【通信原理】利用Matlab仿真ASK、FSK、PSK和QAM信号的调制与解调（GUI实现）

最新推荐文章于 2025-05-31 10:48:34 发布

pd162

最新推荐文章于 2025-05-31 10:48:34 发布

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分类专栏：通信原理学习文章标签： matlab

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一、实验题目

利用Matlab仿真ASK、FSK、PSK和QAM信号的调制与解调过程。

二、实验原理

1、数字带通传输系统原理

设有随机信号
$s(t)=\sum_n a_n g(t-nT_s)$
其中an为二进制随机序列

2ASK

$e_{2ASK}=s(t)cos\omega_ct$

即调制过程为随机信号与载波直接相乘，实现流程图如下：

在这里插入图片描述

本实验的2ASK的解调过程采用相干解调，具体框图如下：

在这里插入图片描述

2FSK

$e_{2FSK}=s_1(t)cos\omega_1t+s_2(t)cos\omega_2t$

其中
$s_1(t)=s(t)$

$s_2(t)=1-s(t)$

即原码乘一个频率的载波，反码乘另一个频率的载波，最后相加。

在这里插入图片描述

解调即分别乘各自载波最后经过低通滤波器，再经过抽样判决恢复出原始信号。框图如下

在这里插入图片描述

2PSK

$Cannot read properties of undefined (reading 'type')$

$s(t)=\sum_n a_n g(t-nT_s)$

$e_{2PSK}=s(t)cos\omega_ct$

在这里插入图片描述

解调与2ASK相干解调相似，如下图所示：

在这里插入图片描述

QAM

调制过程：

(1)首先，一串二进制序列进入串/并变换中，进行4比特划分后再进行2比特划分成一组，按照奇数送同相路，偶数送入正交路。

(2)进入2/L电平变换，就是说二进制数变成4个十进制数，而4个十进制数是由自己的星座图设定的，即00,01,11,10分别对应于-3,-1,1,3。

(3)送入低通后滤除较小的抖动波。

(4)进入相乘器，载波cosωct与同相路波SI(t)相乘变为SI(t) cosωct, 载波cosωct经过相位移动90°与正交路波SQ(t)相乘变为-SQ(t) sinωct。

(5)两路波形经过相乘器后，进行相加，变为
$e_{QAM}=S_I(t)cosω_ct- S_Q(t)sinω_ct。$
实现框图为

在这里插入图片描述

解调过程

(1)经过调制后的波形再分别与相乘器相乘，通过载波cosωct和载波cosωct经过相位移动90°后各自提取出同相分量和正交分量。

(2)进入低通形成包络波形。

(3)再进入采样判决器，选取采样点形成原始的二进制矩形波形。

4)最后进入并/串变换，按照原先的奇偶原则形成完成的原始二进制信号。

2、GUI程序实现设计思路

前端：使用MATLAB自带的APP设计工具设计

GUI核心回调函数 refreshplot

根据下拉框返回的结果利用生成的数据更新图像

后端数据：用各模块生成各种调制解调的数据，输入前端。

文件结构

digitalBandPassTransSystem.m------communicationData.mat

|-----test.mlx--------ask2.m

|-------fsk2.m

|-------psk2.m

|-------gen_random_signal.m

|-------T2F.m

|-------F2T.m

三、实验成果展示

1、各模块展示

2ASK

在这里插入图片描述

2FSK

在这里插入图片描述

2PSK

在这里插入图片描述

16QAM

在这里插入图片描述

2、GUI展示

2FSK已调信号

在这里插入图片描述

2ASK已调信号

在这里插入图片描述

2PSK解调信号
在这里插入图片描述

四、源代码

1、GUI

classdef digitalBandPassTransSystem < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        PatientsDisplayUIFigure  matlab.ui.Figure
        GridLayout               matlab.ui.container.GridLayout
        LeftPanel                matlab.ui.container.Panel
        Panel2_4                 matlab.ui.container.Panel
        DropDownLabel            matlab.ui.control.Label
        DropDown                 matlab.ui.control.DropDown
        Label                    matlab.ui.control.Label
        Panel2_5                 matlab.ui.container.Panel
        DropDown_2Label          matlab.ui.control.Label
        DropDown_2               matlab.ui.control.DropDown
        RightPanel               matlab.ui.container.Panel
        TabGroup                 matlab.ui.container.TabGroup
        PlotTab                  matlab.ui.container.Tab
        UIAxes                   matlab.ui.control.UIAxes

    end

    % Properties that correspond to apps with auto-reflow
    properties (Access = private)
        onePanelWidth = 576;
    end

