Renesas Electronics Corporation

Takeshi Uchitomi

Yutaka Igarashi

Norio Hayashi

Tomomitsu Kitamura

Yasuku Katsube

Satoshi Arayashiki

To implement a filter circuit with low noise and a low cutoff frequency in a smaller area, a filter circuit has a first circuit which receives an input signal supplied to an input terminal, amplifies the signal, and outputs the amplified signal to an output terminal, a first differential amplification circuit for receiving the output signal of the first circuit through a first capacitance element, a first resistance element for forming a negative feedback path between the input and output of the first differential amplification circuit, and a second resistance element for forming a negative feedback path between the output of the first differential amplification circuit and the input of the first circuit.

Filter circuit and receiving device

Variable operating currents are generated in relation to input signal power and output signal power and achieving both low noise and low power consumption. Emitter follower circuits are attached to output terminals of a frequency divider for generating a local signal. By adjusting the currents flowing through the emitter follower circuits, the amounts of currents flowing into mixers is adjusted. When the amounts of currents of local signals flowing into the mixers increases, the effect of noise suppression is expected. The amounts of the currents flowing through the emitter follower circuits is changed depending on the amplification factor of variable amplifiers.

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Chiyoda-ku, Japan

Takeshi Uchitomi