| 摘要 |
PROBLEM TO BE SOLVED: To automatically reset a VCO circuit by detecting 1/n counter output and to avoid a dead lock state. SOLUTION: An output of a 1/n counter 5 is inputted to a detecting part 6, and the output of the detecting part 6 differs depending on the state of the point A. When the point A has a clock exceeding an operation frequency of the 1/n counter 5, the 1/n counter 5 cannot operate normally. Therefore, no pulse is generated at the point B but a signal selecting the zero side of a selector 3 is outputted at the output point C of the detecting part 6. The selector 3 outputs such a fixed voltage that the clock outputted from the VCO circuit 4 satisfies the operation frequency of the 1/n counter 5 and an output value of the detecting part 6 selects the side '1' of the selector 3. In this manner, the 1/n counter 5 obtains an input enabling operation; outputs normal pulses; generates pulses at the point B again; the point C outputs a signal selecting '1' side of the selector 3; and a normal operation is reset. Namely, a dead lock state is avoided. |
