本系统分电压测量和信号产生输出两大部分，电压测量部分以模拟电路为主，配合放大模块、A/D转化模块、显示模块；通过凌阳单片机进行数据处理，在误差允许范围内显示测量电压值。信号产生以直接数字式频率合成器(Direct Digital Frequency Synthesis,简称DDS或DDFS)为核心，经过AT89S52对DDS芯片内部进行控制，使之输出标准正弦波形，利用编程实现频率预置、步进，达到电压输出频率的可调节步进。通过调试与测量完成了题目的基本部分和全部发挥部分的要求并有自己的创新-This system consists of the parts of the voltage measurement and the signal generation output. The voltage measurement mainly focuses on analog electric circuit, with using amplifier module, A/D conversion module and displaying module. In the certain range where errors are allowed to deal with data through SPCE061A microcontroller, the signal generation regards direct Digital Frequency, or DDS/DDFS as the centre, which is controlled by AT89S52 to output sine waveform. Then it can set up frequency and step to adjust the step of voltage output frequency. Through to debugging and measure the system performs the basic and expanding demands .we have some addition innovation.

Keywords：SPCE061A ，AT89S52 ，millivoltmeter , DDS