基于FPGA的实用多功能信号发生器的设计与制作

基于FPGA的实用多功能信号发生器的设计与制作基于FPGA的实用多功能信号发生器的设计与制作摘要多功能信号发生器已成为现代测试领域应用最为广泛的通用仪器之一，代表了信号源的发展方向。直接数字频率合成(DDS)是二十世纪七十年代初提出的一种全数字的频率合成技术，其查表合成波形的方法可以满足产生任意波形的要求。由于现场可编程门阵列(FPGA)具有高集成度、高速度、可实现大容量存储器功能的特性，能有效地实现DDS技术，极大的提高函数发生器的性能，降低生产成本。本文首先介绍了函数信号发生器的研究背景和DDS的理论。然后详尽地叙述了利用VerilogHDL描述DDS模块的设计过程，以及设计过程中应注意的问题。文中详细地介绍了多种信号的发生理论、实现方法、实现过程、部分VerilogHDL代码以及利用Modelsim仿真的结果。文中还介绍了Altera公司的DE2多媒体开发平台的部分功能及使用，并最终利用DE2平台完成了多功能信号发生器的大部分功能。包括由LCD显示和按键输入构成的人机界面和多种信号的发生。数字模拟转换器是BURR-BROWN公司生产的DAC902。该信号发生器能输出8种不同的信号，并且能对输出信号的频率、相位以及调制信号的频率进行修改设定。关键词：信号发生器；DDS；FPGA；DE2PracticalFPGA-basedmultifunctionsignalgeneratordesignandproductionAbstractMultifunctionsignalgeneratorhasbecomethemostwidelyusedinmoderntestingfieldofgeneralinstrument,andhasrepresentedoneofthedevelopmentdirectionofthesource.Directdigitalfrequencysynthesis(DDS)isatotalydigitalfrequencysynthesistechnology,whichbeenputforwardintheearly1970s.Usingalook-uptablemethodtosyntheticwaveform,itcansatisfyanyrequirementofwaveformproduce.Duetothefieldprogrammablegatesarray(FPGA)withhighintegrity,highspeed,andlargestorageproperties,itcanrealizetheDDStechnologyeffectively,increasesignalgenerator’sperformanceandreduceproductioncosts.Firstly,thisarticleintroducedthefunctionsignalgeneratoroftheresearchbackgroundandDDStheory.Then,itdescribedhowtodesignaDDSmodulebyVerilogHDL,andintroducedvarioussignaloccurstheory,methodandtheimplementationprocess,VerilogHDLcodeandsimulationresults.ThispaperalsointroducesthefunctionofDE2multimediadevelopmentplatform,andcompletedmostofthefunctionsofmulti-functionsignalgeneratoronDE2platformfinally.Includingtheoccurrenceofmultiplesignalandtheman-machineinterfacewhichcomposedbyLCDdisplayandkeyinput.Digital-to-analogconvertersisDAC902,whichproducedbycompanyBURR-BROWN.Thissignalgeneratorcanoutputeightdifferentkindsofsignals,andthefrequencyoftheoutputsignal,phaseandmodulationfrequencysignalalsocanbemodifyed.KeyWords:Signalgenerator;DDS;FPGA;DE2目录论文总页数：34页1引言......................................................................11.1课题背景...........................................................11.2国内外波形发生器的发展现状.........................................11.3本文研究的主要内容.................................................22信号发生器原理.............................................................22.1直接数字频率合成技术的基本原理.....................................22.2相位偏移控制.......................................................32.3多种信号的发生.....................................................32.3.1方波的发生.....................................................32.3.2三角波发生.....................................................42.2.3锯齿波发生.....................................................42.3.4PWM信号发生...................................................42.3.5SPWM信号发生..................................................52.3.6AM信号发生....................................................52.3.7FM信号发生....................................................62.4DDS的特点.........................................................72.4.1DDS的优点.....................................................72.4.2DDS系统的缺点.................................................73系统整体设计...............................................................83.1硬件部分...........................................................83.1.1DE2实验板.....................................................83.1.2LCD模块.......................................................93.1.2DAC902........................................................113.2基于VERILOG的FPGA设计...........................................123.3软件工具..........................................................123.3.1Modelsim......................................................123.3.2Quartus.......................................................123.4系统设计..........................................................133.4.1系统初始化模块................................................133.4.2按键模块和LCD模块............................................133.4.3RAM模块......................................................143.4.4数据转换模块..................................................153.4.5DAC驱动模块..................................................153.4.6系统的运行....................................................154VERILOGHDL代码实现与仿真...............................................154.1信号发生器模块....................................................154.1.1频率控制字和相位累加器........................................154.1.2相位偏移控制..................................................164.1.3正弦波发生模块................................................174.1.4方波发生模块..................................................174.1.5三角波发生模块................................................184.1.6锯齿波发生模块................................................184.1.7PWM信号发生模块..............................................194.1.8SPWM信号发生模块.............................................194.1.9AM信号发生模块...............................................204.1.10FM信号发生模块..............................................214.2按键输入模块......................................................224.3LCD显示模块..........................