基于LABVIEW的虚拟滤波器设计

毕业设计（论文）题目基于LabVIEW的虚拟滤波器设计姓名学号所在学院专业班级指导教师日期2013年5月24日I摘要电子技术和计算机技术的快速发展促进了硬件软件化，使基于个人计算机的测控仪器——虚拟仪器得到了快速的发展。虚拟仪器利用计算机强大的处理能力，使得其在智能化程度、处理能力和可操作性等方面均具有明显的技术优势，其应用范围也越来越广泛。LabVIEW是一种基于图形化编程语言的开发环境，为虚拟仪器设计者提供了一个便捷、轻松的设计环境。本文首先用LabVIEW设计一个信号发生器，信号类型(如正弦波、方波、锯齿波等）、幅值、相位、频率等参数均可调，其次，给信号发生器产生的信号加噪（如高斯白噪声、均匀白噪声、随机噪声等），要求噪声的幅值和采样信息等值均可调，然后，用LabVIEW设计一个虚拟数字滤波器要求滤波器的频带类型（如低通、高通、带通、带阻）、最佳特性逼近方式（巴特沃斯、切比雪夫、贝塞尔等）、阶数以及高截止频率和低截止频率等参数均可调，将加噪后的波形通过所设计的虚拟滤波器，将它用波形图显示出来，最后，将原始信号与滤波后的信号进行傅里叶变换，在频域显示幅值和相位。比较加噪后的波形与滤波后的波形，发现噪声很大程度地滤除。关键词：虚拟仪器；滤波器；LabVIEWIIAbstractWiththerapiddevelopmentofelectronictechnologyandcomputertechnology,thehardwareisorientedtosoftware.Thecontrolinstruments---thevirtualinstrumentsbasedonthepersonalcomputerarepromptedrapidly.Thevirtualinstrumentshaveobviousadvantagesinthedegreeofintelligence,processingpowerandmaneuverabilitybecauseofthecomputer’sstrongprocessingpower.Andtheirapplicationismorewide.LabVIEWisadevelopmentenvironmentbasedonthegraphicalprogramming.TheconvenientandrelaxeddesignenvironmentforvirtualinstrumentdesignersisprovidedbyusingLabVIEW.Inthispaper,asignalgeneratorisdesignedbyusingtheLabVIEWatfirst.Thesignalgenerator’ssignaltype(sine,square,sawtooth,etc.),amplitude,phase,frequencyandotherparameterscanbeadjusted.Secondly,anoise(Gaussianwhitenoise,uniformwhitenoiserandomnoise,etc.)isaddedintothesignal.Theamplitudeofthenoiseandthetypeofthenoiseandsamplingtheinformationequivalentscanbeadjusted.ThenadigitalfilterisdesignedbyusingtheLabVIEW.Thefrequencyband(lowpass,highpass,bandpass,bandstop,etc.),thebestcharacteristicsofapproximationway(Butterworth,Chebyshev,Bessel,etc.),thenumberoforderaswellasthefrequencyofthehighcut-offandlowcut-offfrequencyandotherparameterscanbeadjusted.Thewaveintowhichthenoiseisaddedistranferredtothevirtualfilterandthenit’sdisplayedinthewaveform.Finally,theoriginalsignalandthefilteredsignalarehadtheFouriertransformanddisplayedinthefrequencydomainconcludingamplitudeandphase.Comparingtheoriginalwaveandthewavewiththenoise,wefindthatthenoiseisfilteredatalargeextent.Keywords:Virtualinstrument;Wavefilter;LabviewIII目录摘要...............................................................................................................................IAbstract.........................................................................................................................II第一章绪论................................................................................................................11.1虚拟仪器的发展趋势.....................................................................................11.2课题的目的及意义.........................................................................................11.3课题内容.........................................................................................................2第二章LabVIEW与虚拟仪器..................................................................................32.1虚拟仪器技术概述.........................................................................................32.1.1虚拟仪器的定义..................................................................................32.1.2虚拟仪器的分类..................................................................................32.1.3虚拟仪器与传统仪器比较的优势......................................................52.2虚拟仪器开发平台.........................................................................................72.3LabVIEW中的基本概念................................................................................82.4本章小结.........................................................................................................9第三章信号发生器....................................................................................................103.1测试信号的基本类型...................................................................................103.2测试信号的分析处理...................................................................................103.3在LabVIEW中设计信号发生器................................................................113.4本章小结.......................................................................................................13第四章滤波器..........................................................................................................144.1滤波器的概念.......................................................................................144.2滤波器的分类...............................................................................................144.3理想滤波器...................................................................................................174.4实际滤波器的主要参数...............................................................................184.5在LabVIEW中设计滤波器........................................................................204.6本章小结.......................................................................................................21第五章测试信号的频域分析与处理......................................................................225.1离散时间傅里叶变换及其LabVIEW实现................................................225.1.1数字信号处理中存在的误差及其解决办法....................................225.1.2DFT的