数字基带通信系统的设计.docVIP

摘　　　要 本文的主要研究对象是PCM编译码和时分复用多人通话。其中包括：时分复用通话、低通信号的均匀理想抽样定理、非均匀量化、编码和译码等。对量化、编码进行了Matlab仿真实验。麦克风或电话手柄输出的语音模拟信号经放大后送到PCM编码器，得到的数字信号直接通过数字基代通信系统进行传输，然后再送给扬声器，从而实现时分复用多人通信。 时分复用是借助把时间祯划分成若干时隙和各路信号占有各自时隙的方法来实现在同一信道上传输多路信号；抽样包括低通抽样定理和带通抽样定理；量化包括均匀量化和非均匀量化，非均匀量化又分为A律和u律；编码和译码的功能由逐次比较型编码器和译码器来完成；仿真是用Matlab对量化和编码进行了仿真。 关　键　词 时分复用；抽样；量化；编码；译码；仿真 Abstract The main research object of this paper is the PCM and time distributed multi-person communication which includes time distributed multi-person communication, even ideal sampling theorem of lowpass signal, uneven quantitating, coding, decoding etc. We emulate the quantitating and coding using matlab. The speech analog signals exported from microphone or telephone handle will firstly be magnified and then be delivered to PCM coder. The digital signal gained above will be directly transmitted through digital baseband communication system to loudspeaker. The time distributed multi-person communication is thus achieved through the above steps. Time-distributed theory accomplishes transmitting multiplex signals in one channel in virtue of carving the time frame into several subframe and each signal engrosses its own subframe. Sampling includes lowpass sampling theorem and band-pass sampling. Quantitating includes even quantitating and uneven quantitating which is divided into A-low and u-law. The function of coder and decoder is accomplished by gradually-comparing coder and decoder. As mentioned above emulating uses matlab emulated the quantitating and coding. Keyword time-distributed; sampling; quantitating; coding; decoding; emluating 目　　　录 摘　　　要 1 关　键　词 1 Abstract 2 Keyword 3 一、引言 6 二、时分复用 7 （1）、时分复用 7 （2）时分复用中的同步技术 8 （3）时分复用的帧结构 8 （4） PCM复用与数字复接 10 三 、抽样定理 11 （1）低通抽样定理 11 （2）带通抽样定理 11 四、脉冲编码调制（PCM） 11 （1）抽样 12 （2）量化 12 1.均匀量化及Matlab仿真 12 2.非均匀量化及Matlab仿真 14 （3）编码原理及Matlab仿真 16 （4）译码原理 18 六、时分多路电话通信系统 18 谢　　　辞 错误！未定义书签。 参考文献 20 一、引言 通信就是信息传输或消息传输，是从一地向另一地传递和交换信息。实现信息传递所需的一切设备和传输媒质的总和称为通信系统。通信系统的一般模型如图一： 图一 通常，通信系统中传输的消息可以分为两类