Abstract: An acoustic wave filter comprising a piezoelectric substrate body upon which at least two digital structures are formed and which comprise input and output transducers and at least one further digital structure and wherein the filter digital structure has a center frequency of f.sub.2 and wherein the pass band of said two digital structures is at least twice as broad banded as said further digital structure and where the center frequencies f.sub.1 and f.sub.2 of the two digital structures are shifted relative to each other and relative to the center frequency f.sub.2 of the further digital structure.

Abstract: A surface acoustic wave device includes a semiconductor substrate, a piezoelectric film disposed on the semiconductor substrate, at least one pair of comb-shaped electrodes constituting an input transducer, and an output transducer a plurality of surface acoustic wave filters having different bands, which include a plurality of metal electrodes, so disposed that each of them is located between the input and output comb-shaped electrodes of each of the surface acoustic wave filters, a bias voltage applying arrangement for applying bias voltages to each of the metal electrodes; and a bias voltage regulating arrangement for regulating the bias voltages.

Abstract: A surface acoustic wave (SAW) device comprises a piezo-electric surface acoustic substrate, and plural sets of input/output interdigital electrodes disposed on the substrate. A phase shifter is provided between a sending electrode and a reflecting electrode included in the input or output interdigital electrodes for producing an electrical phase difference to implement a unidirectional electrode. The sending electrode and the reflecting electrode are mutually connected through the phase shifter including two pure reactance elements serially connected between the sending and the reflecting electrodes and a pure reactance element connected to the junction between the two serially connected reactance elements so as to form a T-circuit. When the two serially connected pure reactance elements are selected equal to each other, the operating frequency band is broadened. The phase shifter includes no ohmic resistance and thus is lossless.

Abstract: An acoustic surface wave resonator element has first and second interdigital electrodes consisting of pairs of opposed interleaving comb-shaped electrodes formed on one major surface of a piezoelectric substrate and arrayed along an acoustic wave propagation direction on the piezoelectric substrate, and acoustic surface wave reflectors sandwiching the first and second interdigital electrodes along the acoustic surface wave propagation direction. A base has the resonator element mounted thereon. First and second lead terminals are formed on the base and are electrically connected to the pair comb-shaped electrodes constituting the first interdigital electrode. A third lead terminal is electrically connected to one of the pair comb-shaped electrodes constituting the second interdigital electrode. The distance between the first and third lead terminals is substantially equal to that between the second and third lead terminals.

Abstract: A monolithic surface acoustic wave convolver has a structure of piezoelectric layer/insulative layer/p(n)-type semiconductive layer/n(p)-type semiconductive layer/n.sup.+ (p.sup.+)-type semiconductive substrate in which the p(n)-type semiconductive layer has a uniform thickness, and its acceptor (donor) concentration and thickness are selected to allow a depletion layer to expand throughout it under zero bias. The p(n)-type semiconductive layer and n(p)-type semiconductive layer are made by epitaxially growing the n(p)-type semiconductive layer on the n.sup.+ (p.sup.+)-type semiconductive substrate and subsequently change the conductivity of the surface portion of the epitaxial layer by impurity diffusion or ion implantation.

Abstract: Digital structures of a surface wave filter are manufactured in a photolithographic method with a lift-off or with an etching technique. The surface wave filter comprises at least one resonator structure, this resonator structure having auxiliary coatings of the substrate surface allocated to it. These auxiliary coatings are continuations of existing, neighboring pads which compensate during an exposure step associated with manufacture of the digital structures.

Abstract: A surface wave filter is provided with digital structures formed of strip-shaped coatings which are photolithographically produced. The digital structures have groups allocated to them which are also formed of strip-shaped coatings and which follow a respective digital structure. By use of such groups, which do not produce interfering reflections, a level exposure during formation of the digital structures is achieved.

