一、简介
语音信号处理技术是语音处理领域中新近发展起来的一个学科分支，而频谱分析技术是进行语音信号处理的基础。DFT及FFT变换是进行数字信号频谱分析的重要方法。DFT是FFT的基础, FFT是DFT的快速算法。MATLAB是一个数据分析和处理功能十分强大的工程实用软件，运用它来进行语音信号的采集、分析和处理相当方便。本文介绍了在MATLAB环境中如何采集声音信号和采集后的频谱分析方法，并使用MATLAB软件的GUI模块，设计了一个简易的声音信号频谱分析仪。
1 概述
随着信息时代和数字世界的到来,数字信号处理己成为当今一门极其重要的学科和技术领域,数字信号处理在通信、语音、图像、自动控制、医疗和家用电器等众多领域得到了广泛的应用。任意一个信号都具有时域与频域特性,信号的频谱完全代表了信号,因而研究信号的频谱就等于研究信号本身。通常从频域角度对信号进行分析与处理,容易对信号的特性获得深入的了解。因此,信号的频谱分析是数字信号处理技术中的一种较为重要的工具。
声卡是计算机最基本的配置硬件之一，价格便宜，使用方便。MATLAB工具箱集成了一些语音处理功能函数。本文将给出基于声卡与MATLAB的声音信号频谱分析仪的设计原理与实现方法。
2 设计原理
频谱分析用傅立叶变换将波形x(t)变换为频谱X(f)，从另一角度来了解信号特征。常见傅里叶变换有DFT和FFT。DFT是FFT的基础, FFT是DFT的快速算法,在MATLAB中可以利用函数fft来计算序列的离散傅里叶变换DFT。FFT是时域和频域转换的基本运算。
二、源代码
function varargout = SpectrumAnalysis(varargin)
% SPECTRUMANALYSIS MATLAB code for SpectrumAnalysis.fig
% SPECTRUMANALYSIS, by itself, creates a new SPECTRUMANALYSIS or raises the existing
% singleton*.
%
% H = SPECTRUMANALYSIS returns the handle to a new SPECTRUMANALYSIS or the handle to
% the existing singleton*.
%
% SPECTRUMANALYSIS('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in SPECTRUMANALYSIS.M with the given input arguments.
%
% SPECTRUMANALYSIS('Property','Value',...) creates a new SPECTRUMANALYSIS or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before SpectrumAnalysis_OpeningFcn gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to SpectrumAnalysis_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 SpectrumAnalysis
% Last Modified by GUIDE v2.5 02-Nov-2011 15:49:23
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @SpectrumAnalysis_OpeningFcn, ...
'gui_OutputFcn', @SpectrumAnalysis_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 SpectrumAnalysis is made visible.
function SpectrumAnalysis_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 SpectrumAnalysis (see VARARGIN)
% Choose default command line output for SpectrumAnalysis
handles.output = hObject;
xlabel(handles.axes1,'Time (s)','fontweight','bold');
xlabel(handles.axes2,'Freqency (Hz)','fontweight','bold');
xlabel(handles.axes3,'Freqency (Hz)','fontweight','bold');
ylabel(handles.axes1,'Amplitude','fontweight','bold');
ylabel(handles.axes2,'Amplitude','fontweight','bold');
ylabel(handles.axes3,'Amplitude','fontweight','bold');
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes SpectrumAnalysis wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = SpectrumAnalysis_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;
function edit_Fs_Callback(hObject, eventdata, handles)
% hObject handle to edit_Fs (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 edit_Fs as text
% str2double(get(hObject,'String')) returns contents of edit_Fs as a double
% --- Executes during object creation, after setting all properties.
function edit_Fs_CreateFcn(hObject, eventdata, handles)
% hObject handle to edit_Fs (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 edit_TestA_Callback(hObject, eventdata, handles)
% hObject handle to edit_TestA (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 edit_TestA as text
% str2double(get(hObject,'String')) returns contents of edit_TestA as a double
% --- Executes during object creation, after setting all properties.
function edit_TestA_CreateFcn(hObject, eventdata, handles)
% hObject handle to edit_TestA (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 edit_TestF_Callback(hObject, eventdata, handles)
% hObject handle to edit_TestF (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 edit_TestF as text
% str2double(get(hObject,'String')) returns contents of edit_TestF as a double
% --- Executes during object creation, after setting all properties.
function edit_TestF_CreateFcn(hObject, eventdata, handles)
% hObject handle to edit_TestF (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
三、运行结果
四、备注
2014a
