ENOB测试程序

修改老师的程序 测试ENOB

%**************************************************************************

%  Read AD result from file to evaluate TMS320F2812 AD performance

%

%                                    2010.04.18

%**************************************************************************

clc;

clear;

close all;

[FileName,PathName] = uigetfile('*.txt','Select the *.dat file'); 

f = fullfile(PathName,filesep,FileName);

fid = fopen(f,'r');

 [data,M] = fscanf(fid,'%x');

 fclose(fid);

 data = data';                                       

data1 = zeros(1,2*length(data));             

data1(1:2:end) = bitand(data,hex2dec('ffff'));

data1(2:2:end) = fix(data/hex2dec('ffff'));  

N=2*M;

 data2=data1;  

 for i = 1:N

   if(data1(i)>2^15-1)

      data2(i)=data1(i)-2^16;

   end

 end                        

 

figure(1)

plot(data2);

datfft = fft(data2);

nordat = abs(datfft)/max(abs(datfft));%归一化

figure(2)

stem(nordat);

datfft(1) = 0;

[maxval,pos] = max(abs(datfft(1:N)));

datfft_hf = nordat(1:N/2);

sig_rms = (norm(datfft_hf(pos-5:pos+5)));

nos_rms = sqrt((sum(datfft_hf(2:N/2).^2)-sig_rms.^2));

SINAD = 20*log10(sig_rms/nos_rms);

ENOB = (SINAD-1.76)/6.02;

fs = 32e3;

figure(3),

plot([0:N/2-1]*fs/N/1000,20*log10(nordat(1:N/2)));xlabel('频率/KHz');ylabel('幅度/dB');axis tight;  

title(['SINAD=',num2str(SINAD),'dB',char(10),'ENOB=',num2str(ENOB),'bit']);