Abstract: A surface wave filter (1, 11, 21, 31, 41) having a shielding structure (13, 23, 33, 43, 53) arranged between the inter-digital, asymmetrically operating structures (2, 3), which encompasses two such sub-structures (14, 24, 34, 44, 44a) and/or (15, 25, 35, 45, 35a), which are individually connected with the finger structures of the adjacent transducer structure (2 and/or 3) that are at reference ground potential.

Abstract: In a surface acoustic wave device including launching and receiving transducers (2, 3) and a reflective multistrip coupler (4), the inner boundaries of the input and output electrode arrays (5, 6) of the reflective coupler (4) are defined both electrically and acoustically by an electrically discontinuous strip (23) formed for example by isolated islands of metalization (24) in conjunction with corresponding adjacent portions of interconnecting conductors (16). This enables the effective apertures of the input and output arrays (5, 6) to be better matched to the transducers (2, 3). The arrangement can reduce the insertion loss in low-loss SAW devices (i.e. in which both ends of the transducers (2, 3) are coupled via corresponding reflective couplers (4)) and also in single symmetrical guided mode SAW devices in which the strip 23 can provide an effective inner guiding bus bar whose surface mass loading corresponds to that of the outer bus bars (9, 10).

Abstract: A SAW device using a first reflector (13) and a second reflector (14) is arranged to provide compensation for temperature effects. The temperature effects are due to the anisotropic characteristics of piezoelectric material commonly used as the substrate and wave medium for the acoustic waves in the SAW devices. These materials typically exhibit a temperature dependent, preferential direction of transmission which if not compensated results in a temperature dependent signal attenuation. An additional technique using a non-reflective portion 22 offsets non-uniformity which occurs in the amplitude distribution of the reflected acoustic wave. Each reflector (13 and 14) may include its respective non-reflective portion (A.sub.1 and A.sub.2).

Abstract: In a surface acoustic wave device which includes a relfective multistrip coupler (4, 4'), direct electrical breakthrough resulting from the adjacent location of the input and output transducers (2, 3) is reduced by including at least one forward multistrip coupler (24,25) in each path coupling the transducers (2,3) via the reflective couplers (4,4') so as to space the transducers (2,3) from one another. In a so-called low-loss device in which both ends of the transducers (2,3) are reflectively coupled, the arrangement enables the input/output track separation (23) of the reflective couplers to be reduced thereby significantly reducing the insertion loss of the device.

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 acoustic transducer is arranged as a ladder having uprights and rungs consisting of contact pads and interdigital fingers respectively. The transducer has inter-rung spaces 17 occupied by arrays of reflector strips. Each reflector strip is offset by .lambda./8 from a respective position distant 1/2n.lambda. from a transducer finger center, .lambda. being the transducer finger center and n as integer. The .lambda./8 offset reflector strips provide constructive interference between transducer output waves travelling in one direction and destructive interference in the opposite direction. This provides a transducer with undirectional properties which can be manufactured in one metal deposition process. Unwanted reflections at fingers may be reduced by additional blooming reflector banks or by repositioning reflector strips to provide both unidirectional and blooming properties.

Abstract: Compensation for the effects of environmentally caused changes and aging on piezoelectric acoustic wave devices is electrically provided by the application of a signal, such as a DC bias voltage, to the finger elements of an interdigital transducer formed on the surface of the acoustic wave device. This produces very large field concentrations at the finger edges which act to magnify the electric field and accordingly the electroacoustic effect which alters the acoustic velocity of surface acoustic waves, shallow bulk acoustic waves and reflected bulk acoustic waves propagating in a piezoelectric substrate between input and output interdigital transducers.

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 surface acoustic wave (SAW) meander type delay line (FIG. 8) is provided by a plurality of multistrip reflecting track changers (82, 84, 86, 88, 89) on a piezoelectric substrate (80) for folding back a SAW propagation path (106, 108) in serpentine manner. The meander delay line is tapped by simple RF tap means comprising single lossless coupling strips (110, 112) in the track changers removing only that portion of the SAW signal actually tapped out and converted to RF, and directly coupling out such signal portion over the entire bandwidth of the track changer. The single strips are on the center line between the arms of respective U-shaped multistrip couplers (102, 104) of the track changers. The structure enables high impedance direct RF multitap bus connection facilitating RF bus summation of many taps without a plural switching network.

