Abstract: An elastic wave device includes a piezoelectric substrate with first and second main surfaces internally facing each other, an elastic-wave element that includes an interdigital transducer electrode provided on or in the first main surface of the piezoelectric substrate, and a first protective film that is provided on the first main surface of the piezoelectric substrate so as to cover the IDT electrode. The IDT electrode includes a main electrode layer made of a metal having a density higher than that of the first protective film. The piezoelectric substrate has a thickness of about 0.35 mm or smaller, and irregularities are located on the second main surface.

Abstract: Systems and related methods providing for touch sensors having segmented reflective arrays including waveguide cores are discussed herein. A touch sensor may include a substrate configured to propagate surface acoustic waves. The substrate may include two or more segmented reflective arrays. A segmented reflective array may include a major reflective array configured to propagate surface acoustic waves and a waveguide core configured to concentrate acoustic energy of the surface acoustic waves. Two segmented reflective arrays may further include adjacent portions that define an overlap region of the substrate. In some embodiments, the segmented reflective array may further include a beam dump configured to decrease intensity of surface acoustic wave propagation past the end of the segmented reflective array.

Abstract: A process and apparatus for performing a ground fault test of a device is disclosed. A current level may be selected from a plurality of predetermined current levels. A ground fault current may be generated between a first power line and a ground at the selected current level until a ground fault interrupter within the device trips, or until expiration of an on-time period associated with the selected current level. The ground fault current may then be set to zero for an off-time period associated with the selected current level. The process may be repeated for each of the plurality of current levels. When the ground fault interrupter within the device trips, the current level and a time interval from an onset of the ground fault current at the selected level and a time when the ground fault interrupter tripped may be recorded.

Abstract: A system for measuring properties of a surface under test with surface waves includes a surface wave network including a dielectric substrate, a reactive grid of a plurality of metallic patches on a first surface of the dielectric substrate, a plurality of electronic nodes on the first surface of the dielectric substrate, and a ground plane on a second surface of the dielectric substrate permeable to RF fields of the surface waves, and a controller configured for causing a respective one of the electronic nodes to transmit at least one surface wave and configured for collecting data for signals received by at least one other of the plurality of electronic nodes.

Abstract: System and method for enabling the cohabitation of licensed and unlicensed communications devices. A method comprises at a receiver, receiving transmitted data, demodulating the transmitted data to produce spread symbols, despreading the spread symbols to produce received data, wherein the despreading comprises using an orthogonal sequence selected from a list of orthogonal sequences for use by all transmissions in the wireless network, and processing the received data.

Abstract: An anti-reflective acoustic diffusion device is provided by a group of irregularly dimensioned diffusing elements positioned on an acoustic wave substrate end that diffuse the SAW and eliminate unwanted acoustic reflections from the end of the substrate. The irregularly dimensioned diffusing elements are substantially irregular in size, shape, composition, and location and provide the desired diffusion into a nearly uniform distributed acoustic energy with a random phase. The anti-reflective acoustic diffusion device can be used with SAW, BAW or multiple acoustic wave configurations. This invention also encompasses an anti-reflective acoustic diffusion system and methods for diffusing acoustic reflections with anti-reflective acoustic diffusing elements.

Abstract: Channel quality can be detected accurately in a wireless transmission system such as an HSDPA method. In the case of estimating a channel quality of a signal transmitted by a Code Division Multiple Access method and of estimating the channel quality in a system having a synchronization channel not orthogonal to a channel receiving data, a noise component of a desired channel is estimated; degree of a noise component caused by the synchronization channel is estimated with respect to the estimated noise; and a channel quality of a receiving channel is detected based on the estimated degree of the noise component.

Abstract: Impedance mismatching points such as a VIA and a connector on a differential line between a differential driver element and a differential receiver element are arranged in predetermined positions. That is, the impedance mismatching points are arranged in such positions that a transmission time of a digital signal transmitted through a main differential line becomes (integral multiple of UI)±0.5×Trf, whereby noises are generated within the rise and fall times of a signal to be able to maintain an excellent waveform of the signal.

