噪音测试仪设计-课程设计VIP专享VIP免费

噪音测试仪设计摘要：本文提出了一个噪音测试仪的设计方案，此测试仪能将外界噪声经过传声器转换成电信号。由运放LM324构成三级放大电路，峰值检波网络输出直流电平反应了噪声声压的大小。由LM331构成电压/频率转换电路，输出的频率信号变成TTL电平送给单片机的T0管脚，作为T0的计数脉冲。系统的核心部分是单片机AT89C51，其3.5引脚接入NE555构成的定时器输出的方波，通过T1中断去控制T0定时计数。从T0端输入的计数脉冲频率即反应了所测声压大小。最后经CC4511译码再驱动三位LED数码管显示。本设计的优点是电路简单、精度较高、实用性较强。关键词：噪声测试仪，传声器，电压/频率，AT89C51，LEDAbstract:Thispaperpresentsadesignofnoisetester,thistestercanoutsidenoisethroughthemicrophoneintoelectricalsignals.PosedbythethreeopampLM324amplifier,peakdetectornetworkoutputDClevelresponsetothesizeofthenoisesoundpressure.ConstitutedbytheLM331V/Fconverter,theoutputfrequencysignalintoaTTLleveltogivethemicrocontrollerT0pincountastheT0pulse.CoreofthesystemisthemicrocontrollerAT89C51,the3.5pinaccessNE555timeroutputconsistingofasquarewave,throughtheT1T0timerinterrupttocontrolthecount.T0-endedinputcountfromthepulsefrequencythatreflectsthesizeofthemeasuredsoundpressure.CC4511decodingandthendrivethefinalthreebytheLEDdigitaldisplay.Thisdesignhastheadvantageofsimplecircuit,highprecisionandstrongpracticability.Keywords:Noisetester,microphone,V/F,AT89C51,LED目录1前言...................................................................................................................................................................................12整体方案设计..................................................................................................................................................................22.1方案论证..................................................................................................................................................................22.2方案比较..................................................................................................................................................................33单元模块设计...................................................................................................................................................................43.1驻极体传声器..........................................................................................................................................................43.2集成四运放LM324...................................................................................................................................................43.3峰值检波电路..........................................................................................................................................................53.4LM331频率电压转换器...........................................................................................................................................63.5NE555构成的方波输出电路...................................................................................................................................73.6CC4511译码驱动电路.............................................................................................................................................83.7七段发光二极管数码管..........................................................................................................................