在介绍超声波相关流量计工作原理基础上,论证了产生高精度正弦波的必要性。分析了DDS 技术的工作原理及结构,最后还提出了一种应用DDS 芯片AD9850 和DSP 芯片TMS320VC5402 组成的正弦波信号、AM 和FM 信号发生器。通过实测数据表明,本文所讨论的方法和研制的系统是可行的、有效的。 关键词:直接数字频率合成(Direct Digital Synthesis);DSP;互相关;FPGA Abstract: Principle and measure method of ultrasonic correlative flowmeter is introduced in this paper at first. On the basis of it, the necessity of generating high precision sine wave is demonstrated. Not only structure and rule of DDS technology, but also basic principle and performance of AD9850 are discussed. Finally, not only sine wave signal generator but also AM and FM signal generator composed of DDS chip AD9850 and DSP chip TMS320VC5402 are designed. The results of experiments verify that the technique and the system in this paper are feasible and effective. Keyword: DDS; DSP; correlation; FPGA