Alps Electric Co., Ltd.

Tsutomu Kunishima

Akira Takayama

An amplification circuit includes a semiconductor amplification element, a current feedback circuit that is connected to a terminal close to a ground side of the semiconductor amplification element and can control gain reduction, and a voltage feedback circuit that is connected between an input terminal and an output terminal of the semiconductor amplification element and can control feedback voltage. The feedback voltage of the voltage feedback circuit may be varied according to the gain reduction controlled by the current feedback circuit.

Amplification circuit

A high frequency amplifier for amplifying inputted television signals; a mixer for subjecting the television signals which have been amplified to frequency conversion into intermediate frequency signals; a SAW filter for selecting, out of the intermediate frequency signals, intra-range intermediate frequency signals emerging in a range within a prescribed intermediate frequency band; and an intermediate frequency amplifier for amplifying the intra-range intermediate frequency signals are provided, and wide band detecting means for detecting the intermediate frequency signals inputted to the SAW filter and generating a first AGC voltage is provided to control a gain of the high frequency amplifier with the first AGC voltage.

Television tuner in which influence from analog signals is suppressed when receiving digital signals

A television signal receiving tuner comprises a variable attenuating circuit for attenuating an inputted television signal and outputting the attenuated signal, a preamplifying circuit for amplifying the attenuated signal outputted from the variable attenuating circuit, an input tuning circuit for tuning the amplified television signal outputted from the preamplifying circuit, and a variable gain amplifying circuit for amplifying the tuned television signal outputted from the input tuning circuit.

Growing community of inventors

Miyagi-ken, Japan

Tsutomu Kunishima