Abstract: In a surface acoustic wave elastic convolver capable of showing sufficiently high convolution efficiency with a simple structure, the convolver comprises a piezo-electric substrate, plural input transducers formed on the substrate for respectively generating surface acoustic waves corresponding to input signals, an output transducer for obtaining a convolution signal of the input signals, from a surface acoustic wave generated by non-linear interaction, of the surface acoustic waves generated by those input transducers, and a dielectric film of a non-linear effect larger than that of the substrate, formed on the substrate in at least an area where the output transducer is formed.

Abstract: The invention provides a method of producing surface wave dispersive filters of RAC type, in which, in an RAC of known type, one of the input or output transducers is replaced by a transducer forming a surface wave filter and whose transfer function allows the errors of the initial transfer function of the RAC to be corrected.

Abstract: A differential phase shift keying convolver having a plurality of tracks includes at least one track where an opposite phase convolution output is produced. Each track includes two output gates spaced at the center for differential phase shift keying demodulation. Among these output gates, some gates selected in accordance with the phase relationship between convolution outputs are connected to provide sum and/or difference outputs of the convolution signals. The opposite phase convolution outputs can be produced by arranging at least one of the input transducers in a step-like configuration, by using multistrip couplers, or by providing a metal film in a selected position of the traveling path of surface acoustic waves for application of a control voltage.

Abstract: A surface acoustic wave (SAW) filter has a piezoelectric substrate and a conductive transducer formed over the substrate. The transducer has first and second bus bars arranged in parallel at a prescribed interval from each other, a plurality of pairs of first electrode fingers having the same lengths, and a plurality of pairs of second electrode fingers having the same lengths. The tips of the second electrode fingers are positioned opposite those of the first electrode fingers. The transducer also has first and second weighted electrode pairs positioned between two adjacent pairs of the first electrode fingers and two adjacent pairs of the second electrode fingers, respectively.

Abstract: A frequency characteristic of a surface acoustic wave filter having at least a first transducer and a second transducer is determined by a product of a frequency amplitude characteristic of the first transducer and that of the second transducer so that the electrodes of the both transducers are formed in such a way that third harmonics band in the frequency characteristic of the first transducer is shifted out that of the second transducer in order to prevent third harmonics.

Abstract: This invention relates to the structure of a band-pass or band-rejection filters by combining a plurality of one-port surface acoustic wave resonators whose interdigital electrode fingers are disposed on a piezoelectric substrate. The filter combining surface acoustic wave resonators of the present invention consists of a series circuit of the one-port surface acoustic wave resonators disposed on a piezoelectric substrate for transmitting elastic surface wave and a plurality of circuit elements containing capacitance elements, and one-port surface acoustic wave resonators disposed between the electrodes of the plurality of circuit elements and the common ground. This structure can accomplish a filter having a low loss, high power handling capability and high design freedom of rejection- and passing-band.

Abstract: In order to present an asymmetric frequency characteristic in an unidirectional acoustic surface wave device with a simple external phase shifter, a transducer formed on a substrate have three interaction areas (acoustic sources) defined by different three electrodes, first electrode being common, second electrode being connected to one end of the phase shifter, third electrode being connected to another end of the phase shifter, and distances between interaction areas being unequal to 2n (n:integer).

Abstract: A transducer for a filter arrangement with acoustic waves which includes a transducer 1 and 2 comprising groups (3, 4, 6 and 7) of alternating interdigitally spaced electrode fingers (10) in which the neighboring groups (3, 4 or, respectively, 4, 3 or, respectively, 6, 7) are arranged so that they are 80 degrees out of phase relative to each other at the fundamental frequency of the groups.

Abstract: A surface-wave resonator filter having at least two reflector structures and at least one interdigital transducer. At least a portion of one of the reflector structures has interruptions in the metallization strips thereof to define subsections of the metallization strip. Connecting metallizations are provided parallel to the wave propagation direction x between neighboring sub-sections of neighboring sub-divided metallization strips to electrically connect the neighboring sub-sections such that no two sub-sections of the same sub-divided metallization strip are electrically connected.

