Wideband Low Spurious Dds Signal Generator Developed

With the development of frequency synthesis theory and high speed LSI (Large Scale Integration), the more demands of signal source are preferred, whether in military field or business field. So the higher speed DDS (Direct Digital Synthesizer) has emerged as the times require. DDS has many advantages, for example, high speed of frequency converting,high frequency distinguishing rate,compact package and programmable etc. Of course, DDS also has some demerits, such as narrow-band and high-spur. Fortunately, AD9858 is an extraordinary powerful DDS chip, which not only has all the advantages of general DDS, also has broad-band and low-spur, bringing more conveniences in the processing of the design. This design is mostly utilizing its advantages and decreasing its demerits influence. The first chapter introduces the development of frequency synthesis technology and DDS (Direct Digital Synthesizer) technology. The principle ,configuration and the spur distribution of DDS are introduced in the second chapter. The third chapter mostly introduces two chips -AD9858 and C8051F020 in the design. firstly, it demonstrates the design of the whole system, including bandwidth and spur; Secondly, the two parts including hardware and software are introduced in detail in the fourth chapter. The fifth chapter clarifies some problems that should be paid attention to in the process of debugging and testing. What's more, the author also puts forward some own opinions in this design. In the end, some testing results are presented, and all the parameters of the result attain the demands.