Nihon Dempa Kogyo Co., Ltd.

Junichiro Yamakawa

Kazuo Akaike

Toshimasa Tsuda

Tatsunori Onzuka

Mikio Takano

Yasushi Yamamoto

Susumu Yoshimoto

Kenji Kawahata

Hiroshi Hoshigami

Hiroyuki Kukita

Mitsuaki Koyama

Tomoya Yorita

Takeru Mutoh

Shigenori Watanabe

Takashi Nakaoka

Kietsu Saito

Yuichiro Arai

Naoto Inouchi

Masazumi Kubota

There is provided a voltage controlled oscillator that is compact and can be manufactured at low cost. The voltage controlled oscillator is structured to include: a resonance part including a variable capacitance element and an inductance element, the variable capacitance element having a capacitance that varies according to a control voltage for frequency control input from an external part, and a series resonant frequency of the resonance part being adjusted according to the capacitance; an amplifying part amplifying a frequency signal from the resonance part; and a feedback part including a capacitance element for feedback and feeding the frequency signal amplified by the amplifying part back to the resonance part to form an oscillation loop together with the amplifying part and the resonance part, wherein the amplifying part is provided in an integrated circuit chip, and the resonance part and the capacitance element for feedback are formed as circuit components separate from the integrated circuit chip. The circuit components are selected according to an oscillation frequency.

Voltage controlled oscillator

To provide a voltage controlled oscillator having small size and capable of obtaining a low phase noise characteristic over a large span of adjustable range of frequency. A quartz crystal having a characteristic (dielectric loss tangent: tan &#x3b4;) better than that of fluorocarbon resin, LTCC or the like conventionally used as a substrate of a resonance part, and on which a fine pattern of metal film can be formed through a photolithography method, is used as a quartz-crystal substrate, and a conductive line is formed on the quartz-crystal substrate to form an inductance element in the resonance part. Accordingly, since the resonance part having a high Q value can be formed, it is possible to obtain a voltage controlled oscillator having small size and low loss over a wide frequency range.

Voltage controlled oscillator and electronic component

There is provided a voltage controlled oscillator using a Colpitts circuit capable of suppressing deterioration (decrease) in variable range (adjustable range) of an output frequency due to the influence of an inductance component on a conductive line, which connects a connection point between two capacitors of a feedback part and an emitter of a transistor. In a VCO using a Colpitts circuit, with respect to capacitorsof a feedback part, a first feedback capacitance element (capacitor)is disposed so as to directly couple a terminal for base (connection part) and a terminal for emitter on a base substrate, to which a terminal part(T) extending from a base of a transistorand a terminal part(T) extending from an emitter of the transistorare fitted, respectively, and a second feedback capacitance element (capacitor)is disposed so as to directly couple the terminal for emitter and the terminal for grounding (ground electrode).

To shorten the time required for an oscillation frequency to stabilize in a sensing device sensing a substance to be sensed by using the fact that a natural frequency of a piezoelectric resonator changes when the substance to be sensed is adsorbed by an adsorption layer formed on the piezoelectric resonator. A sensing device includes: an oscillator circuitoscillating a quartz-crystal resonator; and an intense excitation circuit that is formed by the oscillator circuitincluding a series circuit of a resistorand a third transistorof PNP type and that intensely excites the quartz-crystal resonatorconnected to the oscillator circuitfor a period of time preset by a one-shot circuitby supplying the quartz-crystal resonatorwith high power equal to or more than twice regular power supplied at the time of the measurement of the substance to be sensed, to stabilize the oscillation of the quartz-crystal resonator. When the connection of the quartz-crystal resonatoris detected, the one-shot circuitbrings the oscillator circuitinto an aging state and the high power is supplied to the quartz-crystal resonatorto intensely excite the quartz-crystal resonator, thereby eliminating the distortion and stress of a quartz-crystal plate

Sensing device

To provide a piezoelectric sensor in which a first electrode for measurement and a second electrode for reference are provided apart from each other on one surface side of a piezoelectric piece and a common electrode is provided on an opposite surface side so as to face the first and second electrodes. A piezoelectric sensor includes: a first electrode for measurement and a second electrode for reference provided apart from each other on one surface side of a piezoelectric piece; a common electrode provided on an opposite surface side of the piezoelectric piece commonly for the first electrode and the second electrode to face the first electrode and the second electrode; and an adsorption layer formed on an area, of the common electrode, to which the first electrode is faced across the piezoelectric piece, to adsorb a substance to be sensed.

Piezoelectric sensor and sensing instrument

A low-noise voltage controlled oscillator is provided, to improve a phase noise characteristic and widen a frequency variable range. The low-noise voltage controlled oscillator is configured so that an oscillation element and a capacitorare connected in series between a collector C and an emitter E of a transistor, capacitorsandare connected in series between the collector C and the emitter E, an electrical potential between the capacitorsandis applied to a base B of the transistor; a one-port circuitis provided between the collector C and the capacitor; and a capacitor for correctionis connected in parallel with the capacitorsand. The one-port circuitincludes a tuned circuit provided with a variable capacitor adjusting a capacity thereof smaller and an inductor adjusting a value of inductance larger so as to set a value of impedance relatively large.

Low-noise voltage controlled oscillator

To provide an oscillation module which is able to improve an input level by passing signals in a main signal band while removing near noise and far noise. An oscillation module is provided with an OCXO, an amplifier, and a noise elimination filter. The noise elimination filter includes: a BPF passing a signal in the main signal band and eliminating far noise with respect to the main signal band; an L-BEF eliminating near noise in a low frequency band with respect to the main signal band; and an H-BEF eliminating near noise in a high frequency band with respect to the main signal band. Each filter is configured with a crystal filter.

Growing community of inventors

Sayama, Japan

Junichiro Yamakawa