Abstract: A surface acoustic wave device includes a substrate which supports surface acoustic wave propagation having a predetermined surface acoustic wave velocity characteristic and a pair of interdigitated transducers coupled to said surface wave propagation surface. The pair of interdigitated transducers are spaced by a region of said surface wave propagation surface. To adjust the surface wave velocity characteristic of said surface wave device, a thin layer of a nonconducting elastic material, such as aluminum oxide or zinc sulfide is deposited onto a portion of the region disposed between the pair of interdigitated transducers, to change the surface wave velocity characteristic of the surface wave device.

Abstract: A hybrid programmable transversal filter (HPTF) is described that employs a LiNbO.sub.3 SAW delay line and two monolithic dual-gate GaAs FET arrays to control magnitude and sign of the 16 tap weights. The HPTF is completely programmable and is constrained only by the bandwidth (100 MHz centered at 250 MHz) and the number of taps. Theoretical calculations of tap weight control range and dynamic range are presented, compared with experiment and used to justify the hybrid LiNbO.sub.3 SAW - GaAs FET combination. Dynamic range of 85 dB and a continuously variable tap weight control range of 70 dB are demonstrated.

Abstract: A simple compact, high performance SAW multiplexer is provided by utilizing an input transducer in which hyperbolic tapered electrode fingers are provided. These hyperbolic electrode fingers provide a low frequency output acoustic wave at locations where the spacing between the fingers is relatively large, and a higher frequency signal at points where the spacing is relatively closer. A series of pickup taps which are preferably located on both sides of the input transducer which are also constructed with hyperbolically tapered fingers, but these pickup elements are separated into segments, and isolated by ground straps so that each pickup finger pad will be responsive only to a portion of the frequencies launched by the input transducer. The frequency of the pickup pads varies from a low frequency to a high frequency in alternate manner from one side of the multiplexer to the other.

Abstract: The surface acoustic wave device includes a plurality of output gate electrodes provided between two signal input transducers on a piezoelectric layer on a semiconductor substrate, so that each output gate electrode receives a bias voltage unique to it and supplies an output signal based on the unique bias voltage.

Abstract: A single mode waveguide dispersive surface acoustic wave (SAW) delay line is formed by aligning an elongated input transducer, which has a pattern of interdigital electrode fingers which launches a wideband SAW, with a beam compressor that feeds an input waveguide. The input SAW passes down the waveguide to a 3 dB coupler which extracts one-half of the power of the incoming SAW and feeds it in the direction opposite to the input wave. Both portions of the SAW are passed to dispersive reflective arrays along a folded path. A series of additional couplers and reflective dispersive arrays that form the folded path serve to further delay the SAW until it reaches a beam expander at the output end which feeds the SAW to an output transducer that is constructed in a manner similar or analogous to the input transducer.

Abstract: In a directional transducer for SAW filters on a piezoelectric substrate, the transducer is formed of a plurality of groups which are connected in half-groups to busbars for two phases. The half-groups are alternately distributed into two or more channels such that the finger electrodes of each phase form a more or less gap-free series as viewed over all channels. A common, meandering busbar for both phases is associated with each channel.

Abstract: A surface acoustic wave filter comprising; a first bidirectional ID transducer (5) of symmetrical form; a second ID transducer (1) acoustically coupled with the first transducer and comprising two parts (1A, 1B) each of which parts is in the form of one half of a respective bidirectional ID transducer (9 or 11) of symmetrical form, the two parts being positioned with respect to one another and the first transducer so that when respectively excited by corresponding signals of different phases they co-operate to produce a unidirectional acoustic signal propagating towards the first transducer from one side thereof; and a third transducer (3) acoustically coupled with the first transducer and comprising two parts (3A, 3B ), each of which parts is electrically connected in parallel with a respective one of the two parts of said second transducer, and each of which parts of the third transducer is effectively in the form of the mirror image about the center line (7) of the first transducer of the other half of the

Abstract: A dispersive transducer 100 which has non-equidistant distribution of the finger electrodes 6, 7, 16 and 17 according to band-width such that the finger electrodes 16 and 17 of the low frequency portion 11 of the transducer have a width c and spacing d1 (or d2) which are equal to the corresponding portions of the highest frequency part 13 of the transducer such that reflections are substantially reduced or eliminated.

