Temperature-compensated crystal oscillator
AssigneeNihon Dempa Kogyo Co., Ltd.
InventorsKuichi Kubo, Fumio Asamura
Life of this patent
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Abstract
A temperature-compensated crystal oscillator (TCXO) comprises a voltage-controlled crystal oscillator (VCXO) having a crystal unit, a compensating voltage generator for generating a compensating voltage applied to the voltage-controlled crystal oscillator, a low pass filter inserted between the compensating voltage generator and voltage-controlled crystal oscillator, and a switching element connected in parallel with the low pass filter for short-circuiting across the low pass filter. In a manufacturing process of the temperature-compensated crystal oscillator, switching element is brought into a conducting state when an excitation electrode of the crystal unit is irradiated with an ion beam for adjusting the oscillation frequency.
Claims7
A temperature-compensated crystal oscillator comprising:
- a voltage-controlled crystal oscillator having a crystal unit;
- a compensating voltage generator for generating a compensating voltage applied to said voltage-controlled crystal oscillator;
- a low pass filter inserted between said compensating voltage generator and said voltage-controlled crystal oscillator;
- a switching element connected in parallel with said low pass filter for short-circuiting across said low pass filter;
- and
- control means for controlling said switching element into a conducting state when an excitation electrode of said crystal oscillator is irradiated with an ion beam for adjusting an oscillation frequency.
A temperature-compensated crystal oscillator comprising:
- a voltage-controlled crystal oscillator having a crystal unit;
- a compensating voltage generator for generating a compensating voltage applied to said voltage-controlled crystal oscillator;
- a low pass filter inserted between said compensating voltage generator and said voltage-controlled crystal oscillator;
- a switching element connected in parallel with said low pass filter for short-circuiting across said low pass filter;
- a starting control circuit for generating “1” for a predetermined time after said temperature-compensated crystal oscillator is powered on and subsequently generating “0”;
- a memory circuit for delivering “0” or “1” in response to an external input;
- and
- a selector for controlling said switching element into a short-circuited state when at least one of said starting control circuit and said memory circuit delivers “1” and for otherwise controlling said switching element into a cut-off state.
Dependencies are inferred from the claim text.