Abstract: A tunable surface wave resonator is disclosed comprising a substrate of piezoelectric material having acoustic surface wave absorbing extremities, a pair of spaced acoustic surface wave gradient reflectors positioned adjacent to the absorbing extremities of the substrate, a pair of spaced multiphase surface wave tuning transducers selectively positioned between the pair of gradient reflectors over antinode positions of desired resonant frequency standing wave, and an acoustic surface wave transducer selectively placed for optimum coupling of energy into the acoustic resonant cavity formed by the pair of gradient reflectors.

Abstract: A surface acoustic wave filter having a piezo-electric substrate with a major surface and input and output transducers, each haing a plurality of finger electrodes formed on the major surface to define a propagation path for surface acoustic waves. Finger electrodes of one of the transducers have a step-like configuration to divide the surface wave propagation path into a plurality of surface wave propagation channels. The phase differences of the channels and the length of the steps of the finger electrodes are selected to minimize the multiple reflection echo between the input and output transducers to reduce ripples in the pass band.

Abstract: An electronic flash unit for use with a flash-trigger mechanism having a piezoelectric generator. An RF coil or inductor interconnects the piezo crystal and flash-trigger electrode and operates to modify the energy distribution of the piezo output pulse so as to more reliably fire the flashtube for a given amount of charge on the flash unit firing capacitor.

Abstract: Shock-absorbing members are provided in the vicinity of free ends of vibratory reeds of an electromechanical reed filter and deformable in at least two stages so as to stepwisely absorb external shocks being imparted to the filter for ensuring stability of the operation of the filter.

Abstract: A filter circuit includes an acoustic surface-wave filter device having an input transducer comprised of a set of interleaved electrodes disposed on a first portion of a body of piezo-electric material adapted to propagate acoustic surface waves for producing an acoustic surface-wave signal in response to an input signal applied to the input transducer, and an output transducer comprised of a set of similar interleaved electrodes disposed on a second portion of the piezo-electric body spaced a selected distance from the first portion for receiving the acoustic surface-wave signals so as to produce a corresponding output signal having a selected frequency response. The frequency response (e.g., bandwidth) of the acoustic surface-wave filter device is controlled by selectively changing the number of conductor elements constituting the interleaved electrodes of the input and output transducers.

Abstract: A compensation circuit is provided for a piezo-electric quartz crystal in a filter circuit for reducing the influence of the secondary resonance frequencies of the crystal on the filter characteristic. The Q-value of the crystal at one or several secondary resonance frequencies is reduced by connecting to the crystal a two-terminal network the impedance of which has a real and an imaginary part so that the real part gives an ohmic contribution which at the resonance frequency of the imaginary part reduces the Q-value of the crystal.

Abstract: A piezoelectric motor, bases on utilization of the reverse piezoelectric effect for continuous conversion of electric power into mechanical energy of rotation of the rotor. The piezoelectric motor includes a rotor and a stator, at least one of them incorporating a vibrator of mechanical oscillation, having a piezoelectric device connected to a voltage source and converting electric power into mechanical vibrations. The piezoelectric motor contains no windings and provides considerable driving torques, owing to the stator and rotor being urged against each other. The structure of the piezoelectric motor is determined by the arrangement of the piezoelectric device in the rotor and stator, the type of oscillation being excited, the shape of the piezoelectric device, the arrangement of its electrodes, their shape and electrical connection, as well as by the polarization of the piezoelectric material.

Abstract: A surface acoustic wave device including a synchronous reflection array disposed in a delay line between the input and output transducers, the synchronous reflection array having a synchronous reflection frequency that distorts the beam profile of propagating surface acoustic wave energy in the delay line so that when the beam profile is amplitude averaged at the output transducer, the transducer output signal has a relatively deep notch in amplitude at the synchronous reflection frequency.

Abstract: A tubular resonator is coupled coaxially to a half wavelength extensional resonator at a nodal region of the vibratory motion in a direction parallel to the longitudinal axis of the extensional resonator. The frequency of the vibratory motion is in the sonic or ultrasonic frequency range, typically in the range from 1 kHz to 100 kHz. The radially directed vibratory motion at the nodal region of the extensional resonator is coupled to the tubular resonator and is converted by the tubular resonator into radial flexural vibratory motion which motion travels along the wall of the tubular resonator in a direction parallel to the longitudinal axis. A fluid within the flexural resonator thus is subjected to intense vibratory energy.

Abstract: A broadband electroacoustic converter incorporating a two-layer acoustic coupler is disclosed for efficiently converting between electrical signals carried on an electrical network having a specified electrical impedance and acoustic signals carried in a load medium having a specified acoustic impedance.