Abstract: The present invention discloses a double TRU (Transceiver Unit) (45). The output signals from the power amplifiers (64, 84) are combined to one common output signal provided to an antenna arrangement (91). A DSP (Digital Signal Processor) (52, 72) of each TRU (50, 70) comprises means for a constant-envelope modulation scheme (54, 74) and a non-constant envelope scheme (53, 73). The DSP:s (52, 72) select the modulation scheme according to modulation information (49, 69). In such a way, a switching between different modulation schemes can be performed even on a time-slot basis. For non-constant-envelope modulation, the modulated signal is separated into two component signals. Each TRU (50, 70) takes care of the amplification of one component. A phase compensation of at least one of the TRU:s (50, 70) is performed in order to correct for different paths of phases of the power amplifiers (64, 84). The non-constant envelope modulated signal can also be a multi-carrier signal, e.g.

Abstract: The number of times for averaging operation for averaging a correlation value of a received signal and a reference signal is properly controlled. When the correlation value is not averaged, since a lower limit value TH_A of a correlation level of a distribution of timings of which a path exists is larger than an upper limit value TH_B of a correlation level of a distribution of timings of which a path does not exist, the correlation value of a path is hidden by noise. Since the averaging operation is repeated until the relation of TH_A>TH_B is satisfied, the averaging operation is stopped when the relation is satisfied. The TH_A and TH_B are decided in accordance with RSCP and ISCP of a pilot channel and RSSI of a received base band signal.

Abstract: A method of Partial Parallel Interference Cancellation (PPIC) is provided for recursively eliminating the Multiple Access Interference from a received signal. Such method is to use a recursion way to eliminate all the Multiple Access Interference (MAI) one by one from the received signal. Moreover, the present invention is to take the output of the pre-stage as the input of the present stage with the recursion method so that we can use only one operating circuit to obtain the function the MAI eliminating.

Abstract: The present invention provides a surface acoustic wave device that allows a plurality of surface acoustic wave filters to be formed on a single chip and permits greater miniaturization. The surface acoustic wave device comprises a piezoelectric substrate, a first surface acoustic wave resonator formed on the piezoelectric substrate, and a second surface acoustic wave resonator formed on the piezoelectric substrate in the surface acoustic wave propagation direction of the first surface acoustic wave resonator. The positions in which the first and second surface acoustic wave resonators are formed on the piezoelectric substrate are in an at least partially overlapping relationship in a surface acoustic wave propagation region that is defined by virtually extending the respective openings of the first and second surface acoustic wave resonators.

Abstract: A surface acoustic wave sensor or identification device has a piezoelectric material, and an interdigitated transducer (IDT) input/output mounted on the piezoelectric material for receiving a radio frequency (RF) signal and propagating a corresponding surface acoustic wave along a surface of the piezoelectric material. An IDT finger electrode array is mounted on the piezoelectric material and is operable to communicate with the IDT input/output for transmission of a modified RF signal from the device. The IDT finger electrode array has at least one finger electrode segment whose propagating characteristics are controlled to control the nature of the modified RF signal. A biolayer is mounted on the piezoelectric material and is associated with the finger electrode segment, and a fluidic chamber is associated with the biolayer.

Abstract: A surface acoustic wave sensor or identification device has a piezoelectric substrate, an interdigitated transducer (IDT) input/output mounted on a substrate for receiving a radio frequency (RF) signal and propagating a corresponding surface acoustic wave along a surface of the substrate. An IDT reflector array is mounted on the substrate and operable to receive a surface acoustic wave and reflect the surface acoustic wave in modified form back to the IDT input/output for transmission of a corresponding modified RF signal from the device. The IDT reflector array has at least one reflector segment whose reflectivity characteristics are controlled to control the nature of the modified RF signal.

