SAM_ADC_Animated.m

%InnovateFPGA 2019
%Team Number: EM002
%Project Name: Successive-approximation-memory (SAM) analog-to-digital converter (ADC)

clear all;

function y = SquareWave(n,x)
  y = 1.5 + sin(x * (4 + n));
  %y = 1.5 + (sin(x * (4 + n)) > 0) * 2 - 1.0;
endfunction

f_width = 500;
f_height = 150;
%f_width = 1500;
%f_height = 550;
h = figure('position',[100,100,f_width,f_height]);
filename = 'SAM_ADC_Animated.gif';

xMAX = 10;
xSTEP = 0.01;
xNUM = (xMAX/xSTEP) + 1;
iterNUM = 6;

x = 0:xSTEP:xMAX;
SignalIN = SquareWave(0,x);
ComparatorOUT = ones(1, xNUM);
ApproximationLogicOUT = zeros(1, xNUM);
DACOUT = zeros(1, xNUM);

for n = 1:1:iterNUM
  DACOUT = ApproximationLogicOUT;
  ComparatorOUT = (SignalIN - DACOUT > 0.0) * 2 - 1;
  ApproximationLogicOUT = ApproximationLogicOUT + (ComparatorOUT * 3 / (2^n));
  plot(x,SignalIN,"b;Signal input;",...
       x,DACOUT,"g;DAC output;",...
       x,ComparatorOUT * 0.3,"m;Comparator result;");
  axis([0, 10, -0.4, 3]);
  drawnow;
  % Capture the plot as an image
  frame = getframe(h,[1,1,f_width-1,f_height-3]);
  im = frame2im(frame);
  [imind,cm] = rgb2ind(im);
  % Write to the GIF File
  if n == 1
    imwrite(imind,cm,filename,'gif','WriteMode','overwrite','Loopcount',inf,'DelayTime',1.5);
  elseif n == iterNUM
    imwrite(imind,cm,filename,'gif','WriteMode','append','DelayTime',6.5);
  else
    imwrite(imind,cm,filename,'gif','WriteMode','append','DelayTime',1.5);
  endif
end
delete(h);