DeltaSigmaModulator/SigmaDelta.m at main · 3dfernando/DeltaSigmaModulator · GitHub

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clear; clc; close all;

VrefPlus=5;
VrefMinus=-5;

VDAC=VrefPlus;
Vintegrator1=0;
Vintegrator2=0;
% expConst1=0.00001;
% expConst2=0.000001;

clockCycles=20; %integrator simulation

Vin=0;
nBits=6;


v=VideoWriter('SigmaDelta_2v.avi');
v.Quality=95;
v.FrameRate=20;
open(v)

%%
nCycles=200;
Vin_Array=zeros(nCycles*clockCycles,1);
Vintegrator_Array=zeros(nCycles*clockCycles,1);
VDAC_Array=zeros(nCycles*clockCycles,1);
Clock_Array=zeros(nCycles*clockCycles,1);
Sigma_Array=zeros(nCycles*clockCycles,1);
t=1:length(Vintegrator_Array);

NyquistFrequency=1/(2*(2^nBits)*clockCycles);

i=0;
SigmaBuffer=0;
SigmaValue=0;
nClockCycles=0;
figure('Position',[882 99 1024 892],'color','k');
frq=0.1;
while 1
    i=i+1;

    %Vin=5*sin(2*pi*0.000025*i) + 0.5*sin((2*pi*NyquistFrequency*1.5)*i);
    Vin=5*sin((2*pi*NyquistFrequency*(frq/64))*i);
    Vin=2;
    %frq=frq+0.0025;

    VSum=Vin-VDAC;

    %Normal integrator
%     Vintegrator1=Vintegrator1*(1-expConst1)+expConst1*VSum;
%     Vintegrator2=Vintegrator2*(1-expConst2)+expConst2*VSum;
    Vintegrator2=Vintegrator2+VSum;

    if mod(i,clockCycles)==1
        if Vintegrator2>0
            VDAC=VrefPlus;
        else
            VDAC=VrefMinus;
        end
        SigmaBuffer=SigmaBuffer+VDAC/(2^nBits);
        if mod(nClockCycles,2^nBits)==1
            SigmaValue=SigmaBuffer;
        	SigmaBuffer=0;
        end
        Clock=1;
        nClockCycles=nClockCycles+1;
    elseif mod(i,clockCycles)==floor(clockCycles/2)
        Clock=0;
    end

    Vin_Array=circshift(Vin_Array,-1);
    VDAC_Array=circshift(VDAC_Array,-1);
    Vintegrator_Array=circshift(Vintegrator_Array,-1);
    Clock_Array=circshift(Clock_Array,-1);
    Sigma_Array=circshift(Sigma_Array,-1);

    Vin_Array(end)=Vin;
    VDAC_Array(end)=VDAC;
    Vintegrator_Array(end)=Vintegrator2;
    Clock_Array(end)=Clock;
    Sigma_Array(end)=SigmaValue;


    if mod(i,round(nCycles*clockCycles/100))==1

        subplot(4,1,1)
        cla
        plot(t,VDAC_Array,'w-','linewidth',2);
        set(gca,'color','k')
        ylim([-5 5])

        subplot(4,1,2)
        cla
        plot(t,Vintegrator_Array,'b-','linewidth',2);
        set(gca,'color','k')
        ylim([-1 1]*200)

        subplot(4,1,3)
        cla
        plot(t,Vin_Array,'y-','linewidth',2);
        set(gca,'color','k')
        ylim([-5 5])
        set(gca,'ytick',-5:1:5)
        set(gca,'xtick',[])
        set(gca,'GridColor',[1 1 1]*0.8)
        grid on

        subplot(4,1,4)
        cla
        plot(t,Sigma_Array,'y-','linewidth',2);
        set(gca,'color','k')
        ylim([-5 5])
        set(gca,'ytick',-5:1:5)
        set(gca,'xtick',[])
        set(gca,'GridColor',[1 1 1]*0.8)
        grid on

        drawnow
        pause(0.01)
        F=getframe(gcf);
        writeVideo(v,F);
    end

end


close(v)