USA As Represented by Secretary of the Navy

Arthur L Moorcroft

Gerald L Assard

Michael J Sullivan

Raymond E D'Addio

A transmitter for generating a steerable, variable frequency signal from an rray of projectors. An analog signal to be transmitted is sampled, digitized and stored in a circulating memory. A delay storage circuit includes time delays for each projector for each of predetermined beam directions. The successive locations in the recirculating memory correspond to signals having a time correspondence at predetermined unit delays from the signal then at the input terminal. The delay storage unit then produces a reading address for recovering, for each of the projector drivers, a signal value corresponding to an appropriate delay for obtaining the desired steering angle with a constant beamwidth signal. Frequency sensing circuitry can further compensate the signals by assigning each to a frequency bin and utilizing that bin to further define the delay for each projector and control the amplitude of the signal being sent to each projector. The output from a linear array of transducers is steerable over the entire range and operates with a constant band width even with significant frequency variations.

Steerable beamformer

A relatively solid mounting surface, which may be part of a leveling gimb supports a piezoelectric bearing mount which has the properties of an acoustic transducer. The transducer has electrodes thereon which are powered from multi-phase electrical sources causing the bearing mount, and a bearing jewel which is rigid therewith, to move so as to dither the jewel in a rotary or other preselected fashion, thereby reducing bearing friction. Bandwidth, level and phasing sequence of the power sources are adjustable permitting optimized average dynamic motion and corresponding increased readout accuracy.

Precise bearing support ditherer with piezoelectric drive means

A system for detecting and identifying acoustic sound sources using a pluity of identical data acquisition modules spaced at preselected intervals along a line array. Two small diameter coaxial cables provide intermodular connections for power, timing control and sequential data transmission to a remote receiver. A control clock waveform leading edge simultaneously triggers sampling and holding of sensor data at each module of the array while the waveform trailing edge is delayed for a preselected interval at each module to provide squential data output.

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Norwich, CT, United States of America

Arthur L Moorcroft