View Single Post
  #6   Report Post  
Old September 1st 03, 08:12 PM
Cecil Moore
 
Posts: n/a
Default

Cecil Moore wrote:
Some people here seem to incorrectly think you can
have a return gain with a passive network...


Does anyone remember what is the absolute value of a
complex number?


Found the answer in, "Higher Mathematics for Engineers and Physicists".
I suspect the square of the absolute value of the voltage reflection
coefficient is the volt-amp reflection coefficient, not the power
reflection coefficient.

With a complex characteristic impedance, what is being reflected is
volt-amps. I suspect the reflected volt-amps can be higher than the
incident volt-amps. I seriously doubt that the reflected watts
can be higher than the incident watts. The correct *power* reflection
coefficient therefore may be something like |Re(rho)|^2 where 'Re'
means "the real part of". The simpler |rho|^2 may be the volt-amp
reflection coefficient when Z0 is complex.

Using deductive reasoning, since the real part of the voltage
reflection coefficient cannot be greater than 1.0, it seems to
me that |1.0|^2 may be the maximum power reflection coefficient.
The complex voltage reflection coefficient squared may be the
volt-amp reflection coefficient which can be greater than 1.0.

In a transmission line with a complex characteristic impedance, the
reflected voltage and reflected current would not be in phase.
Therefore, their product would be volt-amps, not watts. Reflected
watts could be obtained from Vref*Iref*cos(theta) which would always
be less than (or equal to) Vref*Iref.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----