| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an automatic frequency monitoring circuit, an electronic device, an automatic frequency monitoring method and an automatic frequency monitoring program, automatically monitoring a clock. <P>SOLUTION: (1) This automatic frequency monitoring circuit repeats edge detection during the detection period for the number of times of sampling. The number of times of detecting an edge, which is detected for the number of times of sampling, is averaged by the number of times of sampling. The maximum value and the minimum value of the number of times of detecting an edge, which are obtained depending on the preceding average and a preset value, are calculated and stored. (2) Subsequently the circuit detects an edge during the monitoring period. It is verified whether or not the detected number of times of detecting an edge falls in the range between the maximum value and the minimum value of the number of times of detecting an edge, which are calculated in the above (1), and (3) when the verification result is negative, the information to the effect that the frequency of a clock is abnormal is given. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
