Audio Engineering

662 Chapter 22

either constructive or destructive according to the degree of phase difference. When the
interference is destructive, the resultant signal may be so weak that the receiver will not
be able to recover the program material.

The arrangement shown in Figure 22.10(b) greatly reduces the probability that there
will be a complete loss of program material. In this arrangement, two antennas located
somewhat less than a wavelength apart are employed. In this arrangement, the refl ected
signal may not even arrive at the second antenna as shown. Even when this is not the case
or when there are other refl ecting objects, the chances that both antennas are subjected to
destructive interference simultaneously are reduced greatly.

There are several techniques for handling the signals that appear in the space diversity
antennas. In one technique the space diversity receiver is fi tted with separate radio
frequency amplifi ers for each antenna. The signals from each of these amplifi ers are

Reflecting object

(a) Multipath reception

Transmitter Receiver

Figure 22.10 : Multipath and space diversity reception.

Reflecting object

(b) Space diversity reception

Transmitter Receiver