Abstract: Apparatus is provided for adapting an analog depth sounder for the calling out of the depth at regular time intervals. In one embodiment, a self-contained adapter module is mounted to the face of the depth sounder so as to cover the depth sounder display, with the module including a transparent plate carrying a detector array and with electronics and speaker carried at the center of the array. In this embodiment, the detectors are arranged in thin radially extending lines to permit accommodation to displays of different diameter. Alternatively, small detectors are arranged along a circle having a diameter which overlies at least a portion of the orbiting radiating element which radiates along a considerable length. This alternative array configuration also accommodates a range of display diameters. As a further alternative, to accommodate different diameter displays, the thin line detectors may be replaced with radially extending light pipes with detectors at their ends.

Abstract: Determination of the impulse response of a system such as a hydrophone is determined by generating a broad band reproducible test signal which after propagation is received and a replica of the broad band test signal is produced; either the received signal is compensated for fluctuations in propagation time of the test signal through the system and cross correlation of the compensated signal with the non-compensated signal is effected to derive the system response. A secondary signal may be used with the broad band test signal whereby the Doppler shift of the secondary signal can be utilized to determine the required compensation. Feed-back shift registers are disclosed for generating pseudo random noise for the test signal and the replica thereof. The invention permits calibration of a hydrophone in circumstances in which noise is present and variation in path length of the propagated test signal occurs.

Abstract: Acoustic transponders are attached to sections of a submarine cable for use in accurately locating the cable during deployment or retrieval. An acoustic signal at one frequency, transmitted from the surface or elsewhere, stimulates one of the transponders to generate a first reply signal at a different frequency. The acoustic reply signal generated by each transponder is used to determine the location of that transponder and thus the location of its associated section of the cable. In order to measure cable tension during deployment or retrieval, a strain gauge at each transponder senses the tension of the cable at the location of its associated transponder. After each transponder transmits its first reply signal, it transmits a second reply signal delayed from the first reply signal by a time interval which is controlled by the output of its associated strain gauge.

Abstract: A solid state transmit/receive switching circuit is provided by a system which, in accordance with the invention, comprises a solid state relay which, when energized, causes an optically controlled resistor connected to an input terminal of a preamplifier of the receiver to change its resistance and hence the sensitivity of the preamplifier according to the transmitter transmission state.

Abstract: The invention relates to underwater acoustic devices and arrays formed from such devices, and which in use are suspended in water from a buoy as other flotation equipment. An underwater device in accordance with the invention comprises an elongate tubular structure which is preferably suspended from a buoy having an aerial mounted on the buoy and connected to a radio transceiver housed within the buoy, wherein the tubular structure includes a plurality of transducer elements spaced apart along a common axis, preferably by spacer tubers wherein each of the transducer elements comprises a tube, or part of a tube, composed of a piezoelectric material, preferably polyvinylidene fluoride, and electrical terminal means contacting inner and outer curved surfaces of each tubular element.

Abstract: Apparatus for remotely controlling the horizontal and vertical direction of a pendulously suspended transducer by means of concentric generally vertical control shafts is disclosed. A frame in which the transducer is mounted for rotation about a tilt axis is pendulously suspended from one control shaft. The other control shaft is rotatably coupled through a universal joint to a first pulley mounted in the frame for rotation about a vertical axis. The first pulley is rotatably coupled to a second pulley mounted on the transducer for rotation therewith about the tilt axis by means of a cable routed over guide pulleys which change cable direction.

Abstract: Provided is an ultrasonic transducer having a resonator which defines a space together with a bimorph cell disposed in the ultrasonic transducer. The space is fluid-tightly closed by the top portion of the resonator, thereby to keep water, such as for example, rainwater or cleaning water from entering into the space.

Abstract: A range measurement system for a submarine also having a passive monitoring system with a beam forming circuit, one beam of which may be selected by a signal V.sub.N from a tracking computer. Two assemblies of three hydrophones are located respectively on the port side and on the starboard side of the submarine. The signals supplied by these receivers are correlated with a beam signal S.sub.V of the passive monitoring system selected supplying the delays of these signals. A computer receiving these delay values supplies to the tracking computer the values of the bearing angle .alpha. and the distance D of the noise source.

Abstract: A remote oceanographic data recording system which is self-contained batt operated and removably attachable to an external surface of a submerged hull without a need to penetrate said hull is presented. The system is capable of gathering and recording oceanographic data and may be joined to the hull of a submarine without interfering in submarine operation in any way. The system receives analog ac and dc electrical input signals from a variety of oceanographic data sensors and converts the signals to digital data signals for recording on magnetic tape cassette. The housing for the system is watertight and capable of withstanding external hydrostatic pressures up to 1620 psi.

