| 摘要 |
PROBLEM TO BE SOLVED: To suppress a communication error resulting from a frequency change attended with a temperature change by compensating temperature of the digital temperature compensation piezoelectric oscillator at a time just before a reception standby of the communication system. SOLUTION: Power is supplied to the digital temperature compensation piezoelectric oscillator in the AFC state for 40 msec of first ranges a, b where the main power supply is supplied to a portable telephone set to bring the telephone set to a reception wait state. Then temperature is compensated only for 1 msec just before the reception wait state in each 20 msec of the ranges a, b. The power is interrupted from tone digital temperature compensation piezoelectric oscillator to reduce the power consumption of the portable telephone set for 20×36 msec after a range (c) to avoid temperature compensation, power is supplied again for an AFC control time for 20 msec of a range (d), the frequency is fine-adjusted and temperature is compensated only for 1 msec just before the reception wait state. Succeedingly, the operation for the ranges c-d is repeated and the reception waiting is continued till the main power supply of the portable telephone set itself is interrupted.
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