**EN123 Feedback Quiz: Take Home Honor System:
2002**

*name________________________________ *

*Take an hour to try to answer the question below:
do not discuss with fellow students or any so-called Automatic Control Experts.
Consult any reference you like, including the EN123 archive website, and
the supplemental notes on feedback, on the main 123 index.*

* The problem below is a simplification of a model for optokinetic
reflex. *

__Your answer is due by noon, Dec 2, 2002. __

For credit you must show some work, and derive the correct answer.

Study the feedback diagram below, where L is an external load.

Your problem: Find an expression for OUT(s) such that

OUT(s) = T1(s)*L(s) + T2(s)*IN(s)

you need to figure out Laplace transfer functions T1 and T2.

There is integral control on the negative feedback error signal.

(1/s stands for integration in Laplace transform notation)

Notice you have an inner positive feedback loop and an out negative feedback
loop.

You might start by solving for the inner positive loop transfer function,

then work on the outer negative loop.