| 摘要 |
PURPOSE:To guarantee logic when the thresholding of a signal received by a photodetector is performed even in transient response by attaching the same transient characteristic for the rise of a common power source on both amplifier output and a reference signal. CONSTITUTION:When a power source Vcc is applied, the potential of a connection point 36 connected to the output terminal on one side of a comparator 13 rises in curved shape by a second time constant circuit 22. The similar change is shown at the potential of the input terminal on the other side of the comparator 13 and that of the connection point 38 of an amplifier 12 by a first time constant circuit 21. Therefore, assuming that an optical signal is received by the photodetector 11 at a time t1 soon after the power source is applied, the potential of the connection point 38 by such reception of the optical signal is rocked in both positive and negative directions centering about reference potential, and a digital signal 23 can be generated by surely binarizing the output signal of the amplifier 12 by the comparator 13. |
