标签: nyquist

DirectNyquistarraydesignofPIDcontrollersforboiler-turbineunitsbasedongainandphasemargins

ADC和DAC基础(第一部分).ADC和DAC基础（第一部分）本系列文章分为5个部分，第一部分介绍采样的概念以及奈奎斯特（Nyquist）采样准则。第5部分同样也说明了如何运用欠采样和抗混叠滤波器。ByWaltKesterandJamesBryant,AnalogDevices作者：WaltKester和JamesBryant，美国模拟器件公司引言图2-1所示为典型的采样数据DSP系统的方框图。在实际模拟到数字的转换之前，模拟信号一般要经过某些种类的信号调节电路，这些信号要执行像放大、衰减和滤波这样的功能。需要用低通/带通滤波器把不需要的信号从有用带宽中消除掉，并能防止混叠发生。图2-1：基本的采样数据系统图2-1所示的系统为一个实时系统，也就是说到ADC的信号是以等于fs的速率被连续地采样，然后ADC又以这样的速率向DSP提供新的样本。为了保持实时的工作，DSP必须在采样间隔内执行所有需要的计算1/fs，并在来自ACD的下一个样本出现之前，把输出样本提供给DAC。典型的DSP功能的实例即是数字滤波器。在FFT分析中，数据模块首先被传输到DSP内存中。FFT在新的数据模块被传输到存储器时被计算，以便保持实时的操作。在数据传输间隔期间，DSP必需计算FFT，以便为处理下一个数据模块做好准备。要注意的是：只有在DSP数据必须被转换回模拟信号(例如在语音带宽或视频应用)的情况下，才需要DAC。在许多应用中，在最初的A/D转换后，信号要完全地保持数字格式。同样，在一些应用中，如在CD播放器电子设备中,DSP单独负责产生到DAC的信号。如果采用DAC，也必须采用抗镜像滤波器把镜像频率消除。在实际的模拟到数字和数字到模拟的转换过……

Abstract:Thisarticleanswersmostofthecommonquestionsregardingdataconverters.PresentedinaclassicFAQformat,itaddressestopicsincluding:defininganADCandDAC,andunderstandingtheirprincipalfunctions;theNyquist,effectsofchargeinjection;techniquesfordigitalfiltering;interfacingtoaserialport,I²Cinterface,andSPI™interface;bitbanging;MICROWIREinterface;PCB(PC-board)layouttipsandguidelines;groundingtips;bypasscapacitor(s)'effectonperformance;debuggingADCaccuracy;anddebuggingnoisymeasurements.Maxim>AppNotes>A/DandD/AConversion/SamplingCircuitsKeywords:ADC,DAC,analogtodigital,digitaltoanalog,convertor,converter,dataconverter,dataconvertor,Sep24,2009glossary,FAQ,nyquist,chargeinjection,digitalfiltering,serialport,I2C,SPI,bitbanging,microwire,PCboardlayout,groundingtips,bypassAPPLICATIONNOTE801FrequentlyAskedQuestionsaboutDataConvertersAbstract:Thisarticleanswersmostofthecommonquestionsregardingdataconverters.PresentedinaclassicFAQformat,itaddressestopicsincluding:defininganADCandDAC,andunderstandingtheirprincipalfunctions;theNyquist,effectsofchargeinjection;techniquesfordigitalfiltering;interfacingtoaserialport,ICinterface,andSPIinterface;bitbanging;MICROWIRE……

Abstract:Thefollowingapplicationnoteprovidesaninsightintothemathematicaldefinitionsofquantizationandthermalnoise,parameterswhichcansignificantlyaffectthesignal-to-noiseratio(SNR)andsignal-to-noiseplusdistortion(SINAD)specificationsofanalog-to-digitalconverters(ADCs)inRFreceiverapplications.ItconcludesbycomparingtheirimpactontheeffectivenoisefigureforaNyquistandoversamplingADC.Maxim>AppNotes>A/DandD/ACONVERSION/SAMPLINGCIRCUITSBASESTATIONS/WIRELESSINFRASTRUCTUREHIGH-SPEEDSIGNALPROCESSINGKeywords:quantizationnoise,thermalnoise,noisefigure,ADC,analogtodigitalconverter,NyquistADC,Sep09,2002oversampling,signaltonoiseratio,SNR,signaltonoiseanddistortion,SINAD,noisepowerdensity,RF,receiver,highspeedADCs,analogdigitalconverAPPLICATIONNOTE1197HowQuantizationandThermalNoiseDetermineanADC'sEffectiveNoiseFigureAbstract:Thefollowingapplicationnoteprovidesaninsightintothemathematicaldefinitionsofquantizationandthermalnoise,parameterswhichcansignificantlyaffectthesignal-to-noiseratio(SNR)andsignal-to-noiseplusdistortion(SINAD)specificationsofanalog-to-digitalconverte……

