毕业论文 - 高保真音响设计

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毕业设计(论文)说明书

题 目： 高保真音响设计制作

题目类型： 理论研究 实验研究 √ 工程设计 工程技术研究 软件开发

2005年 06 月 12日

摘 要

随着国家经济蒸蒸日上，现代科技不断发展，这些使人们在物质享受之余，也有了更多的精神享受的需要。其中之一：音乐，便是一种古老的享受形式。而高保真音响就是欣赏音乐的物质基础。

本论文将以性价比为导向，兼顾基本的高保真的技术指标，讨论了适合初级发烧友的高保真功放。论文由浅至深，结合图示给出了高保真音响的相关知识，以及整个功放的工作过程的细节。同时还介绍了各个主要芯片自身的特点及如何去设计这个系统来满足一定的技术指标。论文尽可能通俗地来介绍高保真音响，让大家能从中学到基本的高保真音响的知识的同时，还能学会如何制作高保真音频放大器。

在技术层面上，系统主要是采用集成芯片来完成的，因此对于一个初级发烧友来说相对简单，这个设计中用到了NE5532(曾经的“运放之皇”)做前置放大芯片，典型的增益为20dB；用NSC公司的LM1036做音调芯片，通过改变直流控制电压来实现音调控制。后级功率放大部分用的也是NSC公司的一款经典芯片――LM1875芯片，用4片LM1875驳接成了左右声道的BTL电路,以取得更大的功率以及更好的音效。

在论文的后面部分，着重的讲述了制作和调试中遇到的软件、硬件上的问题以及如何解决，并给出了高保真音频放大器性能指标的国家标准测量方法。这些可以成为大家制作过程中的一些的提示以及测试的依据。

关键词：高保真；集成芯片；BTL；音调控制

Abstract

With the development of our country’s economy and the modern technology. People no –longer just enjoy the happy brought from material, they also learned to enjoy the spiritual things. For instance: Music, an old fashion of the enjoyments. And Hi-Fi(high fidelity) audio system is the very suitable intermedia for enjoying music.

So this dissertation focused on the Hi-Fi amplifiers for those primary audiophiles on this field. It tried to let people cost less and at the same moment , get enough enjoyment from Hi-Fi amplifiers and satisfy those basic standards of Hi-Fi system. This dissertation presented the ideas from easy to hard, and described the relative knowledge of the Hi-Fi audio system

with those graphics and diagrams. It also wrote about the details of the whole working process of this design gradually. This dissertation also introduced those characteristics of those chips used in my design, and how to realize those system’s targets given .The dissertation tried to introduce Hi-Fi audio system commonly,and let you learn some basic knowledge of this Hi-Fi system, at the same time , eventually learn how to accomplish a Hi-Fi audio amplifier.

Refer to the technology, IC was used to finish this graduate design, because it's relatively easier for primary audiophiles to design a audio amplifier. The pre-amp is NE5532, which was ever called as \by NSC(National Semiconductor Company) was used here for tone adjustment IC. And LM1036’s tone control can be controlled by changing the DC control voltage. The second amplifier IC is LM1875, also made by NSC. It is very classical . Four LM1875 chips were used to make a BTL(Balanced Transformer Less) circuit of each channel to achieve more power and to make the whole system’s timbre to be better.

The last paragraph of this dissertation, I mainly introduce some software and hardware problems I met during making the board and debugging, and how I solved those problems. Also I presented you the national standard test methods for audio amplifier characteristics. Hope these can be your hints and help during your executing for audio amplifier.

Key words: Hi-Fi; Integrated Circuit; BTL; Tone control

目 录

引言........................................................... 1 1 高保真音响系统 .............................................. 1

1.1 高保真音响系统定义 .................................................... 1 1.2 高保真音响系统组成 .................................................... 2

2 高保真功率放大器 ............................................ 3

2.1 功率放大器种类 ........................................................ 3 2.2 高保真功率放大器主要技术指标 .......................................... 4

3 功放电源 .................................................... 8

3.1 功放电源概述 .......................................................... 8 3.2 功放电源组成 .......................................................... 8 3.3 整流滤波电路 ......................................................... 10 3.4 稳压电路 ............................................................. 13

4 方案论证及阐述 ............................................. 14

4.1 设计要求 ............................................................. 14 4.2 方案论证 ............................................................. 14 4.2.1后级放大器方案选定 ................................................................................................... 14 4.2.2前置放大器方案选定 ................................................................................................... 14 4.2.3音调芯片方案选定 ....................................................................................................... 15 4.2.4电源方案选定 ............................................................................................................... 15 4.3 具体方案阐述 ......................................................... 15 4.3.1前级放大器方案阐述 ................................................................................................... 15 4.3.2后级放大器方案阐述 ................................................................................................... 19 4.3.3功放电源方案阐述 ....................................................................................................... 22

5 高保真功放制板 ............................................. 23

5.1 制板注意事项 ......................................................... 23 5.2 制板经验总结 ......................................................... 24 5.2.1制板步骤 ....................................................................................................................... 24 5.2.2Protel99se的使用经验总结 ....................................................................................... 25 5.2.3制板遇到的问题 ........................................................................................................... 26

6 功放调试 ................................................... 26

6.1 调试步骤 ............................................................. 27 6.2 模块调试 ............................................................. 27 6.2.1电源调试 ....................................................................................................................... 27 6.2.2音调模块调试 ............................................................................................................... 27 6.2.3前置放大模块调试 ....................................................................................................... 28 6.2.4后级功放模块调试 ....................................................................................................... 28 6.3 整体调试 ............................................................. 28

7 高保真功放性能指标测试 ..................................... 29

7.1 性能指标测试的必要性 ................................................. 29 7.2 主要性能指标测试 ..................................................... 29 7.3 测试所用仪器 ......................................................... 32 7.4 测试结论 ............................................................. 32

8 总结 ....................................................... 33

8.1 完成程度 ............................................................. 33 8.2 技术优点 ............................................................. 33 8.3 技术缺陷 ............................................................. 33 8.4 毕设感受 ............................................................. 33

谢 辞 ........................................................ 34 参考文献 ...................................................... 35 附 录 ........................................................ 36

附录1电路原理图 ......................................................... 36 附录2 PCB 图 ............................................................ 39

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