两路语音PCM时分复用系统的设计

摘要数字通信系统是采用数字信号来传递信息的通信系统，数字通信过程中主要涉及信源编码与译码、信道编码与译码、数字调制与解调等技术问题。而脉冲编码调制就是一种常用的信源编码方法，将模拟信号抽样、量化，直到转换成为二进制符号的基本过程。为了扩大通信系统链路的容量，在一条链路上传输多路独立的信号，为此引入了一种复用技术来实现多路信号共同传输的目的。

而在本系统设计中，所运用的复用技术是时分复用，同时基于现场可编程门阵列器件作为主控芯片，在Quartus II软件中使用硬件描述语言Verilog HDL编写PCM编译码和时分复用模块的程序，再对其进行波形仿真以验证程序的正确性，从而设计出语音信号的PCM编码与译码、时分复用的过程。本设计中，将两路语音信号通过外围硬件电路模块送至FPGA中进行PCM编码、译码处理，最后通过后级外围电路实现语音信号的重现。

关键词：语音脉冲编码调制时分复用FPGA

Design of Two-way V oice PCM System

by Time Division Multiplexing

ABSTRACT A digital communication system is a communication system that transmit information by using digital signal, and digital communication mainly relates to the source coding and decoding, channel coding and decoding, digital modulation and demodulation technology. Pulse code modulation is a common source coding, and it is that the analog signal sampling ,quantization ,until the transformation become the basic process of binary symbols. In order to expand the capacity of communication link system ,a transmission of multiple independent signal on a link, therefore introduction of a division multiplexing technology to achieve the purpose of multiplexing.

In this system design, we use a time division multiplexing technology, and based on the Field Programmable Gate Array, using Verilog HDL hardware description language to write PCM encoding and decoding and time division multiplexing module in Quartus II, then Waveform simulation to verify the correctness of the program, thus design a voice signal process of PCM encoding and decoding, time division multiplexing. In this system design, The two-way voice signal through the peripheral hardware circuit module is sent to the FPGA for PCM encoding and decoding, finally to achieve reproducible speech signal through the peripheral circuit. Key Words：V oice Pulse code modulation Time division multiplexing FPGA

目录

摘要................................................................ I ABSTRACT........................................................... I I 目录

1 引言 (1)

1.1 选题背景与意义 (1)

1.2 QuartusⅡ软件 (2)

1.3 FPGA的介绍 (3)

1.4 本文内容简介 (4)

1.5 实施过程简介 (4)

1.6 设计结果简介 (4)

2 基本原理介绍 (5)

2.1 模拟信号的数字化 (5)

2.1.1 采样定理 (5)

2.1.2 量化原理 (5)

2.1.3 A律13折线 (5)

2.2 脉冲编码调制 (7)

2.3 时分复用技术 (9)

2.4 PCM一次群帧结构 (10)

3 系统设计介绍 (11)

3.1 总体框图 (11)

3.2 外围硬件电路的介绍 (12)

3.2.1 拾音电路 (12)

3.2.2 仪用放大器 (12)

3.2.3 带通滤波器 (13)

3.2.4 抬升电路 (13)

3.2.5 A/D转换电路 (14)

3.2.6 D/A转换电路 (14)

3.2.7 功率放大器 (15)

3.3 基于FPGA的模块设计 (16)

3.3.1 系统时钟的设计 (16)

3.3.2 前端模块设计 (16)