping you up. The > AM >>>> radio broadcast signals you like to cite contain "information" because >>>> they're modulated with a significant degree of random components. As >>>> has been pointed out previously, you may not have an adequate grasp on >>>> what "random" means in this context, either. So not getting >>>> "information" and "random" right in this context may be the root of >>>> what's led you astray. >>>> >>>> I shall point out again, as have others, that if you introduce some >>>> genuine randomness (i.e., information) into your test signals you will >>>> be able to demonstrate whether your claims of propagation faster than > c >>>> are true (if you are, in fact, still claiming that) or not. Until > then >>>> I will again point out that your current test signals are NOT adequate >>>> for that purpose. Jerry pointed out long ago that your signals are >>>> completely deterministic, and, therefore, not random. Anybody with > the >>>> most basic knowledge of trigonometry can predict the exact value of > the >>>> signal at ANY point in the future given the initial parameters. In >>>> fact, your simulation can do that, too! And it is! That proves >>>> absolutely nothing and does not support the claims that you have been >>>> making of propagation faster than the speed of light. >>>> >>>> The same can not be said of a typical AM radio broadcast signal > because >>>> those do, in fact, have random components due to the changing nature > of >>>> the modulating signals. The parameters of your modulating signals, > the >>>> amplitudes and relative phases of the initial input sinusoids, do not >>>> change and therefore carry no information beyond those initial >>>> parameters. This means that a short window of observation is all that >>>> is needed to extract what little information there is in the signal, >>>> because there isn't any additional information added beyond that. >>>> After that, no information is carried in the signal other than "no >>>> change", and there certainly aren't any random components by which to >>>> measure information propagation. >>>> >>>> A static '1' has minimal information, and observing it's state past >>>> reliable detection of the initial transition into that state will > reveal >>>> no additional information by which propagation speed can be measured. >>>> This is the case with your test signals as well. The relative phases > of >>>> the signals are NOT indicative of propagation velocity. You need to > add >>>> a perturbation of some sort, i.e., new modulating information, and >>>> detect the propagation velocity of that new modulated information. >>>> Until you do that it appears to me that you have no basis on which to >>>> make claims of any unexpected phenomena. >>>> >>>> >>>> >>>>> >>>>> William >>>>> >>>>> >>>>>> On 3/24/2010 8:04 AM, WWalker wrote: >>>>>>> Eric, >>>>>>> >>>>>>> There is fundamental difference between a phase shift caused by a >>>>> filter >>>>>>> and a time delay caused by wave propagation across a region of > space. >>>>> The >>>>>>> Op Amp filter circuit is simply phase shifting the harmonic >>> components >>>>> of >>>>>>> the signal such that the overall signal appears like it has arrived >>>>> before >>>>>>> it was transmitted. The circuit is not really predicting the signal >>> it >>>>> is >>>>>>> only phase shifting it. >>>>>> >>>>>> Yes, this is fundamental. Still, of note, is that the way to >>>>>> distinguish between such a phase shift and an increase in > propagation >>>>>> velocity is to introduce a perturbation, as Andor did, so that it > can >>> be >>>>>> seen whether the prediction is due to negative group delay or >>>>>> accelerated propagation. Andor's experiment is revealing in that > it >>>>>> offers a method to demonstrate that what appears to be accelerated >>>>>> propagation is really narrow-band prediction. As far as I can tell >>> you >>>>>> have not yet done the same, and are instead claiming the rather >>>>>> grandiose explanation of virtual photons (which cannot be used in > the >>>>>> context of information transfer) and propagation faster than the > speed >>>>>> of light. >>>>>> >>>>>> It could be cleared up pretty easily by demonstrating actual >>> information >>>>>> transmission, but it seems to me that you resort to hand waving >>> instead. >>>>>> >>>>>>> In my system, the time delay of the signal is completely due to > wave >>>>>>> propagation across space. It is not a filter. >>>>>> >>>>>> You have not yet demonstrated that. >>>>>> >>>>>>> The simulation I presented simply shows the time delay of the >>> modulation >>>>> of >>>>>>> an AM signal transmission between two nearfield dipole antennas. If >>> you >>>>>>> zoom