Encoded transmission and reception which reduces time side lobe are realized while suppressing increase of circuit scale. Transmission signals corresponding to a composite modulation code sequence composed from two or more modulation code sequences are outputted as transmission signals. A reception means demodulates reception signals stepwise by two or more demodulators. The demodulator can be thereby divided into two or more stages, and therefore with a circuit scale corresponding to the sum of the operation circuit numbers of two or more demodulators, time side lobe reduction effect can be obtained at a level equivalent to that obtainable with a circuit scale corresponding to the product of the operation circuit numbers of two or more demodulators.

Ultrasonic diagnostic apparatus

A surface-acoustic-wave device comprises a piezoelectric substrate and first and second comb-shaped electrodes each having a bus-bar portion parallel to a propagation direction of a surface acoustic wave in the substrate. Respective electrode fingers are periodically formed on the piezoelectric substrate and extend in directions perpendicular to the propagation direction, wherein the electrode fingers of the first comb-shaped electrode and the electrode fingers of the second comb-shaped electrode are separated away from the bus-bar portion of the opposing comb-shaped electrode. The respective electrode fingers being periodically arrayed in the propagation direction of the surface-acoustic-wave, and the electrode fingers of each comb-shaped electrode are inclined at root portions thereof outwardly right and left from the bus-bar portion of the corresponding comb-shaped electrode so that the inclined portions of the electrode fingers face a direction of a leaking surface-acoustic-wave perpendicularly.

Surface Acoustic Wave Device

PROBLEM TO BE SOLVED: To provide a cascaded multiplex mode surface acoustic wave filter with small insertion loss in a passband and with a wide passband SOLUTION: Three interdigital electrodes (IDT) 202, 203 and 204 or 208, 209 and 210 are closely provided along the propagation direction of exciting surface acoustic waves on a piezoelectric substrate, and reflectors 205 and 206 or 211 and 212 are provided on both sides of the series of IDTs, thereby providing 3IDT cascaded duplex mode filters 201 and 207 utilizing at least a primary or third-order oscillation mode generated by acoustic coupling among the three IDTs A dummy electrode finger 224 is provided between electrode fingers 202a, 202b, 208a and 208b of the IDTs and a bus bar to suppress slant radiation of the surface acoustic waves COPYRIGHT: (C)2005,JPO&NCIPI

Surface acoustic wave filter

A surface acoustic wave resonator so constructed that multiple reflection of a surface acoustic wave in interdigital electrodes is suppressed, no sub-resonance caused by the multiple reflection occurs in the inductive areas, and the resonator effects a reliable excitation.

Surface-acoustic-wave resonator

The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle. Problems of crosstalk and wave reflection may produce spurious code pulses in systems of this type. The invention provides techniques for eliminating or reducing these unwanted pulses.

Patterned transducer apparatus for correcting spurious signals in said devices

PURPOSE:To suppress triple transit echo, by zeroing the reflection based on the discontinity of auido impedance, through the arrangement of fingers of an inter digital transducer with a given distance.

Elastic surface wave transducer

PURPOSE:To eliminate the need of an impedance converter circuit for circuit connection, by suppressing a triple transit echo by fixing a relation between the width and interval of electrode fingers in relation to the wavelength of an elastic surface wave.

Elastic surface wave element

PURPOSE:To compensate characteristics of group delay time deviation by means of the video IF circuit employing an elastic surface wave filter

Color television picture receiver

PURPOSE:To easily realize the characteristics by means of a surface acoustic wave filter, by picking up a video signal and an audio signal component through separation and a video carrier component in combination with the audio signal component. CONSTITUTION:A TV signal received with an antenna 1 is converted into a video intermediate frequency signal and applied to a composite surface acoustic wave filter 3. In the filter 3, a video channel is formed among an input electrode 3A and an output electrode 3B and an audio channel is formed among the electrode 3A and an output electrode 3C. The video signal component in which the audio carrier component is suppressed is amplified 4 and applied to a detector 7, and a synthesized signal including the audio signal component and the video carrier component is amplified 5 and given to a detector 8. These signals are multiplied and detected with the output of a carrier filter 6 at the detectors 7 and 8 and the video signal and the 2nd audio intermediate signal are obtained at output terminals 9 and 10 respectively. Thus, the desired characteristics can be obtained by means of a surface acoustic wave filter of a practical size.

Detector for television signal

PURPOSE:To obtain signals which operate accurately and have no cross-color disturbance by delaying correctly the output of the second sampling unit which has a phase difference of 180 deg. against the output of the first sampling unit by 1H.

Hazama Takeshi

Papers

Elastic surface wave transducer

Elastic surface wave element

Color television picture receiver

Detector for television signal

Chrominance components processing unit