| 摘要 |
PROBLEM TO BE SOLVED: To show a necessary transmission characteristics in light transmission without the expensive complicated processing of a non-reflection terminal even when the number of characteristics on a reception side fluctuates and the number of light branching fluctuates by adjusting the light modulation degree of a light emitter on the transmission side of a light signal and maintaining a light transmission characteristic to the necessary one. SOLUTION: In the light transmission system, the variable gain amplifier 17 of a transmission device-side 14 adjusts the gain of a radio frequency signal inputted to an electric-optic converter 18 and adjusts the light modulation degree of the electric-optic converter 18. Thus, the fluctuation of the noise characteristics on a reception device side 13 is suppressed. Namely, the noise characteristic of the electric output of a photodiode constituting the optic-electric converter 16 is made constant by a necessary value. This, the fluctuation of the noise characteristic on the reception side owing to the fluctuation of light reception quantity is corrected by changing the light modulation degree while having the relation of a prescribed expression at the transmission device-side 14. |
