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: 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: 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: A small low frequency acoustic receiver which is formed into a cylinder or ing by use of a plurality of separate elements of piezoelectric material. Each element is secured with its sides in face-to-face relationship with an electrode between each joined face in contact with each adjacent element. The electrodes are alternately connected into an electrical circuitry for transmitting electrical signals to a receiver.Other construction techniques may be used to assemble separate elements in a cylindrical arrangement. Over a band of very low frequencies, the cylinder or ring has a high sensitivity (i.e., it produces a large electrical signal) to sound incident in the axial direction compared with its sensitivity in the radial direction. Over this band of very low frequencies the sensitivity of the cylinder or ring is relatively constant for sound incident in the axial direction.

Abstract: An elastic surface wave device comprises a piezoelectric body and interdigital type electric signal-surface wave conversion conductors formed one at each end portion of one surface of the piezoelectric body. A groove elongated in a surface wave propagation direction is provided in a surface opposite to the surface on which the conversion conductors are formed.

Abstract: A video signal processor for repetitive line data, such as the typical TV horizontal scan line. An acoustic surface wave delay line comprising a piezoelectric substrate with an input wave launcher and a plurality of interdigital taps is provided. The video signal line "fits" in the overall delay and electronic circuits (preferably of the integrated circuit type) are connected to the taps. Individual taps each have a weighting amplifier weighting from line center to early and late extremes, and their outputs are summed on the same basis. The sum has a polarity indicative of the signal line centroid sense vis-a-vis the line center and has an amplitude indicative of centroid spacing with respect to said line center.

Abstract: Apparatus and method for providing electro-acoustic transducers of an acoustic surface wave device with an increased density of transducer elements. An increased density of transducer elements provides more accurate generation and reproduction of a desired frequency response above the design center frequency. By providing the sets of transducer elements which exchange signals by means of electro-acoustic surface waves with different densities of transducer elements, the transfer of undesired frequency components, introduced by the oversampled density of the transducer element sets, is reduced.

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: A surface acoustic wave device comprises a piezoelectric substrate which carries input and output transducers for launching and receiving surface acoustic waves on the substrate, one or more reflective arrays for reflecting surface acoustic waves between the two transducers, wherein at least one array comprises numerous spaced reflecting elements of varying lengths arranged in two sets, one set being angled to reflect surface acoustic wave in one direction while the other set is angled to reflect surface acoustic wave in another direction. Varying the lengths of the reflecting elements provides weighting of signals passing through the device. Additionally pulse compression and expansion may be arranged with or without frequency dispersion.

Abstract: A surface acoustic wave device comprises a substrate able to support surface acoustic waves, an input transducer for launching surface acoustic waves along a first track on the substrate, an output transducer for receiving surface acoustic waves from a second track on the substrate, and first and second reflective array structures arranged to reflect surface acoustic waves from the first track into the second track, the first and second reflective array structures each comprising numerous reflecting strips or grooves arranged parallel to one another in echalon across the first and second tracks respectively. Varying the lengths of the reflecting elements provides weighting of signals passing through the device, and varying the spacing between the reflecting elements provides pulse compression or expansion with a frequency sweep.

Abstract: Solid-state diodes constituted by a semiconductor 3 and an insulated electrode 1 are aligned upon a piezoelectric substrate 4 at the surface of which there propagate the acoustic waves induced by the signals applied to transducers 7 and 8. With each diode there is associated a capacitor whose dielectric is constituted by a portion of the substrate 4; 9 designates the terminals of the electrodes 2 and 5 between which a voltage pulse is applied, in order to charge up the capacitors, after a first high frequency signal has been applied to the transducer 7. Thus, there is stored the high frequency signal at the terminals of the capacitor. During discharge of the capacitor, a second signal is applied to one of the transducers 7 or 8. At 9, there is picked off either the correlation or the convolution of the stored signal and the second signal.

Abstract: An elastic surface wave apparatus, wherein transmission and reception electrode pairs for conversion of electric signals into elastic surface waves are spatially disposed so as to cause said surface waves to be propagated over the X-Z axis surface of a Y-cut lithium niobate (LiNbO.sub.3) piezoelectric element in a direction inclined 0.5 to 7 degrees relative to the Z axis.

