| 摘要 |
PURPOSE:To make the mean frequency of a clocking signal constant through simple circuit constitution without reference to temperature by using no AT crystal vibrator, etc., large in electric current consumption, by freely selecting the temperature at which frequencies of two oscillating circuits agree with each other. CONSTITUTION:The 1st and 2nd oscillating circuits 1 and 2 differing in frequency- temperature characteristic are provided; and phase difference detecting circuit 3 detects a difference frequency between oscillation frequency signals from those circuits 1 and 2 and slow-speed deciding circuit 5 decides whether which frequency is greater between both the signals from circuits 1 and 2. Outputs of those circuits 3 and 5 are applied to compensation control circuit 9, alpha timer 6 of which counts a signal from circuit 3 up to a fixed number and on the end of the count operation, beta timer 7 counts one signal that circuit 5 has decided for a certain time. Then, outputs of timers 6 and 7 and that of circuit 5 are applied to signal change-over circuit 8 receiving signals from oscillators 1 and 2 and circuit 8 selects and applies a signal, agreeing in frequency, to another compensation control circuit 9. |