in one can see that the modulations arrive earlier than a > light >>>>>>> propagated signal. >>>>>> >>>>>> Except that with the signals you're using the propagation cannot be >>>>>> distinguished from a phase shift. Again, the point of Andor's > paper >>> is >>>>>> that there's a simple way to distinguish the difference. Until you >>> do >>>>>> so you should not expect much respect of your grandiose claims when >>>>>> there's a much simpler explanation. >>>>>> >>>>>>> This is not phase velocity, this is group velocity i.e. time delay > of >>>>> the >>>>>>> envelope. >>>>>>> >>>>>>> William >>>>>> >>>>>> It doesn't matter which it is or whether the conditions are linear > so >>>>>> that they're the same, you haven't demonstrated that the propagation >>> has >>>>>> accelerated. Either demonstrate some actual information > transmission >>>>>> or expect people to keep pushing back on you. You have a high > burden >>> of >>>>>> proof to make the claims that you're making, but you don't seem to >>> want >>>>>> to offer anything substantial. >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> On 3/23/2010 6:06 PM, WWalker wrote: >>>>>>>>> Eric, >>>>>>>>> >>>>>>>>> Interesting article, but I don't see how it applies to my system. >>> The >>>>>>>>> system described in the paper is a bandpass filter in a feedback >>>>> loop, >>>>>>>>> where the bandpass filter phase function is altered by the >>> feedback. >>>>>>> The >>>>>>>>> feedback forces the endpoints of the phase to zero, creating >>> regions >>>>> of >>>>>>>>> possitive slope, which yield negative group delays for narrow > band >>>>>>> signals. >>>>>>>>> This causes narrow band signals at the output of the circuit > appear >>>>> to >>>>>>>>> arrive earlier than signals at the input of the circuit. Because >>> the >>>>>>>>> information in the signals is slightly redundant, the circuit is >>> able >>>>>>> to >>>>>>>>> reconstruct future parts of the signal from the present part of > the >>>>>>>>> signal. >>>>>>>> >>>>>>>> Snipped context to allow bottom-posting. >>>>>>>> >>>>>>>> Feedback is not necessary to produce negative group delay. > Here's >>>>>>>> another example with a passive notch filter that exhibits negative >>>>> group >>>>>>>> delay. >>>>>>>> >>>>>>>> http://www.radiolab.com.au/DesignFile/DN004.pdf >>>>>>>> >>>>>>>> It doesn't matter what's inside a black box if it has a negative >>> group >>>>>>>> delay characteristic if the transfer function is LTI. Whether >>>>> there's >>>>>>>> feedback or not in the implementation is inconsequential. > Consider >>>>>>>> that the passive notch filter could also be implemented as an > active >>>>>>>> circuit with feedback, and if the transfer functions are > equivalent >>>>> they >>>>>>>> are functionally equivalent. This is fundamental. I don't think >>> the >>>>>>>> feedback has anything to do with it. >>>>>>>> >>>>>>>> You're argument on the redundancy, though, is spot-on. Note > that, >>> as >>>>>>>> others have already pointed out multiple times, the signals you're >>>>> using >>>>>>>> in your experiment are HIGHLY redundant, so much so that they > carry >>>>>>>> almost no information. These signals are therefore not suitable >>> for >>>>>>>> proving anything about information propagation. >>>>>>>> >>>>>>>> >>>>>>>>> First of all, this is a circuit which alters the phase function >>> with >>>>>>>>> respect to time and not space, as it is in my system. The phase >>>>> function >>>>>>> in >>>>>>>>> the circuit is not due to wave propagaton, where mine is. >>>>>>>> >>>>>>>> As far as I've been able to tell, your evidence is based on a >>>>>>>> simulation, in which case dimensionalities are abstractions. You >>> are >>>>>>>> not performing anything in either time or space, you're performing > a >>>>>>>> numerical simulation. Space-time transforms are not at all > unusual >>>>> and >>>>>>>> it is likely that a substitution is easily performed. Nothing has >>>>>>>> propagated in your simulation in either time or space. >>>>>>>> >>>>>>>>> Secondly,unlike the circuit, my system is causal. The recieved >>> signal >>>>> in >>>>>>> my >>>>>>>>> system arrives after the signal is transmitted. It just travels >>>>> faster >>>>>>> than >>>>>>>>> light. >>>>>>>> >>>>>>>> Uh, the circuit is causal. That was the point. >>>>>>>> >>>>>>>> You have not demonstrated that your system is causal or not > causal. >>>>>>>> That cannot be concluded using the waveforms you show in your > paper >>>>> due >>>>>>>> to the high determinism and narrow band characteristics. >>>>>>>> >>>>>>>>> Thirdly, the negative group delay in the circuit was accomplished >>> by >>>>>>> using >>>>>>>>> feedback which does not exist in my