Page 73 - Introduction to Information Optics

58 1. Entropy Information and Optics

distribution at a given temperature T e ^ T:

/-in
7(v)) = (1.197)

where T e is defined as the effective temperature.
Since the output entropy can be determined by

(U98)
Icln2

the quantum mechanical channel capacity can be evaluated as given by

(...99,

(nkT') 2
v

In view of the total output power

0.200,

the effective temperature T e can be written as

6hS '
(1.201
(nk)

Thus, the capacity of a photon channel can be shown to be

(1.201)

We would further note that high signal-to-noise ratio corresponds to high-
frequency transmission (hv » kT), for which we have

6hS