编号：
毕业设计(论文)说明书
题 目： 合成立体声FM发射机设计 院 （系）： 专 业： 电子信息工程 学生姓名：
年 6 月 10 日
摘 要
发射机的主要任务是完成有用的低频信号对高频载波的调制，并将其变为在某一中心频率上具有一定带宽、适合通过无线发射的电磁波。调频发射机，首先将音频信号和高频载波调制为调频波，使高频载波的频率随音频信号发生变化，再对所产生的高频信号进行放大、激励、功放和一系列阻抗匹配，使信号输出到天线，发送出去的装置。高频信号的产生现在有频率合成。
本毕业设计利用所学的电子电路、射频、通信技术等方面的有关知识，实现了一个高品质频率合成立体声FM发射机系统的设计。该系统的发射功率为0.5W，工作频率在88MHz--108MHz可调，带宽为9kHz，灵敏度为200μV ，立体声输入方式。电路可靠有效发射距离为20米。用立体声FM收音机把频率调到发射频率上，可收到发射机发射的高保真音频信号。
关键字：调频发射机；电子电路；射频；通信技术；高保真音频信号
Abstract
The main task is to complete the transmitter useful in the low frequency signal carrier frequency modulation, and turn it into a center frequency at a certain bandwidth for wireless transmission by electromagnetic waves. FM transmitter, audio signal and the first for the FM frequency modulation wave, so that the frequency of the carrier frequency changes with the audio signal, and then on the generation of high-frequency signal amplification, motivation, power amplifier and a series of impedance matching, so that signal output to the antenna, sending out the device. High-frequency signal generation now has frequency synthesis.
The graduation use their electronic circuits, radio frequency, communications technology, knowledge, to achieve a high quality stereo FM transmitter frequency synthesizer system design, the system transmitting power to 0.5W, the operating frequency in the 88MHz - 108MHz adjustable bandwidth of 9kHz, the sensitivity is 200μV, stereo input. Circuit is reliable and effective transmission range of 20 meters. Stereo FM radio with frequency transferred to the transmitting frequency, the transmitter can receive high-fidelity audio signals emitted。
electronic circuits；RF；communications technology；high-fidelity Keywords: FM transmitter；audio signals
目 录
引言 ..................................................................... 1 1 概述 .................................................................. 1
1.1 调频发射机研究背景 .................................................... 1 1.2 调频发射机发展趋势 .................................................... 1
2 系统设计 ............................................................. 2
2.1 设计要求 .............................................................. 2 2.2 方案选择 .............................................................. 2 2.3 系统设计 .............................................................. 3
3 主要器件介绍 ........................................................ 4
3.1 单片机AT89S52 ........................................................ 4 3.1.1 AT89S52简介 ........................................................ 4 3.1.2存储器 .............................................................. 4 3.1.3定时器/计数器 ....................................................... 6 3.1.4 串口 ................................................................ 7 3.1.5 中断系统 ............................................................ 8 3.1.6编程语言和编程环境的介绍 ........................................... 10 3.2 BH1415集成芯片 ...................................................... 11 3.2.1BH1415概要 ......................................................... 11 3.2.2电路应用说明 ....................................... 错误！未定义书签。 3.3 LCD1602液晶 ......................................................... 12 3.3.1液晶显示简介 ....................................................... 12 3.3.21602字符型LCD ...................................................... 13
4 硬件设计 ............................................................ 17
4.1 单片机控制显示模块 ................................................... 17 4.2 发射模块 ............................................................. 18 4.2.1音频编码器 ......................................................... 18 4.2.2调频调制模块 ....................................................... 18 4.2.3功率放大模块 ....................................................... 19 4.2.4ALC控制模块 ........................................................ 19
5 软件设计 ............................................................ 20
5.1 系统程序框图 ......................................................... 20 5.2 各部分程序 ........................................................... 22
5.2.1初始化主程序 ....................................................... 22 5.2.2LCD1062的驱动程序 .................................................. 23 5.2.3按键检测 ........................................................... 24
6 硬件制作注意事项................................................... 25
6.1 布线注意事项 ......................................................... 25 6.2 腐蚀电路板注意事项 ................................................... 25 6.3 电路板检测与调试应注意的问题 ......................................... 26
7 系统实现的功能与系统调试 ......................................... 26
7.1 系统实现的功能 ....................................................... 26 7.2 系统功能调试 ......................................................... 26 7.2.1系统调试使用的设备 ................................................. 27 7.2.2系统调试步骤 ....................................................... 27 7.2.3系统调试遇到的问题 ................................................. 28
8 结论 ................................................................. 29 谢辞 .................................................................... 31 参考文献 ............................................................... 32