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: The present invention relates to surface elastic wave electromechanical devices. The electromechanical device in accordance with the invention comprises a central common transducer and two identical transducers interconnected electrically. The central transducer produces bi-directional radiation, and intermediate means are provided to selectively modify the propagation of the surface elastic waves.

Abstract: Monolithic acoustoelectric imager using a multistrip coupled convolver. The multistrip coupler of the convolver senses the electric fields associated with counter-propagating surface acoustic waves on a piezoelectric film. The interaction product of the sensed electric fields scans a screen including one or more strips of radiation-sensitive semiconductor material and the convolver output is modulated by the varying intensity of illumination from an image projected onto the screen.

Abstract: A base of piezoelectrically active material having a plurality of spaced apart reflectors formed thereon and transducers positioned between at least some of said adjacent reflectors to produce standing waves at a predetermined frequency, the reflectors between transducers being formed with less than one hundred percent reflectivity so that energy from a standing wave between a pair of adjacent reflectors is coupled through the system to other pairs of reflectors for producing standing waves therebetween. The transducers may operate as electrical energy inputs or as taps to remove energy from the system.

Abstract: A flexural mode quartz crystal vibrator formed from a quartz crystal plate having first and second opposed substantially planar surfaces, with a plurality of electrodes on at least one side thereof, is provided. The vibrator is characterized by the placement of electrodes on at least one of the opposed surfaces of the quartz crystal plate, the placement of the electrodes providing a vibrator having a thickness of 0.5 mm or less.

Abstract: A surface wave TV I.F. filter has a transducer with two passbands. Each is unsymmetrical with respect to itself and a mirror image of the other. A second transducer suppresses one of the passbands.

Abstract: The present invention relates to electromechanical resonance devices comprising a piezo-electric crystalline plate and electrodes arranged opposite one another upon the principal faces of said plate. In accordance with the invention, the piezo-electric wafer is cut from a lithium niobate crystal, in accordance with the Y + 37.degree. cut.

Abstract: An acoustic surface wave device having an interdigital array of parallel electrodes includes a set of four parallel active electrodes spaced apart and with a transverse overlap. The second and third electrodes are aligned. The first and third and second and fourth electrodes are respectively connected together and to corresponding other electrodes of the electrode array.

Abstract: This invention comprises in combination a body of piezoelectric material, means for propagating an acoustic wave in a first mode, means for converting a portion of the acoustic wave energy into an acoustic wave in a second mode, a resonant structure in which the acoustic wave energy in the second mode is resonant, means for reconverting the acoustic wave energy in the second mode into surface acoustic wave energy in the first mode, means for providing a predetermined phase shift of the reconverted acoustic wave energy relative to the original propagated acoustic wave energy, and means for recovering the combined acoustic wave energy of the original and phase shift reconverted acoustic wave energies as an electric output signal.

Abstract: A temperature compensated surface acoustic wave device having an SiO.sub.2 film layer upon a substrate of piezoelectric material. The positive temperature coefficient of delay of the piezoelectric substrate is counterbalanced by the negative temperature coefficient of the SiO.sub.2 layer. The thickness and shape of the SiO.sub.2 layer are chosen to give a zero first order temperature coefficient for the composite device. Lithium niobate and lithium tantalate are preferred piezoelectric materials for the substrate. A high degree of temperature stability is thereby obtained with coupling coefficients much greater than were previously obtained by prior temperature compensated surface acoustic wave devices.

Abstract: A highly stable variable frequency oscillator is disclosed which employs a ultitap surface acoustic wave device as a frequency standard. A feedback path which includes a voltage controlled switch for selecting a desired output tap drives a differential amplifier, phase detector, low pass filter, voltage controlled oscillator and phase splitter for driving the input tap of the surface acoustic wave device. Various additional feedback paths are also employed. The variable frequency signal is taken from the output of the voltage controlled oscillator.