system. >>>>>>>> >>>>>>>> As I stated above, this is inconsequential. >>>>>>>> >>>>>>>> >>>>>>>>> Information (modulations) are clearly transmitted using > narrowband >>> AM >>>>>>> radio >>>>>>>>> communication, just listen to an AM radio. The simulation I >>> presented >>>>>>>>> simply shows that random AM modulations arrive undistorted across >>>>> space, >>>>>>> in >>>>>>>>> the nearfield, earlier than a light speed propagated signal. >>>>>>>> >>>>>>>> Your simulation does not demonstrate that. Turn the signal off, >>> even >>>>> at >>>>>>>> a zero crossing if you want to minimize perturbations, and see > what >>>>>>> happens. >>>>>>>> >>>>>>>>> Signal purturbations can not be used to measure the signal >>>>> propagation >>>>>>> in >>>>>>>>> the nearfield because they distort in the nearfield, and group >>> speed >>>>> has >>>>>>> no >>>>>>>>> meaning if the signal distorts as it propagates. >>>>>>>>> >>>>>>>>> William >>>>>>>> >>>>>>>> If you cannot use a perturbation (i.e., information transmission) > to >>>>>>>> measure signal propagation then you cannot demonstrate the speed > of >>>>>>>> information propagation. Until you can actually demonstrate >>>>> something >>>>>>>> other than phase velocity (which is NOT information transmission > and >>>>>>>> many here have acknowledged can be faster than c, as do I), then > you >>>>>>>> cannot make the conclusions that you are claiming. >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Eric Jacobsen >>>>>>>> Minister of Algorithms >>>>>>>> Abineau Communications >>>>>>>> http://www.abineau.com >>>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Eric Jacobsen >>>>>> Minister of Algorithms >>>>>> Abineau Communications >>>>>> http://www.abineau.com >>>>>> >>>> >>>> >>>> -- >>>> Eric Jacobsen >>>> Minister of Algorithms >>>> Abineau Communications >>>> http://www.abineau.com >>>> >> >> >> -- >> Eric Jacobsen >> Minister of Algorithms >> Abineau Communications >> http://www.abineau.com >> -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com
From: Rune Allnor on 26 Mar 2010 16:28 On 24 Mar, 01:20, Eric Jacobsen <eric.jacob...(a)ieee.org> wrote: > On 3/23/2010 4:51 PM, Rune Allnor wrote: > You sim doesn't run very well under my version of Octave, but the bit > about the phase velocity on oblique angles is fundamental. It's wave physics 101, be it in the context of acustic, optical or microwave EM waveguides. Anyone who have taken an intro class on either topic would recognize the phase velocity at oblique angles. > I haven't > been able to sort out what WW is doing well enough to know for certain You don't need to. It suffices to recognize what he does *not* do, know or understand: - He has no concept of phase fronts in wave fields - He has no concept of Poynting's vector, that describes energy flux in EM wave fields, http://en.wikipedia.org/wiki/Poynting_vector - He has no concept of "information" as a random process http://en.wikipedia.org/wiki/Information_entropy (I am sure somebody can come up with a link to Shannons's result that information == energy) - He has no concept of the monochromatic signal's *irrelevane* in transmission systems - He has no concept of "AM modulation" for information-carrying signals of non-vanishing bandwidth - He has no concept of the role of transient cahnges in information-carrying signals No matter what apporach one investigates this sham from, one can shoot it down using little more than entry-level basics. In fact, it's a feat that one person can consistently do so many, so basic blunders in every possiblefield or craft he attempts to employ. And if I get the timings right, he has persisted in this manner for almost a decade and a half. A truly remarkable intellectual capacity, if nothing else. Rune
From: Jerry Avins on 26 Mar 2010 17:02
Rune Allnor wrote: > On 24 Mar, 01:20, Eric Jacobsen <eric.jacob...(a)ieee.org> wrote: >> On 3/23/2010 4:51 PM, Rune Allnor wrote: > >> You sim doesn't run very well under my version of Octave, but the bit >> about the phase velocity on oblique angles is fundamental. I don't think the illusion is based on obliquity. Walter is wrong about faster-than-light signaling, but he's not naive. Close in, the near field predominates, but it fades faster than the far field, so there's a transition as the distance from the antenna increases. There's a net shift of pi/2 when shifting between the two field components. That's subtle enough to take someone in without engendering too much embarrassment. ... Jerry -- Discovery consists of seeing what everybody has seen, and thinking what nobody has thought. .. Albert Szent-Gyorgi ����������������������������������������������������������������������� |