| 摘要 |
PURPOSE:To improve reliability by sharing (2n+2) number of light-emitting element groups by means of an up reproduction relaying circuit and a down reproduction relaying circuit. CONSTITUTION:A first switching means 4 transmitting two inputted up and down signals from two output terminals among (2n+2) number of output terminals in correspondence with a first control signal, and a second switching means 6 outputting two optical signals inputted from corresponding terminals among (2n+2) number of input terminals in correspondence with a second control signal are provided. The title circuit is made into redundant constitution in which the light-emitting element groups 5 are shared by the up reproduction relaying part 2 and the down reproduction relaying part 3, and 2n number of standby light-emitting elements are given for two present light-emitting elements. The number of degrees of freedom for selecting the standby light- emitting elements is enlarged compared to a conventional example. Thus, reliability can be improved without increasing cost as the reproduction relaying circuit. |
