Based On The Dds Frequency Synthesizer Design

The technology of frequency synthesis is important in latter-day communication system.It's widely used in wireless communication and electron system.With the high-speed development of technologies, higher stability, higher purity, broader range and larger output number of frequency are required in the frequency source of Frequency synthesizer which is the core of this technology.Single manner of frequency synthesis can have perfect effect on certain target. But no single one can meet all the technology requirements. In fact every manner has advantages and disadvantages, so we can simultaneously use several ones'advantages which is called mixed frequency synthesis technology. DDS and PLL mixed frequency synthesis technology is the most widely used one. Its basic principle is that we use the output of DDS to be the referenced input of PLL to resolve the conflict of frequency resolution and phase noise.This thesis first introduces the principle of DDS briefly in the dissertation, analyzes the function of each module, the frequency spectrum and spurs influence, and also points out the advantages and disadvantages. Then it gives the detailed introduction to the basic principle of PLL, and analysis of each module and the noise performance. Through the analysis and comparison among each realization method and performance of frequency synthesizers and as the topic require relatively large band width, we finally chose DDS + PLL scheme to achieve this topic and carried on the feasibility proof which shows that this scheme can meet the requirement of the system. In the realization process, we chose AD9854 and ADF4001 made by AD Corporation in the USA. And we selected ADSP2183 to be the control chip. This thesis has made simple introduction to the function and the use of these chips. At last we introduce the realization of all the parts, the problem in the circuit design and the measured data. The results show that the designed system has met the requirement.In this dissertation, direct digital synthesis technology has been used in the phase-locked frequency synthesizer, which can make full use of the characteristics of direct digital synthesis technology such as flexible output wave shape and continuous...