摘要：多功能励磁器电路的设计核心是信号源的设计。信号源，广泛地应用于电子电路、自动控制系统和教学实验等领域。目前使用的信号源大部分是函数信号发生器，且特殊波形发生器的价格昂贵。因此，设计出性能良好的新型信号源产品是必然趋势，而多功能励磁器电路的设计对新型信号源的发展具有重要的实际意义。

　　　本文在研究国内外相关领域的文献和资料的基础上，对现今信号源技术开展了深入的研究，并设计一款新型的多功能信号源。本设计使用的是AT89c51单片机构成的发生器，可产生正弦信号和直流信号，正弦信号的励磁频率可用程序控制改变。在单片机上加外围器件距阵式键盘，通过键盘控制波形频率的增减以及波形的选择，并用了LCD显示频率大小。在单片机的输出端口接DAC0832进行D/A转换，再通过运放进行波形调整，最后输出波形接在示波器上显示。并具体分析了各个部分的实现技术以及相互之间的关系。其次重点阐述了液晶显示模块，给出了硬件接线图，以及硬件时序图和相关程序并作出简单介绍。本设计具有线路简单、结构紧凑、价格低廉、性能优越等优点。

    本文研究内容对信号源的发展具有重要的意义，随着社会的发展，信号源系统结构和运行方式的日趋复杂，对信号源运行的可靠性、稳定性、经济性和灵活性提出了更高的要求。因此,开发出性能良好的新型信号源产品，无论对于信号源理论研究还是对实际应用都有着重大的意义。 

关键词：信号源 AT89c51单片机 D/A转换

ABSTRACT：Multi-function exciter circuit design of the core is the design of signal source. Signal source, widely used in electronic circuits, automatic control system and the teaching experiment and other fields. Currently use most of the signal source is the function signal generator, and special waveform generator is expensive. Therefore, designed a new signal source of good performance products is the inevitable trend, and the design of the multi-function exciter circuit has important practical significance to the development of a new signal source.

   Based on the study of domestic and foreign related literature and data, on the basis of the current source technology conducted in-depth research, and designed a new type of multifunctional signal source. This design use AT89c51 generator that can produce sine signal and the dc signal, the excitation frequency sinusoidal signal available process control change. On the single chip microcomputer and peripheral devices from the matrix keyboard, through the keyboard control waveform frequency and waveform selection, increase or decrease with the size of LCD display frequency. In single-chip output port connect DAC0832 D/A conversion, again through the op-amp waveform adjustment, the output waveform displayed on the oscilloscope. And each part of the implementation of the technology are analyzed in detail, and the relationship between each other. Secondly expounds the liquid crystal display module, the hardware wiring diagram, timing diagram and hardware and related program and make a simple introduction. This design has the circuit simple, compact structure, low cost, superior performance etc.

   In this paper, the research content has important significance to the development of signal source, with the development of the society, the growing sophistication of signal source system structure and operation mode of signal source running reliability, stability, economy and flexibility to put forward higher request. Therefore, developed a new source of products performance is good, no matter theoretical research or in practical application for signal source is of great significance.

Keywords: Signal source；AT89c51 single-chip；D/A conversion

 经过考虑，本设计的主要内容是利用AT89C51单片机采用程序设计方法产生正弦信号和直流信号两种信号，再通过D/A转换器DAC0832将数字信号转换成模拟信号，滤波放大，最终由示波器显示出来，通过键盘来控制两种波形的类型选择、频率变化，最终输出显示其各自的类型以及数值。主要介绍设计的方案论证；系统硬件设计包括各单元电路设计；系统软件设计包括主程序和各个子程序；还有显示模块等。