    % The app displays the data by using the scatter plot, histogram, and table.
    % It makes use of tabs to separate the ploting options output from the table display of the data.
    % There are several graphical elements used such as checkboxes, slider, switch, dropdown, and radiobutton group.
    % The data used in the app is shipped with the product.
    
    properties (Access = private)
        % Declare properties of the PatientsDisplay class.
        Data
        SelectedModMethods
        SelectedPlots
    end
    
    methods (Access = private)
        
        function annotateScatterPlot(app)
            % Update X and Y Labels
            app.UIAxes.XLabel.String = 'Time';
            app.UIAxes.YLabel.String = 'Amplitude';
        end
    end

    % Callbacks that handle component events
    methods (Access = public)

        % Code that executes after component creation
        function startupFcn(app)
            % Load the data.
            load('communicationData.mat',"t","signal_delay","signal_psk2","signal_fsk2","signal_ask2","msgmod2","signal_ask_reconstruction","signal_psk_reconstruction","signal_fsk_reconstruction","y2");
            % Store the data in a table and display it in one of the App's tabs.
            app.Data = table(t, signal_delay, signal_ask2, signal_fsk2, signal_psk2, msgmod2, signal_ask_reconstruction, signal_fsk_reconstruction, signal_psk_reconstruction, y2);

            % Update the axes with the corresponding data.
            refreshplot(app)
        end

        % Changes arrangement of the app based on UIFigure width
        function updateAppLayout(app, event)
            currentFigureWidth = app.PatientsDisplayUIFigure.Position(3);
            if(currentFigureWidth <= app.onePanelWidth)
                % Change to a 2x1 grid
                app.GridLayout.RowHeight = {472, 472};
                app.GridLayout.ColumnWidth = {'1x'};
                app.RightPanel.Layout.Row = 2;
                app.RightPanel.Layout.Column = 1;
            else
                % Change to a 1x2 grid
                app.GridLayout.RowHeight = {'1x'};
                app.GridLayout.ColumnWidth = {282, '1x'};
                app.RightPanel.Layout.Row = 1;
                app.RightPanel.Layout.Column = 2;
            end
        end

        % Callback function
        function refreshplot(app, event)
            ModMethods = app.SelectedModMethods;
            Plots = app.SelectedPlots;
            % Start with a fresh plot
            cla(app.UIAxes)
            hold(app.UIAxes,'on')            
            % Select relevant segment of data
            xdata = app.Data.t;
            
            % Filter the data according to the controls
            % filterData(app);
            
            % Create either a scatter plot or histogram, based on selection
            switch app.DropDown.Value
                case '2ASK'
                    switch app.DropDown_2.Value
                        case '调制信号'
                            plot(app.UIAxes,xdata,app.Data.signal_delay);
                            annotateScatterPlot(app)
                        case '已调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_ask2);
                            annotateScatterPlot(app)
                        case '解调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_ask_reconstruction);
                            annotateScatterPlot(app)
                    end
                case '2FSK'
                    switch app.DropDown_2.Value
                        case '调制信号'
                            plot(app.UIAxes,xdata,app.Data.signal_delay);
                            annotateScatterPlot(app)
                        case '已调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_fsk2);
                            annotateScatterPlot(app)
                        case '解调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_fsk_reconstruction);
                            annotateScatterPlot(app)
                    end
                 case '2PSK'
                    switch app.DropDown_2.Value
                        case '调制信号'
                            plot(app.UIAxes,xdata,app.Data.signal_delay);
                            annotateScatterPlot(app)
                        case '已调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_psk2);
                            annotateScatterPlot(app)
                        case '解调信号'
                            plot(app.UIAxes,xdata,app.Data.signal_psk_reconstruction);
                            annotateScatterPlot(app)
                    end
                 case '2QAM'
                    switch app.DropDown_2.Value
                        case '调制信号'
                            plot(app.UIAxes,xdata,app.Data.signal_delay);
                            annotateScatterPlot(app)
                        case '已调信号'
                            plot(app.UIAxes,xdata,app.Data.msgmod2);
                            annotateScatterPlot(app)
                        case '解调信号'
                            plot(app.UIAxes,xdata,app.Data.y2);
                            annotateScatterPlot(app)
                     end
            end
            drawnow;
        end