Abstract: A piezoelectric device comprisng a thin plate of a piezoelectric material which has a Poisson's ratio of less than one-third, and has an electrode region and a non-electrode region, wherein the thickness relation between the electode region and the non-electrode region is arranged so that the thickness of the electrode region is smaller than the thickness of the non-electrode region when a value of equations represented by (.pi.p/4)+(4/k.sup.3)cot(.pi.kp/2) Q for the thickness-extensional mode, and (.pi.q/4)+(4/k)cot(.pi. q/2k) Q for the thickness-shear mode is negative respectively for a desired vibratory mode, and that the thickness of the electrode region is larger than the thickness of the non-electrode region when the value of the above equations are positive respectively for a desired thickness vibration mode.

Abstract: A spinel-type oxide exhibiting a cooperative Jahn-Teller effect shows an extraordinary reduction of sound velocity therethrough at temperatures near the Jahn-Teller phase transition temperature thereof. The sound velocity and effective temperature range can be varied over wide ranges by using a solid solution of such an oxide and another spinel-type oxide not exhibiting the Jahn-Teller effect. NiCr.sub.2 O.sub.4 and ZnCr.sub.2 O.sub.4 are particularly advantageous as the former and latter oxides, respectively.

Abstract: A surface wave device (SWD) programmable to produce any one of a plurality of phase coded SWD digital delay line configurations from a single transducer pattern characterized by parallel transducer electrode arrays to provide for each of two opposite phase alternatives of acoustic surface waves being propagated. Each transducer comprises pairs of interdigital taps, each tap characterizing a single binary bit. Transducer phase coding is accomplished by severing in selected taps all metalized fingers of like polarity from their common conductor bar. Critical configuration tolerances prohibitive to programmed operations are thus obviated.

Abstract: A surface wave device having a periodic frequency response characteristic is disclosed. At least two reflective grating structures are located at the surface of the surface wave device such that acoustic surface wave standing wave resonance can occur in the region between the two reflector structures. The spacing between the reflector structures is sufficiently large to insure that standing wave resonance can occur at any of a plurality of discrete resonance frequencies, all falling within the bandwidth of the grating reflectors themselves.

Abstract: A method of manufacturing an acoustic surface wave filter includes forming a first and second pair of transducers and a multistrip coupler upon the surface of a piezoelectric medium in a rectangular configuration with the transducers occupying its corners. Each transmitting transducer is diagonally oriented with its respective receiving transducer and the multistrip coupler is interposed between the transmitting and receiving transducers substantially orthogonal to the direction of surface wave propagation. Test signals are applied to each transducer pair to select the most favorable for use. The other pair is disabled. A SWIF manufactured in accordance with the method is disclosed having one pair of transducers disabled.

Abstract: A .theta.-rotated Y-cut X-propagating piezoelectric substrate of crystalline lithium niobate for use in an elastic surface wave device, wherein the angle .theta. at which the substrate is cut out is chosen to range between 125.6.degree. and 130.1.degree. to suppress spurious wave components.

Abstract: An acoustic surface wave filter comprising a monocrystalline wafer of bismuth silicon oxide having a special orientation of the ASW propagation surface and the interdigital transducers relative to the crystal plane whereby pick-up of undesired bulk waves is reduced.

Abstract: An insulating substrate, on which is at least one single crystalline electrode and a single crystalline layer of piezoelectric material on the electrode, forms an efficient surface acoustic wave device.

Abstract: A temperature compensated acoustic surface wave device, such as a surface wave delay line is provided in which temperature compensation is provided by the deposition of an interdigital electrode structure on a substrate with an overlay film surface of piezoelectric material of a predetermined thickness. A double substrate arrangement is also disclosed in which the interdigital electrode structure is deposited upon the surface of a non-piezo-electric layer which in turn is placed upon the surface of a piezoelectric substrate.

Abstract: A surface acoustic wave device wherein spaced input and output transducers are disposed on a piezoelectric substrate and wherein a time delay or insertion phase compensation structure is disposed between the transducers in the path of the propagating surface acoustic wave energy, the structure including a group of transversely disposed conductive electrodes initially conductively interconnected outside the propagating energy path whereby a desired time delay or insertion phase may be obtained by electrically insulating a number of the electrodes from the group of initially conductively interconnected electrodes.

