Keith Dysart wrote:
Cecil Moore wrote:
The physical rho
at point y is zero. The physical rho at point x is 0.8. That's
the difference. Reflections occur only at physical impedance
discontinuities.

Certainly true. To be somewhat more complete there is another
rho at x. You have correctly computed rho from the generator
to the line, but there is also a rho from the line to the
generator: -0.8.

Not exactly correct. Rho is calculated at a point
of discontinuity, not from-to along a line. The
reverse rho at point x is -0.8. There could
exist another point of discontinuity inside the
source but unless reflections are allowed to reach
the source, we have no clue what it might be. If
100 volts is supplied at point x in the example,
we have no way of knowing what the source impedance
might be.
--
73, Cecil http://www.w5dxp.com