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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 EDITgui_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});endif 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_pianohandles.output = hObject;% Update handles structureguidata(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 structurevarargout{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

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