ADC与DAC 动态性能测试

1、A,1,ADC,与,DAC,衡量指标,静态指标,DNL, INL,动态指标,SNR, SINAD, THD ,ENOB,IMD,etc,A,2,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,VEDIO DAC, TXDAC,TX ADC,等,A,3,动态指标,2,SNR: Signal to Noise Ratio,SINAD: Signal to Noise And Distortion,Ratio,T

2、HD: Total Harmonic Distortion,ENOB: Effective Number Of Bits,SFDR: Spurious-Free Dynamic Range,Two,tone IMD,A,4,Frequency Domain Analysis,Ft,M,Frequency,M,a,g,n,i,t,u,d,e,S,H2 H3 H4 H5,Noise,Harmonics,Fundamental,Signal,Spurious,A,5,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,DAC,数字源,

3、频谱分析仪,A,6,动态特性的测试方法,2,DUT,ADC,Analog,Source,Digital,Capture,Data,Processing,FFT,Sinusoidal Wave,Frequency Spectrum,n,bits,Clock,Source,A,7,RXADC,测试环境要求,1,Input signal requests,1,Quality of signal,SNR, THD,2,Amplitude , frequency and common,voltage of signal,3,four orthogonal differential signals,A,8

4、,RXADC,测试环境要求,2,How to select sample numbers,coherent sampling,Fin / Fsample = Ncycle / Nrecord,Fin : Periodic input signal,Fsample : Sampling frequency of the ADC,Ncycle : Integer number of cycles within,the sampling window,Nrecord : Number of data points in the,sampling window or FFT,A,9,Coherent

5、sampling,A,10,Uncoherent sampling,A,11,Windowing,A,12,RXADC,测试环境要求,3,在,rxadc,的测试中,Fin= N,cycle,Fsample / Nrecord,Fin (kHz,Fsamp (kHz,Nrecord,Ncycle,10.3819,270.833,600,23,40.1736,270.833,600,89,60.0347,270.833,600,133,A,13,RXADC,测试环境要求,4,Spectral leakage,sample sequence not meets coherent,sampling,W

6、indowing,minimizes spectral leakage,A,14,Window function,Window types: Rectangular, Hamming,Hanning, Blackman,How to select window function,1: -3dB bandwidth,2: -6dB bandwidth,3: maximum side-lobe level,4: side-lobe roll-off rate,Blackman windows -single tone test,A,15,Windows function,A,16,Windows

7、function,A,17,Calculation (1): FFT,Ps = sumPf(m-k):1:Pf(m+k,Pdc = sumPf(1:k,Ph = sumPh(2:n),Ph(i)= sumPh(i-1:i+1,Pn = sum(Pf),Ps,Pdc,Ph,Signal bin,的选择,A,18,Calculation (2): FFT,S/N = 10* log(Ps/Pn,SINAD = 10* logPs/(Pn+Ph,THD = 10* log(Ph/Ps,SFDR = 10* logPs,Pmax.spurious,Level,ENOB = (SINAD,1.763)/ 6.02,A,19,Signal bin,S/N = 10* log(Ps/Pn,S/N = 10* logPs(1+)/Pn(1,10,10*log10/9+log(Ps/Pn,0.46 + S/N,A,20,I/Q match,An ideal sinusoidal I/Q signal pair,y(t),A exp(i(t +,A cos(t +,i A sin(t +,A,21,I/Q mismatch,Amplitude mismatch and phase,mismatch,y(t,A cos(t