Home |
Search |
Today's Posts |
#11
![]() |
|||
|
|||
![]()
Roy:
[snip] You didn't show differently in your analysis, and no one has stepped forward with a contrary proof, derivation from known principles, or numerical example that shows otherwise. Roy Lewallen, W7EL [snip] Yes I did. I guess that you missed that post. I'll paste a little bit of that posting here below so that you can see it again. [begin paste] We are discussing *very* fine points here, but... [snip] ratio of the reflected to incident voltage as rho = b/a would yeild the usual formula: rho = b/a = (Z - R)i/(Z + R)i = (Z - R)/(Z+ R). In which no conjugates appear! Now if we take the internal/reference impedance R to be complex as R = r + jx then for a "conjugate match" the unknown Z would be the conjugate of the internal/reference impedance and so that would be: Z = r - jx Thus the total driving point impedance faced by the incident voltage a would be 2r: R + Z = r + jx + r - jx = 2r and the current i through Z would be i = a/2r with the voltage v across Z being v = a/2. Now the reflected voltage under this conjugate match would not be zero, rather it would be: b = (Z - R)i = ((r - jx) - (r + jx))i = (r - r -jx -jx)i = -2jxi = -2jxa/2r = -jax/r and the reflection coefficient value under this conjugate match would be simply: b/a = rho = - jx/r Thus I conclude that, under the classical definitions, when one has a "conjugate match" [i.e. maximum power transfer] the reflected voltage and the reflection coefficient are not zero. : : In summary: Under the classical definition of rho = (Z - R)/(Z + R) rho will be not be zero for a "conjugate match" and in fact there will be a "residual" reflected voltage of -jx/r times the incident voltage at a conjugate match. The only time the classical definition of rho and the reflected voltage is null is for an "image match" when the load equals the reference impedance. : : Unless one changes ones definition of the reflected voltage/reflection coefficient to utilize the conjugate of the internal impedance as the "reference" impedance then the reflected voltage is not zero at a conjugate match. End of story. [snip] Regards, -- Peter K1PO Indialantic By-the-Sea, FL. |