Crystal oscillator
AssigneeNihon Dempa Kogyo Co., Ltd.
InventorsAtsuhiro Ishikawa, Hideo Hashimoto
Life of this patent
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Abstract
A quartz crystal oscillator in which phase noise is reduced includes: a resonance circuit having a quartz crystal unit and a split capacitor connected to the crystal unit; a transistor for oscillation having its base connected to the node of the crystal unit and the split capacitor; an output line for connecting the mutual node of the split capacitor to the emitter of the transistor; a quartz crystal resonator that is inserted in the output line; and a temperature compensation mechanism for compensating the frequency-temperature characteristics of both the crystal unit and the crystal resonator.
Claims5
A crystal oscillator comprising:
- a resonance circuit having a crystal unit and a split capacitor connected to said crystal unit;
- a transistor for oscillation having a base connected to a node of said crystal unit and said split capacitor;
- an output line for connecting an emitter of said transistor to a mutual node of said split capacitor;
- a crystal resonator inserted in said output line;
- and
- a temperature compensation mechanism for compensating frequency-temperature characteristics of both said crystal unit and said crystal resonator,
- wherein said temperature compensation mechanism comprises a first voltage-variable capacitance element connected to said crystal unit, a second voltage-variable capacitance element connected to said crystal resonator, and a single compensating voltage generation circuit for generating a compensating voltage according to ambient temperature, wherein said compensation voltage is applied to said first and second voltage-variable capacitance elements.
A crystal oscillator comprising:
- a resonance circuit having a crystal unit and a split capacitor connected to said crystal unit;
- a transistor for oscillation having a base connected to a node of said crystal unit and said split capacitor;
- an output line for connecting an emitter of said transistor to a mutual node of said split capacitor;
- a crystal resonator inserted in said output line;
- and
- a temperature compensation mechanism for compensating frequency-temperature characteristics of both said crystal unit and said crystal resonator,
- wherein said temperature compensation mechanism comprises a first temperature compensation circuit that is connected to said crystal unit, and a second temperature compensation circuit that is connected to said crystal resonator, wherein each of said temperature compensation circuits is provided with a thermistor and a capacitor.
A crystal oscillator comprising:
- a resonance circuit having a crystal unit and a split capacitor connected to said crystal unit;
- a transistor for oscillation having a base connected to a node of said crystal unit and said split capacitor;
- an output line for connecting an emitter of said transistor to a mutual node of said split capacitor;
- a crystal resonator inserted in said output line;
- and
- a temperature compensation mechanism for compensating frequency-temperature characteristics of both said crystal unit and said crystal resonator,
- wherein said temperature compensation mechanism comprises a first temperature compensation circuit that is connected to said crystal unit, and a second temperature compensation circuit that is connected to said crystal resonator, wherein each of said temperature compensation circuits is provided with a thermistor and a capacitor,
- wherein each of said temperature compensation circuits includes a high-temperature compensation circuit in which a first thermistor and a first capacitor are connected in parallel, and a low-temperature compensation circuit in which a second thermistor and a second capacitor are connected in parallel, wherein said high-temperature compensation circuit and said low-temperature compensation circuit are connected in series.
Dependencies are inferred from the claim text.