Abstract: A convolver has a piezoelectric film layer, an insulator layer and a semi-conductor layer. A surface resistance measurement part permits measurement of a surface resistance related to the surface resistance seen by a gate electrode of the convolver. The surface resistance part is changeable by a bias voltage applied to the convolver. The amplitude of the bias voltage is controlled to set the surface resistance at a value which produces a desired convolution efficiency of the convolver. The convolver is adaptable to be fabricated as an integrated circuit with a simple structure. A transmitter/receiver system is disclosed in which a transmitted SSC signal is modulated by a pseudo-noise (PN) signal, as well as by a normal modulation. In the receiver, the PN component of the signal is removed using a convolver according to the present invention, to correlate the received signal before detection thereof.

Abstract: In an SAW convolver device constructed by sealing an SAW convolver element having a piezoelectric film/insulator/semiconductor structure by means of a cover of a package, according to the present invention, an insulating base plate is disposed on a part of a metallic base plate of the package, on which insulating base plate there is disposed a resistor or a coil, and the gate electrode of the convolver is grounded in a DC-like manner through the resistor or coil.Owing to the construction described above, it is possible to prevent that a voltage due to electrostatic charge, an accidental voltage due to erroneous handling, etc. are applied to the gate electrode of a zero bias type SAW convolver. As the result, it is possible to stabilize characteristics of the zero bias type SAW convolver for a long period of time and to improve the reliability thereof.

Abstract: A surface acoustic wave filter device includes a plurality of surface acoustic wave convolvers each having an output electrode between two input transducers, one of the input transducers of each convolver receiving a reference signal through a respective matching circuit. The other input transducer of one of the convolvers receives an input signal through a matching circuit, and the other input transducer of the rest of the convolvers receives through a respective input matching circuit and low pass filter from a respective mixing circuit a mixture of the reference signal and a respective output signal received from the output of a respective output matching circuit having an input coupled to the output electrode of a respective convolver. The remaining convolver has an output electrode coupled to a further output matching circuit. In one embodiment, a low pass filter receives from a mixing circuit a mixture of the reference signal and the output from the further output matching circuit.

Abstract: A control apparatus for a surface acoustic wave convolver element having a gate electrode, a grounded electrode and a piezoelectric layer therebetween. A bias voltage variable within a predetermined range is applied to the gate electrode so as to cause the convolver element to operate at the optimum convolution efficiency. A first mode signal is output when the variable bias voltage is in the proximity of either end of the predetermined range, and a second mode signal is output when the variable bias voltage is in a range defined by excluding the first range from the predetermined range. The variable bias voltage is applied to the convolver element when the second mode signal is output. When the first mode signal is output, the characteristics of the convolver element are controlled at an increased rate relative to a control rate when said variable bias voltage is used.

Abstract: An SAW convolver having a piezoelectric film / insulating layer / low impurity concentration Si epitaxial layer / high impurity concentration Si epitaxial layer structure is disclosed, in which the low impurity concentration Si epitaxial layer is replaced by a GaAs epitaxial layer. In this way, it is possible to improve concentration characteristics with respect to those obtained by the prior art structure described above and it is unnecessary to control the thickness of the epitaxial layer so strictly as for the prior art structure.

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: A correlation processing device using a surface acoustic wave convolver, is disclosed, in which there are disposed gate sections in the in- and output stages of the convolver and these gates are controlled synchronously to reduce the self convolution in the convolver.

Abstract: A surface acoustic wave device according to the present invention can be molded surely with resin, leaving a free space over exciting portions and a propagating portion by disposing a recess portion formed over the exciting portions and the propagating portion on a piezoelectric substrate without using any metallic package.

Abstract: In a SAW convolver having a multi-layer structure consisting of a piezoelectric layer, insulation layer and semiconductor layer and having at least one combshaped electrode fed with an input signal and a gate electrode for exerting a convolution output, an interface in the form of a jaggedness is formed between the insulation layer and the semiconductor layer to improve the convolution efficiency.

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 SAW convolver is disclosed, in which an auxiliary electrode is disposed between the gate electrode and each of two input electrodes and self convolution is reduced by applying to the auxiliary electrodes such a bias voltage that the portion of the semiconductor layer below each auxiliary electrode is inverted.

Abstract: A surface-acoustic-wave convolver includes a refraction means provided between two input electrodes to refract surface acoustic waves travelling from the respective input electrodes so as to suppress self-convolutions.

Abstract: An optimum bias circuit for a convolver according to this invention searches automatically a bias voltage, which makes the convolution efficiency of a surface acoustic wave convolver highest and applies it to the gate electrode of the convolver.

Abstract: A monolithic SAW convolver comprises a piezoelectric film, an insulator, a semiconductive epitaxial film and a high-concentrated semiconductive substrate. The semiconductive epitaxial film has a thickness in a predetermined range to improve the efficiency and the temperature property of the convolver.

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 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 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: A surface acoustic wave device includes a plurality of surface acoustic wave elements provided on a piezoelectric substrate. The device further includes a metal electrode provided on the piezoelectric substrate between and around the respective elements, and a bias voltage is supplied to the metal electrode to cause local attenuation.