| 摘要 |
PURPOSE:To improve the identification sensitivity of a reception signal by controlling the positive amplitude and the negative amplitude of a transmission signal in response to the characteristic of a light emitting diode. CONSTITUTION:When the positive and negative signals with equal amplitude are giving to an adder 5 by amplifiers 18, 19 whose amplification factor is not controlled, the output signal becomes an AMI(Alternate Mark Inversion) signal. An LED drive circuit 6 applies a drive current 32 to a light emitting diode 7 in response to the AMI signal. The light emitting diode 7 outputs an optical signal 33 whose positive pulse amplitude and negative pulse amplitude differ if the drive current/optical output (I/L) characteristic is deteriorated. When the optical signal 33 is given to an optical reception input plug (RX) 9, amplitude detectors 20, 21 control the amplification factor of the amplifiers 18, 19 at the sender side so that the positive side signal is increased. Thus, the identification sensitivity of the reception signal is improved by the AMI signal receiver at the receiver side. |
