在介紹超聲波相關流量計工作原理基礎上，論證了產生高精度正弦波的必要性。分析了DDS 技術的工作原理及結構，最后還提出了一種應用DDS 芯片AD9850 和DSP 芯片TMS320VC5402 組成的正弦波信號、AM 和FM 信號發生器。通過實測數據表明，本文所討論的方法和研制的系統是可行的、有效的。
關鍵詞：直接數字頻率合成（Direct Digital Synthesis）；DSP；互相關；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