The Design Of DDS Based On FPGA

The technology of Frequency synthesis which contains of Direct Synthesis, Phase-locked Synthesis and Direct Digital Synthesis is widely used in the field of communication, radar, electronic confrontation, aeronautics, instrument and so on.The direct digital frequeney synthesizer is a kind of fully digitized fequeney synthesizer, which based on digital sampling technology and consists of phase accumulator,ROM look-up table, digital to analog converter, and low pass filter. It has the advantages of high frequency resolution,fast frequeney switching speed, the ability to maintaining constant phase while switch frequency,low phase noise. The error brought by quantization has been the challenges facing digital circuit, the design use 32-bits phase accumulator, meanwhile proposed ROM compression algorithm, which greatly improved the accuracy .Firstly,the dissertation reviews the history of frequeney synthesis techniques,and summarized the characteristics of the direct digital frequeney synthesis techniques and application in all fields,and analysis the feasibility and significance of realizing the dircet digital frequeneyt technique based on Field Programmable Gate Array(FPGA);Secondly, it analysis the structure of the direct digital frequency analysis and the relationship between input and output, then analysis the spectrum characteristics of the output signal in detail,meanwhile it discusses the source of the stray and the method to inhibit the stray; Thirdly, it introduces the FPGA devices made by Altera company and the development software and design process;Then,it designes each module of DDS system by Verilog language and integrates simulation, and produces sine wave, cosine wave, square wave, sawtooth wave ;Finally, it analysis the results of the output。...