The book focuses on design technology of high-speed and high-performance direct digital frequency synthesizer (DDS) chip. The technologies involves phase to amplitude converter design, D/A converter design, phase accumulator design, multi-chip synchronization circuit design, etc. In each chapter, the concept of the technology is explained first, and then the features of different implementation schemes are introduced through the real design cases. More over, a design case of a 2.5GHz monolithic DDS in 0.18 m CMOS which was designed by the authors are introduced in detail, which can help the reader understanding about the of DDS design deeply. The book is suitable for the readers who are interested to learn practical design technology in DDS. The book can benefit researchers, engineers, and graduate students in fields of mix-signal IC design, communication engineering, electronics engineering, and radar engineering, etc.