puzzled with the negative feedback system

[zhenyuanwu@gmail.com]

In the negative feedback system ,why should we consider the feedback
block as an isolate
block to the amplifying block? Should't we consider about the input
resistance of the the
amplifying block? If the input resistance of the amplifying block is
considered, there will
be a complexed problem in the transistor circuit. What should we do
while we are analysising
the analog negative feedback system?
Thanks in advance!

 

[Virus]

<zhenyuanwu@gmail.com> wrote in message
news:1143793086.283974.66480@v46g2000cwv.googlegroups.com...
.. What should we do

while we are analysising
the analog negative feedback system?

A lots of things.
Depends on design application and application of design..
OK?