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Do one-dimensional signals truly exist?

  1. Dec 17, 2012 #1
    I would like to know more about the interactions in nature. Here's an example based on the observation of how radio waves efficiently transmit music from the radio stations.

    You can carry the radio with you around the city, and the signal never disappears. It seems as though the position and the orientation of the radio in space do not represent any particular filter for the incoming signals. Of course, some glitches are possible when you are driving in a bus. I conclude that the radio signal is "one-dimensional", because it does not possess any directionality or "shape". It is just a series of oscillations in space that are affecting the receiving antenna wherever it is located.

    The radio is not that perfect, however. You could find a special kind of directional antenna and point out the direction of the radio station emitter. You could find the obstacles that the radio waves cannot pass. Most of the time, none of this seems to represent a problem. Most of the time the radio signals seem to have a single dimension.

    Mobile/cell phones operate at higher frequencies and their signals possess much smaller "shape"; their wavelength is measured in centimeters. Their signal reception is more sensitive to direction and the obstacles make the signals bounce around. Also, there are many more antennas for mobile operators all around the neighborhood.

    It seems that the classical radio creates the best illusion of having a one-dimensional signal. What does it mean to be one-dimensional?

    Imagine a computer screen. It has many individual pixels in different colors. The light coming from each pixel to the eyes is keeping its direction in some relevant way, so that we can distinguish the individual pixels.

    A grid of radio antennas cannot accomplish the same thing as pixels can. They are all fuzzy in the "eye" of a common radio receiver. It can only choose a single frequency and listen to whichever antenna or antennas are broadcasting at that frequency.

    My question is the following. Are there any true one-dimensional signals in the nature?
  2. jcsd
  3. Dec 17, 2012 #2


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    Electromagnetic waves (including your radio waves and mobile phone transmissions) have a direction. In a town, you usually get a lot of reflections - it does not matter where exactly you are and which orientation your radio antenna has, there is some signal from somewhere.

    I do not understand your description of your definition of one-dimensional signals.

    A grid of radio antennas can be sensitive to the direction of the signal.
  4. Dec 17, 2012 #3
    I graduated physics 5 years ago, but only this summer I managed to read Feynman's "QED", popular book from the 1980s. I think that the book is remarkable - it gives meaning to all that I learned. It is as if I never really studied QM, because I did not hear about its foundation slowly and simply.

    Feynman mentions little arrow, but he does not use the word "vector", and associates the propagation of a photon with the arrow. He conveniently uses the idea of a clock (the timing of the emission) that enables one to compute what will happen to the photon depending from the time (phase) of its arrival. He claims that the square of arrow length represents certain probability.

    He introduces Feynman diagrams as simple diagrams that analyze simple, everyday events such as reflection of light from a mirror. In order to analyze events in full, events that are not entirely simple, we need to calculate all possible ways in which a Feynman diagram associated with an event can be drawn. A more complete calculation approaches the numbers that the experiments are giving us, he says. It is a more accurate calculation.

    Some diagrams are mysterious, because they introduce at least theoretically, virtual particles, antiparticles, and even a special view on antiparticles as particles that are going backwards in time. Indeed, who would say that the virtual photons are not real, physical entities, given that there is something in nature that enters the final calculation, regardless of how you want to call it.

    I liked the topic so much, that my heart made a promise to think about all these mysteries of nature once again.

    I noticed that all the interactions suggested in this book and in other textbooks, seem to include two particle interactions with the binary outcome. I must warn you that I did not learn much about these things. I found the terminology without any mainstream literature. Usually, a particle can hit another particle, or not hit it at all. (Newton noted that the simultaneous collision of three particles does not exist, because it is unlikely.)

    Particle pathways play the key role in the shape of the events, so all these interactions remind me of small "wires", given that one path is one such "wire" or a "string". The interactions on a fundamental level are always directional; they are never one-dimensional. A thump of a large loudspeaker is perhaps one-dimensional to a small particle standing right in front of it, but what the particle receives is after all, a series of collisions if in a gas, or deformations if in fluids and solids that effectively push and pull the particle once away and towards the speaker.