Abstract:Digital-to-analogconverters(DACs)convertdigitaldatatoanalogvoltageorcurrentinapplicationssuchasinstrumentationandwirelesscommunications.ADAC'soutputfrequencygenerallyrangesfromDCtolessthanfS/2,wherefSistheinput-updatingfrequency.TheoutputfrequencyresponseformostDACs,however,rollsoffaccordingtothesin(x)/x(sinc)frequency-responseenvelope.Maxim>AppNotes>A/DandD/ACONVERSION/SAMPLINGCIRCUITSBASESTATIONS/WIRELESSINFRASTRUCTUREDIGITALPOTENTIOMETERSHIGH-SPEEDSIGNALPROCESSINGWIRELESS,RF,ANDCABLEKeywords:preequalization,postequalization,frequencyresponse,sinx/x,sincfunction,interpolation,Nyquist,imageJun01,2006frequency,reconstructionfilter,FIR,roll-offAPPLICATIONNOTE3853EqualizingTechniquesFlattenDACFrequencyResponseAbstract:Digital-to-analogconverters(DACs)convertdigitaldatatoanalogvoltageorcurrentinapplicationssuchasinstrumentationandwirelesscommunications.ADAC'soutputfrequencygenerallyrangesfromDCtolessthanfS/2,wherefSistheinput-updatingfrequency.TheoutputfrequencyresponseformostDACs,however,rollsoffaccordingtothesin(x……

Abstract:Acommonviewholdsthatdigitalcircuitsjustworknaturally,butanalogcircuitsarehardtoimplement.Thereistruthtothatoldbelief—analoginterfaceisanexpertsubjectthatrequirestraining.Itis,moreover,alwaysbettertoavoidanissuethantotrytosolveitlater.Thisispreciselywhyweshouldtakeadvantageofsomebasicconceptsthatexperiencedanalogengineersperformasareflex.Thisapplicationnoteprovidessomebasicremindersandconceptsaboutamplifiersandfiltersforyoutoconsiderduringadesign.Maxim>Designsupport>Appnotes>A/DandD/AConversion/SamplingCircuits>APP4993Maxim>Designsupport>Appnotes>AmplifierandComparatorCircuits>APP4993Maxim>Designsupport>Appnotes>AnalogSwitchesandMultiplexers>APP4993Keywords:digitalpotentiometer,lowpassfilter,filter,low-passfilter,lowpassfilte,antialiasing,sampleddatasystem,folded,Nyquist,dataconverters,spectrum,harmonics,FFT,ADC,convolution,DAC,opamps,RC,LC,ButterworthMar08,2011APPLICATIONNOTE4993ReducetheChancesofHumanError:Part2,SuperAmpsandFiltersforAnalogInterfaceBy:BillLaumeister,StrategicApplicationsEngineerAb……

摘要：本应用笔记提供了量化和热噪声，它可以显着影响信号信噪比（SNR）和信号与噪声加失真比（SINAD）规格的模拟参数的数学定义的洞察力-数字转换器（ADC）的RF接收器应用。最后通过比较为奈奎斯特采样ADC的有效噪声系数的影响。Maxim>AppNotes>A/DandD/ACONVERSION/SAMPLINGCIRCUITSBASESTATIONS/WIRELESSINFRASTRUCTUREHIGH-SPEEDSIGNALPROCESSINGKeywords:quantizationnoise,thermalnoise,noisefigure,ADC,analogtodigitalconverter,NyquistADC,Sep09,2002oversampling,signaltonoiseratio,SNR,signaltonoiseanddistortion,SINAD,noisepowerdensity,RF,receiver,highspeedADCs,analogdigitalconverAPPLICATIONNOTE1197HowQuantizationandThermalNoiseDetermineanADC'sEffectiveNoiseFigureAbstract:Thefollowingapplicationnoteprovidesaninsightintothemathematicaldefinitionsofquantizationandthermalnoise,parameterswhichcansignificantlyaffectthesignal-to-noiseratio(SNR)andsignal-to-noiseplusdistortion(SINAD)specificationsofanalog-to-digitalconverte……

