| 摘要 |
PURPOSE:To improve the time tone signal discriminating function, by differentiating a time tone signal to convert it to a pulse train of a narrow width when the signal reaches a certain level. CONSTITUTION:A time tone signal which reaches a certain level is differentiated by an inverted output Schmitt trigger circuit 12, an inverter 13, a D type FF 14, an AND gate 15, etc. of a differential circuit 3; a D type FF 14, an AND gate 15, etc. of a differential circuit 3; and when the signal voltage in the data input terminal of the FF 14 becomes a threshold or more, a constant-duty pulse train of a narrow width corresponding to clocks inputted to the clock terminal is generated. The period of output pulses of the circuit 3 is prescribed for every one period of the time tone signal to generate one or plural pulse trains at every one period of the time tone signal from a timer circuit 4, and thus, the time tone signal discriminating function which corrects automatically the time of an electronic clock is improved by a constant-duty pulse train. |
