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1、梧州学院毕业论文论文题目基于DDS的信号发生器系别电子信息工程系专业电子信息工程班级06电本6班学号学生姓名梁 平指导教师(签名)完成时间2010年1月摘 要本文论述了直接数字频率合成技术(DDS)的信号发生器的设计与实现。本设计以DDS芯片AD9850为频率合成器,以AVR单片机ATmega16为进程控制和任务调度核心,用AD603实现增益控制(AGC)和功率放大,串行数模转换器(D/A)MAX531实现方波占空比调节,并用LCD12864液晶显示及键盘构成幅度、频率、方波占空比均可调的函数信号发生器。在对AD9850频率控制字及参数的计算、增益控制、方波占空比调节、两相正弦波相位差调节
2、、LCD显示原理、底层驱动程序等简要讨论的基础上进行了研究,提出了该设计中所涉及到的问题以及解决方案,该信号发生器输出正弦波信号频率范围为1Hz~12MHz,方波信号频率范围为500Hz~500KHz;步进1Hz,10Hz,100Hz,lkHz,10kHz,100kHz,1MHz可键盘选取;正弦波的电压峰峰值可以在1~5V范围内步进调节,幅度调节精度达0.1V;方波占空比从10%~90%可任意设定;此外,该信号发生器能同时产生两相正弦波,相位差可以是0°,45°,90°。测试表明,该DDS信号发生器具有工作稳定、精度高、失真度小、频率范围大、步进选择多、控制灵活的优点,具有广泛的实际应用前
3、景。关键词:DDS芯片AD9850 AVR单片机 幅度调节 占空比调节IVAbstractThisarticleelaboratedthesignalgeneratingdevicedesignandtherealizationoftheDirectDigitalFrequencySynthesisTechnology(shortforDDS).ThedesignregardsDDSchipAD9850asfrequencysynthesizer,withAVRMicrocontroller(MCU)ATmega16fortheprocessingcontrolandtaskschedul
4、ing,andwithAD603torealizethegaincontrolandpoweramplification(AGC),andwithserialDAC(D/A)MAX531tocometosquare-wavedutycycleregulation,thenusingLCD12864liquidcrystaldisplayandkeyboardtocompositethefunctionsignalgenerationwithadjustedamplitude,frequency,dutycyclewave.Iwouldliketoproposetheinvolvingiss
5、uesandresolvingproposalsonthebasisofsimplyresearchingofwordsandparameterscountedwithAD9850control,gaincontrolanddutycyclewaveregulation,twophasesinewavephasedifferenceadjustment,LCDdisplayingprinciple,low-leveldrivers.Thesinewavesignalrateoutputtingfromsignalgeneratoris1Hz~2MHz:squaresignalrateis5
6、00Hz~500KHz;thestep-by-stepcanbechoosefromkeyboardby1Hz,10Hz,100Hz,1kHz,10kHz,100kHz,1MHz;sinewavevoltagepeakcanbeadjustedrangingfrom1to5Vbystep,amplitudemodulationreaches0.1V;dutycyclewavecanbeenactedarbitrarily;besides,thesignalgeneratorcancreatetwosinewaveatthesametime,andthedifferencecanbe0°,4
7、5°,90°.ItshowsthatDDSsignalgeneratorgetsthevirtuesofstableworking,highaccuracy,smalldistortion,largefrequencyrange,multi-stepselection,flexiblecontrol,owningawideprospectofpracticalapplication.Keywords:DDSchipAD9