说明：  DDS介绍了一种DDS专用芯片AD9835,并利用该芯片设计了一种高精度频率信号发生器,讨论了DDS芯片的基本原理、应用及其与计算机、单片机的接口。
(A special chip AD9835 for DDS is introduced, and a high precision frequency signal generator is designed with this chip. The basic principle and application of DDS chip and its interface with computer and MCU are discussed.)