| 摘要 |
PURPOSE:To attain highly accurate data transmission with a simple device by sending a differential optical signal comprising lights of different wavelengths through a single optical transmission medium. CONSTITUTION:A differential drive circuit 1 converting a digital signal inputted from an input terminal 7 into complementary signals D, inverse of D and applying them to 1st light emitting element 11 and a 2nd light emitting element 12 is provided in an optical transmitter 10. The optical signals of wavelengths lambda1, lambda2 sent from the light emitting elements 11, 12 are collected to an optical transmission line 15 such as an optical fiber and sent by an optical means 8. A signal of repetitive 1, 0 from the optical transmitter 10 to a photodetector 20 is sent as an optical signal. A midpoint of output levels 0, 1 of the digital signal is always constant in the case of reception by the optical communication method. Thus, it is possible to fix a reference voltage in the discrimination circuit and communication with high accuracy is attained. |
