Abstract: The present invention comprises an apparatus and method for producing a high resolution acoustic signal from a single point source while achieving a commercially acceptable secondary bubble suppression. More specifically, the present invention comprises first and second explosive generators which sequentially create two explosions or one explosion and injection, within the body of water; said first explosion producing within the body of water a powerful acoustic pulse in an expanding cavity of very low pressure, said second explosion or injection establishing hydrostatic pressure within the cavity about the same time the volume of the cavity reaches its maximum volume, thereby substantially reducing the secondary pressure pulses.

Abstract: The present invention relates to a method for generation of elliptically polarized shear waves in an earth medium using two shear wave vibrators engaged to the earth medium in cross-polarized attitude and driven at sweep rates having variable phase displacement.

Abstract: Acoustic delay means are interposed between the face of a transducer and the bottom of a vessel, with the delay being equal to or greater than the shallowest depth the associated depth sounder capable of, whereby subtracting out the depth associated with the acoustic delay, the water under the vessel can be measured down to zero feet. In a preferred embodiment, a water column is utilized as the delay media, with the transducer being mounted at the top of the water column and with the water column being terminated at the bottom of the boat. The transducer pulses are projected through the water/hull/water interface to the water beneath the vessel. For digital depth sounders, the depth associated with the water column may be subtracted out to give the zero reading.

Abstract: A hydrophone (16) having a short-baseline array of transducers (12A, 12B, and 12C) as well as a long-baseline array of transducers (14A, 14B, and 14C) includes switches 30A, 30B, and 30C) for selectively connecting the outputs of the arrays to a cable (18) that carries the signals to processing circuitry (20) aboard an ocean-going vessel (24). The switches (30A, 30B and 30C) change state in accordance with the output of a narrow-band filter (42), which indicates whether the received signal is of a predetermined frequency and thus is likely to have been produced by an intended source. Due to the delay inherent in the narrow-band filter 42, the processing circuitry (20) thus processes the response of the long-baseline array to the first part of a beacon pulse and the response of the short-baseline array to the second part of the beacon pulse.

Abstract: An improved electrical transmission system for transmitting electrical power and data signals within a well bore having a string of tubular members suspended within it, each tubular member having a receiving end adapted for receiving data signals and a transmitting end for transmitting data signals, said receiving end and transmitting end being electrically coupled by a flexible printed planar conductor of the type having at least one substantially planar conductive band disposed between at least two layers of electrically insulating material.

Abstract: The invention is directed to a piezo-electric transducer having electrodes that adhere well both to ceramic as well as to plastics and that are composed of intrinsically conductive plastic. The invention is also directed to a method for the manufacture thereof. A conductive polymer layer is produced on the surface of a piezo-ceramic component by chemical or anodic oxidation of a monomer. The monomers are selected from the class of 5-member heterocycles containing sulfur or nitrogen as heteroatom, or aniline, azuline, or derivatives of the said compounds. The components provided with the economical electrodes can be advantageously composed to form sandwich-like transducers having plastic intermediate layers that exhibit good electro-acoustical properties.

Abstract: A quadrature signal generator is provided which includes a voltage dependent resistance capacitance phase-shifting network (12) and a phase detector (26) for detecting any difference, from 90.degree., between the phases of the in-phase and quadrature phase signals (2, 24) generated by the network (12) and for producing a control signal in dependence upon such difference. The control signal is applied to the network (12) to vary the phase-shifting characteristic thereof to restore and maintain the 90.degree. phase difference.

Abstract: A low frequency sound producer including a plurality of magnetostrictive vibrators arranged seriatim end to end to define a ring. Each vibrator unit includes a plurality of laterally related magnetostrictive rods which, in the illustrated embodiment, are formed of rare earth magnetostrictive material. Structure is provided for compressively prestressing the rods. The prestressing structure includes permanent magnets for providing a permanent magnetic bias in the rods. Coils are magnetically coupled to the rods for causing the desired magnetostriction thereof corresponding to an input AC signal applied to the coils. Opposite ends of the individual vibrator units define facial abutments in defining the continuous ring configuration. In the illustrated embodiment, the ring configuration is polygonal and the facial abutment surfaces at the ends of the units define a 60.degree. included angle.

Abstract: A special cultivating machine, lawn care apparatus and process are provided to properly prepare, efficiently condition, and gently cultivate the soil, turf and lawn in a uniform manner without uprooting, ruining, or damaging existing healthy plants and grass and without substantial thatching. The special cultivating machine, lawn care apparatus and process attain excellent seed and soil contact for virtually all soil compositions, textures, and conditions, and accurately follow the contour of the ground soil, turf, or lawn, regardless of mounds, hills, valleys, irregularities, clumps, and other soil conditions. The cultivating machine and lawn care apparatus has spring biased, rearwardly facing, scratching arms (cultivation fingers) which are reciprocatingly driven by a crankshaft. The crankshaft is smoothly rotated by a chain and sprocket arrangement. Desirably, the crankshaft and scratching arms can be raised or lowered by a height adjustment assembly to vary the depth and angle of soil penetration.

Abstract: A flextensional transducer driven by magnetically biased rare earth rods 31. The rods 31 are arranged in stacks with rare earth magnets 34 mounted on each end of each stack for providing the bias field. The rods 31 are slotted to reduce eddy currents and surrounded by a slotted drive coil 32 with a slot 32a in the coil bobbin. The ends of the flextensional shell associated with the shell major axis have a full radius curvature which stiffens the shell ends so that the axial bias and drive forces will not break the rare earth magnets 34 in flexure.