Abstract: A notch filter which utilizes a quadrature coupler with the input signal on one of its four terminals, a first tuned surface acoustic wave device coupled to a second on of the terminals for receiving the input signal at 0.degree. phase shift, a second tuned surface acoustic wave device coupled to a third one of the terminals for receiving the input signal with a 90.degree. phase shift and the fourth terminal being utilized as the output signal terminal.

Abstract: A surface wave filter with an input transducer and an output transducer. The input and output transducers have finger weightings such that a finger-overlap profile of the input/output transducer repeats in multiple fashion in the output/input transducer.

Abstract: An interdigitated transducer (IDT) has parallel electrodes extending inwardly from one voltage rail and parallel electrodes extending inwardly from another voltage rail. The respective electrodes are interleaved to give a region of overlap or apodization within which the SAW is generated or received, the width of the apodized area varying along the length of the IDT. To prevent performance degradation in the event of an open circuit in a non-overlap region, the electrodes associated with a particular voltage rail are additionally linked by a thin conductor positioned near the boundaries between the apodized or overlap region and each of the non-overlap regions.

Abstract: A surface wave filter having an interdigital structure in which last active fingers of a first comb structure, which is to be connected to ground, extend as close as possible to a busbar of an opposite comb structure. Interference signals based on the discontinuity of the end of the interdigital structure are eliminated.

Abstract: A monolithic programmable signal processor with piezoelectric insulator FETs and an InP substrate. The piezoelectric insulator FETs are capable of being constructed on the same substrate with circuits associated with the signal processor and optical components.

Abstract: A surface-acoustic-wave filter is of a multi-transducer arrangement including a plurality of input interdigital transducers and a plurality of output interdigital transducers. These input and output transducers are alternately and parallelly disposed on a piezo-electric substrate so as to be spaced intercentral distances l.sub.1 through l.sub.n apart. When one of the intercentral distances is a reference distance l.sub.1, the respective intercentral distances l.sub.1 through l.sub.n satisfies the following relationships:l.sub.1 =m.sub.1 .multidot..lambda., l.sub.2 =l.sub.1+ m.sub.2 .multidot..lambda., l.sub.3 =l.sub.1 +m.sub.3 .multidot..lambda., . . . l.sub.n =l.sub.1 +m.sub.n .multidot..lambda.where m.sub.1 is an arbitrary positive real number, m.sub.2 through m.sub.n are respectively arbitrary integers (0, .+-.1, .+-.2, . . . ), and .lambda. is a wavelength of the surface-acoustic-wave.

Abstract: The invention of this disclosure comprises a system that simultaneously determines the frequency and direction of arrival of incoming signals. The apparatus of this invention comprises a layered half space dispersive delay line which is utilized as a beam forming element in a device that performs a two-dimensional Fourier transform on a function which is both time and space dependent.A pulse appears at the end of the delay line at a time which corresponds to the frequency of the incoming signal and the position of the pulse along the edge of the delay line is related to the direction of arrival of the incoming signals.

Abstract: A surface acoustic wave-convolver arrangement having transducers whose fingers are curved such that they correspond to a respective wave front of a wave issuing from the integration electrode.

Abstract: An IDT is arranged at the center of a piezoelectric substrate formed of Li.sub.2 B.sub.4 O.sub.7 single crystals. Grating reflectors are arranged on either side of the IDT. The IDT and the grating reflectors are formed of 6,000 .ANG. thick aluminum films. The IDT comprises a pair of comb-shaped transducers having a plurality of electrode fingers which are arranged parallel to each other at equal distances, so that the electrode fingers of the respective transducers are alternately arranged. The grating reflectors have a plurality of reflective arrays arranged parallel to each other at equal distances. The pitch (Pg) between the reflective arrays of the grating reflectors, and the pitch (Pt) between the electrode fingers of the IDT is set to be 98.8% of half the wavelength of a surface acoustic wave in the resonance mode. Distance d between the IDT and the grating reflector is half the wavelength of a surface acoustic wave in the resonance mode.

Abstract: A dispersive Surface Wave Acoustic (SAW) filter is provided by a dispersive reflective array, and input and output transducers that we aligned with respect to the array so that the angle of incidence of a SAW from the input transducer is approximately equal to the angle of reflection from the reflective array over the entire range of the dispersive array, wherein the transducers are constructed to provide a frequency response which is matched to the periodicity of the dispersive array. Such design may be accomplished by forming the transducers with hyperbolically curved electrode fingers. The transducers may consist of relatively narrower inner electrode fingers and relatively wider outer electrode fingers. The transducers may also be divided into a plurality of tracks with each of the tracks being subdivided into a plurality of subtransducer elements which are capacitively coupled in electrical series.

