Sanyo Electric Co., Ltd.

Tokyo University of Science

Keiji Morijiri

Masahiro Umewaka

Hiroya Yamamoto

Keitaro Sekine

Akira Hyogo

Akira Hyougo

Keitarou Sekine

There is disclosed a tuning circuit having a coil and a capacitor comprises a resistance-adjustment circuit connected in parallel with the coil and the capacitor. The resistance-adjustment circuit changes a resistance of the tuning circuit when resonant. The resistance-adjustment circuit comprises a series circuit of a resistor and a switching element having an ON-resistance smaller than the resistance of the resistor, and turning on/off the switching element causes the resistance of the tuning circuit when resonant to change.

Tuning circuit with amplitude attenuation function and integrated circuit for radio communication apparatus

A tuning circuit having an amplitude-varying function is disclosed that comprises a coil, a capacitor, and a resistance-adjusting element connected in parallel to the coil and the capacitor for varying resistance at time of resonance of the tuning circuit, wherein the amplitude of an output signal of the tuning circuit is varied by varying the resistance with the resistance-adjusting element.

Tuning circuit having amplitude-varying function

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Gunma-ken, Japan

Keiji Morijiri