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: An array of sonar transmitting and receiving transducers are so physically rranged and their signal voltage so combined as to form beams pointing to various points of the compass. In this invention a signal is formed on a different conductor for each beam and the conductors are wiped in rapid succession to determine the presence of any beam signal. Since any signal may be short-lived the total sampling process must be in milliseconds. Any signal that occurs is converted to digital form and is fed into a first recirculating delay line time compression storage loop. All signals are stored in the first loop. Then the cluster of signals pertaining to one beam is read out to a second recirculating delay line time compression storage loop from when it is read out to a variable frequency super-heterodyne and displayed on a cathode ray tube.