自己在做adc的仿真，分享一下仿真adc静态参数和动态参数的matlab代码

kongc · 发表于 2020-12-31 10:26:57

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本帖最后由 kongc 于 2020-12-31 10:30 编辑

代码是网上找的资料，然后又改的，有需要的可以参考一下。输入的文件都是numpt行，N列的数字输出数据。
静态参数

%Code density/histofgram test to calculate INL and DNL require a large number of samples.
%Step 1: Apply a close to full-scale sine wave (but not clipping) and find the mid-code for the applied signal.
%Step 2: Apply the same sine wave input, but slightly larger amplitude to clip the ADC slightly.
%Run the following program, enter the number of samples, resolution and mid-code from Step 1and continue.
%Copyright Au/Hofner, Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA94086
%This program is believed to be accurate and reliable. This program may get altered without prior notification.
%用于计算INL和DNL的％代码密度/直方图测试需要大量样本。
%步骤1：施加接近满量程的正弦波（但不削波），并找到所施加信号的中间码。
%步骤2：施加相同的正弦波输入，但幅度稍大些，以对ADC进行稍稍削波。
%运行以下程序，输入步骤1中的样本数量，分辨率和中间代码，然后继续。版权所有Au / Hofner，Maxim Integrated Products，120 San Gabriel Drive，Sunnyvale，CA94086
%该程序被认为是准确和可靠的。该程序可能会更改，恕不另行通知。
filename=csvread('adc_data.csv');
adc_data=round(filename);
numpt=32768;
numbit=12;
mid_code=2048;
d11=1;d10=2;d9=3;d8=4;d7=5;d6=6;d5=7;d4=8;d3=9;d2=10;d1=11;d0=12;
for i=1:numpt
dout(i)=adc_data(i,d11)*2048+adc_data(i,d10)*1024+adc_data(i,d9)*512 ...
+adc_data(i,d8)*256+adc_data(i,d7)*128+adc_data(i,d6)*64 ...
+adc_data(i,d5)*32+adc_data(i,d4)*16+adc_data(i,d3)*8 ...
+adc_data(i,d2)*4+adc_data(i,d1)*2+adc_data(i,d0)*1;%通过转换器出来的结果，恢复原来的波形
doute(i)=dout(i)-0.5;%将正弦波的共模电平偏置为0
%doute(i)=dout(i)-mean(dout(i));
end
[a,b]=size(dout);
if(a>b)
dout=dout(:,1)';
else
dout=dout(1,:);
end
mid_file=[dout ; dout];
mid_file=double(mid_file);
v1=mid_file';
code=v1(:,2);
code_count=zeros(1,2^numbit);
for i=1:2^numbit
count=0;%附值
for j=1:numpt
if code(j)==i-1
count=count+1;
else count=count;
end
end
code_count(i)=count;
end
if code_count(1) == 0 | code_count(2^numbit) == 0 | ...
(code_count(1) < code_count(2)) | (code_count(2^numbit-1) > code_count(2^numbit))
disp('ADC not clipping ... Increase sinewave amplitude!');
% break;
end
A=max(mid_code,2^numbit-1-mid_code)+0.1;
vin=(0:2^numbit-1)-mid_code;
sin2ramp=1./(pi*sqrt(A^2*ones(size(vin))-vin.*vin));
while sum(code_count(2:2^numbit-1)) < numpt*sum(sin2ramp(2:2^numbit-1))
A=A+0.1;
sin2ramp=1./(pi*sqrt(A^2*ones(size(vin))-vin.*vin));
end
disp('You Have Applied a Sine Wave of (dBFS): ');
Amplitude=A/(2^numbit/2)
figure;
plot([0:2^numbit-1],code_count,[0:2^numbit-1],sin2ramp*numpt);
title('CODE HISTOGRAM - SINE WAVE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('COUNTS');
axis([0 2^numbit-1 0 max(code_count)]);
code_countn=code_count(2:2^numbit-1)./(numpt*sin2ramp(2:2^numbit-1));
figure;
plot([1:2^numbit-2],code_countn);
title('CODE HISTOGRAM - NORMALIZED')
xlabel('DIGITAL OUTPUT CODE');
ylabel('NORMALIZED COUNTS');
dnl=code_countn-1;
inl=zeros(size(dnl));
for j=1:size(inl')
inl(j)=sum(dnl(1:j));
end
%End-Point fit INL
%[p,S]=polyfit([1,2^numbit-2],[inl(1),inl(2^numbit-2)],1);
%Best-straight-line fit INL
[p,S]=polyfit([1:2^numbit-2],inl,1);
inl=inl-p(1)*[1:2^numbit-2]-p(2);
disp('End Points Eliminated for DNL and INL Calculations');
figure;
plot([1:2^numbit-2],dnl);
grid on;
title('DIFFERENTIAL NONLINEARITY vs. DIGITAL OUTPUT CODE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('DNL (LSB)');
figure;
plot([1:2^numbit-2],inl);
grid on;
title('INTEGRAL NONLINEARITY vs. DIGITAL OUTPUT CODE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('INL(LSB)');

