| 摘要 |
PCT No. PCT/FR95/00510 Sec. 371 Date Dec. 13, 1995 Sec. 102(e) Date Dec. 13, 1995 PCT Filed Apr. 20, 1995 PCT Pub. No. WO95/29539 PCT Pub. Date Nov. 2, 1995An optical transmission method and device consisting of coding a binary data pattern (SI) to be transmitted in the form of a second binary signal (SM), by differential coding; filtering the second binary signal (SM) to obtain a duobinary signal (SMF having three meaningful values (-1, 0+/- epsilon , +a) and a narrower bandwidth; and modulating an optical carrier according to the values assumed by the filtered signal (SMF), the modulated carrier having a maximal amplitude to represent the maximal value (+a) and the minimal value (+a) of the duobinary signal (SMF), the phase of the modulated carrier being shifted by theta 1 and theta 2= theta 1+180 DEG , respectively, and a minimal amplitude to represent values (0+/- epsilon ) near 0 if the duobinary signal. The method of this invention is suitable for long distance fiber-optic transmissions. |