Abstract: A passive transponder for use in an interrogation/transponder system comprises a substrate having a substrate surface defining a path of travel for surface acoustic waves; a launch transducer element arranged on the surface for converting interrogating signals into surface acoustic waves which propagate along the path of travel; a plurality of tap transducer elements arranged on the surface at spaced intervals along the path of travel for converting surface acoustic waves into respective output signals; and a circuit, connected to the tap transducer elements, for combining the output signals of these transducer elements to form reply signals. In order to control the delay time from transducer element to transducer element, one or more "delay pads" are provided on the substrate surface between these transducer elements.

Abstract: A passive transponder for use in an interrogation/transponder system comprises a substrate having a substrate surface defining a path of travel for surface acoustic waves; a launch transducer element arranged on the surface for converting interrogating signals into surface acoustic waves which propagate along the path of travel; a plurality of tap transducer elements arranged on the surface at spaced intervals along the path of travel for converting surface acoustic waves into respective output signals; and a circuit, connected to the tap transducer elements, for combining the output signals of these transducer elements to form reply signals. In order to reduce the effect of spurious signals, the tap transducers are arranged both in series and in parallel with respect to the path of travel.

Abstract: An electronics component operating with reflected acoustic waves having a division of weighted reflector fingers into respective sequences of sub-pieces which have a weighting offset relative to one another. A continuation of the fingers extending beyond a principal path is provided by additional, weighted sub-pieces. The additional weighted sub-pieces are at least a fundamental repetition of the sequence of sub-pieces of the corresponding weighted finger of the principal path. The additional sub-pieces are provided in view of distortions which occur causing the waves to follow a path which laterally deviates from the principal path.

Abstract: A resonator, resonator filter having an output transducer of typical design and conductance response and an input transducer whose conductance response can be adjusted to offset adverse conductance response of said output transducer thereby providing a unique improved overall conductance response of the resonator, resonator filter.

Abstract: A surface acoustical wave (SAW) filter is provided by placing at least one pair resonator channels consisting of reflectors and input and output transducers on the surface of a suitable substrate, such as a piezo-electric crystal. One channel of the pair consists of an input transducer and an output transducer which are aligned in a path along which the SAW progresses. The two channels are identical except that the separation distance between the transducers and the reflectors, in one channel is slightly different than the corresponding distance in the other channel. This separation difference serves to broaden the passband for applications which require a broader passband than is obtainable with a single channel resonator filter. Differential detection of the SAW in one section with respect to the other channel is achieved by using a symetrically inverted output transducer, in one embodiment. In another embodiment an offset transducer is used to accomplish the differential sensing.

Abstract: A surface acoustic wave device disclosed herein has input and output electrodes (21, 22) one of which (21) comprises a first interdigital electrode (23) defining even components of a frequency response and a second interdigital electrode (24) defining odd components thereof, the second interdigital electrode (24) being disposed outside the envelope of the first interdigital electrode (23). A portion of the second interdigital electrode (24) is disposed within a non-overlapping region of the first interdigital electrode (23), that is a region outside the envelope of the first interdigital electrode (23) and especially a region environed with a straight line running through the top of the envelope in a direction parallel with the propagating direction of the surface waves.

Abstract: The frequency response of an intermediate frequency filter for an intercarrier sound television receiver is modified to provide a substantially constant gain response portion over a predetermined range of frequencies centered about the 45.75 MHz intermediate frequency picture carrier. Picture carrier phase modulation induced by the Nyquist slope of the conventional intermediate frequency response is thereby eliminated over the predetermined frequency range reducing audio "buzz" by decreasing the phase modulation transferred to the 4.5 MHz intercarrier sound signal by the intermediate frequency picture carrier. In a preferred embodiment, the modified intermediate frequency response is established by a surface acoustic wave filter.