Abstract: A surface acoustic wave delay line for use with an amplifier to form an oscillator has the spacing of its two transducers arranged to provide the desired mode of oscillation and the frequency responses of one or both transducers arranged to suppress unwanted moles of oscillation. Various transducers configuration are provided to reduce reflection problems between and within the transducers. The oscillator may be frequency modulated.

Abstract: This invention relates to a remotely controlled variable capacitor, more ticularly, to an electromechanical capacitor with one of the capacitor electrodes mounted on one surface of a bimorph element and the other capacitor electrode mounted on the surface of a superimposed bimorph element. In response to a DC electrical signal, there is a mechanical motion separating the capacitor electrodes to vary the capacitance therebetween.

Abstract: A piezoelectric beam is fixed at one end and is subdivided into segments, each of which is deflected by a logic one in one of the magnitude bit locations of a digital word. The total deflection of the beam is related to the total magnitude of the digital word. The segment closest to the fixed end is controlled by the most significant bit, and the segment closest to the free end is controlled by the least significant bit. The free end is connected to the cone of a speaker so that the acoustic signal resulting from the motion of the cone is related to the digital word. A buffer regulates the polarity of the voltages applied to each segment according to the sign bit in the word so that the beam deflects in either of two directions depending on the polarity of the digital word.

Abstract: The invention concerns acoustic surface wave devices with multistrip couplers. The coupler of such a device comprises two arrays of N conductive strips connected by a connecting array and having at least one characteristic, such as for example their periodicity which is distinct for the two arrays. In modifying, for example, the ratio p.sub.1 /p.sub.2 of the periodicities of the arrays, the operation of this device is modified. This device permits in particular the construction, for wide frequency bands of utilisation of n dB couplers, energy concentrators or unidirectional transducers.

Abstract: A device for generating or sensing transverse elastic bulk waves in solids includes a piezoelectric material engaging a surface of the solid and having a two-fold axis or equivalent symmetry extending parallel to the surface of the solid. A pair of electrodes are located on a surface of the transducer extending perpendicular to the surface of the solid which the material contacts. Each electrode has one or more conductive fingers elongated in a direction parallel to the two-fold axis of the material. The fingers of the electrodes are interlaced. When used as a generator of bulk waves, a source of alternating voltage excites the electrodes. The electrodes thus generate deep surface waves in the piezoelectric material which are transformed into bulk waves in the test solid. Similarly, bulk waves in the test solid are transformed into deep surface waves in the piezoelectric material which may then be sensed by the electrodes.

Abstract: It is disclosed a quartz crystal vibrator for a timepiece having a partial electrode which is able to offset the charge produced by higher harmonic oscillation.According to this invention, higher harmonic oscillation is prevented and vibrators oscillate by only fundamental frequency.

Abstract: Prior art methods for shaping the impulse response of a surface wave delay line interdigital transducer include finger width weighting and finger overlap weighting. The new method for shaping the transducer impulse response disclosed herein overcomes several objectional characteristics of the prior art methods. The new method involves removal of individual fingers or groups of fingers from selected portions of the transducer. The amplitude of the impulse response in those regions from which fingers have been removed is reduced below the value which it would have if no fingers had been removed. The method thus provides the capability to control the relative amplitudes of the impulse response along the length of the transducer.

Abstract: Acoustic waveguides, acoustic filters and acoustic reflectors are based upon the discovery of increased acoustic wave velocity in materials such as lithium niobate and lithium tantalate into which a metal such as titanium, nickel or chromium has been diffused. Velocity increases larger than 1 percent have been obtained; and negligible effect on acoustic loss is incurred thereby. The technique and the resulting devices result in a simpler structure than provided by the metallic strips or the ion beam etched surface regions of prior acoustic devices in which velocity perturbations of comparable magnitude have been desired.

