【數字信號調製】基於matlab GUI通訊（AM+FM+DSB+SSB）系統【Matlab1212

時間 2021-08-14

標籤 markdown app ide 工具性能 this 翻譯 3d code 欄目 MATLAB 简体版

原文原文鏈接

1、簡介

1 緒論
調製：把消息信號寄託到載波的某個參數上，造成已調信號。
解調：調製的逆過程，從已調信號中恢復消息信號。markdown

2 調製的目的
無線通訊中，匹配信道特性，提升發射信號的頻率，減少天線尺寸；頻譜搬移，一條信道中同時傳輸多路信號，多路複用，提升信道利用率；擴展信號帶寬，提升系統抗干擾能力；實現帶寬與信噪比的互換（有效性和可靠性）；利用電話線將PC機接入Internet，須要翻譯模/數信號。app

3 調製的分類
3.1 涉及的信號
消息信號，又稱調製信號、基帶信號；
載波：運載工具，經常使用的是正弦波、脈衝序列；
已調信號：受調載波，載有消息信號的信息，具備多種形式。
3.2 能夠從不一樣角度分類
按調製信號的類型：模擬調製/數字調製
按已調信號的頻譜結構：線性調製/非線性調製
按正弦載波的受調參量：幅度調製/頻率調製/相位調製
按載波信號的類型：連續波調製/脈衝調製ide

4 幅度調製
4.1 通常模型
（1）理論基礎：傅里葉變換
（2）通常模型
幅度調製：消息信號控制正弦載波的幅度。
方法：用消息信號經過相乘器乘上載波信號，再經過帶通濾波器（時域卷積濾波器特性）。
舉例：AM、DSB、SSB、VSB。工具

4.2 常規雙邊帶調幅AM
t 域：已調信號的波形，調製/解調方法
f 域：已調信號的頻譜，帶寬B
AM信號的包絡正比於消息信號的規律，所以能夠採用簡單的包絡檢波方法（非相干解調）解調；
頻譜由載波、上邊帶USB、下邊帶LSB組成。帶寬BAM=2fH；
幅度調製又稱爲線性調製；
應用：中短波調幅廣播。
缺點：功率利用率低，最多達到50%性能

4.3 抑制載波雙邊帶DSB
頻譜由上邊帶USB、下邊帶LSB組成，沒有了載波份量。帶寬BDSB=BAM=2fH；
調製效率可達100%。
採用相干解調：
方法：用消息信號經過想乘器乘上相干載波信號，再經過低通濾波器（時域卷積濾波器特性）。
要求：載波同步（相干載波和載波信號同頻同相）ui

4.4 單邊帶調製SSB
只傳輸一個邊帶，頻帶利用率高。帶寬BSSB=BAM/2=fH；在頻譜擁擠的通訊場合，如短波通訊、多路載波電話系統。低功耗特性。使用於移動通訊系統。
缺點：設備複雜，存在技術難點，須要相干解調。this

4.5 殘留邊帶調製VSB
殘留邊帶濾波器特性：在載頻處具備互補對稱特性；介於單邊帶與雙邊帶之間的方案。翻譯

5 角度調製
正弦載波有三個參量：幅度、頻率、相位。均可以攜帶消息信號。
其中，頻率（FM）和相位（PM）都稱爲角度調製。
頻率調製（FM）
幅度恆定，對瞬時相位對t求微分，獲得瞬時角頻率。
調頻的頻譜由載頻份量wc兩側的無數多對邊頻wc±nwm組成，其幅度取決於mf；
理論上，調頻的帶寬無窮大；
實際中，用卡森公式計算FM帶寬：BFM=2(mf+1)fm。fm爲調製信號的最高頻率
FM調製爲非線性調製。FM解調也稱鑑頻，採用微分電路+包絡檢波實現。
FM的特色和應用
特色：幅度不變，包絡恆定。
優點：抗噪能力強；
代價：佔用較大信道帶寬，頻譜利用率低；
應用：高質量或信道噪聲大的場合。如衛星通訊、移動通訊、微波通訊等。3d

6 抗噪聲性能
性能指標：輸出信噪比、制度增益
輸入信噪比：Ni=n0B。n0是噪聲的單邊功率譜密度，B=2fH是帶寬，是基帶帶寬的2倍。code

AM DSB SSB VSB（幅度調製）
相干解調器：線性解調，信號和噪聲能夠分開處理。
雙邊帶和單邊帶調製的抗噪聲性能相同。
小信噪比時，信號被幹擾爲噪聲，產生門限效應。緣由是包絡檢波的非線性解調做用。
信噪比固定。
FM（角度調製）
FM系統能夠經過增長傳輸帶寬來改善抗噪聲性能（信噪比）。