Abstract: Very low passband ripple is provided in a wide bandwidth high frequency SAW FIR filter using slanted finger IDTs by one or more of three techniques: cancelling regenerated SAWs at parallel-connected input IDTs of two SAW filters which are similar except for a quarter-wavelength difference in spacing of the input and output IDTs, this difference varying with wavelength across the IDT aperture; shaping edges of shield electrodes to provide quarter-wavelength differences in, and hence cancellation of, SAWs reflected at the edges, the differences varying with wavelength across the IDT aperture; and making pairs of slanted shield electrodes symmetrical to compensate for refraction of SAWs by the shield electrodes.

Abstract: A base material made of C-faced sapphire single crystal is set on a susceptor installed in a reactor arranged horizontally. Then, a trimethyl-aluminum and an ammonia are introduced as raw material gases into the reactor and supplied onto the substrate, to form an AlN film. In this case, the temperature of the base material is set to 1100° C. or over, and the ratio (V raw material gas/III raw material gas) is set to 800 or below, and the forming pressure is set within a range of 7-17 Torr. As a result, the crystallinity of the AlN film is developed to 90 arcsec or below in FWHM of X-ray rocking curve, and the surface flatness of the AlN film is developed to 20 Å or below. Therefore, a substrate composed of the base material and the AlN film is preferably usable for an acoustic surface wave device, and if the substrate is employed, the deviation from the theoretical propagation velocity is set to 1.5 m/sec or below.

Abstract: A surface-acoustic-wave filter has a piezoelectric substrate; and a plurality of transversal surface-acoustic-wave (SAW) filters set on the piezoelectric substrate and respectively having at least two inter-digital transducer (IDT) electrodes for transcieving surface acoustic waves, characterized in that periods for surface acoustic waves to propagate from inputs to outputs of the SAW filters differ in the SAW filters and thereby, timings of outputs from the SAW filters are different from each other.

Abstract: A ZnO monolithically integrated tunable surface acoustic wave (MITSAW) device uses tunable acousto-electric and acouso-optic interaction between surface acoustic waves (SAW) and a two dimensional electron gas (2DEG) in a ZnO/MgxZn1−xO quantum well. The high electromechanical coupling coefficients of piezoelectric ZnO in conjunction with the low acoustic loss and high velocity of sapphire (Al2O3) offers high frequency and low loss RF applications. The 2DEG interacts with the lateral electric field resulting in ohmic loss which attenuates and slows the surface acoustic wave. This mechanism is used to tune the acoustic velocity. The high coupling coefficients offered by the ZnO/R—(Al2O3) systems allows large velocity tuning. Combined with the optical characteristics of the wide and direct band gap (about 3.3 eV) semiconductor and transparent ZnO electrodes, the MITSAW chip can be used for UV optical signal processing.

Abstract: Method and system for a programmable analog tapped delay line filter are disclosed. One embodiment of the present invention is a programmable analog tapped delay line filter comprising an input line, an output line, and one or more gaincells or taps coupled between the input line and the output line. The input and output lines each comprises a cascade of one or more differential delay cells, and each of the one or more gaincells or taps corresponds to a tap weight or coefficient. Furthermore, the input and output lines are terminated in impedances and the filter produces one or more outputs.

Abstract: A ZnO monolithically integrated tunable surface acoustic wave (MITSAW) device uses tunable acousto-electric and acouso-optic interaction between surface acoustic waves (SAW) and a two dimensional electron gas (2DEG) in a ZnO/MgxZn1-xO quantum well. The high electromechanical coupling coefficients of piezoelectric ZnO in conjunction with the low acoustic loss and high velocity of sapphire (Al2O3) offers high frequency and low loss RF applications. The 2DEG interacts with the lateral electric field resulting in ohmic loss which attenuates and slows the surface acoustic wave. This mechanism is used to tune the acoustic velocity. The high coupling coefficients offered by the ZnO/R-(Al2O3) systems allows large velocity tuning. Combined with the optical characteristics of the wide and direct band gap (about 3.3 eV) semiconductor and transparent ZnO electrodes, the MITSAW chip can be used for UV optical signal processing.

