| 摘要 |
PURPOSE:To maximize the signal/noise ratio of the input of an optical receiver by making the duty cycle of the pulse of a digital signal variable. CONSTITUTION:In a system consisting of a light transmitting part 20, which converts the pulse of the output of a digital signal generating means 10 into an optical signal, and a light receiving part 40, which receives the output of the light transmitting part 20, and converts it into an electric signal, the duty cycle of the pulse of the output of the digital signal generating means 10 can be set so that the signal/noise ratio of the input of the light receiving part 40 comes maximum, by branching the input of the light receiving part 40 and adding it to a duty cycle varying means 50. Consequently, the duty cycle can be made larger than 50 % in order to prevent the deterioration of the signal/ noise ratio of the optical receiver due to a mode distribution noise, and on the other hand, the duty cycle can be made smaller than 100% in order to reduce the quantity of an inter-code interference, and the value of the duty cycle can be set at the optimum value. |