Abstract: An electronic device, such as a Surface Wave, Bulk Wave or pyroelectric device, exploiting the polar nature of an active material in which the active material is lithium tetraborate or a closely related compound for example one which is slightly deficient in Lithium or Boron e.g. (Li.sub.2.-+..delta.1)B.sub.4 O.sub.7 or Li.sub.2 (B.sub.4.-+..delta.2)O.sub.7 where .delta..sub.1 and .delta..sub.2 are small numbers.

Abstract: An acoustic surface wave device is configured as a bandstop filter. The device has groups of sinusoidal corrugations cut into the top surface of a piezoelectric substrate between the input and output sets of interdigital transducers. The groups of corrugations selectively scatter certain surface acoustic wave spectral components traveling between the input and output transducers. The scattered components are converted to bulk vibration and do not impinge upon the output transducer; other components travel from input to output transducer relatively undiminished. Thus, a band of scattered surface acoustic spectral components is filtered from the input spectrum.

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 surface acoustic wave device comprises a transducer 1 consisting of two electrodes 2 and 3 deposited on the surface of a substrate 4. Transducer 1 is a slanted chirped transducer with short fingers 5 and 6 to focus any acoustic wave generated in the transducer to a position along a line 8 spaced from transducer dependent on the frequency of the signal.

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; at least one transducer element arranged on the surface for converting between electrical energy and surface acoustic wave energy which propagates along the path of travel; and a circuit, connected to the transducer element(s), for supplying interrogating signals to the transducer element(s) and for receiving reply signals therefrom. In order to minimize insertion losses in the substrate, acoustic wave reflectors are provided to reflect the surface acoustic waves back towards the transducer element(s).

Abstract: In a surface acoustic wave dispersive delay line of the type comprising a substrate made of piezoelectric material along which surface acoustic wave propagates, an input transducer formed on the substrate for producing the surface acoustic wave in response to an input electric signal, a first reflector including a plurality of reflection gatings formed at different spacings on the substrate for reflecting the surface acoustic wave from the input transducer, a second reflector including a plurality of reflection gratings formed at different spacings on the substrate for reflecting the surface acoustic wave reflected by the first reflector, an output transducer for converting the surface acoustic wave reflected by the second reflector into an electric signal, there is provided a device for eliminating concentration of the surface acoustic wave formed by the first and second reflectors.

Abstract: A surface acoustic wave resonator filter comprises reflector structures whose metallization strips are repeatedly interrupted in length, whereby the arrangement of the interruptions for the individual strips corresponds to a randon distribution.

Abstract: A surface acoustic wave device in a piezoelectric medium includes input and output transducers for launching and detecting a surface acoustic wave along the piezoelectric medium. The device is arranged in a ring loop to process the bidirectional acoustic wave launched from the input transducer. Multistrip couplers in the ring loop between the input and output transducers are used to achieve low loss characteristics. A phase shift introduced by the multistrip couplers between portions of the surface acoustic wave is used to cancel triple-transit reflections.

Abstract: Dynamic variation of the functional properties of a surface acoustic wave (SAW) device is achieved by using photoconductive material on a wave propagating substrate and illuminating the material with changing light patterns. Photoconductive materials, such as lead sulfide or cadmium sulfide, are used that are essentially dielectrics and have substantially no effect on SAW propagation when not illuminated, but under suitable levels of illumination become resistive and interact with the electric fields of the waves to dissipate energy as heat. Scanning control of the areas of illumination may be used to attenuate sidelobes and scattering in a wideband system, while intensity variations may be used to amplitude modulate the waves.

