| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly precise real time clock at a low cost. SOLUTION: This real time clock RTC 2 with an error correction function forms a real time clock. An AT quartz resonator 3 is provided with a flatter temperature characteristic in comparison with a tuning fork type quartz resonator 1 within a usage temperature range. A counter 4 counts a reference clock, which inputs only oscillations of the AT quartz resonator 3 in an initial time, as a source of time counting. A memory 5 stores a count value. In an actual use time, the counter 4 counts oscillations of the AT quartz resonator 3 as a source of time counting for the real time clock. A CPU 6 computes a correction value minimizing an error of the real time clock from a differential between the count value of the actual use time and the count value of the memory 5 to set it to the real time clock RTC 2. COPYRIGHT: (C)2003,JPO
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