扩音电话机的设计

论文编号:JD790 任务书,开题报告， 论文字数:20793,页数:50

摘  要

本扩音对讲电话系统广泛应用于石油、化工、冶金、医药、煤炭等行业的生产场所，满足在此类易燃、易爆、强噪声的特定场合下对通信系统的要求。
本论文通过对扩音对讲电话系统所应具有的功能、以及其实用价值进行深入分析的基础上，提出了单片机结合软件程序控制系统协调工作的软/硬件方案，并且给出了详细的硬件电路介绍以及软件实现机理。主要介绍了扩音电话的整个工作过程，以及实现放大振铃和主叫话音的方法。由此最终实现了对振铃和主叫话音的放大。
本论文解决了普通电话在某些特定的工业生产场所难以满足通信要求的问题，为扩音电话在工业生产场所的广泛应用提供了有益探索。
扩音电话具有成本低、利用率高，通信联系迅速，使用和维护简便等优点，具有广泛的应用前景和使用价值。

关键词：电话；扩音；AT89C2051

ABSTRACT

Amplifying call and telephone talk system is extensively applied in the production place of professions, such as oil, chemistry, metallurgy, medicine and coal mining etc., meeting the demands of communication system in the inflammable and explosive, large-scaled and strong-noised working place.   
Based on the thorough analyzing function and practical value which amplifying call and telephone talk system should have, this thesis proposed the hardware and software scheme, which PC with software program controls system to work hormonally, and presented the introduction of hardware-circuit and software-realizati- on processes in detail. it mainly introduced the whole work process of amplifying call and telephone talk system, and the realization method that amplified the bell and calling sound of the amplifying call and telephone talk system .then this ultimately carried out the amplify of the bell and calling sound.
This thesis solved the problem that a common telephone hard satisfied the correspondence request at some particular industry producing place and provided beneficial quest of the amplifying call and telephone talk system extensively applied in the industrial filed.
Amplifying call and telephone talk system has many advantages such as low cost, high utilization ,fast communication ,convenience for using and maintaining and so on. It has a wide prospect and high value of application.

Key words：telephone; amplifying; AT89C2051

目  录
 
前   言 1
第一章 系统的组成和功能 2
1.1 系统的组成 2
1.2 系统的功能 3
第二章 扩音电话硬件设计 4
2.1 总体设计思想 4
2.2 扩音电话的硬件组成 4
2.3 电话机部分 5
2.3.1 通话电路 6
2.3.2 拨号电路 8
2.3.3 振铃电路 10
2.4 单片机控制部分 12
2.4.1 单片机AT89C2051简介 12
2.4.2 输出控制电路 15
2.4.3 输入电路 16
2.4.4 功率放大电路 19
第三章 系统的软件设计 21
3.1 8051的编程语言 21
3.1.1 C语言的特点 21
3.1.2 CX51编译器---KEIL 22
3.1.3 软件开发流程 23
3.2 系统程序 25
3.3 主程序模块 25
3.4 T0中断服务子程序 26
3.5 系统工作过程 28
第四章 系统的抗干扰措施 29
4.1 干扰及干扰对系统的影响 29
4.1.1 干扰源 29
4.1.2 干扰窜入系统的渠道 29
4.1.3 干扰对系统的影响 30
4.2 抗干扰的硬件措施 30
4.2.1 去藕滤波 30
4.2.2 印刷电路板设计 31
4.2.3 反电势抑制 32
4.3 抗干扰软件措施 33
4.3.1 数字滤波 33
4.3.2 重复执行 33
4.3.3 数字量输入锁存 33
4.3.4 软件看门狗 34
结  论 35
参考文献 36
附   录 37
谢    辞 47