| 摘要 |
PURPOSE:To allow the circuit to be made free from occasional adjustment even if the period of a pulse train is changed by using a voltage proportional to the period of an input pulse as a reference value. CONSTITUTION:A capacitor 6 repeats charge/discharge by a period 7 of a pulse train inputted to a transistor (TR)5 and a ramp voltage of a period tau is generated. A potential of a capacitor 14 charged via a diode 9 at an output terminal of the 1st comparator 7 is always equal to a peak voltage of the pulse train. If the pulse train has a missing bit, a voltage inputted from the capacitor 6 to the 2nd comparator 8 is larger than a value 1.5Vpa inputted from an operational amplifier 10 and a detection signal is generated from the comparator 8. As the reference voltage of the comparator 8, a value being 1.5 time the peak voltage Vpa of the inputted pulse train is obtained at all times and the reference voltage is not fluctuated by the fluctuation of the period of the pulse train. |
