| 摘要 |
PURPOSE:To increase the reliability for a transmission of digital signals, by transmitting the positive and negative pulses of a bipolar signal after modulating said pules into the optical signals of separate wavelengths. CONSTITUTION:A bipolar signal itself is easily checked for its error with a high reliability, and only a unipolar signal is acceptable for an optical transmission. In this connection, the bipolar signal is divided through a separating circuit 11 into a positive pole signal and a negative pole signal. The unipolar signal of positive pole is converted into an optical signal of wavelength lambda1 by a modulating circuit 13; and the unipolar signal of negative pole is converted into an optical signal of wavelength lambda2 by a modulating circuit 14. These optical signals are synthesized through an optical synthesizing circuit 15 and then transmitted. At the reception side the input optical signal is divided into two optical signals of wavelengths lambda1 and lambda2 and synthesized after conversion into the electric signals. In such a way, a bipolar signal is obtained. |
