FFT在单片机上的实现.doc

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1、.FFT在单片机上的实现摘要音频信号分析仪是一种可广泛见于各种音响、调音和录音设备上的，能实时地采样及分析输入的音频信号的频谱，并将其显示在显示屏上的设备，使人在聆听音乐时能对音乐的高低频能有直观的了解。本文所介绍的即是这样一个音频信号分析系统。系统的硬件由信号调理、控制处理器、显示模块三部分组成。信号调理电路使信号可输入300mV~3V的交流音频信号。这里只对单路信号处理：当电压较低时使用LM324运放获得增益，对超过12800Hz的信号进行滤波处理。另外设置输出音频接口以便监听。控制处理器采用51内核1T单片机STC12C60A5

2、S2，晶振频率为32.768MHz。该单片机自带8路10位高速ADC，这里只用1路ADC的高8位。对信号连续采32个点进行浮点型FFT运算。一次完整采样的时间为1.25ms，最高采样频率为25600Hz，分辨频率为800Hz~12800Hz，分16级。显示部分主体为1602液晶显示屏，其具有2行×16列的8×5点显示点阵。16分频谱将分别以柱高形式显示在显示屏上。程序中设置了频率下落效果以使观感更好。另设置了对比度调节电阻，使屏幕对比度可调。关键词：FFT单片机音频频谱..THEREALIZATIONOFFFTINTHEMICROCO

3、NTROALERABSTRACTAudiosignalanalyzerisakindofdevicewhichcanbewidelyfoundinvariousofaudio,mixingandrecordingdevices,andcansamplingandanalysisofthespectrumoftheinputhaveanintuitiveaudiosignalanddisplaysitonthedisplayinreal-time,peoplecanarelisteningtoMusicformusicwhenhighf

4、requencyunderstanding.Whatpresentedinthisarticleisjustsuchanaudiosignalanalysissystem.Thehardwareofthesystemareformedwiththreeparts:thesignalconditioner,thecontrolprocessor and thedisplaymodule.Signalconditioningcircuitmakesthesignalof300mV~3VACaudiosignalavailableforin

5、putting.Inthissystem,weonlyprocesswithsingle-channelsignal:WhenthevoltageislowerthesystemusesLM324opamptogainvoltage,andastosignalsmorethan12800Hzitfiltersthem.Inadditionthesystemsetsanoutputaudiointerfaceformonitoring.Thecontrolprocessorofthesystemisthe51cores1TMCUSTC1

6、2C60A5S2,with32.768MHzcrystalfrequency.Thedevicecomeswith8-channel&10-bithigh-speedADC,whereonlyonechannelADChigh8.Thesignalcollected32pointsinconsecutivefloating-pointFFToperation.Acompletesamplingtimeis1.25ms,themaximumsamplingfrequencyis25600Hz,andthedistinguishfrequ

7、encyis800Hz~12800Hz,with16levels.Themaindisplaysectionis1602LCDscreen,whichhas2rows×16columns-8×5dotdisplaymatrix.16pointstothecolumnheightspectrumwillbedisplayedonthedisplay.Theprocessofsettingofthefrequencydropintheperceptionofbettereffect...Thereisalsocontrastadjustm

8、entresistor,whichmakesthescreencontrastadjustable.KEYWORDS：FFT,MCU,AUDIOSPECTRUM目录第1章绪论1§1.1研究的背景及意义1§1.1.1课题研