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动态参数：（主函数）

d_in=csvread('adc_data.csv');%以字符形式打开文件
d11=1;d10=2;d9=3;d8=4;d7=5;d6=6;d5=7;d4=8;d3=9;d2=10;d1=11;d0=12;%标示样本矩阵的列
vref=1;
numpt=32768;
%adc_data=d_in;
adc_data=round(d_in);
for i=1:numpt
dout(i)=adc_data(i,d11)/2+adc_data(i,d10)/4+adc_data(i,d9)/8 ...
+adc_data(i,d8)/16+adc_data(i,d7)/32+adc_data(i,d6)/64 ...
+adc_data(i,d5)/128+adc_data(i,d4)/254+adc_data(i,d3)/512 ...
+adc_data(i,d2)/1024+adc_data(i,d1)/2048+adc_data(i,d0)/4096;%通过转换器出来的结果，恢复原来的波形
doute(i)=dout(i)-0.5;%将正弦波的共模电平偏置为0
%doute(i)=dout(i)-mean(dout(i));
end
[ENOB, SNDR, SFDR, SNR, THD] = prettyFFT(dout,10e7,9,0,0,0);
% function [ENOB, SNDR, SFDR, SNR, THD] = prettyFFT(wave,f_S,maxh,no_annotation,no_plot,baseline);

