摘 要：在电子技术领域，经常要用一些信号作为测量基准信号与输入信号，即是所谓的信号源。传统信号源采用振荡器，只能产生少数波形，自动化程度、灵活性以及准确性较低，而且仪器体积较大。现在要求信号源能产生波形种类多、频率高，而且还要求体积小、操作灵活、可靠性高、使用方便及可由计算机控制。所以要实现高性能的信号源，必须在技术上有新的突破。

本文设计了以STC89C51单片机为控制核心的高频信号源，该信号源包括AD9850信号产生模块、键盘和显示器等。AD9850能够产生正弦波信号，该正弦波信号可以通过其内置比较器转换为方波信号输出。键盘使用常用的4×4键盘，用于设定频率值，或者通过歩进值调整频率；LCD1602主要显示频率，实现人机信息交换。本设计可以同时产生正弦波、方波，并且电路具有搭建简单、调试方便、性能稳定和成本低的优点。93447

毕业论文关键词：高频信号发生器，单片机，AD9850，键盘，LCD1602液晶显示器

Abstract：In the field of electronic technology, it is often to use some signals acted as reference signal and the input signal, and that is what called signal source。 The traditional signal source uses the oscillator, it only can produce a few waveforms, the degree of automation,the flexibility and the accuracy is low, and the instrument volume is too big, Now, it is required that the signal source can generate many kinds and high frequency of waveforms, and signal source should be small size, flexible operation, high reliability, convenient operation and can be controlled by computer。 Therefore, in order to achieve high-performance signal source, there must be a new breakthrough in technology。

In this paper, we design a high frequency signal source, which is based on STC89C51 microcontroller。 The signal source comprises an AD9850 signal generation module, a keyboard, a display, etc。 AD9850 can generate sine wave signal, the sine wave signal can be converted into square wave signal output by its built-in comparator。 Use the keyboard used 4 x 4 keyboard is used to set the frequency value, or by advances in value adjustment frequency; LCD1602 display frequency, human-computer information exchange。 The design can produce sine wave and square wave at the same time, and the circuit has the advantages of simple structure, convenient debugging, stable performance and low cost。源F于K优B尔C论V文N网WwW.youeRw.com 原文+QQ752^018766

Keywords：High frequency signal generator, Micro controllers, AD9850, keyboard, LCD1602 liquid crystal display。

目录

1 引言 2

1。1 选题背景 2

1。2 设计任务和要求 4

2 总体设计方案 4

2。1系统设计原理 4

3 系统硬件模块的设计 5

3。2 键盘模块电路设计 8

3。3 LCD显示模块 8

3。4 AD9850 与单片机接口设计 10

3。5。滤波电路设计 14

4。2软件调试 16

5  硬件电路制作与调试 16

5。1 电路实现的基本步骤 16

5。2 原理图的绘制 17

5。3 印制线路板设计的主要问题 17

5。4 设计结果与调试