ADC與DAC-動態(tài)性能測試

ADC與DAC衡量指標(biāo)：

靜態(tài)指標(biāo)：DNL,INL;

動態(tài)指標(biāo)：SNR,SINAD,THD,ENOB,IMD,etc.

動態(tài)指標(biāo)（1）靜態(tài)指標(biāo)反映的特點有限，主要是慢速變化特性，也稱之為DC傳輸特性，對于高速D/A,A/D來說，更需要AC傳輸特性來表征，反映不同頻率信號的響應(yīng)。主要反映了D/A,A/D器件的高速工作情況下的性能，諸如，VEDIODAC,TXDAC，TXADC等，動態(tài)指標(biāo)（2）SNR:SignaltoNoiseRatioSINAD:SignaltoNoiseAndDistortionRatioTHD:TotalHarmonicDistortionENOB:EffectiveNumberOfBitsSFDR:Spurious-FreeDynamicRangeTwo-toneIMD……..FrequencyDomainAnalysis

Ft(M)FrequencyMagnitudeSH2H3H4H5NoiseHarmonicsFundamentalSignalSpurious動態(tài)特性的測試方法（1）對于DAC來說，相對簡單一些，通過編程產(chǎn)生單頻信號，然后將輸出的信號發(fā)送到頻譜分析儀。動態(tài)特性的測試方法（2）DUT(ADC)AnalogSourceDigitalCaptureDataProcessing(FFT)SinusoidalWaveFrequencySpectrum

nbitsClockSourceRXADC測試環(huán)境要求（1）Inputsignalrequests：

1：Qualityofsignal：SNR,THD…….2：Amplitude,frequencyandcommonvoltageofsignal.3：fourorthogonaldifferentialsignals；RXADC測試環(huán)境要求（2）Howtoselectsamplenumbers-----coherentsamplingFin/Fsample=Ncycle/Nrecord,Fin:Periodicinputsignal

Fsample:SamplingfrequencyoftheADCNcycle:Integernumberofcycleswithinthesamplingwindow

Nrecord:NumberofdatapointsinthesamplingwindoworFFTCoherentsamplingUncoherentsamplingWindowingRXADC測試環(huán)境要求（3）在rxadc的測試中，

Fin=Ncycle*Fsample/Nrecord

Fin(kHz)Fsamp(kHz)NrecordNcycle10.3819270.8336002340.1736270.8336008960.0347270.833600133RXADC測試環(huán)境要求（4）Spectralleakage

samplesequencenotmeetscoherentsamplingWindowingminimizesspectralleakageWindowfunctionWindowtypes:Rectangular,Hamming,Hanning,Blackman……Howtoselectwindowfunction:1:-3dBbandwidth;2:-6dBbandwidth3:maximumside-lobelevel4:side-loberoll-offrateBlackmanwindows----singletonetestWindowsfunctionWindowsfunctionCalculation(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的選擇：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=(SINAD-1.763)/6.02Signalbin

S/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/QmismatchAmplitudemismatchαandphasemismatchε:

y(t)

=

Acos(ωt+φ)

+

iαAsin(ωt+φ+ε)

=0.5(1+α