Abstract: An output side electrode of a surface acoustic wave matched filter with portions having different delay times between taps. The output side electrode may be provided by arranging parallelly a plurality of output side electrodes having different scales, different tap distances, or by forming output side electrodes in an inclined fashion or in a dog-leg shape viewed in a direction of an aperture length, or by arranging, between electrode fingers, thin films having different dimensions or thicknesses viewed in the direction of the aperture length, or by forming, between electrode fingers, recessed portions having different dimension or depth viewed in the direction of the aperture length.

Abstract: An acoustic wave identification transponder device, having a substrate, an electroacoustic transducer generating an acoustic wave in said substrate and a set of encoding elements disposed in a path of the acoustic wave for modifying the acoustic wave, having elements which reflect portions of the acoustic wave having a component orthogonal to the incident wave. The reflectors may be, for example, trackchangers or reflective arrays compressors (RAC). The wave may be phase-amplitude modulated for increased efficiency expressed in bits per tap. Such phase amplitude modulation is preferably imposed by partial beam width phase delay elements disposed within an acoustic beam path.

Abstract: A reflective array compressor for a fast pattern recognition system. The system includes a combination of digital and analog processing circuitry which allows the system to achieve super computing processing speeds within an open personal computer architecture. The system receives a bit map which is representative of the unknown pattern, such as a picture of an unknown person. The bit map could have multiple people in it--no other system has "faces in the crowd" ability. The bit map associated with the unknown pattern is then pre-processed and compared against a plurality of known patterns in a database to determine how well the unknown pattern correlates with the known patterns. The reflective array compressor employs concave input and output transducers, and curved reflectors.

Abstract: A method (100) of providing a time delay to a signal utilizing a surface acoustic wave ladder filter includes a first step (102) of providing a piezoelectric substrate. A second step (104) includes disposing series and shunt coupled surface acoustic wave transducers in a ladder configuration on the substrate with each of the transducers having an associated aperture and an associated number of interdigital electrode elements. A third step (106) includes configuring the associated aperture and an associated number of interdigital electrode elements for each surface acoustic wave transducer for maximum phase linearity of the ladder filter and uniform group delay response from the ladder filter. A fourth step (108) includes adjusting the number of transducers in the ladder filter to provide a desired average group delay. Subsequently passing a signal through the ladder filter will delay the signal by a time equal to the group delay.

Abstract: An identification mark operating with acoustical surface waves includes at least one reflector having higher reflectivity than a reflectivity of other reflectors.

Abstract: An identification and/or sensor system includes an identification and/or sensor configuration having resonators for determining at least one parameter to be interrogated. The resonators have a quality being good enough to effect a storage of energy in the resonators. A transmitting and receiving apparatus transmits interrogation signals by radio to the identification and/or sensor configuration and receives and evaluates reply signals transmitted back from the identification and/or sensor configuration. The transmitting and receiving apparatus is a broadband device.

Abstract: Acoustic frequency mixing devices for controlling high frequency signals by the generation of acoustic waves are disclosed. The devices include (a) a crystalline substrate of MTiOXO.sub.4 (wherein M is K, Rb, Tl and/or NH.sub.4 and X is P and/or As) having a surface with at least two input areas; and (b) an input interdigital transducer deposited on each of at least two signal input areas of said substrate surface, each IDT suitable for connection to a source of electric signal and for inverse piezoelectrically generating acoustic waves (e.g., SAWs or B-G waves) in the substrate. For controlling high frequency electrical signals, the substrate surface has a output area and the device typically includes an output electrode (e.g.

