毕业设计说明书学生姓名：张俊学号： 20077455 专业年级：电子信息工程2 班题目： 基带传输系统中扰码与解码电路的设计指导教师：陈亚妮 2011 年 4 月 15 日中 文 摘 要本文设计的是数字通信系统中扰码与解码电路，由于通常假设信源序列是随机序列，而实际信源发出的序列不一定满足这个条件，特别是出现长0 串时，给接受端提取定时信号带来一定困难。解决这个问题可用M 序列对信源序列进行“加扰”处理，以使信源序列随机化。在接受端再把“加乱”了的序列，用同样的M 序列“解扰”，恢复原有的信源序列。在图像通信中，扰码可以很好地抑制静态图像的抖动，能使数字传输系统对各种数字信息具有透明性。本次设计用信号发生器产生6Hz 的方波作为整个系统的时钟，用三片级联的74LS19474产生长度为 31 的 PRBS序列，作为扰码，和信息序列异或完成加扰过程。解扰端完成相反的过程，恢复信息序列。矚 慫 润 厲 钐 瘗 睞 枥 庑 赖 。关 键 词M 序 列扰 码解 码外 文 摘 要Title In the baseband transmission system trouble 聞創沟燴鐺險爱氇谴净。code and decoding circuit's design Abstract What this article designs is in the baseband transmission system harasses the code and the demoding circuit, because the usual supposition source sequence is the random sequence, but the actual source sends out when the sequence not necessarily satisfies this condition, the string, for accepts the end extraction timing signal to bring certain difficulty. Solves this M sequence to carry on " to the source sequence; Canada harasses " Processing, causes the source sequence randomisation. Is accepting end again " Adds chaotic " Sequence, with same M sequence " The solution harasses " , restores the original source sequence. In the visual communication, harasses the code to be possible to suppress the frozen picture well the vibration, can enable the digital transmission system to have the transparency to each kind of numerical information.残骛楼諍锩瀨濟溆塹籟。KeywordsBaseband transmi...
