| 摘要 |
PURPOSE:To receive an optical pulse signal without distortion with standardized intensity by providing a photoelectric conversion circuit consisting of a photodiode and an operational amplifier and a comparator circuit. CONSTITUTION:In receiving an optical pulse A, an output B of an operational amplifier OP1 is inputted to a comparator circuit COM while its waveform remains distorted. On the other hand, since a voltage applied to a capacitor C is charged while a voltage at a point A is at high level and discharged via a resistor R1 when the voltage is at a low level, waveform C is obtained. In selecting the resistor R1 as a value so that the capacitor C is nearly discharged when a dark state for several pulses continues, then the voltage C corresponds to the maximum pulse voltage for nearly several pulses. Since nearly the same waveform as that at the point A is applied to an inverting input of an opera tional amplifier OP3, nearly the same waveform voltage as a voltage at a point B is applied to an output point C. The voltage at the point C is divided by resistors R2, R3 to form a voltage at a point D. A comparator circuit COM compares the quantity of the waveforms B and E, resulting that an output voltage F is caused. Thus, a pulse train without distortion with standardized strength is received. |
