| 摘要 |
PROBLEM TO BE SOLVED: To suppress the increase in circuit cost and adjusting man-hours at the time of suppressing the fluctuation in circuit characteristics due to the temperature change in a PLL circuit. SOLUTION: This circuit is provided with a temperature sensor 9 for converting surrounding temperature into a voltage value, an A/D converter 10 for converting the output of the temperature sensor 9 into a digital signal, a memory 11 for storing compensation data corresponding to an address by using the output of the A/D converter 10 as this address, a D/A converter 12 for converting the output of the memory 11 into a voltage value, and a low-pass filter 13 for smoothing the rapid change of the output of the D/A converter 12 as a temperature compensation output generating means. In this case, an arithmetic amplifier 14 inputs the output of a phase comparator 1, which compares a phase difference between an input signal and the output of a frequency dividing circuit 4 which frequency-divides the output of a voltage control oscillator 3 and the output of the temperature compensation output generating means, calculates it, and applies it as a control input for the voltage control oscillator 3. |
