毕业设计（论文）--基于AT89S52单片机的DDS信号发生器设计.doc

摘　要 信号发生器又称信号源或振荡器，在生产实践和科技领域中有着广泛的应用。各种波形曲线均可以用三角函数方程式来表示。例如在通信、广播、电视系统中，都需要射频（高频）发射，这里的射频波就是载波，把音频（低频）、视频信号或脉冲信号运载出去，就需要能够产生高频的振荡器。在工业、农业、生物医学等领域内，如高频感应加热、熔炼、淬火、超声诊断、核磁共振成像等，都需要功率或大或小、频率或高或低的振荡器。 本设计主要有三大模块，主控制器模块、信号发生模块和液晶显示模块。采用AT89S52单片机为主控制器，由它来控制DDS芯片AD9835再通过DAC0832，它是一个8位的数模转换器，可以完成数字量输入到模拟量输出的转换，然后经运放调节电压幅度，产生1MHz～15MHz的正弦波和方波，最后由液晶屏显示。液晶屏采用的是四线电阻触摸式。其重点讨论了AD9835基本工作原理、DAC数模转换及其与89S52单片机控制系统的硬件结构和软件设计框图，此外还增加了触摸屏，应用起来比较方便。 关键词：单片机89S52；AD9835芯片；DAC0832；触摸屏 Abstract Signal generator is signal power or oscillator in production practice and science and technology has been widely used in the field. Various waveform curve can be expressed by trigonometric function equations. For example in telecommunications, broadcasting and television systems, high-frequency radio frequency (need) emission, here is the carrier of radio frequency waves, video and audio (low) signals or carrying out the pulse signal, need to be able to produce high-frequency oscillator. In industry, agriculture, biomedical fields, such as in high-frequency heating, smelting, quenching, ultrasonic diagnosis, nuclear magnetic resonance imaging, etc, all need power or big or small, high or low frequency or the oscillator. The three main module design, control module, signal module and LCD module. AT89S52 SCM, mainly adopted by it to control the controller chip AD9835 DAC0832 through spurious again, it is a of 8 bits can be completed digital-to-analog converters, digital input to the analog output conversion, then the op-amp regulation, to meet the requirements of the voltage waveform, finally by the display on the LCD panel. LCD USES is four line resistance feeling. This paper discusses the basic principle of work, and AD9835 89S52 interface, the single chip microcomputer control system, the hardware structure and software design, working principle and touch screen. Key words: SCM；AD9835 chip；DAC0832；TouchScreen 目 录 1 绪论 1 1.1 课题研究的意义与作用 1 1.2 DDS的研究现状与发展趋势 1 1.3 DDS系统简介 2 1.3.1 DDS的基本原理 2 1.3