1、 I 摘 要 在 数字通信 信道中传输的 信号 是数字信号， 数字传输随着微电子技术和计算机技术的发展，其优越性日益明显，优点是抗干扰强、失真小、传输特性稳定、远距离中继噪声不积累、还可以有效编码、译码和保密编码来提高通信系统的有效性，可靠性和保密性。另外，还可以存储，时间标度变换，复杂计算处理等。 而 模拟信号数字化属信源编码范围，当然信源编码还包括并 /串转换、加密和数据压缩。这里重点讨论模拟信号数字化的基本方法 脉冲编码调制，而模拟信号数字化的过程（得到数字信号）一般分三步：抽样、量化和编码。 本文讲述了 PCM（脉冲编 码调制）的简单介绍，以及 PCM 编码的原理，并分别对 PCM 的
2、各个过程，如基带抽样、带通抽样、 13 折线量化、 PCM 编码以及 PCM译码进行了详细的论述，并对各过程在 MATLAB7.0 上进行仿真，通过仿真结果，对语音信号的均匀量化 以及非均匀量化进行比较，我们得出非均匀量化教均匀量化更加有优势。 关键词： 脉冲编码调制 抽样 非均匀量化 编码 译码 II Abstract In the digital communication channel signal is digital signal transmission, digital transmission with the microelectronics and computer te
3、chnology, its advantages become increasingly evident, the advantage of strong anti-interference, distortion, transmission characteristics of stable, long-distance relay is not the accumulation of noise Can also be effective encoding, decoding and security codes to improve the effectiveness of commun
4、ications systems, reliability and confidentiality. Digitized analog signal range of source coding is, of course, also include the source code and / serial conversion, encryption and data compression. This focus on the simulation of the basic methods of digital signals - pulse code modulation, while
5、the analog signal the digital process (to get digital signals) generally three steps: sampling, quantization and coding. This paper describes the PCM (pulse code modulation) in a brief introduction, and the PCM coding theory, and were all on the PCM process, such as baseband sampling, bandpass sampl
6、ing, 13 line quantization, PCM encoding and decoding PCM a detailed Are discussed and the process is simulated on MATLAB7.0, the simulation results, the uniformity of the speech signal quantification and comparison of non-uniform quantization, we have come to teach non-uniform quantization advantage
7、 of more than uniform quantization Keywords ： Pulse Code Modulation Sampling Non-uniform quantization Coding Decoding III 目录 1 前 言 1 2 PCM 原理 2 2.1 引言 2 2.2 抽样 (Sampling) 3 2.2.1. 低通模拟信号的抽样定理 3 2.2.2 抽样定理 4 2.2.3. 带通模拟信号的抽样定理 7 2.3 量化（ Quantizing） 8 2.3.1 量化原理 8 2.3.2 均匀量化 10 2.3.3 非均匀量化 11 2.4 编码（ Coding） 18 2.5 译码 24 2.6 PCM 处理过程的其他步骤 26 2.7 PCM 系统中噪声的影响 27 3 算例分析 29 3.1 无噪声干扰时 PCM 编码 30 3.2 噪声干扰下的 PCM 编码 36 结论 42 致谢 43 参考文献 44 附录 45
