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语音信号处理技术与频谱分析仪设计

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。数字傅里叶变换（DFT）及快速傅里叶变换（FFT）是进行数字信号频谱分析的重要方法。MATLAB是一个功能强大的数据分析和处理工具，能够方便地实现语音信号的采集、分析和处理。本文将介绍在MATLAB环境中如何采集声音信号以及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。

概述

随着信息时代的到来，数字信号处理已成为重要的技术领域，广泛应用于通信、语音、图像、自动控制、医疗和家用电器等多个领域。任何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本身。因此，研究信号的频谱就等于研究信号本身。从频域角度对信号进行分析与处理，能够更深入地了解信号的特性。因此，信号的频谱分析是数字信号处理技术中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，价格便宜且使用方便。MATLAB工具箱集成了一些语音处理功能函数。本文将介绍基于声卡与MATLAB的声音信号频谱分析仪的设计原理与实现方法。

设计原理

频谱分析通过傅里叶变换将波形 ( x(t) ) 变换为频谱 ( X(f) )，从而从另一角度了解信号特征。常见的傅里叶变换有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。

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});
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 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)
handles.output = hObject;
xlabel(handles.axes1,'Time (s)','fontweight','bold');
xlabel(handles.axes2,'Frequency (Hz)','fontweight','bold');
xlabel(handles.axes3,'Frequency (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

运行结果

通过实验验证，本设计的语音信号频谱分析仪能够实现语音信号的采集与频谱分析。系统运行稳定，用户操作简单，能够直观地显示语音信号的频谱分布。实验结果表明，该工具能够有效地分析语音信号的频率成分，便于进一步的语音处理任务。

备注

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