Abstract: Apparatus for detecting a load within a preselected bin of an automatic storage rack has a transducer for directing an ultrasonic beam into the bin and for detecting an echo reflected from a load struck by the beam; a digital counter adapted to generate plural bit binary pulses which is started upon initial transmission of the ultrasonic beam; and a programmable memory coupled to the counter and programmed to generate a given bin-ful output signal upon initial transmission of the beam and to subsequently generate the opposite binary bin-empty output signal if no echo has been detected when the pulses from the counter stored in the memory indicate that sufficient time has elapsed after initial transmission for the beam to travel a predetermined distance into the bin and for an echo from a load struck by the beam to return to the transducer.

Abstract: A Scanning Sonar Display System comprised of a TV monitor, a scanning mechanism with transducer, control logic with image memory and timing, a power source such as a 12 volt storage battery and a set of operator controls. The type of TV monitor used is well known and similar to those used by raster scan computer terminals. The scanning mechanism has a stepping motor with a 10 to 1 reduction cable drive system to rotate the transducer with home initializing contacts. The control logic includes two counters used as image memory address registers. The first, the refresh counter, is used for reading the image memory during refresh and for determining the horizontal and vertical sync for the TV monitor. The second, the entry counter, is used for writing sonar and depth data into the image memory and is also used for control of the stepping motor. Home initializing contacts are used to initialize this counter.

Abstract: A method for calibrating acoustic backscattering instrumentation utilizing spherical body as a standard target. A spherical body made of high specific acoustic impedance material, such as tungsten carbide, is positioned a given distance from a source/receiver transducer which is energized to produce a short acoustic pulse directed toward the sphere. Acoustic signals reflected from the sphere are detected by the transducer and processed in the time domain to separate the rigid portion of the return from the elastic portions. The rigid portion is corrected for the transducer to sphere distance, the reflectivity of the sphere, and for the radius of the sphere. The resultant corrected signal represents the incident acoustic pulse produced by the transducer.

Abstract: A Tactical Expendable Device (TED) adapted to be ejected into the water f a variety of launch platforms and to achieve and remain substantially stationary at a predetermined operating depth for a predetermined time interval or to sink at a predetermined rate for sensing acoustic signals and transmitting such signals to the launch platform through a long, small diameter connecting cable such as a fiber optic filament. The TED system comprises the TED cannister, a long connecting cable, deployment means on the launch platform including a launch tube with integral dereeler, a buffer and onboard signal processing/display equipment. The TED cannister further comprises a sensing element, a buffer, a power source and a dereeling device.

Abstract: The data selection circuit includes a multiplexer circuit which receives a plurality of inputs and individually connects each of the inputs to an output line. The multiplexer is sequenced by signals from a timing circuit which causes inputs having a higher signal level to be connected to the multiplexer output for a greater length of time. The data selection circuit is particularly suitable for enhancing the image on a CRT of a continuous tone frequency modulated sonar system.

Abstract: A sonic energy scanning apparatus in which two directional primary sonic energy beams at two different frequencies are radiated into a medium capable of producing nonlinear acoustic effects to produce a third sonic energy beam having a given directional characteristic and a frequency equal to the difference between the frequencies of the primary beams. Scanning with the third beam is effected by varying the direction of the axes of, and the frequency difference between, the two primary beams in discrete steps for correspondingly varying the direction of the axis of the third beam over a selected angular sector and the frequency of the third beam such that each direction of the third beam axis is associated with a respectively different frequency, and by identifying the direction to a source of echoes of the third beam by determining the frequency of such echoes.

Abstract: A calibrator for determining the directivity pattern and complex sensitiv of a line hydrophone array including a calibration chamber, filled with a selected fluid, for sealing the array therein. Projectors, for generating acoustic waves, and monitors, for measuring the amplitude and phase of acoustic waves incident thereon, are mounted within the chamber. The projectors and monitors are connected to a computerized control circuit that drives the projectors to generate a calibration wave, with a predetermined amplitude and phase relative to the center of the array, corresponding to a free plane wave incident at an angle .theta. to the axis of the chamber.

Abstract: A distance sensing apparatus is provided in the form of a case housing electronic equipment including a piezoelectric transducer for radiating pulsed sonic or ultrasonic signals along a measurement path through a sound horn (3) which creates a narrow beam. Reflected signals received back through the horn are received by the transducer and converted into electric measurement signals. A time measurement device is providing for determining the time lapse between radiation of a pulse and receipt of a reflected signal so as to provide a distance signal which will be representative of the path distance between the apparatus and the surface which will trigger a display (7) to give a distance reading.

Abstract: 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.

Abstract: A modulation/signal processing technique for acoustic communication in show water. Digital information is transmitted in a time expended version of frequency shift keying where a tone burst at a first frequency represents a logical zero and a tone burst at a second frequency represents a logical one. There is a long quiet time between bits to allow multipath interference to decay. A relative energy detector with a fast attack/slow decay circuit for Doppler compensation is used to receive the transmitted tone bursts and reproduce a digital data train equivalent to the transmitted pulse train. A single communication channel employs two frequencies to transmit an identity code as a signal validating and identification method and two frequencies to simultaneously transmit telemetry data.

Abstract: Acoustic intensity measuring apparatus for determining sound energy intensity utilizing a probe having a pair of microphones and an associated ambient noise shield.