Abstract: An ultrasonic transducer and a method for manufacture thereof in which a piezoelectric crystal is bonded to a flat diaphragm with the neutral bending axis of the crystal/diaphragm combination being within the bonding agent. The diaphragm is then pressed into the open end of a hollow shell. The resonant frequency of the shell, diaphragm and crystal combination is determined by the extent to which the diaphragm is pressed into the shell and, in the preferred example disclosed, is set at about 19.8 KHz. The shell cavity is then filled with a mixture of RTV and a nonconductive particulate material at a weight ratio between 5/1 and 20/1. This mixture lowers the Q of the transducer while also raising its resonant frequency to the desired 20 KHz.

Abstract: Pressure sensor comprising a rigid tubular element housing an elongated support member, solid or fixed with the sensitive element in the vicinity of one of its end portions, said support element being made of a deformable material and comprising an enlargement shifted or extended with respect to said end portions and in contact with the internal surface of the tubular element.

Abstract: A piezoelectric monolithic crystal filter having shunt trimming capacitors incorporated into the design of the filter as electrode strips at the edges of the crystal element. This eliminates the need to use discrete low value shunt trimming capacitors which generally are of a few pico-farad capacitance and are expensive and introduce objectionable lead inductance which is non-linear with frequency. A means is provided for producing filters which are less expensive and improve performance over conventional filters, particularly at higher frequencies.

Abstract: The invention relates to elastic surface wave resonators and filters. The device in accordance with the invention is based mainly on the selective reflection of the elastic surface waves. It comprises a crystalline substrate in the upper face of which at least one grating of reflective elements is formed by ion implantation for locally altering the regular arrangement of the atoms in the lattice structure of the substrate.

Abstract: Resonators adapted to be supported from a single support arm are made by a rocess wherein the resonator and its support arm are blanked in a single piece from a flat plate of piezoelectric material. The resonator electrodes are formed on the resonator and conductors formed on the support arm in a single metallization operation. If desired, the support arm may be left attached to the flat plate by a region of reduced cross section after the blanking step. The metallization step may include metallization of a portion of the flat plate to form a circuit over the conductor to the electrodes. The resonator may then be vibrated and tested while its support arm is still attached to the flat plate by applying an electrical potential to the metallized portion of the plate. After testing, the resonator support arm may be broken away from the flat plate at the region of reduced cross section. Several resonators may be made simultaneously by the process from a single flat plate of piezoelectric material.

Abstract: An ultrasonic transducer employs a ceramic disc which, when excited by a d-c pulse, vibrates in its planar resonant frequency mode. The sensitivity is selectively increased for the second positive half cycle of the transient oscillation of the disc and a method is described for using the selectively improved transient response to greatly increase the precision of measurement of the time interval for a transient pulse of ultrasonic energy to travel the distance between an ultrasonic transmitter and an ultrasonic receiver.

Abstract: The electromechanical acoustic emission detector of this invention comprises a plurality of sensor elements secured in an areal array on a base plate. The spacing and arrangement of the sensor elements are such that the transducer is "tuned" to acoustic emission waves that travel along the surface of the vessel to which the transducer is attached. Because of the non-linear character of the array the transducer detects waves arriving from different directions with substantially equal sensitivity.

Abstract: An electro-mechanical filter is configured from a single thin metal sheet and comprises a base portion, at least four vibratory tines extending outwardly from the base portion, and a plurality of supporting members also extending outwardly from the base portion. The tines and supporting members are arranged circumferentially around the base portion in alternate relationship and extend from the base portion in parallel with each other. The tines may extend in either the same or the opposite direction as the supporting members. A piezo-electric element is coupled to each tine and the elements are differentially connected together to form a filter.

Abstract: A band-pass filter comprising a plurality of coupled electromechanical filters is disclosed. Each electromechanical filter has a frequency pass-band centered about a fundamental frequency and a plurality of higher frequency pass-bands which are centered about overtones of the fundamental frequency. At least one of the electromechanical filters has a fundamental frequency that is different from the other filters and all the filters have a common overtone frequency. The band-pass filter will pass all frequencies falling within the band about the common overtone frequency, while all other frequencies will be suppressed.

Abstract: An electroacoustical transducer element comprises a piezoelectric disc flatwise bonded to a metal diaphragm, the bond being at the plane of neutral stress. The transducer element defines the front wall of a sealed chamber that serves as an infinite baffle. In front of the element is a resonant acoustical cavity that matches impedance of the element to that of the ambient medium and comprises concentric axially short large and small diameter cylindrical chamber portions, the small diameter portion providing a front outlet from the large diameter one.