    Two atoms are also directional emitters and receivers. One atom could do something and the particles that it emits would hit perhaps another atom or two, but the exchange would stop there. Atom would not announce its presence in any other way, not by emitting a single photon in certain direction.

    On the other hand, complex, macroscopic events seem to offer more "light". Objects do announce their presence in all directions - perhaps by means of a local field that surrounds them. A huge number of particles are responsible for what we call an electrostatic field.

    If an atom is to do the same and "exist" in some way for its neighbors, it needs to exchange a lot of particles. If an atom would emit just a single photon from time to time, that would require energy and would not form the kind of interaction that would tell its neighbors that it is one element in a row of many, in a solid crystal lattice. There are many small-scale events happening in and around atom than just a single photon emission. Rushing electrons are a reminder that there is more activity there going on in any given atom.

    The orbital motion of electrons is coordinated by the exchange of particles that establish the electric field between the electrons and the protons in the atomic nucleus. This continuous exchange gives me the impression of a feedback system, where communication is quite lively, especially since we divided our scale of observation into the smallest, fine-grained time and space.

    Obviously, it's a bit too much to calculate and say how an atom works. The particle's directionality or dimensionality and motion seems to defy further reduction. The continuous exchange, which I called the "feedback" underlies the basic structures of matter. At this point the dimensionality might change, because an electron can "tune-in" to the proton's presence and continue in any direction along its circular path.

    This is just a view that I think could be really beneficial for further study. There is no end to this story in sight, so it is also about story telling, expansion of thoughts into the incalculable?
  5. Dec 17, 2012 #4
    One dimensional signals?

    Are you talking about polarisation or perhaps longitudinal waves?
  6. Dec 17, 2012 #5
    I also heard long time ago, about radio wave reflections. Within certain limits, it appears as though the ether is saturated with the radio stations battling for their share of the (market). A grid of emitters close to each other do not mean a thing to any ordinary radio receiver, I was about to say. They are not like pixels for a number of reasons. All this creates an illusion I'd say, worthy of question. The radio receiver is insensitive locally to the orientation and small-scale changes in position. Could this be the last case in the whole of nature on all scales and in all experiments in which the frequency, i.e. tuning to the frequency represents the only parameter you can set and find the source of emission?
  7. Dec 17, 2012 #6
    Longitudinal waves could be the right thing to imagine. Also, the frequency, as a single parameter required to set in order to catch the signal.
  8. Dec 17, 2012 #7


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    What do you mean by "One Dimensional"?
    The degree to which diffraction effects can be observed merely depends upon the wavelength involved but all the same basic rules apply for all EM waves.
  9. Dec 17, 2012 #8


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    This is just a technical issue - a radio receiver does not need this sensitivity to play music. You can build better receivers.
  10. Dec 17, 2012 #9


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    This is getting a bit 'new age'. Where are you trying to take this? What did your Physics course tell you about EM waves and time varying signals? From what you are writing here, you seem to want to change all that.
    An array of light sensors will measure the varying illuminatiion over an image, formed by a lens. Light is a short wavelength so you can obtain a high resolution (diffraction limits apply). Those same diffraction rules tell you that, because of the much longer wavelengths involved (tens of millions of times longer) the spatial resolution that you can obtain with a set of radio frequency sensors is a lot less. Nothing magical - just a difference in geometry and scale.

    I am sure you learned that EM waves are Transverse. Do you really want to ignore this and suggest that they are Longitudinal?
    Look up some of the basic ways that radio and TV signals are used to carry information. There is loads of accessible stuff available via google about all this. Radio antenna are also described on many web pages, to various technical levels.

