| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a duo-binary optical communication system for improving spectrum efficiency, using a pulse amplitude modulation (PAM) technique. <P>SOLUTION: A PAM duo binary optical transmitter is designed to transform a plurality of input bits into an N-level signal by using the PAM technique, to generate a 2N-1 level signal by adding the present N level signal to the preceding N level signal, and to transform the 2N-1 level signal into an optical signal to be transmitted to a receiver. A PAM duo-binary optical receiver is designed to detect a power level of the received optical signal (encoded by using the pulse amplitude modulation technique for encoding a plurality of bits, and a duo-binary encoding technique), for mapping the detected power level into a plurality of bits, and to restore transmission information. An illustrated PAM-4 duo-binary optical communication system is designed to improve the spectral efficiency quadruply as a whole, by reducing the bandwidth of the optical signal, after combining a PAM-4 modulation technique to a duo-binary pulse shaping technique. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