Abstract: An echographic technique based method for prospecting of the subsoil or sea bottom and the like, by means of acoustic waves and carried out by the use of an apparatus constitued, in combination of a known acoustic wave transmitting equipment (1) comprising of a body (6, 8) in the inside of which a chamber (9) is formed defined by an internal reflecting surface (7) shaped like a round paraboloid of axis (Y--Y), closed at the base by an elastic diaphragm (5) and filled with a proper liquid, into which acoustic waves are emitted produced by a pair of main electrodes (10a, 10b) associated with an auxiliary discharge priming electrode (11) put between the first ones.

Abstract: A method for transmitting ultrasonic amplitude and time travel information obtained from borehole logging operations over a logging cable allows accurate measurement of the time travel by surface equipment. The time travel information is transmitted by a time travel pulse, which is produced at a time interval from a synchronization pulse corresponding to the time of travel of an acoustic return. The peak amplitude of the acoustic return is transmitted by a separate amplitude pulse.

Abstract: A well logging system and method of the present invention determines the dielectric constant and/or conductivity of earth formations some of which have fluid invasion. The system and method of the present invention includes the transmission of electromagnetic energy into the earth formation from a first location in a borehole in the formations at a frequency which enables the electromagnetic energy to propagate throughout the surrounding earth formations. Electromagnetic energy is received by receivers at three locations in the borehole which are spaced longitudinally from the location of the transmission of the electromagnetic energy. The receivers provide signals representative of the total electromagnetic fields at those locations. The dielectric constant and/or resistivity of the earth formations are determined in accordance with portions of the signals from the three receivers corresponding to secondary electromagnetic fields at the three receiving locations.

Abstract: A sonar system for a water craft including a transducer assembly mounted to the hull of the water craft, and a control circuit for applying signals to the transducer for forward transmission by the transducer and for sensing signals reflected from objects forwardly of the craft and for causing actuation of an alarm. The transducer assembly is mounted for pivotal movement relative to the hull such that during pitching motion of the craft, the signals transmitted by the transducer remain in a horizontal plane.

Abstract: The level of signal noise caused by fluid flow at a pressure transducer, such as a hydrophone or geophone, is determined by measuring the electric field induced when the fluid flow through a magnetic field. The electric field, which is proportional to flow rate, is measured by electrodes positioned about the transducer. The pressure due to the flow is derived from the flow rate voltage by a digital filter which may be adaptive, to allow for varying flow conditions, or which may employ a predetermined electric field/flow noise relation. This flow noise is then subtracted from the received signal, the resultant signal then being substantially noise free.

Abstract: A transducer assembly for use along the surface of the earth or in a borehole to detect seismic signals along mutually orthogonal axes. The transducer assembly includes at least two geophones or accelerometers gimbally-mounted within a housing such that when the housing is oriented at substantially any angle, the enclosed geophones remain in their respective planes with respect to gravity and their axes of sensitivity to the seismic signals remain orthogonal to each other.

Abstract: A high temperature and high pressure fiber optic feedthrough is set forth to enable communication to the interior of a pressure housing making up a downhole logging tool. An optical fiber is stripped of protective wraps and coverings other than a fluorocarbon coating. It is inserted into a feedthrough fitting formed of an elongate body that feeds to the pressure housing. There is an axial bore which has an internal cavity at the upper end. This cavity receives a conic section of a resilient body which is deformable. Through the use of a specially designed syringe, the optical fiber is passed through this cavity and is positioned on the interior bore of the body. The resilient material is able to expand on application of pressure. The cavity is closed by means of a retainer nut and wear washer. When the nut is tightened, the resilient material extrudes around and along the optical fiber and seals against it to perfect a high pressure, high temperature seal against the intrusion of well fluids.

Abstract: The present invention provides an improved method for transmitting logging data from a logging apparatus operating in a well borehole to surface equipment over a logging cable. The logging data has variations in amplitude, which are converted to a frequency-modulated signal. The center frequency of the frequency-modulated signal is relocated to a lower frequency, which is within the bandwidth of the logging cable. The frequency-modulated signal is transmitted over the logging cable and received by the surface equipment, where the logging data is reconstructed.

Abstract: A remotely actuable boom assembly for floating and positioning a sonar transducer in otherwise inaccessible positions for fishermen. A rigid, supportive frame assembly adapted to be coupled in a desired position upon the side of a conventional fishing boat pivotally mounts an articulated, elongated boom assembly comprised of a pair of control arms which extend generally horizontally outwardly from the side of the boat. The arms are normally spring biased into a preferred operational orientation. The outermost control arm terminates in a housing which is floated upon the water. The suspension system dynamically compensates for wave action or movement during use of the apparatus. The floating housing mounts and controls an internally disposed sonar transducer which may be remotely pivoted by a cable to sweep or scan various regions under the water. A pair of levers associated with the frame enable remote control of the boom and the captivated sonar sensor.

Abstract: An improvement in a capacitance type electrostatic transducer for transmitting and/or receiving pressure energy, wherein the transducer includes a relatively inflexible backplate with at least one major surface thereof formed of electrically conductive material, a relatively flexible membrane including a layer of electrically conductive material stretched across and coextensive with the one major surface of the backplate, electrically insulating means for maintaining a capacitor forming spacing between the major surface and the stretched membrane and wherein the major surface has protrusions extending through the spacing for supporting the membrane. The improvement is providing the protrusions as a multitude of discrete pedestals distributed over the major surface and formed by etching away the major surface except in photographically selected areas defining the pedestals.