function varargout = homework3(varargin)
% HOMEWORK3 M-file for homework3.fig
%      HOMEWORK3, by itself, creates a new HOMEWORK3 or raises the existing
%      singleton*.
%
%      H = HOMEWORK3 returns the handle to a new HOMEWORK3 or the handle to
%      the existing singleton*.
%
%      HOMEWORK3('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in HOMEWORK3.M with the given input arguments.
%
%      HOMEWORK3('Property','Value',...) creates a new HOMEWORK3 or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before homework3_OpeningFunction gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to homework3_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help homework3

% Last Modified by GUIDE v2.5 08-Oct-2007 20:51:41

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @homework3_OpeningFcn, ...
                   'gui_OutputFcn',  @homework3_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT


% --- Executes just before homework3 is made visible.
function homework3_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to homework3 (see VARARGIN)

% Choose default command line output for homework3
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes homework3 wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = homework3_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;


% --- Executes on selection change in popupmenu1.
function popupmenu1_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = get(hObject,'String') returns popupmenu1 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu1


% --- Executes during object creation, after setting all properties.
function popupmenu1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to popupmenu1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: popupmenu 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 pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
    % hObject    handle to pushbutton1 (see GCBO)
    % eventdata  reserved - to be defined in a future version of MATLAB
    % handles    structure with handles and user data (see GUIDATA)

    % 確定所選的信號
    type=get(handles.popupmenu1,'Value');
    % 信號的采樣頻率均為100Hz
    % 產生時長為10s的信號(-5s到5s)
    axes1_title = char('白噪聲' ,'單位沖激信號' ,'單位階越信號', '正弦波', '方波', '三角波', '鋸齒波');

    t = -5 : 0.01 : 5;
    switch type
        case 1                                 
            %產生時長為10s的白噪聲(-5s到5s)
            x = wgn(1001,1,1);
        case 2                              
            %產生時長為10s的單位沖激信號(-5s到5s)
            x = zeros(1001,1);
            x(501) = 1;
        case 3                                
            %產生時長為10s的單位階越信號(-5s到5s)
            x = zeros(1001,1);
            x(501:1001) = 1;
         case 4                              
            % 產生時長為10s,頻率為1Hz的正弦波信號
            x = sin (2*pi*t);
        case 5
            % 產生時長為10s,頻率為1Hz的方波信號
            x = square (2*pi*t);
        case 6                               
            %產生時長為10s,頻率為1Hz的三角波信號    
            x = sawtooth (2*pi*t,0.5);
        case 7                                  
            %產生時長為10s,頻率為1Hz的鋸齒波信號
            x = sawtooth(2*pi*t);
    end

    % 繪制axes1
    plot (handles.axes1, x);
    axis (handles.axes1, [0,1000,-1.5,1.5]);
    title(handles.axes1, axes1_title(type,:));
    xlabel(handles.axes1,'times(s)');
    ylabel(handles.axes1,'x(t)');

    % 按照能量信號的自相關函數公式計算-0.5s到0.5s內的自相關函數值
    co = zeros(101,1);
    for m = -50:50
        for k=-450:450;
            co(m+51)=co(m+51)+x(501+k)*x(501+k+m);
        end
    end
    co = co/901;
    t2 = [-0.5:0.01:0.5];
    % 繪制axes2
    plot (handles.axes2, t2, co);
    %axis (handles.axes2, [-0.5,0.5,-1,1]);
    title(handles.axes2, '自相關函數');
%     xlabel(handles.axes2,'times(s)');
%     ylabel(handles.axes2,'自相關函數值');

    N = 2^ceil(log2(length(x)));

    % 繪制axes3    
    fft1 = fft(x, N);
    plot (handles.axes3, fft1);
    title(handles.axes3, 'Matlab的fft結果');
    
    % 繪制axes5
    ifft1 = ifft(fft1, N);
    plot (handles.axes5, ifft1);
    axis (handles.axes5, [0,1000,-1.5,1.5]);
    title(handles.axes5, 'Matlab的ifft結果');
    
    % 繪制axes4
    fft2 = fft_rec(x, N);
    plot (handles.axes4, fft2);
    title(handles.axes4, '我的fft結果');
    
    % 繪制axes6
    ifft2 = myifft(fft2, N);
%     axis (handles.axes6, [-5,5,-1.5,1.5]);
%     ifft2 = idft(fft2);
    plot (handles.axes6, ifft2);
    title(handles.axes6, '我的ifft結果');