| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of transmission quality and shorten the total extending distance of a fiber by connecting light signals without converting them to electric signals in an optical fiber formed in a lop form. SOLUTION: A slave machine 2a receives the light signals from a master machine and a light-emitting unit 23 light-converts the electric signals transmitted to the master machine. A light mixing/branching unit 21 superposes the signals on the down signals of the master machine and up signals are outputted with a carrier frequency different from those of down signals. The branching unit 21 transmits them to the adjacent slave machine 2b and a discrimination unit 24. The discrimination unit 24 discriminates the down signals, converts them into the electric signals and outputs them to an external part. The slave machine 2a takes in the down signals of the master machine. The salve machine 2b similarly takes in the down signals. The lowest slave machine 2n similarly takes in the down signals and superposes them on the up signals. But the outputs are outputted to the master machine since the optical fiber is connected in the loop form. The master machine receives the mix signal of the up signals which are superposed in the slave machines 2a-n and the down signals of self transmission, converts it into the electric signal and outputs it. Thus, a signal addressed to the master machine can be taken in. |