Abstract: A surface acoustic wave filter comprising unidirectional interdigital input and output transducers at least one of which has imperfect unidirectivity and includes two interdigital electrodes arranged to provide a geometrical phase difference .phi..sub.M therebetween and interconnected through a phase shifter which provides an electrical phase difference .phi..sub.E therebetween, the sum of the phase differences .phi..sub.M and .phi..sub.E being unequal to .pi. radians to provide the imperfectness of unidirectivity. The selection range of conductance of an external load or radiation conductance of the unidirectional transducer necessary for suppressing the undesired triple transit echo level can thus be extended while keeping the insertion loss relatively low.

Abstract: An acoustic surface wave device is configured as a bandpass filter. The device employs two interdigital transducer pairs for input and output. Each transducer pair has a slant finger geometry. The fingers are electrodeposited into grooves etched into the substrate. The grooves are deeper at the high frequency side of the substrate. The grooves enhance the electromechanical coupling of high frequency components and thus provide a flatter amplitude response curve.

Abstract: An impedance element formed from a single-port, surface acoustic wave transucer which generates a conductance versus frequency response characteristic having first and second peaks separated by a valley at a predetermined frequency and which generates a susceptance versus frequency response characteristic having a substantially constant portion over a finite bandwidth on both sides of said predetermined frequency.

Abstract: An acoustic surface wave device is configured as a bandpass filter. The device has similar groups of sinusoidal corrugations cut into portions of both the top and bottom surfaces of an otherwise flat piezoelectric substrate. A pair of input interdigital transducers is located upon one end of the top flat surface of the substrate. A similar pair of output interdigital transducers is located on the bottom flat surface of the substrate at the end opposite the input interdigital transducers. When an input RF spectral signal is applied to the input interdigital transducers, the transducers convert the electrical signal spectrum to a surface acoustic wave spectrum. When the surface acoustic wave spectrum strikes the corrugations cut into the top surface of the substrate, the corrugations selectively scatter certain spectral components into bulk vibration.

Abstract: An improvement to the reflective multistrip coupler of the surface acoustic wave device described in EPA No. 0098661 for overcoming the k-determined bandwidth limitation wherein, instead of being uniform, the electrode spacing is varied correspondingly along the input and output arrays of the coupler with the result that different frequency bands will be reflected by different groups of electrodes. At least two reflective couplers (24, 25) with complementary spacing variations are included in the path coupling the input and output transducers (2, 3) so that all frequencies in the overall passband have substantially the same overall time delay. Contiguous bands of frequencies f.sub.1, f.sub.2, f.sub.3, f.sub.4 may be reflected by individual related groups 26, 27, 28, 29 of uniformly spaced electrodes forming either a monotonic or a permutated sequence, or the spacing can be varied continuously and monotonically.

Abstract: A surface acoustic wave (SAW) filter is disclosed which exhibits both low insertion loss and small ripple in the passband, requirements which were considered mutually exclusive in the prior art. In accordance with the present invention, apodized group-type recessed electrodes are utilized to form the transducers. The grouping of the electrodes functions to reduce reflection between electrodes and apodization of the electrodes functions to increase the sideband rejection. However, merely combining these techniques is inadequate since the apodization process produces additional ripple between adjacent electrodes, thus increasing the passband ripple. By recessing the apodized groups of electrodes, this reflection is minimized and a SAW filter formed in accordance with the present invention is thus capable of providing both low insertion loss and small ripple with high sideband rejection.

Abstract: Disclosed is a unidirectional interdigitated surface wave transducer having at least three discrete arrays of conductive elements, each array comprising, in a comb-like structure, a plurality of electrodes electrically interconnected in parallel and having a periodicity corresponding to one acoustic wavelength of the resonance frequency of the transducer. The discrete arrays of electrodes are deposited upon a piezoelectric substrate in an interleaved pattern to define an interdigitated transducer. Respective electrodes of a given array are substantially equidistantly spaced apart from electrodes of the other arrays and are electrically insulated therefrom. The arrays of electrodes are positioned upon the substrate such that there are at least three electrodes per acoustic wavelength at the resonance frequency.

