Hitachi, Ltd.

Mitsuhisa Shinagawa

Takeshi Saitoh

Shigeo Matsuura

Toshio Nagashima

Toshinori Murata

Keiro Shinkawa

Chuichi Sodeyama

Hiroshi Hatashita

Hiroshi Miyamoto

Eisaku Akutsu

Hiroji Shoyama

A thick film multilayer substrate using a green ceramic sheet is constructed such that at least three conductor layers and at least two dielectric layers are alternately arranged in turn on the green ceramic sheet substrate, a power supply line being formed in the second conductor layer and thus interposed between the first and third conductor layers in which grounded conductors are formed.

Thick film multilayer substrate

A high-frequency input circuit suitable for use in a television receiver, which includes a tuning circuit which can operate with a reduced loss and can be tuned to signals in, for example, the VHF and UHF bands at the same time. The high-frequency input circuit provides an integrated tuner capable of receiving all the signals within the range from the VHF band to the UHF band.

Tunable high-frequency input circuit

A self-oscillating mixer circuit to operate mainly at SHF band comprises a single-gate FET and a micro strip line. The gate or source terminal of the FET is connected to a radio frequency signal input line. A feedback path is provided between the drain terminal and the gate or source terminal. An intermediate frequency output line is connected to the drain electrode of the FET. A dielectric resonator is coupled to the radio frequency signal input line to improve the stability of an oscillator frequency and to suppress leakage of a local oscillator signal.

Self-oscillating mixer circuit

A self-oscillation mixer circuit includes a cascade amplifier circuitry which is composed of a first transistor of a common emitter connection having a collector connected to an emitter of a second transistor of a common base connection, a filter circuitry for deriving an intermediate frequency signal and a resonance circuit adapted to resonate at a local oscillation frequency being connected to the collector of the second transistor and a feedback circuitry connected between the resonance circuitry and the emitter of the first transistor.

Self-oscillation mixer circuits

A self-excited mixer circuit using a dual gate type field effect transistor, in which an inductive impedance element inductive with respect to a local oscillation frequency, a first capacitive element and a second capacitive element are connected across the drain and the second gate, across the drain and the source, and across the second gate and the source, respectively, of field effect transistor to constitute an oscillation circuit across the drain and the second gate of transistor, so as to derive an intermediate frequency signal from the drain of the transistor in response to the application of the radio frequency signal to the first gate of transistor.

Self-excited mixer circuit using field effect transistor

A self-oscillating mixer circuit suitable for a television receiver is provided using characteristically a single or two switching diodes. During VHF receiving, the mixer circuit operates in a self-oscillating mixing mode under an optimum bias condition, while, during UHF receiving, it operates under an optimum bias condition for intermediate frequency amplification, ceasing its local oscillation.

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Fujisawa, Japan

Mitsuhisa Shinagawa