       
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            
            % Create PatientsDisplayUIFigure and hide until all components are created
            app.PatientsDisplayUIFigure = uifigure('Visible', 'off');
            app.PatientsDisplayUIFigure.AutoResizeChildren = 'off';
            app.PatientsDisplayUIFigure.Position = [100 100 703 400];
            app.PatientsDisplayUIFigure.Name = 'Patients Display';
            app.PatientsDisplayUIFigure.SizeChangedFcn = createCallbackFcn(app, @updateAppLayout, true);

            % Create GridLayout
            app.GridLayout = uigridlayout(app.PatientsDisplayUIFigure);
            app.GridLayout.ColumnWidth = {282, '1x'};
            app.GridLayout.RowHeight = {'1x'};
            app.GridLayout.ColumnSpacing = 0;
            app.GridLayout.RowSpacing = 0;
            app.GridLayout.Padding = [0 0 0 0];
            app.GridLayout.Scrollable = 'on';

            % Create LeftPanel
            app.LeftPanel = uipanel(app.GridLayout);
            app.LeftPanel.Layout.Row = 1;
            app.LeftPanel.Layout.Column = 1;
            app.LeftPanel.Scrollable = 'on';

            % Create Panel2_4
            app.Panel2_4 = uipanel(app.LeftPanel);
            app.Panel2_4.AutoResizeChildren = 'off';
            app.Panel2_4.Title = '调制方式';
            app.Panel2_4.Position = [7 216 269 97];

            % Create DropDownLabel
            app.DropDownLabel = uilabel(app.Panel2_4);
            app.DropDownLabel.HorizontalAlignment = 'right';
            app.DropDownLabel.Position = [51 25 41 22];
            app.DropDownLabel.Text = '请选择';

            % Create DropDown
            app.DropDown = uidropdown(app.Panel2_4);
            app.DropDown.Items = {'2ASK', '2FSK', '2PSK', '2QAM'};
            app.DropDown.ValueChangedFcn = createCallbackFcn(app, @refreshplot, true);
            app.DropDown.Position = [107 25 153 22];
            app.DropDown.Value = '2ASK';

            % Create Label
            app.Label = uilabel(app.LeftPanel);
            app.Label.HorizontalAlignment = 'center';
            app.Label.FontSize = 15;
            app.Label.FontWeight = 'bold';
            app.Label.Position = [9 356 267 22];
            app.Label.Text = '二进制数字带通传输系统展示';

            % Create Panel2_5
            app.Panel2_5 = uipanel(app.LeftPanel);
            app.Panel2_5.AutoResizeChildren = 'off';
            app.Panel2_5.Title = '展示结果';
            app.Panel2_5.Position = [7 102 269 97];

            % Create DropDown_2Label
            app.DropDown_2Label = uilabel(app.Panel2_5);
            app.DropDown_2Label.HorizontalAlignment = 'right';
            app.DropDown.ValueChangedFcn = createCallbackFcn(app, @refreshplot, true);
            app.DropDown_2Label.Position = [51 25 41 22];
            app.DropDown_2Label.Text = '请选择';

            % Create DropDown_2
            app.DropDown_2 = uidropdown(app.Panel2_5);
            app.DropDown_2.Items = {'调制信号', '已调信号', '解调信号'};
            app.DropDown_2.Position = [107 25 153 22];
            app.DropDown_2.Value = '解调信号';

            % Create RightPanel
            app.RightPanel = uipanel(app.GridLayout);
            app.RightPanel.Layout.Row = 1;
            app.RightPanel.Layout.Column = 2;
            app.RightPanel.Scrollable = 'on';

            % Create TabGroup
            app.TabGroup = uitabgroup(app.RightPanel);
            app.TabGroup.Position = [7 6 408 387];

            % Create PlotTab
            app.PlotTab = uitab(app.TabGroup);
            app.PlotTab.Title = 'Plot';

            % Create UIAxes
            app.UIAxes = uiaxes(app.PlotTab);
            xlabel(app.UIAxes, 'time')
            ylabel(app.UIAxes, 'Amplitude')
            app.UIAxes.GridAlpha = 0.15;
            app.UIAxes.MinorGridAlpha = 0.25;
            app.UIAxes.Box = 'on';
            app.UIAxes.Position = [19 89 376 234];

