Abstract: A method transforms non-speech input signals into the temporal, spectral and redundancy patterns resembling that of human speech.

Abstract: A transducer array is constructed from a constant arc length portion of a ght circular cylindrical shell of piezoelectric transduction material. The constant arc length portion is segmented evenly along the length thereof to define a plurality of transducers. The transducers can be in the free field or mounted on a planar baffle.

Abstract: A sonar array which has a resolving power which is double that of convental sonar arrays includes an array of hydrophones each having an acoustic center, a first projector positioned proximate a first endmost one of the hydrophones for launching a first sound signal during a first transmission time period, a second projector positioned proximate a second endmost one of the hydrophones for launching a second sound signal during a second transmission time period, wherein the hydrophones receive first echo signals and convert the first echo signals into first electrical echo signals during the first transmission time period, and receive second echo signals and convert the second echo signals into second electrical echo signals during the second transmission time period, and, a receiver for receiving and storing the first and second electrical echo signals, and for coherently summing the stored first and second electrical echo signals, to thereby produce a beam having a half-power beam width which is one-half tha

Abstract: A pulsed-transmission, single frequency echo-ranging sonar system has a w-beam acoustic projector with sharp cutoff of energy radiated in directions other than the desired field of view and a nearly constant amount of acoustic energy throughout the desired vertical field.

Abstract: A pulsed-transmission, echo-ranging sonar system of the side scanning type ses a synthetic aperture to form search beams. The system uses multiple projectors, and a multistatic hydrophone array and a four transmission sequence, each originating at the same location thus permitting a shorter array which can travel twice as fast as conventional systems while achieving grating lobe suppression.

Abstract: An apparatus for performing beam pattern measurements for a side-scanning nar. The apparatus consists of a vertically mounted guide affixed to one end of a test pool and a vertically fixed mounting means affixed to the opposite end of the pool, the guide and mounting means orthogonal to each other. A carriage to which the transducer under test is attached is movably secured to travel up and down the guide. A gear motor having a takeup reel winds and unwinds an attached cable, the other end of which connects to the carriage, producing its up and town travel. The motor connects via a motor controller and position cable to a motor controller at a remote instrumentation facility. A position sensing device slaved to the carriage cable sends carriage position information to the facility for motor control. The array is secured immobile to the vertically fixed mounting means.

Abstract: A resolving power target for side-scanning sonars and other sound transming devices such as but not limited to ultrasonic devices. The target is a planar sheet having one smooth surface to which a resolution pattern is masked. An adhesive is applied to the masked pattern and articles such as gravel or other three-dimensional equivalents are introduced to produce the irregularity to the smooth surface within the confines of the resolution pattern. The resolution pattern for a particular application is selected experimentally, however, a Limansky pattern is used in the present invention for side-scanning sonar resolution measurements.

Abstract: A pulsed-transmission, narrow-band, echo-ranging sonar system has a tow b in which the transmit and receive arrays are mounted so that the field searched forms a toroidal volume.

Abstract: A pulsed transmission, single frequency, high resolution sonar system has duced grating (side) lobes achieved by employing mechanically fixed antenna array stave tilt angles together with electronic focussing in which phase shifts are substituted for time delays.

Abstract: A pulsed-transmission, narrow-band sonar system has a first antenna array ich is unshaded and a second array partitioned into four parts, the center two of which are electrically connected in parallel and the outer two of which are connected in series.

Abstract: A continuous transmission FM sonar avoids target ambiguities while utiliz the entire transmitted bandwidth for echo analysis. The sonar is characterized by digital generation of direct and quadrature versions of the transmitted frequency sweep, and balanced modulators responsive thereto to effect complex demodulation of the returned signals prior to analysis, as by a fast fourier transform frequency analyzer for target detection.

Abstract: A device for producing a varying frequency sine wave synthesized so that frequency is swept linearly with time for use in a continuous transmission FM sonar. A crystal clock, divider and a 16 bit digital output sweep counter produce 2.sup.16 counts for each sweep period T.sub.s. The 2.sup.16 counts are applied to a 16 bit digital to analog converter to provide a highly linear voltage ramp (the smoothed result of 2.sup.16 steps). The ramp is converted to a proportional frequency which is applied to a 5 bit digital counter to access a read only memory programmed to provide a digital output representing points along a sine wave. The memory output is applied to a digital to analog converter to produce a voltage output that is a 32 stepped approximation of a sinewave at a frequency which increases betweeen f.sub.1 and f.sub.2 with the linearity of the ramp voltage. A filter smoothes the output.

Abstract: A sonar signal processing and display system is described which converts log return data to digital form for storage in a magnetic core memory, from which the data can be reconstituted as analog video signals for CRT display at a higher frame rate. Described are means for comparing new data to old to select updating data for the memory, and means for effecting CRT display of moving target tracks in a color distinct from stationary background returns.