| 摘要 |
PURPOSE:To automatically adjust the amplitude of a waveform to cancel an its own station sending signal by branching an electric pulse signal to drive an optical element at the sender side, using the identified high-order bit as a required reception digital signal and using the loworder bit as a voltage or the like for adjusting the amplitude of the branch signal automatically. CONSTITUTION:The electric pulse signal to drive the optical element 12 at the transmission side is branched to generate the signal whose polarity, phase and amplitude are adjusted. The signal is added to a pulse waveform signal at a remote end by an adder circuit at the near end reception circuit and waveform-equalized and 2-bit identification is applied and the high-order bit is used as a required reception digital signal, the polarity of low-order bit and the driven electric pulse at the sender side are collated to use as a voltage for the automatic amplitude adjustment of the branch signal. Moreover, the collation between the high-order bit and the low-order bit is taken to use the result as the voltage for gain control of the ACC amplifier 32 of the reception circuit and the presence of both a transmission clock and a reception clock is detected. Thus, even with the fluctuation of transmission optical signal level and transmission line loss, normal collision detection is attained. |
