| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electronic clock for a vehicle which allows for accurate time correction even with variations in environmental temperature and inherent characteristics of a crystal oscillator and variation in the oscillation frequency of a crystal oscillation circuit among individuals, and reduces power consumption to the utmost extent. <P>SOLUTION: An electronic clock for a vehicle having a CPU 22 which counts signals generated based on the original oscillation frequency f0 of a crystal oscillation circuit 24 including a crystal oscillator 30 for ticking time and displays the time with a liquid crystal display unit comprises a temperature measuring part 35 which measures the environmental temperature of the crystal oscillator 30. The CPU 22 comprises a ROM 37 which stores frequency temperature characteristics data of the crystal oscillator 30, a calculation circuit 39 which calculates corrected time value from the detected temperature data S0 measured with the temperature measuring part 35 and the characteristics data of the ROM 37, and an output correction circuit 27 which corrects the counted time of the original oscillation frequency f0 according to the corrected time value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
