| 摘要 |
PURPOSE:To elevate the frequency accuracy by providing an output of the high frequency oscillating circuit and an output of the low frequency oscillating circuit to the phase comparator, and changing and controlling stepwise the frequency of the low frequency oscillating circuit by use of the said output. CONSTITUTION:An output of the high frequency oscillating circuit 1 is provided to D input of the phase comparator 3, and a signal which has divided an output of the low frequency oscillating circuit 2 by a divider 4a is provided to the clock terminal CL. A phase compared output S3 which has been sampled by an output of the divider 4a is divided into two by the T flip-flop, and becomes a frequency control signal S7. When transistors 2i, 2j are ON by the signal S7, the condensers 2g, 2h are short-circuited, frequency of the oscillating circuit 2 becomes low, and in case of reverse, it becomes high. An exact one second signal fs can be obtained from the divider 4b by repeatedly changing both the high and low frequencies by the signal S7. |