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prettyfft函数

function [ENOB, SNDR, SFDR, SNR, THD] = prettyFFT(wave,f_S,maxh,no_annotation,no_plot,baseline);
% Programmed by: Skyler Weaver, Ph.D.
% Date: December 7, 2010
% Version: 1.0
%
% This function plots a very pretty FFT plot and annotates all of the
% relevant data. This is intended to be used by Nyquist guys and expects
% coherently sampled data. Maybe in the future I will modify it to
% automatically detect windowed data for Delta-Sigma or allow two input
% tones. As for now, it is just for single sine-wave test, coherent data.
%
% The full function is:
% [ENOB, SNDR, SFDR, SNR] = prettyFFT(wave,f_S,maxh,no_annotation,no_plot)
% 'wave' can be any length but should be coherently sampled
% (required)
% 'f_S' is the SAMPLING rate (i.e. f_Nyquist * 2)
% (optional, default = 1)
% 'maxh' is the highest harmonic plotted, 0 means all harmonics
% (optional, default = 12) NOTE: lowering this value will affect SNR
% since SNR is calculated as SNDR with harmonics removed. Setting
% maxh to 1 will effectivly set SNR = SNDR. (1 means only the
% fundamental is a 'harmonic')
% 'no_annotation' set to anything but 0 to turn off annotation
% (optional, default = 0)
% 'no_plot' set to anything but 0 to not create a plot
% (optional, default = 0)
% 'baseline' is the minimum value on the y-axis. When set to '0' the
% y-axis is auto-scaled such that some of the noise floor is
% displayed. It is useful to set this parameter when comparing two
% FFT plots by keeping the scale the same.
% (optional, default = 0)
%
% Here are some usage examples:
%
% prettyFFT(some_data)
%
% In it's most default state, it will take some_data, grab the last
% 2^integer data points, FFT it, plot it in a pretty way, normalize the
% x-axis to Nyquist-rate, tag the first 12 harmonics (if above the noise
% floor), annotate SFDR and SNDR/SNR (if there is room on the plot), draw a
% red line where the effective noise floor is, and returns ENOB. Use this
% to just plot an FFT from command line and get some useful visual feedback.
%
% [ENOB,SNDR,SFDR,SNR]=prettyFFT(some_data)
%
% does the same thing, but you now have your stats in variables too.
%
% prettyFFT(some_data,100e6,15)
%
% does the same thing, but the x-axis is normalized to 100MHz sampling rate.
% The default of up to 12 harmonics is overridden to 15. (set to 0, it will
% tag anything significantly above the noise floor, even harmonic 1032 if
% it is high enough)
%
% prettyFFT(some_data,100e6,15,1)
%
% same thing but annotation is turned off. For journals and stuff
%
% prettyFFT(some_data,100e6,15,1,1)
%
% the extra '1' means it doesn't plot. This is in case you have a loop and
% you need to get SNR, but you don't want it to keep plotting.
%
% Feel free to edit, but keep my name at the top.
%
% Enjoy!
% -Skyler
if(nargin <= 0)
disp('prettyFFT: What are you trying to do, exactly?')
wave = rand(1,100);
f_S = 1;
maxh = 1;
no_annotation = 0;
no_plot = 0;
baseline = 0;
end
if(nargin == 1)
f_S = 1;
maxh = 12;
no_annotation = 0;
no_plot = 0;
baseline = 0;
end
if(nargin == 2)
maxh = 12;
no_annotation = 0;
no_plot = 0;
baseline = 0;
end
if(nargin == 3)
no_annotation = 0;
no_plot = 0;
baseline = 0;
end
if(nargin == 4)
no_plot = 0;
baseline = 0;
end
if(nargin == 5)
baseline = 0;
end
if(nargin > 6)
disp('prettyFFT: Too many arguments, man.')
end
text_y_offset = 4; %height above bar for harmonic # txt (def. = 4)
plev = 9; %dB above noise floor to be considered a harmonic (def. = 9)
[a,b]=size(wave);
if(a>b)
wave=wave(:,1)';
else
wave=wave(1,:);
end
fft_ord = floor(log(length(wave))./log(2));
wave = wave(end-2^fft_ord+1:end);
wave=wave-mean(wave); % remove DC offset
f2 = abs(fft(wave)); % fft
f2 = f2(2:floor(length(f2)/2)); % remove bin 1 (DC)
[bin bin] = max(f2);
f2a=[f2(1:(bin-1)) f2((bin+1):end)];
f2a=[f2(1:(bin-1)) mean(f2) f2((bin+1):end)];
step = (bin);
pts = 2*(length(f2)+1);
SNDR = mag2db((f2(bin).^2/(sum(f2.^2)-f2(bin).^2)))/2; % get SNDR (f_in / sum(the rest))
ENOB=(SNDR-1.76)/6.02; % ENOB from SNDR
