Abstract: In apparatus for discriminating targets from clutter, a high threshold circuit for passing only signals with sufficient amplitude and a lower threshold circuit passing signals of a sufficient amplitude to range extent circuitry, which passes only signals within a predetermined duration and which do not have other range signals adjacent thereto, and to frequency extent circuitry, which passes only signals within a predetermined bandwidth and which do not have other frequency signals adjacent thereto. Signals which satisfy the amplitude, range and frequency requirements then provide an output indicative of a target; all other signals are rejected as clutter.

Abstract: A system is disclosed for analyzing in real time the frequency spectrum of an incoming signal of unknown frequency characteristics. This is accomplished by first generating a train of sampling pulses in repetitive frames, where each frame of pulses represents a series of cross-correlation functions in terms of a predetermined number of sampling intervals and a predetermined number of harmonics. These sampling pulses are then multiplied with the incoming signal to generate a train of discrete sampled outputs. The discrete sampled outputs from the multiplying means are accumulated in an accumulator and a frequency domain output signal is produced for each frame of sampling pulses.