Signal Distortion by Directional Broadcast Antennas

Directional broadcast antenna systems are inherently capable of producing signal distortion. One type of distortion, described by Doherty, involves the frequency sensitivity of the antenna input impedance and relationships between this impedance and the transmitter and transmission lines. A second type of distortion results from the directional radiation characteristics of the array, and is caused by differences in the response conditions of a directional array for the carrier and each sideband frequency.