Abstract: A system for determining the direction of an underwater discrete source of acoustic vibrations by sensing acoustic wavefronts produced thereby, which system comprises a neutrally buoyant semirigid underwater platform which may be made of a water inflated soft walled material and having mounted thereon an array of omnidirectional hydrophones arranged in a predetermined geometric pattern. Circuit means are connected to the hydrophones and an array steering means is associated with the circuit means to allow determination of the time relationship of the signals obtained from the hydrophones.

Abstract: In the preferred and illustrated embodiment of the present apparatus, a drilling orientation tool is disclosed utilizing a mud pressure charging system where the pressure charge is converted into hydraulic oil pressure. The hydraulic oil flows is supplied to a four-way, three-position, solenoid operated valve having a closed center position, the valve forming a control signal delivered to an adjustable constriction in the mud flow path through the tool. Variables are encoded dependent on opening and closing of the constriction. Consecutive variables are transmitted in the form of fine and coarse measures. The electrically operated solenoid valve thus encodes two or more variables for transmission to the surface by detecting mud pressure variations in the mud flow line at the surface.

Abstract: Both signal amplitude presentation and noise suppression presentation of sonar signals have been known for some time, but have been incompatible in the same display system. In this disclosure, means are provided for separately processing the received signal in two parallel paths, one through a noise-pulse suppression processor, and the other through a signal amplitude differentiation processor which adds an additional adjustable time delay so that the signals processed through both paths are initiated at the same time and thus can be presented together.

Abstract: A method for determining optimum element spacing for a low frequency, log-periodic acoustic line array comprising a plurality of omnidirectional hydrophones arranged in a line wherein the spacing between hydrophones is based on a logarithmic relationship using multiple dipole pairs, each pair centered about the acoustic axis of the array, such that the distance between each dipole pair bears a constant ratio to the wavelength of the acoustic frequency band to be investigated by that hydrophone pair. Each dipole pair relates to a particular frequency band and the assembled array covers at least a decade range of frequencies through juxtaposition of contiguous frequency bands. The overall arrangement assures retention of selected beam pattern directionality over the entire decade range of frequencies.

Abstract: In an exemplary embodiment, the transducer elements are arranged in rows and columns, the transducer elements bein contacted at both sides by oppositely disposed contact surfaces, and switches being associated with the contacts of the one contact surface as well as with the contacts of the other contact surface for the purpose of adjustment of preselectable transmitting and/or receiving surface of transducer elements during a transmitting/receiving cycle, in particular, for the purpose of dynamic focusing. It is an object of the disclosure to construct an ultrasonic array which can function with an optimally low outlay of switches and which if desired also permits a transition to continuously varied apertures.

Abstract: A self-deploying buoy system which will moor itself in various depths of er. The system has a fixed mid-water buoy and canister. In one end of the canister is an RF telemetry buoy and upper cable pack. In the other end of the canister is a lower cable pack, sensor and anchor assembly. When deployed all the cable in both the upper and lower cable packs is deployed under the force of gravity until no cable is left in either pack.

Abstract: The reflector of an acoustic echo ranging system is matched so as to make up for the influence of the temperature at the bottom of the reflector, on the measurement of the back-reflected signal. The acoustic signal receiver being stationary the transmission frequency is controlled by a temperature responsive electronic circuit so that the receiver is always located at the same pressure antinode. Alternatively, the transmission frequency being fixed, the position of the receiver is controlled by a temperature responsive mechanical gear causing the position of the receiver to coincide with the same pressure antinode.

Abstract: A novel low cost air-launched sonobuoy having a spherical housing of a liweight semi-rigid foam housing encapsulated the electronic components. The housing includes recesses for receiving a hydrophone and cable pack, and for inserting D-size batteries just prior to launching. A vertical antenna is wrapped around the housing and prevents the pack from deployment until the sonobuoy is charged with the batteries and immersed in water. The free end of the antenna is released and unwraps to permit deployment of the hydrophone and cable pack. The sonobuoy is stored without the batteries in a sealed moisture-proof envelope which can be easily torn open and removed when desired.

Abstract: A circuit for exciting an ultrasonic transducer element comprises a diode switch exhibiting a long reverse recovery time duration connected between an input and an output terminal. A transducer exciting signal varying in both positive and negative directions and applied to the input terminal is conducted to the output terminal through the diode switch.

Abstract: It is the aim of the exemplary disclosure to create a simple system with as great a variability as possible wherein a pulse generator for each ultrasonic transducer element comprises a digital frequency control member for controlling the pulses to be fed to the transducer element and at which at least the pulse frequency (f.sub.s) can be selected by means of an input digital value (FW).

Abstract: An improvement for an apparatus for calibrating or otherwise determining low frequency operational parameters of an elongate hose-like array is compact enough to be mounted on a cart-like member which is free to travel the length of the array. The improvement is in the form of a pair of oppositely extending tubes each having a reciprocating element for ensonifying selective portions of the elongate array with low frequency energy. Having the reciprocating elements 180.degree. moving out of phase with respect to one another to exhibit mirror image excursions and at least one flexible radiating surface proximately located to the array assures that performance compromising vibrations are nullified and that low frequency energy is responsively received by the individual transducer elements along the array's length.

