Abstract: A composite piezoelectric component includes a plurality of piezoelectric resonant elements. Each of the plurality of piezoelectric resonant elements includes a substrate having a first major surface and a second major surface disposed opposite to each other. A pair of vibrating electrodes is disposed on the first and second major surfaces, respectively, so as to oppose each other with the substrate disposed therebetween. A ground electrode which is connected to ground is disposed on at least one of the first and second major surfaces. The plurality of piezoelectric resonant elements are stacked on each other so that the major surface of one substrate opposes the major surface of another substrate. A conductive joining member electrically connects at least two of the vibrating electrodes and the ground electrode of the plurality of piezoelectric resonant elements and mechanically bonds the stacked piezoelectric resonant elements.

Abstract: A piezoelectric vibration device is constructed to suppress interference between resonance sections and achieve a satisfactory resonance characteristic and sufficient mechanical strength. In the piezoelectric vibration device, a plurality of resonance sections are provided on a piezoelectric substrate and a slit is provided so as to extend from one side of the piezoelectric substrate toward a center thereof in order to suppress interference between the resonance sections. If the length of the slit is denoted as a, the gap width along the opposing direction of the first and second resonance electrodes in the resonance section as g, the distance from the center of the gap to the nearest side of the piezoelectric substrate and the sides of the slit as L.sub.1, and the external dimension of the piezoelectric substrate along one direction as L, then the expression L.sub.1 -g/2=b, b<a.ltoreq.(3/4)L is satisfied.

Abstract: A piezoelectric filter has a significantly reduced size and a sufficient coupling capacitance while avoiding an uneven outer configuration of an overall shape of the filter. The piezoelectric filter includes a first resonating unit and a second resonating unit and a coupling capacitance unit disposed in a piezoelectric substrate. The coupling capacitance unit is provided with a first coupling capacitance electrode located on an upper surface of the piezoelectric substrate and a second coupling capacitance electrode located on a lower surface thereof and the first and second coupling capacitance electrodes are arranged to extend to side edge surfaces of the piezoelectric substrate.

Abstract: In an energy trapping type ceramic filter vibrating in the thickness shear-slide mode, vibrating electrodes are formed on opposite sides of a piezoelectric ceramic substrate, while an input terminal electrode and an output terminal electrode are provided on both end portions of the substrate so that lead terminals are soldered to the terminal electrodes. A distance l.sub.5 between the input terminal electrode and the adjacent vibrating electrode and a distance l.sub.6 between the output terminal electrode and the adjacent vibrating electrode are set within a range of one to three times the thickness of the substrate. Thus, it is possible to suppress undesired vibration other than principal vibration, thereby improving filter characteristics.

Abstract: A thickness shear vibration type double mode filter includes two or more vibrating elements disposed in parallel on a piezoelectric substrate and a coupling capacitor formed on the piezoelectric substrate at a position intermediate two of the vibrating elements. The coupling capacity includes a capacitor electrode formed on one main surface of the piezoelectric substrate and an opposing ground electrode formed on a second main surface of the substrate. Input/output electrodes of the vibrating elements are formed on the same surface of the piezoelectric substrate as the capacitor electrode. A damper formed of a resin material on which no solder adheres is formed on top of the capacitor electrode and has sufficient mass to suppress undesired vibration in the area of the coupling capacitor.

Abstract: The disclosure is directed to an improved FM demodulating circuit which is simple in circuit construction, with a small number of parts required, and so arranged that in a quadrature detecting circuit, a plurality of piezoelectric resonators, for example, ceramic discriminators employed for a phase shift circuit are changed over by switching circuits for common use of parts other than the ceramic discriminators for the demodulation of the FM intermediate frequency signals.