Abstract: A waveguide for surface acoustic waves comprises a substrate for supporting propagation of surface acoustic waves along a direction at a substrate velocity and a dielectric structure disposed above the substrate along the propagation direction of the surface acoustic waves. The structure includes a central portion disposed along the propagation direction, first and second intermediate portions respectively disposed along each opposed side of the central portion along the propagation direction, and first and second outer portions respectively disposed along each outer side of the first and second intermediate portions along the propagation direction. The central, intermediate and outer portions each has first, second and third intrinsic surface acoustic wave propagation velocities along the propagation direction of the surface acoustic waves, respectively and the first velocity is intermediate of the second and third velocities.

Abstract: To obtain a surface acoustic wave device which can be produced with ease at a low cost and can be reduced in size without causing deterioration of characteristics, a surface acoustic wave device having input and output transducers arranged alternately on the surface of a substrate for propagating a surface acoustic wave includes metal patterns provided outside the transducers along the extension line of the propagation path of the surface acoustic wave and having at least one surface inclined at an angle .theta. (5.degree.<.theta.<85.degree. or -85.degree.<.theta.<-5.degree.) with respect to the propagation direction of the surface acoustic wave.

Abstract: In a surface acoustic wave device, there are arranged a piezoelectric substrate, an input electrode and an output electrode. The input electrode is formed on the substrate, and generates a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal. The output electrode is also formed on the substrate, and converts the surface acoustic wave to an electric signal. One of the input and output electrodes includes a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave. The other one of the input and output electrodes may comprise a pair of taps arranged at a predetermined distance in the propagation direction. The electrode including a plurality of taps or the electrode including a pair of taps satifies a predetermined relation established among a length between the taps, a transmission speed of the input signal, a propagation velocity of the surface acoustic wave and so forth.

Abstract: A surface-wave-type reflective delay line includes an input/output interdigital converter, and a plurality of surface wave reflectors. The surface wave reflectors are disposed at positions corresponding to an order of magnitude of half of a particular desired transit time of a surface wave between the input/output interdigital converter and an applicable surface wave reflector and back. At least some of the surface wave reflectors are each shifted by a mathematically random value out of the positions corresponding to half the particular desired transit time.

Abstract: A SAW reflector structure located between multiple interdigitated generator/receivers located on a piezo-electric substrate forming a ladder type SAW device is described. The reflector structure reduces both reflections due to mechanical-electrical loading from the physical presence of generator/receiver fingers without using a split finger arrangement as well as reflections due to the regenerated reflection from the generator/receiver. The reflector has a first acoustic phase center. The generator/receiver has a second acoustic phase center, a regenerated voltage coefficient of reflection, r.sub.e and a mechanical-electrical loading coefficient of reflection, r.sub.m. The reflector is used for simultaneously reflecting both regenerated and mechanical-electrical loading induced reflections from the generator/receiver. The reflector is sized for a strength of reflection equal to the square root of the sum of the regenerated and mechanical-electrical loading reflections squared.

Abstract: An SAW convolver is disclosed, in which a pair of input transducer means disposed at the left and right end portions on a piezoelectric substrate having a velocity dispersion consists of a plurality of pairs of input transducers and the distance between different pairs of input transducers differs from each other so as to compensate the velocity dispersion.

Abstract: A surface acoustic wave (SAW) chirp signal processor having a piezoelectric substrate, an array of input transducers and an array of output transducers. In its chirp compression mode, the device has chirp signals applied in parallel to its input transducers and produces compressed output pulses at its output transducers, corresponding to selected chirp rates. The input transducers are successively offset with respect to a focal point on the array of output transducers, by distances that successively and linearly increase or decrease from transducer to transducer, consistent with the increase or decrease in the wavelength of the chirp signals. The device may also be used in a pulse expansion mode, by inputting a broadband pulse into a selected one of the output transducers. The input transducers then produce a chirp signal having a rate corresponding the selected to output transducer.

