How to get envelope from AM signal without phase shift
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From: Clay on 1 Apr 2010 11:36 On Mar 31, 6:42 pm, "WWalker" <william.walker(a)n_o_s_p_a_m.imtek.de> wrote: > Hi Clay, > > The propagation distance in my 500MHz carrier simulation is 10cm. But the > distance can be a lot larger for lower carrier frequencies. For example, > if > the carrier frequency (fc) is 1MHz (typical AM radio) then the optimum > propagation distance is 300m (1/6 carrier wavelength) and the envelope > will > arrive 80ns earlier than a light speed (propagating envelope (0.08/fc). > For > lower carrier frequencies, even larger distances and larger light speed > time differences are possible. > > In terms of quantum mechanics I think the following might be happening in > this system. If a photon is created a t=0 then as it propagates, because of > the uncertainty principle, the uncertainty of the velocity of the photon is > much larger than c in the nearfield and much less than c in the farfield. > Which means the photon can be much faster than light in the nearfield but > reduces to the speed of light as it propagates into the farfield. Below is > the argument that shows this. > > Lets calculate the uncertainty of the velocity of a photon that propagates > one wavelength after it is created: According to the Heisenberg uncertainty > principle, the relation between the uncertainty in Energy (dE) and the > uncertainty in time (dt) is: dE*dt >= h. The time for a photon to cross one > wavelength distance is: dt = lambda/c. Since dE = h*df and df=dv/lambda > then dE*dt=h*dv/c, but dE*dt <= h therefore: dv >= c > For smaller distances the uncertianty will be greater and for larger > distances the uncertainty will be much smaller. > > William > > > > > > >On Mar 29, 12:18=A0pm, "WWalker" <william.walker(a)n_o_s_p_a_m.imtek.de> > >wrote: > >> Jerry, > > >> The speed of light is a corner stone in physics and if it is not a > consta= > >nt > >> then many of our theories in physics will be affected. There may be > direc= > >t > >> practical uses as well, but I just guessing: improving accuracy of high > >> speed doppler radar, speeding up communication to spacecraft where time > >> delays are problematic, increasing speed of computers when they are > >> eventually limited by light speed delays etc. As I said, these are only > >> guesses, the main effect would be a change in many of our theories in > >> physics, which would eventually lead to new practical uses and > >> technologies. > > >> William > > >> >Eric Jacobsen wrote: > > >> > =A0 ... > > >> >> 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. =A0 =A0.. Albert Szent-Gyorgi > >> >- Hide quoted text - > > >> - Show quoted text - > > >Hello William, > > >I suggest you 1st study the EPR paradox and then look up Bell's > >theorem and see how it applies to Relativity. You are not going to get > >information over any significant distance with superluminal speed. > >Sure there is a probability that a particle will travel faster than > >light for a short distance (say for example across the nucleus of an > >atom about 10^-14 to 10^-15 meters) but when you start to add up all > >of the paths in a Feynman diagram, you will see the probability of it > >happening across a room is not even likely in a time period of the age > >of the Universe. > > >Clay- Hide quoted text - > > - Show quoted text - Your photons are also influenced by all of the electrons in the antenna, so you can't treat it them like they are independent items. Your transmitting and receiving antennas are highly coupled and the transmission from your antenna has an extra delay compared to when you are transmitting to empty free space. When you include this delay, I'm sure you will see your signal input into the tx's coax cable will not arrive at the rx's coax cable with superluminal speed. This reminds of a case two years ago where I met a guy who claimed to have a machine that created more energy out than he put in. He "verified" this by 1st measuring the amount of power going into the the machine. Then he measured the power out by putting a load on it. Then he concluded he got more power out than he put in. The problem was he needed to measure the power going it to the maching when it was loaded. Once this was done, it was clearly observed that the power out was less than the power in. His investors were not happy! You can google "Sprain Motor" if you want to know about that particular machine. Now think about the loading your receive antenna puts on to the transmitting antenna. This will cause an extra delay compared to when there is no loading on the tx antenna. Clay
From: Eric Jacobsen on 1 Apr 2010 12:00 On 4/1/2010 5:51 AM, WWalker wrote: > Eric, > > I appreciate this discussion and I do understand the points all of you have > been making very clearly. I teach advanced analog and digital signal > processing, mathematics, as well as RF technique, and EM theory, and I have > been looking at this problem for 20 years. I simply do not agree with some > of the conclusions in this discussion for very logical reasons. > > I think maybe the problem is that we are all having difficulty > understanding what is the information in the simulations being discussed, > where is it located, and how does it propagate. Information is not well > understood and I think it needs to be discussed to see if it can be defined > better, as it applies to these simulations. > As I mentioned before, I agree that if the information is the edge of a > sharp pulse, which is passed through a narrowband nearfield dipole AM > transmission and detection system, then the time delay will be the time > delay of the narrowband filter plus the freespace propagation time of the > pulse edge, which propagates at speed c in both the nearfield and farfield. > The pulse will distort in the nearfield but the edge will be clearly > defined and can be used to trigger a bomb. With this type of setup, the > overall time delay of the pulse edge will clearly be less than a light > speed time delay. > But, if the information signal is directly input, bandlimited, in a > narrowband nearfield dipole AM transmission and detection system, then the > time delay of the bandlimited signal will only be the freespace propagation > delay, which is less than light speed as shown in my simulations. I think you have not shown that. There is another, more likely, explanation. Unless and until the more likely explanation is disproven I think it is impossible to claim propagation faster than c. At least two fairly simple ways to further illuminate the issue have been mentioned (interruption of the signal and measurement of initial onset of energy from the zero state). I'm curious as to why you don't