摘要：数字-模拟转换器（DAC）将数字数据转换成模拟电压或电流的仪器和无线通信等应用。一个DAC的输出频率范围从DC到低于FS/2，其中FS是输入更新频率。然而，对于大多数的DAC输出频率响应，推出了根据SIN（X）/X（SINC）频率响应信封。Maxim>AppNotes>A/DandD/ACONVERSION/SAMPLINGCIRCUITSBASESTATIONS/WIRELESSINFRASTRUCTUREDIGITALPOTENTIOMETERSHIGH-SPEEDSIGNALPROCESSINGWIRELESS,RF,ANDCABLEKeywords:preequalization,postequalization,frequencyresponse,sinx/x,sincfunction,interpolation,Nyquist,imageJun01,2006frequency,reconstructionfilter,FIR,roll-offAPPLICATIONNOTE3853EqualizingTechniquesFlattenDACFrequencyResponseAbstract:Digital-to-analogconverters(DACs)convertdigitaldatatoanalogvoltageorcurrentinapplicationssuchasinstrumentationandwirelesscommunications.ADAC'soutputfrequencygenerallyrangesfromDCtolessthanfS/2,wherefSistheinput-updatingfrequency.TheoutputfrequencyresponseformostDACs,however,rollsoffaccordingtothesin(x……

摘要：一种常见的观点认为，数字电路的工作只是自然，但模拟电路是很难实现的。有真相，旧的信仰模拟接口是一个专家的课题，需要培训。，而且，它总是更好，以避免一个问题，而不是试图解决以后。这正是为什么我们应该采取的一些基本概念，有经验的模拟设计工程师作为反射执行的优势。本应用笔记提供了一些基本的提醒有关放大器和滤波器为您和概念设计过程中考虑。Maxim>Designsupport>Appnotes>A/DandD/AConversion/SamplingCircuits>APP4993Maxim>Designsupport>Appnotes>AmplifierandComparatorCircuits>APP4993Maxim>Designsupport>Appnotes>AnalogSwitchesandMultiplexers>APP4993Keywords:digitalpotentiometer,lowpassfilter,filter,low-passfilter,lowpassfilte,antialiasing,sampleddatasystem,folded,Nyquist,dataconverters,spectrum,harmonics,FFT,ADC,convolution,DAC,opamps,RC,LC,ButterworthMar08,2011APPLICATIONNOTE4993ReducetheChancesofHumanError:Part2,SuperAmpsandFiltersforAnalogInterfaceBy:BillLaumeister,StrategicApplicationsEngineerAb……

摘要：本应用笔记提供了一个视频数字化的概述，并产生频谱边带。文章分析到模拟视频转换成数字视频后面的过程，并解释如何视频重建需要适当的过滤技术。提供的例子，以避免或减少云纹效果和图片文物。Maxim>AppNotes>GeneralEngineeringTopicsKeywords:analog,video,reconstruction,moiré,picture,artifacts,digital,quantization,low,pass,filter,anti-alias,converter,ADC,DAC,Sep18,2008clock,sample,boxcar,Nyquist,Standard,Definition,SD,PAL,NTSC,High,HD,ATSC,MPEGAPPLICATIONNOTE4287ReconstructingAnalogVideowiththeMaximVideoFilterFamilyBy:BillLaumeisterAbstract:Thisapplicationnoteprovidesanoverviewofvideodigitization,andthespectrumandsidebandsproduced.Thearticleexaminestheprocessofconvertingdigitalvideobackintoanalogvideoandexplainshowvideoreconstructionrequiresproperfilteringtechniques.Examplesareprovidedtoavoidorminimizemoiréeffectsandpictureartifacts.IntroductionOnceanalogvideoiscapt……