Abstract: Amplitude error compensation is provided for a surface acoustic wave (SAW) reflective array correlator (RAC) device having a first reflective array grating fed by an input interdigital transducer and a second reflective array grating which feeds the reflected SAW signal output from the first array grating to an output interdigital transducer. A third or auxiliary reflective array grating is disposed between the first and second array gratings to reflect a portion of the SAW signals reflected from the first array grating to the second array grating to an acoustic absorber. The portion of the SAW signals reflected to the acoustic absorber are those SAW signals which when present in the output of the second array grating which is fed to the output transducer produce the unwanted amplitude errors. The third reflective array grating is fabricated of a photosensitive polymer material so that the frequency and amplitude selective configuration of the grating may be obtained by using photolithographic techniques.

Abstract: An amplitude error compensated surface acoustic wave reflective array corator is provided having an input interdigital transducer feeding a first slanted reflective array grating, a second slanted reflective array grating feeding an output transducer and a third, amplitude error compensation slanted reflective array grating feeding the output transducer. The third array grating receives only the leakage surface acoustic waves leaking past the second array grating from the first array grating and has a frequency and amplitude selective configuration which enables it to select those leakage surface acoustic wave signals which when added to the output of the second array grating by means of a multistrip coupler and fed to the output transducer provide an amplitude error compensated output RF signal.

Abstract: A surface device with a conversion structure (12) mounted on the substrate (2) but outside the surface of the substrate provided for surface wave propagation. The conversion structure eliminates undesirable surfaces which occur.

Abstract: Amplitude error compensation is provided for a surface acoustic wave (SAW) lanted array correlator (SAC) device having an input interdigital dispersive slanted array transducer feeding a plurality of frequency dispersed SAW signals to an output interdigital dispersive slanted array transducer over a plurality of parallel, frequency dispersed first paths. A reflective array grating having a frequency and amplitude selective configuration is disposed between the input and the output transducers to reflect along a second path to an acoustic absorber a portion of the SAW signals sent from the input transducer to the output transducer. The second path is perpendicular to and traverses the plurality or first paths. The portion of the SAW signals reflected to the acoustic absorber are those SAW signals which when present in the output of the output transducer produce the unwanted amplitude errors.

Abstract: A method of adjusting the center frequency of a SAW device by providing a substrate capable of propagating a surface acoustic wave thereon having input transducer electrode on one end portion thereof, output transducer electrodes on the opposite end portion thereof and a waveguide portion therebetween, applying an RF input signal to the input transducer and providing an indication of the output obtained from the output transducer and etching the entire device with an etchant until the indication has reached a predetermined status.

Abstract: A unitary surface acoustic wave device for continuous quadraphase coding of a high amplitude video impulse with provisions for controlling the rise and fall times of such impulse.

Abstract: In an SAW convolver composed of a substrate having a multi-layered structure comprising at least a piezoelectric film, self convolution is suppressed by disposing a first and a second array electrode disposed between the gate electrode and a pair of input electrodes, respectively, each of which consists of a high impurity concentration semiconductor layer. Further a convolution integrator is constituted by using such a convolver.

Abstract: Techniques for adjusting the surface acoustic wave velocity of a packaged SAW device are described. A first technique involves depositing a film from a cover of the device onto a surface wave propagating surface thereby providing a localized region on said surface where the acoustic properties and, hence, the velocity characteristics of the surface wave propagating surface are altered. An alternate embodiment of a pair of beams are directed through a transparent cover and converge on the surface wave propagating surface, selectively removing a portion of said surface to provide a localized alteration in the acoustic properties of the surface wave propagating surface.

Abstract: A surface elastic wave filter for processing a supplied signal into a signal with nonlinear-phase frequency characteristics has a piezoelectric substrate for propagating a surface elastic wave through a surface layer thereof and spaced input and output electrodes disposed on the surface layer for sending and receiving the surface elastic wave. Each of the input and output electrodes has a pair of common electrodes having comb-shaped interdigitating electrode fingers extending therebetween. The central electrode fingers of the input and output electrodes have central axes across the direction of propagation of the surface elastic wave. The distance along the direction of propagation between the central axes is varied in the direction substantially normal to the direction of propagation.

