| 摘要 |
PURPOSE:To reduce a transmission error rate even when the reception level is low without missing a signal by providing a reception means, a data identification means, a level identification means for identifying a photodetection level and an offset means for applying an offset voltage to an input of the data identification means corresponding to the photodetection level. CONSTITUTION:An optical data signal is amplified by a preamplifier 2 and its output signal is inputted to a data identification circuit 5, where the signal is binary-coded. In this case, a reception level detection circuit 3, based on the said output signal, identifies whether or not the photodetection level is a prescribed level or over and when it is identified that the level is lower than the prescribed level, while an offset voltage is applied to th input of the circuit 5 by the offset circuit 4, the said binary-coding is applied and when it is identified to be higher than a prescribed level, the said binary-coding is applied while the said offset voltage is not applied. |