scaledby = 1./max(f2);
dbf2=mag2db(f2.*scaledby);
dbf2a=[dbf2(1:(bin-1)) dbf2((bin+1):end)];
dbf2a=[dbf2(1:(bin-1)) mean(dbf2) dbf2((bin+1):end)];
[bins bins] =max(dbf2a);
SFDR = -dbf2a(bins);
noise_top = mean(dbf2a)+plev;
noise_floor=mean(dbf2a);
noise_bottom = mean(dbf2a)-plev;
%noise_bottom = min(dbf2a);
% GET HARMONICS
harm = bin;
t=1;
nyqpts=(pts/2-1);
all_harms = harm:step:(harm*nyqpts);
all_harms = mod(all_harms,pts);
all_harms = (pts-all_harms).*(all_harms>nyqpts) ...
+ all_harms.*(all_harms<=nyqpts);
all_harms = all_harms.*(all_harms>0 & all_harms<pts/2) ...
+ (all_harms<=0) ...
+ (all_harms>=pts/2).*nyqpts;
if (maxh==0 || maxh>length(all_harms))
maxh=length(all_harms);
end
for k=1:maxh
if(dbf2(all_harms(k)) > noise_top)
harm(t) = all_harms(k);
hnum(t) = k;
t=t+1;
end
end
% GET REAL SNR
numbins=2.^(fft_ord-1)-1;
non_harm=1:numbins;
non_harm([harm]) = [];
SNR = mag2db((f2(bin).^2/(sum(f2(non_harm).^2))))/2; % get SNR (f_in / sum(the rest))
%SNRpb = db(sqrt((f2(bin).^2/(sum(f2(non_harm).^2))))/numbins)-25 % get SNR (f_in / sum(the rest))
SNRpb = -SNR-3.*(fft_ord-1);
THD = mag2db((sum(f2.^2)-f2(bin).^2-sum(f2(non_harm).^2))/f2(bin).^2)/2;
if(~no_plot)
% MAKE FFT
hold off
f=f_S/nyqpts/2:f_S/nyqpts/2:f_S/2;
h=bar(f,dbf2); %%%% bar plot choice
% h=plot(f,dbf2,'r*'); %%%% line plot choice
if(~baseline)
xx=max([min([SNRpb noise_bottom])-plev -250]);
else
xx=baseline;
end
%set(get(h,"BaseLine"),"BaseValue",xx);
set(h,'BaseValue',xx);
set(h,'ShowBaseLine','off');
set(h,'BarWidth',0.1);
set(h,'LineStyle','none');
axis([f(1)/2 f(end)+f(1)/2 xx 0]);
if(~no_annotation)
% HARMONIC RED SQUARES
hold on
plot(f(harm),dbf2(harm),'rs')
text_y_offset = -xx/100*text_y_offset;
if (length(harm) > 2)
for n=2:length(harm)
if sum(harm(1:n-1)==harm(n))
n=n-1; break, end
end
if (n<length(harm))
disp('prettyFFT: Not prime-coherent sampling!')
end
else
n=length(harm);
end
% PRINT HARMONICS
%text_y_offset = -xx/100*text_y_offset;
for t=2:n
text(f(harm(t)),dbf2(harm(t))+text_y_offset,num2str(hnum(t)),'HorizontalAlignment','center');
end
hold off
hh=line([f(1)/2 f(end)+f(1)/2],[-SFDR -SFDR]);
set(hh,'LineStyle','--');
set(hh,'Color','k');
hh1=line([f(1)/2 f(end)+f(1)/2],[SNRpb SNRpb]);
set(hh1,'LineStyle','-');
set(hh1,'Color','r');
% where to put SFDR arrow
numbins=floor(pts/2);
dbin=round(numbins/32);
if(numbins>4)
if(bin>numbins/2+dbin*2)
if(bins<(numbins/4-dbin))|(bins>(numbins/4+dbin))
abin=round(numbins/4);
elseif (bins>numbins/4)
abin=round(numbins/4)-dbin;
else
abin=round(numbins/4)+dbin;
end
else
if(bins<(3*numbins/4-dbin))|(bins>(3*numbins/4+dbin))
abin=round(3*numbins/4);
elseif (bins>3*numbins/4)
abin=round(3*numbins/4)-dbin;
else
abin=round(3*numbins/4)+dbin;
end
end
else
abin=12;
end
tempSFDR=SFDR;
if(SFDR > -(.13*xx))
if(SFDR>250)
SFDR=250;
end
dx=f(end)/100;
dy=-xx/30;
x=f(abin);
tdx=max([dx (f(2)-f(1))]);
hh2=line([x-dx x x+dx x x x-dx x x+dx],[-dy 0 -dy 0 -SFDR dy-SFDR -SFDR dy-SFDR]);
set(hh2,'LineStyle','-');
set(hh2,'Color','k');
% text(f(abin)+tdx,-SFDR/2,["SFDR =\n" num2str(tempSFDR,4) 'dB'],'HorizontalAlignment','left');
if(SFDR > -(.25*xx))
infostr=...%['ENOB =\newline' num2str(ENOB,4) ' bits\newline\newline' ...
["SNDR =\n" num2str(SNDR,4) "dB \n" ...
"\nSNR =\n" num2str(SNR,4) 'dB'];
else
infostr=...%['ENOB =\newline' num2str(ENOB,4) ' bits\newline\newline' ...
['SNDR = ' num2str(SNDR,4) "dB \n " ...
'SNR =' num2str(SNR,4) 'dB'];
end
%if(bin<numbins/2)
% text(f(bin)+tdx,-SFDR/2,infostr,'HorizontalAlignment','left');
%else
% text(f(bin)-tdx,-SFDR/2,infostr,'HorizontalAlignment','right');
%end
end
ylabel('dB')
xlabel('Frequency(Hz)')
title('ADC spectrum analysis to obtain SFDR/SNDR/SNR')
SFDR = tempSFDR;
end % end if(~no_annotation)
end % end if(~no_plot)
hold on;
s1=sprintf('SFDR = %4.1fdB\n',SFDR);
s2=sprintf('THD = %4.1fdB\n',THD);
s3=sprintf('SNR = %4.1fdB\n',SNR);
s4=sprintf('SNDR = %4.1fdB\n',SNDR);
s5=sprintf('ENOB = %4.2fbit\n',ENOB);
text(25,-10,s1);
text(25,-20,s2);
text(25,-30,s3);
text(25,-40,s4);
text(25,-50,s5);
hold off;