    I think you will get further from reading than writing at this stage. Concentrate on the classical stuff about waves before you launch out on QM.
  11. Dec 17, 2012 #10
    This is good thinking, because you are talking about patterns. Wavelength is equivalent to frequency and that is just one parameter to tune. The wavelength or frequency range represents the window of opportunity to see the patterns.
  12. Dec 17, 2012 #11
    I think that this is how government promised to find us back in the 1990s, to find that we possess a TV set with an antenna, while we are refusing to pay the subscription. They had some kind of directional hand-held antenna to scan the neighborhood. I waited my whole life to find out how that works and in the end, I think that they just did the poll by phone and made some statistics from there.

    BTW, aren't we more interested in omnidirectional antennas that do not depend on many emitters in the neighborhood, unlike the directional receiving antennas? The quality consideration could be reversed.
  13. Dec 17, 2012 #12
    Yes, this is slightly newer than Tesla who allegedly discovered the radio. You want to say that the gigantic wavelength causes the loss of spatial resolution. Perhaps this gives us the approximately one-dimensional signal, which really draws my attention to the question itself - is it really possible that in nature there isn't any one-dimensional signal anywhere?

    If you can have an array of atoms, where each atom can be traced by specific frequency, then the matter and the universe contain much more information than it meets the eye. Perhaps this is in collision with some fundamental law that states that all atoms are indistinguishable. I am not sure what law that would be, but it is good to walk through this :-)
  14. Dec 17, 2012 #13


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    Are you referring to transmitting antennae here? I can't think of a single UHF broadcast transmitting antenna design that is omnidirectional. Any 'Main Station' will consist of a stack of dipoles at the very least, to direct the main beam downwards into the service area. UHF power is too hard to come by just to spray it up into the sky.

    The TV detector vans used an interferometer and looked at the local oscillator radiation from standard receivers. Nothing at all to do with what you are on about. In fact - what are you on about? Could we just deal with one thing at a time, please?
  15. Dec 17, 2012 #14
    OMG, please don't remind the government.... Just kidding. Yes, please just one topic :-)
  16. Dec 17, 2012 #15


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    You still haven't explained what you mean by one of these
    This is just nonsense. In any case, I always bail out when someone mentions Tesla. It usually spells trouble.
  17. Dec 17, 2012 #16
    Well, you tuned your antennas and you know how it goes with the topic of Tesla... but, if you care to notice, after a few pages of my writing, this is really not about Tesla at all.

    This is about math and geometry. For example, you can have a point-like source that oscillates, or the whole space can oscillate. If an excitable atom does not know about the direction of the photon that excites one of its electrons, you can have the same effect, almost. If you did have the full effect, the atoms could share the common information source and sync to it. This is reminiscent of laser pumping. If the atoms do not know about the direction of the pumping, within some limits, it is as if there is a one-dimensional source of pumping from the perspective of atoms. Its also about the degrees of freedom, symmetries... the basic aspects of existence. I need to go now, but I can share some more thoughts tomorrow...

    Thanks for looking into this everybody!
  18. Dec 17, 2012 #17
    I think you are deeply misunderstanding how a radio works. The radio signal drops the farther you go from the radio tower. It's certainly not 1-dimensional. If you go too far away, all you will hear is static. In 3D, signals drop off as 1/r^2 (the inverse square law). Radio might drop off a little less quickly because it bounces off the ionosphere, so it's probably drops off somewhere between 1/r and 1/r^2, so it's probably effectively fractal dimension. In 1-D, the signal doesn't drop off with distance unless it is absorbed.
  19. Dec 17, 2012 #18


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    Only because of 2 things....

    1) as some one else mentioned .... the signal is being bounced/reflected in every direction ... and
    2) when relatively close to the transmitter, the signal strength is so strong

    both of these combine to mainly nullify the effects of the receiver antenna orientation

    its only when you start getting some distance from the transmitter that the effects become noticable and that the orientation of the antenna in the receiver becomes important

  20. Dec 17, 2012 #19


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    no its not ! wavelength is inversely proportional to frequency
    ... As the frequency increases the wavelength decreases

    As sophicentaur said ... you need to do some serious reading up and relearning about
    E-M generation, propagation and reception

  21. Dec 17, 2012 #20
    It's reasonable to say wavelength is equivalent to frequency, since they both contain the same information for light.
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