| 摘要 |
A reproducing circuit is disclosed having a photo-diode for extracting a signal component of a monitor signal from an electric signal converted from an optical signal using a band pass filter 108 and an envelope detector circuit 111. The output of the photo-diode 106 is smoothed by a capacitor 12 via a buffer amplifier 11. A threshold voltage control circuit 13 converts the smoothed signal voltage with a predetermined ratio to produce a threshold voltage. A discriminator 115 converts the extracted monitor signal component into a binary signal using the threshold voltage as a reference. Since the smoothed voltage varies in accordance with the average intensity of optical signal, the monitor signal can be appropriately converted into a binary signal in accordance with the intensity of optical signal. Further, since the smoothing is performed by a capacitor, the circuit structure can be simplified.
|
