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ID:57300793
大小:203.00 KB
页数:22页
时间:2020-08-10
《ADC与DAC 动态性能测试.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、ADC与DAC衡量指标:静态指标:DNL,INL;动态指标:SNR,SINAD,THD,ENOB,IMD,etc.动态指标(1)静态指标反映的特点有限,主要是慢速变化特性,也称之为DC传输特性,对于高速D/A,A/D来说,更需要AC传输特性来表征,反映不同频率信号的响应。主要反映了D/A,A/D器件的高速工作情况下的性能,诸如,VEDIODAC,TXDAC,TXADC等,动态指标(2)SNR:SignaltoNoiseRatioSINAD:SignaltoNoiseAndDistortionRati
2、oTHD:TotalHarmonicDistortionENOB:EffectiveNumberOfBitsSFDR:Spurious-FreeDynamicRangeTwo-toneIMD……..FrequencyDomainAnalysisFt(M)FrequencyMagnitudeSH2H3H4H5NoiseHarmonicsFundamentalSignalSpurious动态特性的测试方法(1)对于DAC来说,相对简单一些,通过编程产生单频信号,然后将输出的信号发送到频谱分析仪。动态特性
3、的测试方法(2)DUT(ADC)AnalogSourceDigitalCaptureDataProcessing(FFT)SinusoidalWaveFrequencySpectrumnbitsClockSourceRXADC测试环境要求(1)Inputsignalrequests:1:Qualityofsignal:SNR,THD…….2:Amplitude,frequencyandcommonvoltageofsignal.3:fourorthogonaldifferentialsignals;
4、RXADC测试环境要求(2)Howtoselectsamplenumbers-----coherentsamplingFin/Fsample=Ncycle/Nrecord,Fin:PeriodicinputsignalFsample:SamplingfrequencyoftheADCNcycle:IntegernumberofcycleswithinthesamplingwindowNrecord:NumberofdatapointsinthesamplingwindoworFFTCoherents
5、amplingUncoherentsamplingWindowingRXADC测试环境要求(3)在rxadc的测试中,Fin=Ncycle*Fsample/NrecordFin(kHz)Fsamp(kHz)NrecordNcycle10.3819270.8336002340.1736270.8336008960.0347270.833600133RXADC测试环境要求(4)SpectralleakagesamplesequencenotmeetscoherentsamplingWindowingmi
6、nimizesspectralleakageWindowfunctionWindowtypes:Rectangular,Hamming,Hanning,Blackman……Howtoselectwindowfunction:1:-3dBbandwidth;2:-6dBbandwidth3:maximumside-lobelevel4:side-loberoll-offrateBlackmanwindows----singletonetestWindowsfunctionWindowsfunction
7、Calculation(1):FFTPs=sum{Pf(m-k):1:Pf(m+k)};Pdc=sum{Pf(1:k)};Ph=sum{Ph(2:n)};Ph(i)=sum{Ph(i-1:i+1)};Pn=sum(Pf)-Ps-Pdc–Ph;Signalbin的选择:Calculation(2):FFTS/N=10*log(Ps/Pn);SINAD=10*log[Ps/(Pn+Ph)];THD=10*log(Ph/Ps);SFDR=10*log[Ps/Pmax.spuriousLevel];ENOB
8、=(SINAD-1.763)/6.02SignalbinS/N=10*log(Ps/Pn);=====S’/N’=10*log[Ps(1+<>)/Pn(1-10%)]=10*log[10/9]+log(Ps/Pn)=0.46+S/NI/QmatchAnidealsinusoidalI/Qsignalpair:y(t)= Aexp(i(ωt+φ))= Acos(ωt+φ) + iAsin(ωt+φ)I/QmismatchAmplitudemismatchαandphas
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