FM/CW Radar

Abstract

In a frequency modulated carrier wave radar the detection of the beat frequency that represents range is interrupted for short intervals that occur near maxima or minima of the modulating signal that controls the frequency of the transmitted carrier wave. During these intervals of interruption the carrier wave is modulated in amplitude so that it can convey information to the target that it illuminates. In a preferred embodiment, the amplitude modulation consists of a variable number of cycles of a voltage controlled oscillator of which the frequency is controlled by an integrated signal which represents the beat frequency. Timing for the short intervals of amplitude modulation and somewhat longer intervals that extend before and after each interval of amplitude modulation is derived from a square wave signal that is produced by an oscillator that governs the frequency of the carrier wave.

Dependencies are inferred from the claim text.