Abstract: The chirp rate in a chirp Z-transform sonar beam former is varied as a function of range to form beams in the near field. The chirp rate may be varied with each range cell under examination or with each group of range cells.

Abstract: Acoustic signals are propagated through the drilling fluid in a well being drilled and reflected acoustic energy from the vicinity of the bottom of the well is displayed, as well as reflections from any kicking medium so as to give advance warning of a possible blow-out.

Abstract: Fouling which occurs in the heat exchangers of a thermal energy conversion power plant causes the heat transfer between the circulating fluid and working fluid to be degraded, diminishing the efficiency of the plant. The invention provides for optimizing the net power level of the plant by perturbing the flow of circulating fluid individually to the heat exchangers to identify the direction of flow change which results in an increase in generated net power level and adjusting the flow of circulating fluid to each heat exchanger. This optimization may be carried out periodically. In another case, when temperature differential of the circulating fluid across at least one of the heat exchangers falls below a predetermined level, only the circulating fluid of the related heat exchangers need be altered to optimize the net power level generated by the plant.

Abstract: An underwater survey system where the existence of a large number of multiplex signals in conjunction with a relatively poor frequency response over a long tow cable, results in a situation where the transmission of a normal 30 frames per second TV picture is impossible. The invention describes a method of transmitting a reduced bandwidth TV system where the signals are modulated on a carrier and the lower sideband used. The large signal loss at the upper frequency is compensated by equalizers, which can result in objectionable interference, when the vehicle is close to the receiving end. A remotely controlled carrier is used to minimize this interference.

Abstract: Apparatus which generates a plurality of sets of radially extending beams in a chirp Z-transform sonar beam former. Only a particular beam from each set is chosen for display.

Abstract: An acoustic homing torpedo having an array of transducers wherein each transducer has a head mass, tail mass, and a main active element therebetween. An auxiliary active element is placed on the tail mass so that when given a predetermined signal it will cause the main element to provide a corresponding output signal so as to simulate the reception of an actual acoustic wave. By energizing the main element, the response of the auxiliary element may be examined for testing the transducer and the array in a transmit mode of operation.

Abstract: Apparatus for forming one or more sonar beams in response to acoustic energy received by a transducer array. To minimize volume utilization, a plurality of CCD's are formed on an integrated circuit chip with the CCD's being of progressively smaller length. Half of the CCD array is folded over to match the other half so that each CCD has an opposing CCD with both CCD's propagating a signal toward a common output diode. By providing one integrated circuit chip for each desired beam with appropriately different clocking frequencies multiple beams may be formed, and with the provision of a variable clocking frequency, one or more beams may be steered.Transversal filter operations may also be performed by the apparatus.

Abstract: In moving target indication or synthetic aperture systems, double pairs of measurements of returned energy are made from displaced spatial locations to enable computation of side and angular deviation from the flight path, without the requirement for inertial navigational measuring instruments.

Abstract: A transducer unit which includes a backing member formulated from a water activated ceramic to which is added a powdered metal.

Abstract: Magnetometer instrumentation which processes the signals from an array of magnetometer assemblies wherein the need for multiple sets of motor driven resistors to change the gain of the signal processing channels is eliminated by the provision of an arrangement which utilizes multiplying digital-to-analog converters that are directly commandable by digital signals.

Abstract: A control system for a Tonpilz transducer which is positioned between the transducer and the transducer drive amplifier. The control system determines the head velocity of the transducer from the input current and voltage and utilizes this determination in a feedback arrangement to maintain proper transducer excitation.

Abstract: A dipole hydrophone having a differential pressure sensing unit, for example, a multi-laminar bender disc, within a liquid filled housing. Two liquid filled acoustic waveguides form extensions of the housing and include pressure sensing ports. A mass of predetermined value is connected to the sensing unit and with a predetermined separation between sensing ports, the mass value is chosen so that the sensing unit response to acceleration is very nearly equal and opposite to its response due to the inertial mass of the liquid.

Abstract: Apparatus for supporting the life, safety, comfort, and usefulness of an underwater diver by pumping seawater, or other ambient water in which the diver may be located, under pressure from a surface site to the submerged diver site, and locally converting by hydraulic friction at the diver site the hydraulic energy of such pressurized pumped seawater into diver-warming heat or/and mechanical energy for operating tools, pumps, etc.

Abstract: A flexible strap-like antenna which may be supported on the outside surface of an aerostat includes a first substrate member having conductors thereon in a pattern which includes a center conductor and dipole antennas on either side of the center conductor. A ground conductor is disposed over the center conductor and is electrically insulated from it by an insulating strip sandwiched between them. A second or covering substrate seals the layered arrangement.To achieve broad band operation, an array of antennas is provided with the width of the center conductor being varied for certain different sections thereof.

Abstract: An underwater transducer which includes a fluid circuit having a valve disposed in a plenum chamber having a small aperture open to the ambient water pressure. Fluid flow into and out of the chamber by way of the valve is governed by controlling the valve opening and closing in accordance with movement of an electrodynamic driver which receives an input signal to be transmitted.

Abstract: A side looking sonar system having a transducer made up of a plurality of active transducer element sections lying along a line and wherein the element sections are relatively phased to provide for all range focusing and multiple beam formation. The element sections are longer in the middle of the transducer and reduce in length toward the ends of the transducer. In one case the line is an arc lying in a plane, with the plane having a certain depression angle.

Abstract: A magnetostatic wave device for microwave signal processing which includes an input or output transducer finger arrangement which allows shaping of the device response. Two sets of interdigitated fingers are connected to receive the same microwave input signal which is power divided between the two sets. The fingers of one set are substantially parallel to, and in side-by-side relationship with, the fingers of the other set. The device may be used for delay lines, filters, signal correlation, oscillators and numerous other microwave signal processing arrangements.

Abstract: An acoustic homing torpedo which has an acoustic window and a nose section with the window-torpedo shell interface being positioned at a location aft of the acoustic transducers in the nose so as to minimize unwanted flow noise.

Abstract: A fluid-filled compliant tube immersed in seawater to detect low frequency sound waves. The tube has only a middle portion of its length exposed to incident acoustic energy waves and a mode conversion causes a corresponding frequency acoustic wave in the tube, but of greatly reduced wavelength. Transducers are positioned at either end of the tube to detect the waves in the tube, the length of which is chosen to be a half wavelength of the waves in the tube.

Abstract: A paramagnetic oxygen sensor wherein a reference chamber is oscillated into and out of an air gap of a magnetic circuit by means of a piezoelectric bender bar. The oscillating reference periodically displaces the ambient gas under measurement in the air gap and causes a varying flux in the magnetic circuit which is sensed, amplified and provided as an output signal indicative of the partial pressure of oxygen of the gas mixture.