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江上飘来 · 发表于 2021-5-26 10:22:47

请教楼主一个问题，谢谢。
我现在在测试一个10bit的SAR_ADC，输入的是一个下图所示的阶梯型波，周期很长ADC转换输出数据被HAPS（我也不知道这个玩意使什么）采集。这个HAPS只把每个输出数据成16进制数据，保存下来。
我需要计算一下DNL和INL，请问，楼主帖子中的代码可以直接用来计算我的数据吗？或者如何修改一下输出数据才能用楼主的代码进行计算？再次说谢谢！

输入信号波形

江上飘来 · 发表于 2021-5-26 10:26:02

另外，想请问一下楼主，有没有从零开始学习ADC的资料呀？可以分享一下吗？
一些原理性的学习资料已经有很多了，但是没有那种设计flow的那种资料，比如从最开始的MATLAB建模和验证到schematic的设计和仿真等等。
期待您的回复，谢谢！！

kongc · 发表于 2021-5-29 16:28:18

江上飘来发表于 2021-5-26 10:22
请教楼主一个问题，谢谢。
我现在在测试一个10bit的SAR_ADC，输入的是一个下图所示的阶梯型波，周期很长ADC ...

测试需要输入一个接近满幅的正弦信号，而且采样频率和信号频率需要满足相干采样。帖子中的代码需要ADC输出的N列数字码，现在我又改了一下代码，可以先用理想DAC输出模拟信号的波形，然后再测试。