Abstract: An improved miniaturized electro-acoustic surface-wave filter device is disclosed having broad, deep, adjacent channel stopbands from uniform aperture transducers. The device includes two spaced, interdigital electrode transducer structures fabricated on one surface of a piezoelectric substrate. Each electrode structure includes a central finger group and a number of flanking finger groups spaced from the central finger group at predetermined temporal locations. The strengths of the flanking groups are adjusted by controlling the number of finger pairs within a group, the overlap length of the fingers, and the strip/gap ratio of the fingers. Aperture uniformity is maintained in reduced overlap flanking groups through the series weighting technique. The subject device is particularly useful for channel selection in the IF portion of a television receiver.

Abstract: A surface acoustic wave bandpass filter having a flat frequency response in the passband and an exponentially decaying out-of-band response is realized by designing its transducer electrodes to have an appropriate number of discretely apodized interdigital fingers. The apodization or overlap coefficients H.sub.o (N) of adjacent fingers are determined from an analytically derived expression that incorporates factors for the filter time length parameter, the filter center frequency, bandwidth, transition bandwidth falloff, and a ripple reduction parameter.

Abstract: An acoustic surface wave filter comprises a piezoelectric substrate defining a propagating surface upon which a transmitting and receiving transducer pair are formed in offset alignment. An interposed multistrip coupler provides surface wave coupling between the offset transducers. An elongated isolating barrier is interposed between the transducers in an orthogonal relationship with the coupler to prevent surface wave propagation between the transducers along other than the primary axis. In one embodiment, an isolating barrier is composed of an acoustic surface wave dampening material, while in another a barrier of acoustic surface wave reflective material is used.

Abstract: A method for stabilizing the vibration frequency of an oscillator which contains a tuning fork-type quartz crystal element comprising a pair of arms each having a given size and a common connecting section connecting the mutually facing ends of the paired arms.

Abstract: A buffer rod for transmitting and receiving ultrasonic waves in a high-temperature gas medium including a plurality of flat discs center coupled along a mechanically tuned buffer rod and connected to a piezoelectric or magnetostrictive element to convert disc vibrations into electrical signals.

Abstract: A piezoelectric electro-acoustic transducer which includes a support means, a piezoelectric diaphragm supported at its edge portions by the support means comprising at least a pair of fixing members arranged to oppose each other, and a resilient backing member brought into a contact with the diaphragm to impart to the diaphragm a suitable tension and/or resiliency. The resilient backing member has an area smaller than the substantial vibration area of the diaphragm so that portions of the diaphragm are left free from contact with the resilient backing member, whereby, it has become possible to improve the frequency characteristics and consequently obtain improved sound characteristics.

Abstract: An ultrasonic transducer that employs a piezoelectric crystal which is made of lead metaniobate so that it has good sensitivity while also having a low Q. The transducer includes a backing support for one face of the crystal which provides damping of the acoustic energy being generated in the reverse direction. The backing support includes an epoxy resin with heavy metal objects moulded therein.

Abstract: An ultrasonic transducer specifically suited to high temperature sodium applications is described. A piezoelectric active element is joined to the transducer faceplate by coating the faceplate and juxtaposed active element face with wetting agents specifically compatible with the bonding procedure employed to achieve the joint. The opposite face of the active element is fitted with a backing member designed to assure continued electrical continuity during adverse operating conditions which can result in the fracturing of the active element. The fit is achieved employing a spring-loaded electrode operably arranged to electrically couple the internal transducer components, enclosed in a hermetically sealed housing, to accessory components normally employed in transducer applications.Two alternative backing members are taught for assuring electrical continuity. The first employs a resilient, discrete multipoint contact electrode in electrical communication with the active element face.

Abstract: A tubular section is constructed for radial and axial resonance. The tubular resonator is clamped along a line of clamping engagement near one end of the tubular section and is driven by means of radially directed oscillatory force applied at a line of driving engagement spaced from the line of clamping engagement. The oscillatory force is obtained from a driver which is formed of an annulus of piezoelectric crystal polarized in a radial direction, having an inner base ring and outer annular driver wedge, triangular in cross section. Since the frequency of radial resonance is a function of the radius of the tubular section, and the frequency of axial resonance is a function of the length of the tubular section, the two frequencies of resonance are made to coincide by proper selection of tube radius and length and the resonant frequencies therefore made to reinforce one another.

