Alps Electric Co., Ltd.

Takeshi Shimizu

Masaki Yamamoto

Takeo Suzuki

Yasuharu Kudo

Masashi Suzuki

Masataka Kumaki

A crystal-oscillator circuit includes an oscillation transistor having the collector or the base thereof at a ground potential. A first capacitor is connected between the base and the emitter of the oscillation transistor. A second capacitor is connected between the emitter and the collector. A quartz crystal resonator and a third capacitor are connected in series between the base and the collector. The third capacitor is disposed at the ground potential side. An oscillation signal is extracted from a node between the quartz crystal resonator and the capacitor.

Crystal-oscillator circuit for preventing stopping of oscillation

Band characteristics between reception bands or reception channels are uniformed. There is provided a television tuner comprising a first tuning circuit which can be tuned to a television channel frequency in a first frequency band, a first amplification circuit for amplifying an output signal from the first tuning circuit, a second tuning circuit which can be tuned to a television channel frequency in a second frequency band, and a second amplification circuit for amplifying an output signal from the second tuning circuit, wherein, to at least one of the first and second tuning circuits, a damper resistor for decreasing Q of the tuning circuit when the tuning circuit is tuned to a frequency in a low-frequency band including each lowest channel in the first or second frequency band is connected.

Growing community of inventors

Fukushima, Japan

Takeshi Shimizu