Abstract: A number of sound detectors are provided on an external enclosure of a pressure vessel of a nuclear reactor. Output signals produced from the individual detectors are combined into a pattern in terms of time difference of the detector output signals relative to the time point at which the detected signal is first produced in response to the sound signal and relative peak values of the detector output signals relative to the magnitude of the output signal produced by the detector which detects the sound signal with the highest sensitivity. The pattern thus obtained is then compared with patterns which have been previously prepared by intentionally producing the sound signals at locations in interest within the pressure vessel, to thereby estimate the location within the pressure vessel at which the sound is produced.

Abstract: An ultrasonic imaging device comprises transducers distributed along a line and operable at a frequency f. A generator delivers electrical pulses to time delay means which provide, in response to each electrical pulse, a plurality of low level pulses delayed by increased time delays in a number lower than the number of transducers. The distribution of the time delays between the transducers is stored in memory means and corresponds to focusing at a point located at a predetermined distance from the line. A plurality of amplifiers are each associated with an individual one of the transducers and deliver an energizing pulse to the associated transducer in response to a particular one of the low level pulses appearing on an associated channel of a bus line which is selected by the memory.

Abstract: A hermaphroditic submarine cable connector link for a multisection seismic marine streamer cable includes identical end fittings mounted at each end of a pair of adjacent cable sections. Identical connector plates are coupled to electrical conductors at each end of the sections. The connector plates from the pair of adjacent cable sections are mated and then linked to the end fittings. A barrel is slipped over the end fittings and around the mated connector plates. The end fittings are locked by the barrel in spaced-apart relationship, employing a ball-and-detent locking arrangement.

Abstract: A bistatic, Doppler sonar that having a plurality of receiver channels det intrusion in an insonified water zone processes return signals in a plurality of discrete up Doppler and down Doppler frequencies to effect short and long term averaging of return energy and short and long term averaging of return energy slope prior to sampling and comparison to generate a multiple bit binary word that is periodically updated and read out in parallel form to detection logic. The detection logic utilizes parallel sets of shift register memories and comparators to detect when rates of occurrence of energy, slope, and stroke conditions exceed predetermined rates, and utilizes a plurality of levels of coincidence gates to detect predetermined combinations of such conditions that will produce an alarm initiating signal.

Abstract: A system for transmitting a parametrically pumped sonic signal through a transmission medium to a remote location is disclosed. The preferred system, which is particularly intended for use as a sonic weapon, comprises a sound source; means for separating the sound into a plurality of discrete frequency components including a fundamental component and at least one additional component, each additional component having a frequency twice that of the next lowest frequency component; means for adjusting the phase difference between each frequency component and the next lowest frequency component to substantially 90.degree.; means for colinearly focusing the components on the remote location; and means for rendering the transmission medium nonlinear between the focusing means and the remote location.

Abstract: An arrangement for generating amplitude-modulated, ultrasonic transmission pulses comprising at least a switching circuit (4) provided with an inductive load (12) for generating the transmission pulses and controlled with a plurality of switching pulses per pulse interval; a memory (2) filled with information about the appropriate pulse width of the switching pulses as required per transmission pulse interval; and a switching-pulse generator (3) for producing switching pulses using the pulse width information and timing signals determining the switching pulse frequency. This arrangement is suitable for sonar applications for the purpose of improving the detection of doppler shifted echo signals.

Abstract: An imaging sonar system is disclosed comprising a transmitter, a receiver, and a rotatable transducer coupled with the transmitter and receiver for generating sound waves and for detecting echoes therefrom. Drive means are provided for rotating the rotatable transducer. Transducer position sensing means are provided for sensing the rotary position of the transducer. Analog to digital converter means are coupled with the receiver for converting receiver emitted signals into digital form. Serial access memory means are provided entering into storage receiver emitted signal data in digital form at a preselected rate and for withdrawing from storage receiver emitted signal data at a rate different than the predetermined rate. Write and read control means are also provided for respectively entering digital data into and recalling digital data from the memory.

Abstract: An automatic focusing system for positioning silicon or other wafer within the focal plane of a photolithographic mask projection system. The position of the wafer is measured at a plurality of points and compared to the position of an optical flat located in the focal plane to provide signals for positioning the wafer at the focal plane of the projection system. The system also includes means for changing the contours of the wafer to cause it to lie in a known plane.

Abstract: The navigation system permits remote maneuvering of a water-borne structure about a stationary object by utilizing dual sonar ranging. The structure can be self-propelled or towed by a surface craft. The transducer portion of the navigation system is mounted on the structure and the system's remaining portion is on the deck of the surface craft. For complete remote navigation, at least three but preferably four transducers are employed for positioning at the four corners of a rectangle. Each transducer is both sound-emitting and sound-receiving. The sonic impulses from each pair of port and starboard transducers are directed downwardly and inwardly. The travel time for each reflected sonic impulse is directly proportional to the slant range between the transducer and the object. The spacing between each pair of port and starboard transducers and the frequency of the emitted sound impulses are selected so that very accurate measurements are obtainable of the position of the object relative to the transducers.