| In the modern testing field, the signal generator is one of the most common, the mostbasic, also the most widely used electronic instruments. In the process of debugging andmaintenance of the electronic equipments, also in the student’s experiment and practice,the single generator is often used. Therefore,the research of the single generator of highaccuracy, good stability, low cost and multi-function is very important.DDS is the English abbreviations of the direct digital frequency synthesizer.Compared with the traditional frequency synthesizer, because of the advantages of lowcost,low power consumption,high resolution and fast converting speed,etc. DDS isWidely used in telecommunications and electronic instruments field, and becomes a keytechnology to realize full digital of the equipment. Because of the Functions of the highcalculation speed, high level of integration, flexible and realizing high capacity memoryfunction etc，DDS is Widely used in the design of the digital application-specificintegrated circuit. FPGA can effectively achieve DDS technology, reduce productioncost and improve the performance of the signal generator, to represent the futuredevelopment direction. At present the main technologies of making the signal sourceinclude: direct synthesis, indirect synthesis method and direct digital frequencysynthesis (DDS).This design applies DDS principle to realize the function of a DDS signalgenerator buited on FPGA, the hardware circuit consists of Power circuit，key showcircuit，AT89S52single-chip microcomputer, the field reprogrammable array FPGA,and high-speed D/A transformation，etc. the wave data of digital can be get from thefield programmable gates array (FPGA) by look-up table, then through high-speedanalog-to-digital conversion output the analog of waveform. The signal generator canaccurately adjust the phase and frequency of the waveform, and output of the wave ofhigh resolution, and finally realizes the digital display. The Design can output with twophase shifting sine signals, with steady waveform, frequency can be set, With an oscilloscope almost no distortion when observing. |
