Common Mode Signal Generator Design Based On DDS

DDS——Direct Digital Frequency Synthesis is a new method of frequency synthesis and a revolution in frequency synthesis. It has a high frequency stability and a high frequency resolution. DDS has high-speed frequency switching time, a continuous phase frequency, low phase noise and digital automation. It can synthesize a variety of waveforms and achieve a high degree of integration.In radar, communications, electronics and other system areas, DDS has become the first choice with its outstanding advantages. It is widely used in spread spectrum, frequency hopping, digital broadcasting, high definition television and other fields. In the electronic measurement instruments, modernization instrumentations and other areas, it also has broad application prospects. DDS has gradually become the core technology of high-performance signal generator.In this paper, a common mode signal generator is designed based on Direct Digital Frequency Synthesis technology. Firstly, the concept of common-mode signal, the research background and significance are described. Secondly, the development of frequency synthesis history and current status are discussed. Thirdly, the principle of Direct Digital Frequency Synthesis technology is introduced, which includes the basic concept of DDS, the phase accumulator and sine look-up table. Fourthly, the common mode signal generator is described, which includes hardware design, software system design and system debugging. Hardware circuit includes the selection of the chip, the circuit design of signal generation, signal input and signal output. Software system includes signal generation module and interpersonal interaction module. Debug section includes hardware debugging, software debugging, and the debugging results. Finally, a brief summary is presented. According to the problems of the design process, the paper presents methods to improve the common mode signal generator.