            % Show the figure after all components are created
            app.PatientsDisplayUIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = digitalBandPassTransSystem

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.PatientsDisplayUIFigure)

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.PatientsDisplayUIFigure)
        end
    end
end

2、test.mlx

% test 
 
clc
clear

gen_num = 10;

signal = gen_random_signal(gen_num);

meta_num = 16384;

signal_delay = delaySignal(signal, meta_num);

plot(1/(meta_num):1/(meta_num):gen_num, signal_delay)

%%%%%%%%%%%%%%%%%%%%%%%  2ASK调制  %%%%%%%%%%%%%%%%%%%%%%%%

fc = 1024;
fs = gen_num * meta_num;
A = 1;
snr = 30;
t = 1/fs:gen_num/fs:gen_num;
signal_ask2 = ask2(signal_delay, fc, fs, A, snr);

plot(t, signal_ask2);


carry_wave = cos(2*pi*fc*t);
plot(t, carry_wave);
title("载波信号");
signal_ask2_temp = signal_ask2 .* carry_wave;
plot(t, signal_ask2_temp)
title("与载波相乘后的信号")
[f, sf] = T2F(t, signal_ask2_temp);
[t, st] = lpf(f, sf, 10);
plot(t, st>0.25);
title("2ASK 相干解调")
signal_ask_reconstruction = nonCoherentDemodulation_2ask(signal_ask2, fc, fs);
plot(t, signal_ask_reconstruction);
title("2ASK 非相干解调")
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%  2FSK调制  %%%%%%%%%%%%%%%%%%%%%%%%
fc = [20, 100];
A = 1;
snr = 30;
signal_fsk2 = fsk2(signal, fc, fs, meta_num, A, snr);
plot(t, signal_fsk2);

carry_wave_1 = cos(2 * pi * fc(1) * t);
carry_wave_2 = cos(2 * pi * fc(2) * t);

signal_fsk2_temp = signal_fsk2 .* carry_wave_1;
plot(t, signal_fsk2_temp);
[f_fsk, sf_fsk] = T2F(t, signal_fsk2_temp);
[t_fsk, st_fsk] = lpf(f_fsk, sf_fsk, 10);
signal_fsk_reconstruction = st_fsk > mean(st_fsk);
plot(t_fsk, signal_fsk_reconstruction);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%  2PSK调制  %%%%%%%%%%%%%%%%%%%%%%%%

fc = 16;
A = 1;
snr = 30;
signal_psk2 = psk2(signal, fc, fs, meta_num, A, snr);
plot(t, signal_psk2);

carry_wave_psk = cos(2 * pi * fc * t);
signal_psk2_temp = carry_wave_psk .* signal_psk2;
plot(t, signal_psk2_temp);

[f_psk, sf_psk] = T2F(t, signal_psk2_temp);
[t_psk, st_psk] = lpf(f_psk, sf_psk, 5);
signal_psk_reconstruction = st_psk>mean(st_psk);
plot(t_psk, signal_psk_reconstruction);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%  QAM调制  %%%%%%%%%%%%%%%%%%%%%%%%
M = 2;
msg=signal_delay;

graycode=[0 1 3 2 4 5 7 6 12 13 15 14 8 9 11 10]; % 格雷码表

EsN0=5:20;
snr1=10.^(EsN0/10); % 噪声容限

msg1=graycode(msg+1);
msgmod2=qammod(msg1,M);
scatterplot(msgmod2);

spow=norm(msgmod2).^ 2/length(msg);

for i=1:length(EsN0)
    sigma=sqrt(spow/(2*snr1(i)));
    rx=msgmod2+sigma*(randn(1,length(msgmod2))+1i*randn(1,length(msgmod2)));
    y2=qamdemod(rx,M);
    decmsg=graycode(y2+1);
    [err1,ber(i)]= biterr(msg,decmsg,log2(M));
    [err2,ser(i)]=symerr(msg,decmsg);
end
subplot(311)
plot(t, msg)
subplot(312)
plot(t, abs(msgmod2))
subplot(313)
plot(t, y2)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%  QAM16调制  %%%%%%%%%%%%%%%%%%%%%%%%
% 使用内置函数qammod qamdemod进行调制解调
M = 16;
msg_length = 100;
msg=randi([0,M-1],1,msg_length);