Abstract: A ferroelectric surface wave transducer device comprising an unpoled ferroelectric substrate having a substantially sinusoidal poled region at a surface thereof. A metal plate electrode is disposed on the opposing surface of the substrate. In operation an A.C. voltage applied across the two electrodes gives rise to a surface elastic wave in the substrate. Also disclosed is a method of producing a surface wave transducer of the type described. A pair of interdigitated metal electrodes are applied to a surface of an unpoled ferroelectric substrate. A poling potential is applied between the electrodes, preferably while the substrate is heated. The interdigitated electrodes are then removed and a metal plate electrode is applied over the region where the interdigitated electrodes had been. Finally, another metal electrode is applied to the opposite surface of the substrate. In a preferred embodiment of the invention the interdigitated electrodes are in the form of a moveable fixture.

Abstract: An acoustically scanned, optical imaging system for converting patterns of light into electrical signals. The system includes a monolithic convolver that scans incident light patterns using two counter propagating acoustic waves. Located in front of the convolver is an opaque grid that places a spatial periodicity into the light patterns. When the frequencies of the two acoustic waves propagating in the convolver are selected so that the difference between them is a function of the spatial periodicity placed in the light patterns, the minimum threshold signal or dark current from the convolver is substantially reduced. The imaging system also includes four alternative signal generating and processing circuits that can provide a one dimensional scan, a fast Fourier transform and a Fresnel transform of the light patterns incident on the convolver. Patterns of colored light also can be convolved into electrical signals by using colored filters as the grid.

Abstract: An improved monolithic crystal filter is disclosed. The filter has input and output ports formed from particular combinations of first, second and third terminals, the latter terminals having been adapted to be connected to certain preselected electrodes of the two adjacent resonators comprising the filter. More specifically, the first terminal is adapted to be connected to one of the electrodes of a first one of the aforesaid two resonators, the second terminal to the other electrode of the first resonator and to one of the electrodes of the second of the two resonators, and the third terminal to the remaining electrode of the second resonator.

Abstract: A flexural mode quartz crystal vibrator formed from a quartz crystal plate having first and second opposed substantially planar surfaces, with a plurality of electrodes on both said surfaces is provided. The vibrator is characterized by the placement of electrodes on both of the opposed surfaces so that the electrodes on each surface do not overlap each other.

Abstract: A surface acoustic wave (SAW) structure is disclosed wherein a SAW device is incorporated as an exterior lamina within a composite laminate in order to temperature stabilize the acoustic device. The composite laminate is synthesized to selectively mismatch the thermal expansion characteristics of the piezoelectric material, which is the body of the acoustic device, along the axis of acoustic propagation and simultaneously approximately match the thermal expansion properties along the orthogonal axis. Compressive force is thereby applied to the acoustic device to keep the substrate length constant and thus provide an approximately zero temperature coefficient over a preferred range of temperatures.

Abstract: The input transducers of a multichannel surface acoustic wave device are electrically connected in a series or series-parallel circuit arrangement and are connected to a single channel electromagnetic wave transmission line through an inductor. The inductance value of the inductor is chosen such that minimum transducer insertion loss is achieved at the center frequency of the midband channel. The circuit arrangement is selected which achieves optimum coupling to the midband channel subject to the constraint that the insertion losses of all the remaining channels, measured at their respective center frequencies, lie at or near the above optimum value within an acceptable prespecified margin.

Abstract: A thyristor-firing apparatus using an acoustic surface wave device wherein an electric signal for firing a thyristor is converted into an acoustic surface wave and again converted into an electric signal which in turn is supplied between the gate and cathode electrodes of the thyristor. The electric signal applied to the acoustic surface wave device is obtained through amplitude modulation of a carrier signal by a control pulse, and an output from the surface wave device is rectified or demodulated to fire the thyristor.

Abstract: Transducer devices employing relative changes in the acoustical propagation characteristics of surface waves traveling on opposite surfaces of a thin elastic cantilever beam yield a measure of the degree of flexing or surface strain of the elastic member. A multiplexed phase comparison loop and signal processing circuit alternately cooperates with the opposite surface waves of the transducer to supply a digital output proportional to strain and relatively free of drift, mode locking, and other spurious interactions.