一、简介
1 背景
电子琴是随着电子技术的广泛应用而产生。1959年，世界上第一台全晶体管双排键电子琴在日本诞生。从此，电子琴技术不断发展成熟，电子琴的普及也越来越广。
电子琴在中国的推广始于20世纪八十年代，至今在音色、音质、演奏的便利性等方面都达到了相当成熟的地步，而且随着集成电路技术的发展，其升级换代可以在保持原有结构不变的情况下，通过简单的芯片更换实现。但是，电子琴也有明显的不足之处：与非电子乐器，如钢琴、管弦乐器等的协奏问题，限制了电子琴在重要音乐场所的使用，这极大的影响了电子琴的应用和推广。协调电子琴与非电子乐器的协奏，是当前音乐界人士和电子琴开发商的当务之急。
2 电子琴发音原理
物体振动时会发出声音，振动的频率不同，声音的音调就不同。在电子琴里，虽然没有振动的弦、簧、管等物体，却有许多特殊的电装置，每个电装置一工作，就会使喇叭发出一定频率的声音。当按动某个琴键时，就会使与它对应的电装置工作，从而使喇叭发出某种音调的声音。
电子琴的音量控制器，实质上是一个可调电阻器。当转动音量控制器旋扭时，可调电阻器的电阻就随着变化。电阻大小的变化，又会引起喇叭声音强弱的变化。所以转动音量控制旋扭时，电子琴发声的响度就随之变化。
当乐器发声时，除了发出某一频率的声音──基音以外，还会发出响度较小、频率加倍的辅助音──谐音。我们听到的乐器的声音是它发出的基音和谐音混合而成的。不同的乐器发出同一基音时，不仅谐音的数目不同，而且各谐音的响度也不同。因而使不同的乐器具有不同的音品。在电子琴里，除了有与基音对应的电装置外，还有与许多谐音对应的电装置，适当地选择不同的谐音电装置，就可以模仿出不同乐器的声音来。
3 基于 Matlab的数字电子琴实现原理
振动频率不同，音调就不同。电子琴的每一按键对应一个频率不同的正弦波，按下按键，产生正弦波，播放波形即可听到对应按键的基音。
二、源代码
function varargout = digtai_piano(varargin)
% DIGTAI_PIANO M-file for digtai_piano.fig
% DIGTAI_PIANO, by itself, creates a new DIGTAI_PIANO or raises the existing
% singleton*.
%
% H = DIGTAI_PIANO returns the handle to a new DIGTAI_PIANO or the handle to
% the existing singleton*.
%
% DIGTAI_PIANO('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in DIGTAI_PIANO.M with the given input arguments.
%
% DIGTAI_PIANO('Property','Value',...) creates a new DIGTAI_PIANO or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before digtai_piano_OpeningFunction gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to digtai_piano_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
% Copyright 2002-2003 The MathWorks, Inc.
% Edit the above text to modify the response to help digtai_piano
% Last Modified by GUIDE v2.5 28-Sep-2007 10:39:23
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @digtai_piano_OpeningFcn, ...
'gui_OutputFcn', @digtai_piano_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 digtai_piano is made visible.
function digtai_piano_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 digtai_piano (see VARARGIN)
% Choose default command line output for digtai_piano
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes digtai_piano wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = digtai_piano_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 pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton3 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
A=1;
f=131;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
% --- Executes on button press in pushbutton4.
function pushbutton4_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton4 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
A=1;
f=147;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
% --- 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)
A=1;
f=165;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
% --- 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)
A=1;
f=175;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
% --- 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)
A=1;
f=196;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
% --- 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)
A=1;
f=220;
Fs=11025;
P=60;
T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);
Phandel=findobj('Tag','edit1')
set(Phandel,'String',f,'FontSize',15.0)
plot(t,y,'r');
grid ;
axis([0,0.1,-1.5,1.5]);
wavplay(y,11025);
pause(1);
cla;
三、运行结果
四、备注
完整代码或者代写添加QQ1575304183
往期回顾>>>>>>