EM pulse detection

If you have ideal measuring devices you can! The error is going be in generating the pulse and recieving it(assuming any dispersion is irrelevant).

It think you need to give more information about such things as in general the lower the frequency the less well defined a "pulse" is. (i.e., a square wave pulese has infinite frequency and is "exact" but a sinewave has one frequency and is inexact)

You might combine different methods of testing and such but you need to determine what "great precision" is and how you can calibrate your system to check your "great precision".

I think your question is just to general to get any specific answer.

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Thank you for your remarks The aim is to measure the speed of light. I don't know if there are devices having the required precision.

Marcel Luttgens

is the receiver situated at some distance from the emitter with a rough terrain or or smooth you can use this formula if you modulate two separate frequecies of coherent light with an Em frequency over any terrain at any distance =E2=88=87=E2=80=B22=CF=88(x=E2=80=B2, z=E2=80=B2, =CF=89) + k2(=CF=89)n2=CF= =88(x=E2=80=B2, z=E2=80=B2, =CF=89) =3D 0 (1) where =CF=88 represents the field for either the vertically or horizontally polarized wave. For vertically polarized wave, =CF=88 is the magnetic field, which has component only along the y direction. For horizontally polarized wave, =CF=88 represents the electric field, which is pointed along the y direction. In addition, =E2=88=87=E2=80=B22 =3D =E2=88= =822/=E2=88=82x=E2=80=B22 + =E2=88=822/=E2=88=82z=E2=80=B22, k2(=CF=89) =3D =CF=892=C2=B50=C7=AB0, and n is the index of refraction of the propagating medium. It can be shown that many important radio wave propagation phenomena can be reduced to this twodimensional problem [3]. In two dimensions, the irregular terrain is described by the function z=E2=80=B2 =3D f(x=E2=80=B2). In this paper the terrain surfac= e profile f(x) is assumed to be a stochastic process. The problem we are concerned with is that of radio wave propagation over irregular terrain, in which a transmitter located at the horizontal position x=E2=80=B2 =3D x0 and at a height of h above ground radiates a transient pulse. The pulse then propagates in the positive x=E2=80=B2 direction until it reaches= a receiver located at the horizontal position x=E2=80=B2 =3D x, and a height of z above ground= . The geometry of the problem under consideration is shown in figure 1, where the horizontal distance between the transmitter and receiver is R. We further assume that the terrain material can be approximated by perfect electric conductors (PEC). Therefore, for vertically polarized wave, equation (1) satisfies the Neumann boundary condition, =E2=88=82=CF=88 =E2=88=82z=E2=80=B2 =0C=0C=0C=0Cz=E2=80=B2=3Df(x=E2=80=B2) =3D 0. (2) While for horizontally polarized wave, the boundary condition is given by the Dirichlet boundary condition, =CF=88|z=E2=80=B2=3Df(x=E2=80=B2) =3D 0. (3) We make the assumption that the terrain elevation varies on a scale length large compare to the wavelength of the radio wave and also that the wave propagates at small grazing angle relative to the x axis. Then, using the forward scattering approximation,

=CF=88(x=E2=80=B2, z=E2=80=B2, =CF=89) =3D 0 (1)

ly

=88=822/=E2=88=82x=E2=80=B22 + =E2=88=822/=E2=88=82z=E2=80=B22,

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Thank you!

Do you think that it would be possible, with a commercial emitter situated on the ground and a commercial receiver carried on a plane moving at a velocity v, for instance 1000 km/h, and situated at some distance from the emitter, to determine if the speed of light is c or c-v ?

Marcel Luttgens

Thank you for your remarks The aim is to measure the speed of light. I don't know if there are devices having the required precision.

Marcel Luttgens

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Is their any specific reason why? It is well known that c = 299792458 m/s.

Chances are you'll be better off using indirect methods

I really don't see any reason why you would want to measure the speed of light as it has already been done and probably to a much greater precision then you will ever be able to do by yourself.

Is this a trick question?

c is the speed of light in a vacuum, aircraft don't work too well without air.

Anyway if you could solve that you'd still need more than 12 significant digits to detect relativistic effects and tell the difference.

Bye. Jasen

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digits

Thank you, Jasen, but the aim of the experiment is not to detect relativistic effects, it is to measure the so-called one-way speed of light. One could try to determine if there is a statistically significative difference between the time taken by an EM pulse (in air, of course) to travel some distance d to a receiver situated on Earth and to a receiver situated at the same distance, but on a plane moving at some velocity, for instance 1000 km/h. But existing devices are perhaps not precise enough.

Marcel Luttgens

One way that this sort of experiment is done is use a mirror. The light pulse is sent from the source and then reflected off of the mirror back to the source location. The time delay between sending the pulse to receiving the reflection is measured.

The experiment, as you described it, would require two separate and very accurate clocks to record the sending and receiving times. It is much simpler to measure the time delay when both the sender and receiver are near to each other.