TABLE OF CONTENTS John W. Taylor, Jr.
Westinghouse Electric Corporation
The function of a radar receiver is to amplify the echoes of the radar transmission and to filter them in a manner that will provide the maximum discrimination between desired echoes and undesired interference. The interference comprises not only the noise generated in the radar receiver but also energy received from galactic sources, neighboring radars and communication equipment, and possibly jammers. The portion of the radar's own radiated energy that is scattered by undesired targets (such as rain, snow, birds, insects, atmospheric perturbations, and chaff) may also be classed as interference. Where airborne radars are used for altimeters or mapping, other aircraft are undesired targets, and the ground is the desired target. More commonly, radars are intended for detection of aircraft, ships, surface vehicles, or personnel, and the reflection from sea or ground is classified as clutter interference.
The boundaries of the radar receiver must be defined arbitrarily. This chapter will consider those elements shown in Fig. 3.1 as the receiver. The input signal is derived from the duplexer, which permits a single antenna to be shared between transmitter and receiver. Some radar antennas include low-noise amplifiers prior to forming the receive beams; although these are generally considered to be antenna rather than receiver elements, they will be discussed in this chapter.
The receiver filters the signal to separate desired echoes from interference in many ways, but some...
