TEMPERATURE COMPENSATING CRYSTAL OSCILLATOR AND ITS ADJUSTMENT METHOD

PROBLEM TO BE SOLVED: To reduce the manufacturing costs of a temperature compensating crystal oscillator by reducing manufacturing process time and manufacturing process equipment of the temperature compensating crystal oscillator. SOLUTION: The temperature compensating crystal oscillator is provided with a crystal oscillation circuit using a quarts resonator 2; and a temperature compensating circuit which is connected to the crystal oscillation circuit and compensates the fluctuations of an oscillation frequency of the crystal oscillation circuit, by the changes of capacitance of a variable capacitance element 3 due to the impression of a control voltage. The temperature compensating circuit has a cubic function generating circuit 4 in which the control voltage to be impressed to the variable capacitance element 3 is generated to an ambient temperature detected by a temperature sensor 5, and a ROM 6 and a RAM 7 which are used when the temperature characteristics are adjusted and store a coefficient and a constant of the cubic function corresponding to the crystal oscillation circuit and its using quarts resonator 2. The coefficient and constant of the function are repeatedly set to the RAM 7, or a plurality of sets of the coefficients and constants of the function are set to the RAM 7. The limited number of the times of data can be written in the ROM 6. A value other than a maximum value and a minimum value in the adjustment range of the coefficient, and constant of the function is set to the RAM 7 during the power supply to the temperature compensating circuit. COPYRIGHT: (C)2006,JPO&NCIPI