Abstract: A surface transverse wave resonator comprises a piezoelectric substrate having at least one surface, wherein said substrate includes a crystalline structure that permits the propagation of transverse waves. The resonator also comprises a transducing set of periodic perturbations which are positioned atop the substrate surface, wherein the transducing set converts electromagnetic energy from an external source into the transverse waves. The resonator further comprises a receiving set of periodic perturbations which are positioned atop the substrate surface remote of the transducing set of periodic perturbations, wherein the receiving set converts the transverse waves into resultant electromagnetic energy. Moreover, the resonator includes a central set of surface-trapping periodic perturbations for maintaining the transverse waves adjacent to the substrate surface, wherein the central set is positioned intermediate the transducing set and the receiving set.

Abstract: A surface acoustic wave device is disclosed which performs frequency channelization in a relatively small volume. The invention utilizes a wide band incline step frequency transducer each step feeding an independent beam width compressor waveguide combination. The waveguides fan out with a wide radius of curvature to contain the wave in off pure mode axis propagation. The output of each waveguide then feeds an independent beam width expander and frequency selector interdigital transducer. The use of the waveguides as a tapping and narrow aperture transport mechanism minimizes defraction, allows the output transducers to be widely separated achieving isolation and permits a larger number of filters per substrate.

Abstract: In a surface acoustic wave element comprising a semiconductor substrate, a piezoelectric layer formed thereon and at least one interdigital electrode disposed on the surface thereof, a semiconductor region having a conductivity type different from that of the semiconductor substrate is disposed on the outer side of the interdigital electrode just below the piezoelectric layer.

Abstract: A surface elastic wave filter has a pair of electrodes on a surface of a piezoelectric body, and at least one of the electrodes is constructed as electrode fingers in the form of comb teeth which are progressively spread away from each other along a direction normal to the direction in which a surface elastic wave is propagated on the surface of the piezoelectric body. A grating or dot structure as a scattering reflector for scattering and reflecting a portion of the surface elastic wave is disposed in a desired position between the electrodes. Alternatively, some of electrode fingers of a surface elastic wave filter are dropped or removed, or divided voltages are applied to electrode fingers, or a scattering reflector is added to a filter with some of its electrode fingers removed or with divided voltages applied to electrode fingers. With such an arrangement, a filter having good selectivity and desired frequency characteristics can be achieved.

Abstract: A surface acoustic wave resonator comprising at least two interdigital electro-acoustic transducers found between two sets of reflective gratings on a crystalline substrate. The period of the electrodes of the transducers is selected to be less than the period of the reflective gratings.

Abstract: A touch control system for a cathode ray tube, or other touch-controlled device capable of recognizing touch positions along a predetermined coordinate axis on a three-dimensionally curved touch surface, includes a substrate comprising a segment of a three-dimensionally curved surface having a touch surface capable of propagating surface acoustic waves. An input surface wave transducer serves to launch a collimated beam of surface acoustic wave energy on the touch surface. If undisturbed, the beam would travel along a path that corresponds to a great circle on the curved surface. An output surface wave transducer develops an electrical output signal upon receipt of surface acoustic wave energy derived from the beam. A reflective array is provided which establishes travel of the beam of energy along a desired path on the touch surface having a contour intermediate a great circle and a parallel.

Abstract: A cantilever mount for a substrate lamina of a surface wave device wherein the substrate lamina 42 of the component is attached only at its one end 45 and is a wedge-shaped structure. The tapered end 46 of the substrate lamina 42 which is remote from the atachment location is mounted above the surface 41 of the base plate 41 which causes minimization of disturbing influences.