pcm.m

这是一个PCM的编码调制方案的仿真程序。其中包含了对信号的量化。

    for i=1:num
        i=int2str(i);
        i=strcat('n',i);
        r.(i)=[];
    end
    s=num*s; % Normalized the signal.
    mins=min(s); % The minimun value in the signal
    maxs=max(s); % The maximum value in the signal
    cb=linspace(mins,maxs,num); % Creates the codeblocks from mins,     
    % to maxs with num divisions
    cbd=[0:(length(cb)-1)]; % Code Created only with symbolic propueses, to
    %make easier the plotting process of the digital signal because it
    %doesn't have negative values.
    e=100; % Initialize the error.
    
    % Quantize the Signal with the algorithm described in the book
    % Telecommunications Demystified.
    for i= 1:limit;
        for j= 1:length(s)
            for k = 1:num
                temp(k)=(s(j)-cb(k))^2;
            end
            index=find(temp==min(temp));
            index=index(1);
            numind=index;
            index=int2str(index);
            index=strcat('n',index);
            r.(index)=horzcat(r.(index),s(j));
            squan(j)=cb(numind);
            squand(j)=cbd(numind);
            if (i==1)
                first=squan;
            end
        end
        err=(s-squan).^2;
        e=mean(err);
        if (e<limit/100)
            break;
        end
        for k = 1:num
            index=int2str(k);
            index=strcat('n',index);
            cbn(k)=mean(r.(index));
        end
        cb=cbn;
    end
    set(handles.text5,'Visible', 'on'); % Makes visible the text5 
    set(handles.text6,'Visible', 'on'); % Makes visible the text6
    set(handles.text6,'String', e); % Puts e on text6
    axes(handles.axesquan) % Select the proper axes
    plot(t,s,t,first,'g',t,squan,'r'); % Plots the quantized signal
    xlabel('Time');
    ylabel('Amplitude');
    legend('Original Signal','First Quantization','After Quantization');
    grid on;
    handles.quan=squan;
    handles.quand=squand;
    handles.nbit=num;
    handles.cbd=cbd;
    handles.cb=cb;
    guidata(gcbo,handles);
elseif (get(handles.radiobutton8,'Value') == get(handles.radiobutton8,'Max'))
    s=handles.signal;
    maxs=max(s);
    t=handles.time;
    [pdfs,xp]=ksdensity(s);
    index=1;
    for i=1:length(xp)
        if (xp(i)<0 & xp(i+1)>0)
            index=i;
            break
        end
    end
    pdfs=pdfs(index:end);
    xp=xp(index:end);
    pdfs=pdfs.^3;
    p=polyfit(pdfs,xp,6);
    psym=poly2sym(p);
    g=int(psym);
    gn=sym2poly(g);
    gn=polyval(gn,t);
    maxgn=max(gn);
    thefact=maxs/maxgn;
    gn=gn*thefact;
    axes(handles.axesquan) % Select the proper axes
    plot(t,gn);
    xlabel('Time');
    ylabel('Amplitude');
    legend('Best G(x) that minimizes the mse')
    grid on;
end

function edit2_Callback(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit2 as text
%        str2double(get(hObject,'String')) returns contents of edit2 as a double


% --- Executes during object creation, after setting all properties.
function edit2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end



function edit3_Callback(hObject, eventdata, handles)
% hObject    handle to edit3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit3 as text
%        str2double(get(hObject,'String')) returns contents of edit3 as a double


% --- Executes during object creation, after setting all properties.
function edit3_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end




% --- Executes on button press in radiobutton8.
function radiobutton8_Callback(hObject, eventdata, handles)
% hObject    handle to radiobutton8 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
set(handles.edit2,'Enable', 'off'); 
set(handles.edit3,'Enable', 'off');
set(handles.text5,'Visible', 'off');
set(handles.text6,'Visible', 'off');
% Hint: get(hObject,'Value') returns toggle state of radiobutton8




% --- Executes on button press in radiobutton7.
function radiobutton7_Callback(hObject, eventdata, handles)
% hObject    handle to radiobutton7 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
set(handles.edit2,'Enable', 'on'); 
set(handles.edit3,'Enable', 'on');
% Hint: get(hObject,'Value') returns toggle state of radiobutton7




% --- Executes during object creation, after setting all properties.
function pushbutton5_CreateFcn(hObject, eventdata, handles)
% hObject    handle to pushbutton5 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called




% --- Executes on button press in pushbutton6.
function pushbutton6_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton6 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
cb=handles.cb;
cbd=handles.cbd;
squand=handles.quand;
nbit=handles.nbit;
nbit=round(sqrt(nbit));
lsquand=length(squand);
for i=1:lsquand
    sbin(i,:)=de2bi(squand(i),nbit);
end
figure
hold on
[m,n]=size(sbin);
liminf=0;
s1={'Quantized Signal','Symbol','Digital Signal'};
bins=dec2bin(cbd,nbit);
xlswrite('Output',s1,'Hoja1','A1');
xlswrite('Output',cb','Hoja1','A2');
xlswrite('Output',cbd','Hoja1','B2');
xlswrite('Output',bins,'Hoja1','C2');
nconst=n;
for i = 1:m
    sbint=sbin(i,:);
    timet=[liminf:n-1];
    if rem(i,2)==0
        stem(timet, sbint,'r');
    else
        stem(timet, sbint,'k');
    end
    liminf=n;
    n=n+nconst;
end
grid on




% --------------------------------------------------------------------
function Untitled_1_Callback(hObject, eventdata, handles)
% hObject    handle to Untitled_1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
helpdlg('In order to understand this program in a deeper way, it is desirable to have the book Telecommunications Demystified of Carl Nassar, it is possible to have an electronic version of the book. You can work with the chapter four of the book.', 'Recomendations');


% --------------------------------------------------------------------
function Untitled_2_Callback(hObject, eventdata, handles)
% hObject    handle to Untitled_2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)




% --- Executes on button press in pushbutton7.
function pushbutton7_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton7 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)