Matlab GUI experiment - realizing a simple signal generator

Command line input Guide to create a blank GUI project

Arrange the controls and modify the tag name and font

Realize the linkage between the slider and the display box. The display box will show the number when the slider is dragged. The value of the function can also be changed by entering a number in the display box (the slider has a range of Min to Max, and the value entered in the display box must be within this range)

% Paste the code under the slider callback function

function fre_sliser_Callback(hObject)

v1 = get(handles.fre_slider,'Value');

s1 = sprintf('%f',v1);

set(handles.fre,'String',s1)

% Paste the code under the callback function of the display box corresponding to the slider

function fre_Callback(hObject)

s1 = get(handles.fre,'String');

v1 = str2double(s1);

set(handles.fre_slider,'Value',v1)

Paste the following code under the callback function of the signal button. In order to make the code concise, use global variables.

global Type;

Type = 1;

my_callback_fcn(handles);

my_callback_fcn is a custom function used to generate signals

function my_callback_fcn(handles)

global Type;

global fs;

global N;

global x;

fs = 44100;

dt = 1.0/fs;

T = 2;

N = T/dt;

t = linspace(0,T,N);

s1 = get(handles.fre,'String');

F = str2double(s1);

s1 = get(handles.amp,'String');

A = str2double(s1);

if Type == 1

x = 0.5*A*randn(1,N);

end

if Type == 2

x = A*sin(2*pi*F*t);

end

if Type == 3

x = A*square(2*pi*F*t);

end

if Type == 4

x = A*sawtooth(2*pi*F*t,0.5);

end

plot(handles.axes1,t,x,'b','LineWidth',5);

axis(handles.axes1,[0,0.01,-2500,2500]);

grid(handles.axes1);

Paste the code under the callback function corresponding to the play button

function Play_Callback(hObject)

global fs;

global x;

y = x*0.0003;% decay

sound(y,fs);

Advanced content, play and pause the signal, set the timer

global mytimer

mytimer = timer('StartDelay',1,'Period',1,'TasksToExecute',150,'ExecutionMode','fixedRate');

mytimer.TimerFcn = {@my_callback_fcn};

% Run the code under the play button callback function

global mytimer;

start(mytimer);

% Code under the Stop pause button callback function

global mytimer;

stop(mytimer);

To generate figure1_CreateFcn in the entire graphical interface, right-click CreateFcn

Final Result

The code comes from "Theory and Practice of Digital Signal Analysis" of Huazhong University of Science and Technology, only for learning summary