Which The Video Output: There are two common methods of eliminating clutter. In one, called noncoherent moving target indication, the target echoes are identified by the beat that occurs between their frequency and the frequency of the ground return received with them. Since the Doppler shift is very slight, the period of the beat frequency is many times greater than the width of the radar's pulses. As a result, the beat between a particular moving target's echoes and the ground return is evidenced by a change, from one repetition period to the next, in the amplitude of the return received from a given range. To detect moving targets, the video output of the receiver is delayed by exactly one repetition period, and the undelayed video is subtracted from the delayed video.
Sometimes it is necessary to search for and track targets simultaneously with the same radar. This may be accomplished by supplementing the radar with data processing equipment to which the video output from the receiver and inputs from the antenna and scynchronizer are fed. The targets to be tracked are detected and designated to this equipment either by an operator or by automatic acquisition circuitry. The rate with which information is received on a given target is much slower than that obtained with a radar that tracks one target continuously.
Power Output.-The power output of a pulsed radar is expressed in terms of both its peak value and its average value. Since the length of the transmitted pulses generally is extremely short as compared with the period between pulses, peak power output is many times a? large as average output. Because range capability depends in part on the power output of the radar.
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Photography