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: An elastic surface wave element which has a grille-shaped electrode formed on a piezoelectric substrate is improved by having the grille-shaped electrode portion thereof covered with an insulating film made of tantalum pentoxide or silicon nitride. The insulating film functions to minimize the degradation of properties suffered by the conventional elastic surface wave element and preclude substantially completely the phenomenon of short-circuit between the electrode bars of the grille-shaped electrode.

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 device is formed by cutting a piezoelectric wafer having a number of input and output electrodes on one surface thereof such that at least one end of the device has a bevel adjacent the upper surface. The bevel suppresses the reflection of surface waves. The bevel may be formed by a rotating cutter having a central disc and opposite frustoconical cutters.

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: A surface acoustic wave device comprises a piezoelectric substrate, a pair of transducers provided on the piezoelectric substrate, a center electrode provided in the center between the both transducers, first shield electrode provided between one of the transducers and the center electrode, and second shield electrode provided between the other transducer and the center electrode, with placement substantially represented by: ##EQU1## where l.sub.1 is the width of the individual shield electrodes, l.sub.2 is the distance from the individual shield electrodes to the center electrode, .lambda..sub.0 is the wavelength of a surface acoustic wave at the center frequency, and n.sub.1 and n.sub.2 are whole numbers.

Abstract: A surface acoustic wave device is provided for sensing the presence of chemical agents by chemo-electronic means. The device includes a quartz substrate and means deposited on the substrate for propagating and receiving surface acoustic waves along the surface of the substrate. Regions are provided on the substrate containing etched tunnels, the walls of the etched tunnel being coated within with a chemical substance sensitive to the chemical agent to be detected. When surface acoustic waves are caused to pass over these regions, the reaction of the chemical agent to be detected with the chemical substance causes a change in the acoustic wave velocity.

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: A crystal sound producer has a piezoelectric crystal plate diaphragm which produces sound waves when applied with a voltage thereacross. A waveform transform plate has slits or linear grooves through which the sound waves from the diaphragm are radiated in semicylindrical waves. As these semicylindrical waves propagate in the air, they superpose one another to form generally plane waves which sound natural to the human hearing. The crystal sound producer can be used in portable articles such as badges.

Abstract: An apparatus for and a method of non-destructively determining properties of a SAW substrate, in which first and second interdigital transducers are formed in a spaced relationship on a single common piezoelectric substrate, a blocking member is formed between said transducers on the substrate for preventing an acoustic wave signal from being transferred between said transducers via the common substrate, spacers are provided for supporting a to-be-determined SAW substrate above the common substrate with a spacing left between the SAW substrate and the fingers of transducers, the SAW substrate to be placed on the spacers is positioned with respect to the transducers so that co-directional mode coupling will, in operation, effectively take place between the SAW substrate and the transducers, adherence between the SAW substrate and the spacers is secured to enhance the co-directional mode coupling, an electric signal is applied to the first transducer for transferring, due to the co-directional mode coupling, an

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 low insertion loss surface acoustic wave filter in which withdrawal weighted launching and output transducers 20, 40 are acoustically coupled by two high efficiency reflective multistrip couplers 6, 6'. To reduce the insertion loss, the inner bus bars 21, 41 are reduced in width so as to reduce the dead space 12 in the coupler. This makes it impossible to form a reliable wire bond connection to the inner bus bars which are therefore connected via a conducting path across the propagation path at the ends of the transducers. Further reduction in the widths of the inner bus bars and consequent increase in resistive losses are offset by several connections to a further bus 23, 43 via groups 25 of dummy electrodes arranged at null points in the weighting pattern.