總結
頻譜利用率 SSB>VSB>DSB/AM>FM
抗噪聲性能：FM>DSB/SSB>VSB>AM
設備複雜度：AM最簡，DSB/FM次之，SSB最複雜

2、部分源代碼

function varargout = signal_generator(varargin)
% SIGNAL_GENERATOR MATLAB code for signal_generator.fig
%      SIGNAL_GENERATOR, by itself, creates a new SIGNAL_GENERATOR or raises the existing
%      singleton*.
%
%      H = SIGNAL_GENERATOR returns the handle to a new SIGNAL_GENERATOR or the handle to
%      the existing singleton*.
%
%      SIGNAL_GENERATOR('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in SIGNAL_GENERATOR.M with the given input arguments.
%
%      SIGNAL_GENERATOR('Property','Value',...) creates a new SIGNAL_GENERATOR or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before signal_generator_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to signal_generator_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 signal_generator

% Last Modified by GUIDE v2.5 12-Jul-2021 20:04:30

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @signal_generator_OpeningFcn, ...
                   'gui_OutputFcn',  @signal_generator_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 signal_generator is made visible.
function signal_generator_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 signal_generator (see VARARGIN)

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

% Update handles structure
guidata(hObject, handles);

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

% --- Outputs from this function are returned to the command line.
function varargout = signal_generator_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 button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)

AM

% --- Executes on button press in pushbutton5.
function pushbutton5_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton5 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

DSB

% --- 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)

SSB

% --- 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)

FM

% --- Executes on button press in pushbutton8.
function pushbutton8_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton8 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

close(handles.figure1);
% --- Executes just before AM is made visible.
function AM_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 AM (see VARARGIN)

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

% Update handles structure
guidata(hObject, handles);

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

% --- Outputs from this function are returned to the command line.
function varargout = AM_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 during object creation, after setting all properties.
function axes3_CreateFcn(hObject, eventdata, handles)
% hObject    handle to axes3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: place code in OpeningFcn to populate axes3

% --- 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)

% --- Executes during object creation, after setting all properties.
function frame1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to frame1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% --- Executes during object creation, after setting all properties.
function text2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to text2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% --- Executes when entered data in editable cell(s) in uitable2.
function uitable2_CellEditCallback(hObject, eventdata, handles)
% hObject    handle to uitable2 (see GCBO)
% eventdata  structure with the following fields (see MATLAB.UI.CONTROL.TABLE)
%   Indices: row and column indices of the cell(s) edited
%   PreviousData: previous data for the cell(s) edited
%   EditData: string(s) entered by the user
%   NewData: EditData or its converted form set on the Data property. Empty if Data was not changed
%   Error: error string when failed to convert EditData to appropriate value for Data
% handles    structure with handles and user data (see GUIDATA)

% --- Executes on selection change in listbox3.
function listbox3_Callback(hObject, eventdata, handles)
% hObject    handle to listbox3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox3 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox3

% --- Executes during object creation, after setting all properties.
function listbox3_CreateFcn(hObject, eventdata, handles)
% hObject    handle to listbox3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: listbox 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 edit1_Callback(hObject, eventdata, handles)
% hObject    handle to edit1 (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 edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double

% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit1 (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 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 pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

f=str2num(get(handles.edit2,'String')); %f=1,1hz基帶信號
A=str2num(get(handles.edit1,'String'));  % A=0.3
fc=str2num(get(handles.edit3,'String')); %fc=64  hz載波
fs=str2num(get(handles.edit4,'String')); %fs=1024;    
t=0:1/fs:2-0.5/fs;    %採樣時間爲0到2秒
x=(1+A*cos(2*pi*f*t)).*cos(2*pi*fc*t);  %調幅表達式
plot(handles.axes1,x);

3、運行結果

4、matlab版本及參考文獻

1 matlab版本
2014a

2 參考文獻[1] 沈再陽.精通MATLAB信號處理[M].清華大學出版社，2015.[2]高寶建,彭進業,王琳,潘建壽.信號與系統——使用MATLAB分析與實現[M].清華大學出版社，2020.[3]王文光,魏少明,任欣.信號處理與系統分析的MATLAB實現[M].電子工業出版社，2018.