Abstract: Herein disclosed is a reed type electromechanical filter device which comprises a vibrator element having a pair of spaced parallel arm portions adapted to vibrate in lateral directions, a pair of piezoelectric ceramic plates or electromechanical transducer elements mounted on the arm portions of the vibrator element, and a pair of elastic metal members respectively mounted on the outer side faces of the arm portions and/or a pair of elastic metal members respectively mounted on the inner side faces of the arm portions. The elastic metal members are effective to prevent the arm portions from directly striking against each other and/or the inner faces of side walls of a housing enclosing the vibrator element in the event the filter device is subjected to a violent impact which would otherwise cause deterioration of the performance quality of the filter device.

Abstract: An electromechanical reed filter has a pair of mechanically resonant reed elements each having an electromechanical transducer. The transducer coupled to a terminal by means a connecting lead is applied with a shock-absorbing member such as resilient adhesive in a position anywhere between the contact point thereof with the transducer and the terminal so that variations in the natural frequency and Q value of the reed elements caused by deformation of the connecting leads due to abnormal shock or other ambient conditions are effectively eliminated.

Abstract: A device for correcting the frequency response of an electromechanical transducer, thus allowing said transducer to be used over a wide frequency band and set at or near its resonance frequency. The device includes a delay element having substantially the inverse transfer function of said transducer. An amplifier may be connected between said transducer and said delay element. Said delay element may comprise a variable delay line such as an adjustable length of coaxial cable, and may also include an integrated delay line.

Abstract: A tuned plate acoustic projector having a tuned plate that has its periph bonded to and supported by a housing. The outer face of the tuned plate is exposed to a fluid medium in which it is desired to generate acoustic waves. One end of a piezoelectric transducer is in contact with the central region of the inner face of the tuned plate and the other end is in contact with a mass slug that has a relatively large inertia base for the transducer. A compressive bias force is applied to the transducer to maintain the transducer in compression and to thereby prevent the generation of excessive tensile stresses in the transducer during operation. The thickness of the tuned plate is selected or tuned so that the propagation velocity of the flexural waves in the tuned plate matches the acoustic propagation velocity of the external fluid medium.

Abstract: A surface acoustic wave filter including a relatively broad band input transducer that launches acoustic energy along a first path, at least one frequency-selective periodic grating filter disposed in the first path and adapted to reflect the energy incident thereon along an intermediate path, at least one frequency selective periodic grating filter disposed in the intermediate path and adapted to reflect the energy incident thereon along an output path to an associated output transducer.

Abstract: Filter chain comprising a number of monolithic units of piezoelectric material, which units vibrate according to the thickness shear mode and are provided with at least two acoustically coupled resonators and are coupled electrically one to another. The acoustic coupling between said resonators is equal for all units, whereas the electric coupling impedances between the units are substantially ohmic. Due to this the pass band of the filter is determined by the acoustic couplings and there is no need for an adjustment of the electric coupling between the units.

Abstract: The present invention relates to electromechanical devices for the transmission of surface acoustic waves between a launching transducer and a receiving transducer arranged upon the main face of a substrate. The transmission device in accordance with the invention comprises ground zones provided in order to scatter the vibrational energy of bulk waves propagating within the thickness of the substrate. The creation of the ground zones involves the use of a jet of sand directed on to the large faces of the substrate.

Abstract: A transducer assembly which generates a cone shaped radiation pattern concentric with a selected axis is formed by a piezoelectric element mounted in a cylindrical resonant cavity defined by a Helmholtz chamber. Circumferentially spaced apart and radially aligned circular apertures are formed in the chamber's cylindrical side wall and an inclined reflecting plate is spaced apart from the apertures a selected distance. The plate extends outwardly from the chamber at an angle of less than 90.degree. to the chamber axis. The cone shaped radiation pattern is produced by generating a plurality of discrete spherical radiation patterns, combining these patterns to form an annular radiation pattern and partially reflecting the annular radiation pattern from an inclined reflection plate extending at an angle to the chamber axis of less than 90.degree. to produce a cone shaped radiation pattern.

Abstract: A piezoelectric electro-acoustic transducer which includes a diaphragm having a piezoelectric property, a base plate of a stiff material, and a resilient backing member which is compressedly covered at one side with the base plate and brought into contact at the other side with the diaphragm to provide the diaphragm with resiliency and/or tension, characterized in that the base plate is provided at one side adjacent said backing member with a surface which has a concave and/or a convex curvature to provide the diaphragm with different suitable pressures through said backing member, whereby it has become possible to improve the frequency characteristics, particularly, the low frequency characteristics of the transducer and a high conversion efficiency thereof.

Abstract: Ultrasonic systems for use in consumer, and other applications, having electromechanical motor systems providing bursts of ultrasonic mechanical vibration at an applicator repeated at a sonic frequency to produce both ultrasonic and sonic vibratory motion and effect during use of said applicator.