seem interested in pursuing them. > For example, if the signal is created by a voltage source that is manualy > slowly adjusted, and if the signal is then mixed with a carrier and sent > though a nearfield dipole system, then the detected envelope will arrive > undistorted earlier than a light propagated signal, as I showed in my > simulations. Each voltage point on the voltage vs time curve of the voltage > source is information about what the voltage was at that time. If that > pattern is reproduced exactly a distance away, then the time delay of each > information voltage point is the propagation time of the information. Except that such a signal is easily predicted, without accelerated propagation, by certain practical processes, and that prediction is easily mistaken for non-causality, time travel, or accelerated propagation (as you seem to have done). Again, a couple simple experiments may help show the difference. Your "accelerated" signals are well within the believable realm of phase advance achieved by a bandlimited prediction process. I haven't noticed you take any steps toward eliminating that explanation. Until you do, expect skepticism and/or dismissal from many. -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com
From: glen herrmannsfeldt on 1 Apr 2010 14:51 Clay <clay(a)claysturner.com> wrote: (snip) > p.s. I think Feyman's 3 volume lecture set should be required reading > for all undergraduate physics majors. I probably agree, but not so early. As far as I know, most schools physics programs in the first two years go through some combination of Newtonian mechanics, E&M and quantum mechanics. The Feynman lectures were originally done for those students, but, as the stories go, more and more professors showed up and, as time went on, fewer and fewer students. But at the third and fourth year, when physics majors get deeper into the subject, yes. Even so, some of my favorite chapters from the books can be read pretty much independent of the rest. One is on how the eye works, including much on color vision. Next is complex exponentiation derived pretty much from scratch. (Start with 10 square roots and you can do everything else from there.) Finally, there is the non-conservation of parity. -- glen
From: dbd on 1 Apr 2010 16:56 On Mar 31, 3:42 pm, "WWalker" <william.walker(a)n_o_s_p_a_m.imtek.de> wrote: >... > > In terms of quantum mechanics I think the following might be happening in > this system. If a photon is created a t=0 then as it propagates, because of > the uncertainty principle, the uncertainty of the velocity of the photon is > much larger than c in the nearfield and much less than c in the farfield. > Which means the photon can be much faster than light in the nearfield but > reduces to the speed of light as it propagates into the farfield. Below is > the argument that shows this. > > Lets calculate the uncertainty of the velocity of a photon that propagates > one wavelength after it is created: According to the Heisenberg uncertainty > principle, the relation between the uncertainty in Energy (dE) and the > uncertainty in time (dt) is: dE*dt >= h. The time for a photon to cross one > wavelength distance is: dt = lambda/c. Since dE = h*df and df=dv/lambda > then dE*dt=h*dv/c, but dE*dt <= h therefore: dv >= c > For smaller distances the uncertianty will be greater and for larger > distances the uncertainty will be much smaller. > > William William The uncertainty principle is a statement of the products of the uncertainties in the simultaneous measurement or knowledge of the values of conjugate pairs of physical quantities. The uncertainty principle does not describe, allow, require or justify photon velocity of other than c, it is about inaccuracy in simultaneous measurement. Where are the measurements in your argument? This is the kind of misrepresentation that Rune pointed out in your wave propagation arguments. The repetition and persistence in your arguments of the misrepresentation of basics from someone of your apparent background suggests that Rune may have been too kind. Dale B. Dalrymple
From: robert bristow-johnson on 1 Apr 2010 21:34
On Apr 1, 4:56 pm, dbd <d...(a)ieee.org> wrote: > On Mar 31, 3:42 pm, "WWalker" <william.walker(a)n_o_s_p_a_m.imtek.de> > wrote: > > > > >... > > > In terms of quantum mechanics I think the following might be happening in > > this system. If a photon is created a t=0 then as it propagates, because of > > the uncertainty principle, the uncertainty of the velocity of the photon is > > much larger than c in the nearfield and much less than c in the farfield. > > Which means the photon can be much faster than light in the nearfield but > > reduces to the speed of light as it propagates into the farfield. Below is > > the argument that shows this. > > > Lets calculate the uncertainty of the velocity of a photon that propagates > > one wavelength after it is created: According to the Heisenberg uncertainty > > principle, the relation between the uncertainty in Energy (dE) and the > > uncertainty in time (dt) is: dE*dt >= h. The time for a photon to cross one > > wavelength distance is: dt = lambda/c. Since dE = h*df and df=dv/lambda > > then dE*dt=h*dv/c, but dE*dt <= h therefore: dv >= c > > For smaller distances the uncertianty will be greater and for larger > > distances the uncertainty will be much smaller. > > > William > > William > > The uncertainty principle is a statement of the products of the > uncertainties in the simultaneous measurement or knowledge of the > values of conjugate pairs of physical quantities. The uncertainty > principle does not describe, allow, require or justify photon velocity > of other than c, actually, i thought the only thing that implies a photon velocity other than c is the photon rest mass (which is 0 which is why they are called "massless particles"). i was thinking that William is trying to construct a theory where the group velocity is faster than the phase velocity for EM waves. and he's trying to signal information with that. > This is the kind of misrepresentation that Rune pointed out in your > wave propagation arguments. The repetition and persistence in your > arguments of the misrepresentation of basics from someone of your > apparent background suggests that Rune may have been too kind. maybe you guys are right. i dunno. William, i have to admit that most theories that contradict SR or GR sound a little cranky to me. and if i had to bet on who has a better grasp of the concepts of space and time and how the EM interaction (or gravity or strong) propagates in such, i would probably bet on Albert rather than William. but i just like to assume the best in anyone. (well, there were exceptions, but i can't remember anyone's name except eBob.) r b-j |