%Code density/histofgram test to calculate INL and DNL require a large number of samples.
%Step 1: Apply a close to full-scale sine wave (but not clipping) and find the mid-code for the applied signal.
%Step 2: Apply the same sine wave input, but slightly larger amplitude to clip the ADC slightly.
%Run the following program, enter the number of samples, resolution and mid-code from Step 1and continue.
%Copyright Au/Hofner, Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA94086
%This program is believed to be accurate and reliable. This program may get altered without prior notification.
%用于计算INL和DNL的％代码密度/直方图测试需要大量样本。
%步骤1：施加接近满量程的正弦波（但不削波），并找到所施加信号的中间码。
%步骤2：施加相同的正弦波输入，但幅度稍大些，以对ADC进行稍稍削波。
%运行以下程序，输入步骤1中的样本数量，分辨率和中间代码，然后继续。版权所有Au / Hofner，Maxim Integrated Products，120 San Gabriel Drive，Sunnyvale，CA94086
%该程序被认为是准确和可靠的。该程序可能会更改，恕不另行通知。
d_in=csvread('filename.csv');%以字符形式打开文件
adc_data=round(d_in);
[numpt,row]=size(d_in);
numbit=12;
mid_code=2048;
d11=1;d10=2;d9=3;d8=4;d7=5;d6=6;d5=7;d4=8;d3=9;d2=10;d1=11;d0=12;
dout=adc_data;
[a,b]=size(dout);
if(a>b)
dout=dout(:,1)';
else
dout=dout(1,:);
end
mid_file=[dout ; dout];
mid_file=double(mid_file);
v1=mid_file';
code=v1(:,2);
code_count=zeros(1,2^numbit);
for i=1:2^numbit
count=0;%附值
for j=1:numpt
if code(j)==i-1
count=count+1;
else count=count;
end
end
code_count(i)=count;
end
if code_count(1) == 0 | code_count(2^numbit) == 0 | ...
(code_count(1) < code_count(2)) | (code_count(2^numbit-1) > code_count(2^numbit))
disp('ADC not clipping ... Increase sinewave amplitude!');
% break;
end
A=max(mid_code,2^numbit-1-mid_code)+0.1;
vin=(0:2^numbit-1)-mid_code;
sin2ramp=1./(pi*sqrt(A^2*ones(size(vin))-vin.*vin));
while sum(code_count(2:2^numbit-1)) < numpt*sum(sin2ramp(2:2^numbit-1))
A=A+0.1;
sin2ramp=1./(pi*sqrt(A^2*ones(size(vin))-vin.*vin));
end
disp('You Have Applied a Sine Wave of (dBFS): ');
Amplitude=A/(2^numbit/2)
figure;
plot([0:2^numbit-1],code_count,[0:2^numbit-1],sin2ramp*numpt);
title('CODE HISTOGRAM - SINE WAVE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('COUNTS');
axis([0 2^numbit-1 0 max(code_count)]);
code_countn=code_count(2:2^numbit-1)./(numpt*sin2ramp(2:2^numbit-1));
figure;
plot([1:2^numbit-2],code_countn);
title('CODE HISTOGRAM - NORMALIZED')
xlabel('DIGITAL OUTPUT CODE');
ylabel('NORMALIZED COUNTS');
dnl=code_countn-1;
inl=zeros(size(dnl));
for j=1:size(inl')
inl(j)=sum(dnl(1:j));
end
%End-Point fit INL
%[p,S]=polyfit([1,2^numbit-2],[inl(1),inl(2^numbit-2)],1);
%Best-straight-line fit INL
[p,S]=polyfit([1:2^numbit-2],inl,1);
inl=inl-p(1)*[1:2^numbit-2]-p(2);
disp('End Points Eliminated for DNL and INL Calculations');
figure;
plot([1:2^numbit-2],dnl);
grid on;
title('DIFFERENTIAL NONLINEARITY vs. DIGITAL OUTPUT CODE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('DNL (LSB)');
figure;
plot([1:2^numbit-2],inl);
grid on;
title('INTEGRAL NONLINEARITY vs. DIGITAL OUTPUT CODE');
xlabel('DIGITAL OUTPUT CODE');
ylabel('INL(LSB)');

复制代码

kongc · 发表于 2021-5-29 16:30:21

江上飘来发表于 2021-5-26 10:26
另外，想请问一下楼主，有没有从零开始学习ADC的资料呀？可以分享一下吗？
一些原理性的学习资料已经有很多 ...

这个没有。matlab模型的话这个论坛里就有

tanei · 发表于 2021-6-10 11:36:29

多谢

zyinghn · 发表于 2021-6-28 14:52:46

ths mark

AzureM · 发表于 2021-7-9 10:20:05

非常感谢

江上飘来 · 发表于 2021-7-13 10:30:19

kongc 发表于 2021-5-29 16:28
测试需要输入一个接近满幅的正弦信号，而且采样频率和信号频率需要满足相干采样。帖子中的代码需要ADC输 ...

楼主，非常感谢您的回复。
再请教个问题。我的ADC不能连续取样，只能配置一次寄存器采样一次。请问可以用这个代码吗?
我听说输入sine波的话，需要保证ADC和sine同步。
我想输入ramp斜波，请问这个代码可以用吗？

fujianweihong · 发表于 2021-8-13 11:48:45

想詢問樓主有輸入.CSV檔案的範例嗎
我怕我不能跑

[资料] 自己在做adc的仿真，分享一下仿真adc静态参数和动态参数的matlab代码

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