Abstract: A thick layer of epoxy resin is used to bond together the piezoelectric member and a stainless steel cap to form an acoustic transducer having a broad frequency response, and specific assembling steps are taken to manufacture the transducer with good reproducibility of the characteristics.

Abstract: A Piezoelectric speaker system with a piezoelectric diaphragm supported in a cylindrical form and provided with a plurality of vibration regions, which is capable of controlling the directional characteristics by easy operation according to necessity or listener's preference.

Abstract: The disclosure pertains to an apparatus for receiving electronic signals and embossing modulated grooves on a carrier medium as a function of the received signals, the apparatus including a support for supporting an embossing assembly and a carrier medium in spaced relationship therewith, as well as apparatus for causing relative motion between the carrier medium and the embossing assembly. In accordance with the invention there is provided a wafer of piezoelectric material affixed to the mount, the wafer having electrodes for application of the electronic signals. Further provided is a horn-shaped stylus member having a relatively blunt end affixed to one side of the wafer and tapering to a relatively pointy stylus end, the stylus end being positionable in contact with the medium. The horn-shaped member serves to match the mechanical impedence as between the wafer and the carrier.

Abstract: An electro-acoustic transducer with a piezoelectric diaphragm which is backed with a plurality of different resilient members for imparting a suitable resiliency and/or tension to said diaphragm to highly improve its acoustic characteristics with a simple construction.

Abstract: To reduce the capacitive coupling between the input and output transducers of a piezoelectric resonator arrangement having a one-piece construction, one or a plurality of coatings disposed between the two transducers, which coatings serve for defining given resonators, are connected to ground on either one or both sides and, if required, one coating of the input and output transducers is also connected to ground.

Abstract: An improved acoustic waveguide structure which comprises a ridge waveguide disposed in a horizontal direction extending outwardly from a substrate. The horizontal orientation of the waveguide which is in the form of a ledge results in particle motion of the ledge predominantly normal to the substrate plane with the largest motion at the free edge of the ledge and almost no motion in the substrate, thereby permitting a plurality of such structures to be densely packed on a common substrate.

Abstract: An electromechanical reed filter has a pair of reed elements secured at one end to each other and supported on a base member. A electromechanical transducer is cemented to the side surface of each of the reed elements intermediate of the opposite ends of the reed. The reed filter is housed in a protective casing and is provided with a shock-absorbing member in the vicinity of the free ends of the reed elements. When an abnormal shock is applied to the filter the reed elements are caused to bend transversely and would strike the inner walls of the casing with the shock-absorbing member being interposed therebetween. The impact energy is effectively absorbed so that the cemented portion of the transducer is protected from deformation or cracks. The shock-absorbing member may be applied to the free ends of the reed elements so that spurious vibrations at frequencies higher than the fundamental frequency can be suppressed.

Abstract: A piezoelectric electro-acoustic transducer employing as a diaphragm a uniaxially stretched film of a shape having the major axis and the minor axis, wherein the expansion-contraction direction of the diaphragm, in which a piezoelectric constant is at a maximum, is substantially in parallel with the minor axis thereof, whereby the piezoelectric electro-acoustic transducer can provide a high converting efficiency, especially in the low frequency range.

Abstract: A crystal resonator is disclosed of a single crystal of the approximate composition Tl.sub.3 BX.sub.4 having two parallel surfaces normal to a zero temperature coefficient of frequency direction and having an electrode mounted on each surface, where B is vanadium, niobium, or tantalum, and X is sulfur or selenium. A filter is disclosed of a crystal resonator coupled to a capacitor or more than one crystal resonator in series each coupled to a capacitor. A voltage controlled crystal oscillator resonator is disclosed of a crystal resonator in parallel with an inductor and a varactor.

Abstract: A quartz crystal vibrator unit having a passive electronic element such as a condenser is disclosed. The passive electronic element having the value to compensate the deviation of oscillating frequency from the predetermined center frequency is selected and fixed on the case of quartz crystal vibrator. Since frequency adjustment at assembling process is eliminated, work efficiency is remarkably increased.

Abstract: A cutterhead assembly suitable for forming a topographic signal-representative pattern in a recording medium such as a disc is constructed with non-parallel external surfaces so as to provide a response relatively free of undesired resonant modes over a relatively wide frequency range. The cutterhead includes a cutting stylus supported in a stylus mount. The stylus mount and therefore the stylus are driven by a piezoelectric element which is mounted on a supporting pedestal. A resilient mounting means is utilized to fasten the supporting pedestal to a mounting bracket.