US Patent No. 10,164,571

CRYSTAL OSCILLATOR AND METHOD OF MANUFACTURING CRYSTAL OSCILLATORS


Patent No. 10,164,571
Issue Date December 25, 2018
Title Crystal Oscillator And Method Of Manufacturing Crystal Oscillators
Inventorship Takashi Nakaoka, Saitama (JP)
Kazuo Akaike, Saitama (JP)
Hiroshi Hoshigami, Saitama (JP)
Kaoru Kobayashi, Hokkaido (JP)
Assignee NIHON DEMPA KOGYO CO., LTD., Tokyo (JP)

Claim of US Patent No. 10,164,571

1. A crystal oscillator, comprising:a crystal resonator, which is an AT-cut crystal resonator;
a first oscillating circuit that oscillates the crystal resonator at a first frequency;
a first impedance adjusting circuit that adjusts an impedance of a first oscillating system including the crystal resonator and the first oscillating circuit;
a second oscillating circuit that oscillates the crystal resonator at a second frequency that is different from the first frequency at the same time with the first oscillating circuit, the second frequency being an overtone frequency of the crystal resonator;
a second impedance adjusting circuit that adjusts an impedance of a second oscillating system including the crystal resonator and the second oscillating circuit; and
a controlling circuit that controls the first impedance adjusting circuit and the second impedance adjusting circuit, wherein
the first impedance adjusting circuit and the second impedance adjusting circuit include a resistance array that comprises a plurality of resistances, and
the controlling circuit adjusts a resistance value of at least any of the first impedance adjusting circuit and the second impedance adjusting circuit by controlling the resistance array.