graycode=[0 1 3 2 4 5 7 6 12 13 15 14 8 9 11 10]; % 格雷码表

EsN0=5:20;
snr1=10.^(EsN0/10); % 噪声容限

msg1=graycode(msg+1);
msgmod=qammod(msg1,M);
scatterplot(msgmod);

spow=norm(msgmod).^ 2/length(msg);

for i=1:length(EsN0)
    sigma=sqrt(spow/(2*snr1(i)));
    rx=msgmod+sigma*(randn(1,length(msgmod))+1i*randn(1,length(msgmod)));
    y=qamdemod(rx,M);
    decmsg=graycode(y+1);
    [err1,ber(i)]= biterr(msg,decmsg,log2(M));
    [err2,ser(i)]=symerr(msg,decmsg);
end
subplot(311)
plot(msg)
subplot(312)
plot(abs(msgmod))
subplot(313)
plot(y)

p4=2*(1-1/sqrt(M))*qfunc(sqrt(3*snr1/(M-1)));
ser1=1-(1-p4).^2;
ber1=1/log2(M)*ser1;
figure()
semilogy(EsN0,ber,'o',EsN0,ser,'*' ,EsN0,ser1, EsN0,ber1,'-');
title('64QAM-AWGN')
xlabel('Es/N0');ylabel('SER AND BER');
legend('ber simulation' ,'ser simulation','ser theory' ,'ber theory');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


save("communicationData.mat","t","signal_delay","signal_psk2","signal_fsk2","signal_ask2","msgmod2","signal_ask_reconstruction","signal_psk_reconstruction","signal_fsk_reconstruction","y2");

3、2ASK

%% 2ASK函数
%  功能：进行2ASK 含有加性高斯白噪声
%  输入：调制信号signal_delay; 载波频率fc; 采样频率fs; 调幅A; 信噪比snr
%  输出：已调信号signal_ask2
%  日期：2021/6/4

function signal_ask2 = ask2(signal_delay, fc, fs, A, snr)  
    t = linspace(0, 10, fs);
    carry_wave = A * cos(2 * pi * fc * t);
    signal_ask2 = carry_wave .*  signal_delay;
    signal_ask2 = awgn(signal_ask2, snr);
end

4、2FSK

%% 2FSK函数
%  功能：进行2FSK 含有加性高斯白噪声
%  输入：调制信号signal; 载波频率fc(1*2); 每个码元的长度meta_num; 调幅A; 信噪比snr
%  输出：已调信号signal_fsk2
%  日期：2021/6/4

function signal_fsk2 = fsk2(signal, fc, fs, meta_num, A, snr)  
    t = linspace(0, 1, fs/10);
    carry_wave_1 = A * cos(2 * pi * fc(1) * t);
    carry_wave_2 = A * cos(2 * pi * fc(2) * t);
    signal_delay = [];
    carry_wave = [];
    for i = 1:length(signal)
        if signal(i) == 1
            signal_delay_temp = ones(1, meta_num);
            carry_wave_temp = carry_wave_1;
        else
            signal_delay_temp = ones(1, meta_num);
            carry_wave_temp = carry_wave_2;
        end
        signal_delay = [signal_delay, signal_delay_temp];
        carry_wave = [carry_wave, carry_wave_temp];
    end
    signal_fsk2 = carry_wave .* signal_delay;
    signal_fsk2 = awgn(signal_fsk2, snr);
end

5、PSK

%% 2PSK函数
%  功能：进行2PSK 含有加性高斯白噪声
%  输入：调制信号signal; 载波频率fc; 每个码元的长度meta_num; 调幅A; 信噪比snr
%  输出：已调信号signal_psk2
%  日期：2021/6/4

function signal_psk2 = psk2(signal, fc, fs, meta_num, A, snr)  
    t = linspace(0, 1, fs/10);
    carry_wave_1 = A * cos(2 * pi * fc * t);
    carry_wave_2 = -A * cos(2 * pi * fc * t);
    signal_delay = [];
    carry_wave = [];
    for i = 1:length(signal)
        if signal(i) == 1
            signal_delay_temp = ones(1, meta_num);
            carry_wave_temp = carry_wave_1;
        else
            signal_delay_temp = ones(1, meta_num);
            carry_wave_temp = carry_wave_2;
        end
        signal_delay = [signal_delay, signal_delay_temp];
        carry_wave = [carry_wave, carry_wave_temp];
    end
    signal_psk2 = carry_wave .* signal_delay;
    signal_psk2 = awgn(signal_psk2, snr);
end