Abstract: A Sonar decoy system receives an interrogating pulse from an energy source nd then distorts, elongates, amplifies, and retransmits the pulse to simulate an echo of that pulse rebounding from the various reflecting surfaces of a moving submarine. To refine the allusion of an actual echo, a portion of the pulse signal is circulated and recirculated through a delay line several times, and then reinserted into the outgoing signal to contribute random additions to and phase cancellations of the various frequency components of the signal.

Abstract: The present invention relates generally to submarine simulating decoy and particular is a sonar system for receiving the acoustical search pulse from an enemy or other vehicle and converting it into a dopplerized sonar signal which is then broadcast back to the enemy vessel for deception and tactical combat purposes.

Abstract: 2.

Abstract: 1. A system for simulating wave reflections from an irregular-shaped moving bject which has been illuminated with energy of frequency F, said system comprising;a receiver (10) for said frequency F;a generator (14) of white noise voltage;means (13) for amplitude modulating frequency F with said white noise voltage to generate random bursts of frequency F;a radiating transducer (11);a bandpass filter (18) having a passband including said frequency F, the output of said filter being coupled to the input of said transducer, and the input of said filter being coupled to the output of said modulator means (13) to radiate said random bursts of frequency F;a second signal path between said modulator and filter including a time delay network (30) for randomly distorting the radiated bursts.

Abstract: 1. A masking-jamming sonar countermeasure system comprising in combination, receiver, a transmitter, a sequence timer connected between said receiver and said transmitter for regulating the operative time intervals thereof, and means coupled to the input of said transmitter for driving same with predetermined sonar signals and psuedo noise signals alternately applied thereto on a time-shared basis.

Abstract: 1. A helicopter destructor comprising in combination,a hydrophone channel,a microphone channel,a barometer channel,an AND gate connected to the outputs of said hydrophone, microphone, and ometer channels,an explosive means, andmeans connected to the outputs of said hydrophone channel and said AND gate for detonating said explosive means when a trio of signals are simultaneously applied to the respective inputs of said AND gate.