Abstract: The invention relates to a filter for demodulating signals modulated in frequency in binary manner by the switching of two frequencies F.sub.a and F.sub.b.On a piezoelectric crystal, is produced two surface wave filtering units, each comprising a transmitting transducer and a receiving transducer with interdigitated electrodes. The number of electrodes of the receiving transducer of the first unit is substantially equal to twice (2F.sub.a -F.sub.b)/2(F.sub.b -F.sub.a ) with a spacing of v/(2F.sub.a -F.sub.b), in which v is the propagation rate. In the case of the second unit, this number is approximately twice (2F.sub.b -F.sub.a)/2(F.sub.b -F.sub.a) with a spacing of v/(2F.sub.b -F.sub.a). The receiving transducers are preferably subdivided in each case into two juxtaposed transducers, whereof one is set back with respect to the other by a distance of approximately v/4F.sub.a for the first unit and v/4F.sub.b for the second.

Abstract: A high frequency narrow-band pass multi-mode filter in constructed in such manner that SAW of SSBW resonators are closely disposed to each other on a single piezo-electric substrate to generate different vibration modes of different resonance frequencies, conditions that the resonators are acoustically coupled to each other to cause these vibration modes, are experimentally found, and the above conditions are satisfied by the filter.In order to reduce the ohmic loss of a very narrow common bus bar, the number of strip pairs of electrode in both interdigital transducers (hereinafter referred to as IDT) is minimized and instead reflectors are provided on the both sides of said TDTs to compensate for the reduction of its Q value. A part of the bus bar for the IDT electrodes is formed integral with some or all of gratings of the reflectors, whereby the connecting positions of the grating electrodes with respect to lead terminals can be positioned with a high freedom.

Abstract: Acoustic surface wave device comprising a lower electrode disposed on an elastic substrate and an upper electrode consisting of two comb-shaped electrodes disposed apart from each other, opposite to said lower electrode through a piezoelectric film covering said lower electrode, at least one of said lower and upper electrodes being constructed as an apodized electrode.

Abstract: A component has a reflector structure with fingers which are weighted by division into sub-fingers in a longitudinal direction. These sub-fingers are offset relative to one another in a wave propagation direction by a dimension of the weighting.

Abstract: A surface acoustic wave (SAW) filter features a ground lead in a transducer that has an aperiodic meander structure. This arrangement permits the self-capacitance and inherent resistance of the transducer to be utilized in forming the RC networks of a phase shifter associated with the transponder.

Abstract: An acoustic surface wave device having an acoustic energy absorber of acoustic surface wave absorbing material positioned between the input transducer and the output transducer. The acoustic energy absorber increases the insertion loss of the device and consequently suppresses triple transit signals in the device.

Abstract: An acoustic wave filter device with low loss and low passband ripple characteristics. The filter comprises three bidirectional electroacoustical transducers disposed along a common axis on the surface of a substrate of piezoelectric material. The two outer transducers of the three function as input transducers and the center transducer functions as an output transducer. One of the input transducers is of the antisymmetric type and has a transfer characteristic that differs in phase angle by ninety degrees with respect to the other input transducer, which is of the symmetric type. This ninety-degree difference applies at all frequencies, so that any energy reflected from the output transducer and again reflected by an input transducer will be subject to a phase shift of 180 degrees in the case of energy reflected from the antisymmetric input transducer, and no phase shift in the case of the symmetric input transducer.

Abstract: An acoustic surface wave device comprising a piezoelectric substrate provided with an input transducer (2), an output transducer (4) and a compact reflective multistrip coupler (6) in which the strips of each pair of comparatively widely spaced strips (7 or 8) in one array of mutually parallel strips are connected to respective strips of a pair of comparatively narrowly spaced strips (8 or 7) in the other array. The wide and narrow spacings alternate along each array. The improvement provides further electrodes 9 located in the relatively wide spaces in each array and electrically interconnected so as to effect a transfer of signal currents along each array and from one array to the other. The device improves efficiency, reduces insertion loss and improves the shape of the pass band.

Abstract: Acoustic surface wave devices of a novel class characterized by the provision of coupling means comprising at least several spaced filamentary electrical conductors extending over a first region and a second region for causing acoustic surface waves propagated across the coupling means in the first region to interact with acoustic surface waves propagated across the coupling means in the second region, by means of alternating electric signals induced on the filamentary electric conductors. The regions to be coupled are preferably formed on piezoelectric material, but modified forms of the coupling means can be made operable with other materials and suitable biassing fields.