The obtained channel transfer characteristic has a typical appearance of a sequence of peaks and valleys ( also called " notches " ); it can be shown that, on average, the distance ( in Hz ) between two consecutive valleys ( or two consecutive peaks ), is roughly inversely proportional to the multipath time.
42.
The transfer characteristic is shown in the picture on the left . The value of the threshold " T " is given by \ frac { R _ 1 } { R _ 2 } { V _ s } and the maximum value of the output " M " is the power supply rail.
43.
The transfer characteristic of RO is usually represented as the electrical resistance of the photoresistor as a function of the current through the light source; it is a convolution of three main factors : the dependence of light source intensity on its current, optical coupling and spectral matching between the light source and photoresistor, and the photoresponse of the photoresistor.
44.
Use of special-quality versions outside of the purpose they were designed for may not be optimal; for example, a version for digital computers may be designed for long life without cathode poisoning when mostly switched to low-current mode in switching applications, but with little attention to parameters of interest only for linear applications such as linearity of transfer characteristic, matching between the two sections, microphony, etc.