Abstract: An acoustic surface wave device employing an input and an output transducer (2, 3) and a multistrip coupler (5). The input and output tracks (11, 12) are separated to avoid unwanted acoustic energy transfer. As a result, a significant loss can occur from the launching of acoustic energy from the interconnecting conductors of the msc. The interconnecting conductors (22, 32') of the multistrip coupler are spaced differently from the, or the equivalent, wide-aperture beam spacing of conductors (16, 17; 36', 37') in either track of the msc so as not to launch any acoustic surface or bulk waves within the frequency passband. In a forward transfer msc different spacings can alternate, and in a reflective msc the spacing can take the mean of the respective equivalent wide-aperture-beam spacings of the coupler electrodes.

Abstract: A surface acoustic wave device comprising a first set of interdigital electrodes that generate surface acoustic waves, a second set of interdigital electrodes that receive and convert surface acoustic waves into electrical signals, and an intermediate electromechanical coupling element provided therebetween. The coupling element comprises a plurality of parallel strips formed on the surface of a piezoelectric substrate such as to receive and change the direction of propagation of the surface acoustic waves, each of these parallel strips being spaced at a predetermined distance from each other and connected therebetween in a given manner to obtain suitable stopband characteristics.

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: In an electronic component having reflecting structures on a substrate body and functioning with reflected acoustic waves traveling thereon, at least one longitudinal lateral edge of the substrate body is aligned at an angle .delta. deviation from a direction parallel relative to an acoustic wave emitted by an input transducer. The dimension of the angle .delta. depends on the arrangement of an output transducer. This construction minimizes the appearance of spurious signals.

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: An acoustic surface wave device having a pair of attenuating transducers positioned between the input transducer and the output transducer. Each attenuating transducer has two sets of interleaved electrodes which are connected together by a thin film resistor. The attenuating transducers are spaced apart so that their reflected signals are 180.degree. out of phase, and thus tend to cancel each other. The attenuating transducer arrangement increases the insertion loss of the device and consequently suppresses triple transit signals in the device.

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: 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: An elastic surface wave device that has good frequency characteristics and no unwanted signals, and is highly suited for mass production, comprising a piezoelectric substrate, at least one pair of transmitting and receiving electrodes on the surface of said substrate, and elastic surface wave absorbers formed by curing a composition, the main component of which is a resin curable by ultraviolet radiation, disposed on at least part of the zone on said piezoelectric substrate that propagates unwanted elastic surface waves.

Abstract: An echo-compensating surface acoustic wave interdigital transducer in which the entire length of the end finger of the transducer at each end is connected directly or indirectly to at least one of the bus bars, the end finger extends only partially across the aperture of the transducer, and the space which is colinear with the end finger across the remaining portion of the aperture is not occupied by any surface-acoustic-wave-reflective structure. The end finger is substantially a quarter of an acoustic wavelength out of phase with the nearest interior finger with respect to an incident wave at the operating frequency of the transducer, so that the acoustic reflections of the end finger and the nearest interior finger are in phase-opposition to each other.

Abstract: Electronic components which operate with acoustic waves are provided as interdigital structures and/or reflective arrangements. An oscillating displacement of the significant plurality of sub-groups is provided parallel to the principal axis of propagation in a weighted region, each sub-group having at least two successive real finger edges and, under certain conditions, virtual finger edges. A plurality of principal groups is provided and in a number which is equal to or greater than the time/bandwidth product. Each principal group has at least two real sub-groups and the respective degree of displacement of the finger edges of the individual sub-group corresponds to an additional oscillating phase modulation for the sequence of the sub-groups of the weighted region with the oscillation being such that the number of oscillations within a principal group is a whole number which is not greater than half the number of the sub-groups therein.

Abstract: A dispersive acoustic delay line using reflection on slanted gratings is provided. This device comprises slanting input and output transducers each formed of pair electrode fingers. The interval of the electrodes of different polarity varying from nv/2f.sub.min to nv/2f.sub.max, where v is the speed of the waves, f.sub.min and f.sub.max the endmost frequencies of the frequency band and n the number of the harmonic on which the transducers operate. The interval of the gratings varies from kv/f.sub.min to kv/f.sub.max, where k is the number of the operating harmonic of the network, with n.noteq.k.