【物理应用】基于matlab的功率谱估计【含Matlab源码 329期】

2022-09-20 09:27:45

一、简介

功率谱估计是一种对信号的功率谱密度进行估计的方法，用于表征信号的能量特征随频率的变化关系，是信号处理领域的常用分析方法。具体可以分为三类：

直接法：周期图法(psd)、pwelch
基于滤波器组方法：Capon、Slapain
基于参数化模型的方法：AR、MA、ARMA
主要分为四章介绍功率谱估计，本章对功率谱估计的基本定义即自相关估计及直接法估计进行描述。
1 基本定义

2 面临的问题
一共有两个面临的问题：

因为加窗的问题会产生分辨率变低，频谱泄露的问题（频带主瓣宽->分辨率低，频谱泄露是固定频率周围有抖动，比如30Hz正弦信号在FFT的30Hz附近有明显的波峰旁瓣，分去了主瓣的能量），如下图所示，如果数据长度越趋近无限，则分辨率越好，中间部分越来越窄，泄露越少。

3 改进方法-直接法
本章主要对直接法这种改进方法进行描述

3.1 周期图法

二、源代码

function varargout = SsbForm(varargin)
% SSBFORM M-file for SsbForm.fig
%      SSBFORM, by itself, creates a new SSBFORM or raises the existing
%      singleton*.
%
%      H = SSBFORM returns the handle to a new SSBFORM or the handle to
%      the existing singleton*.
%
%      SSBFORM('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in SSBFORM.M with the given input arguments.
%
%      SSBFORM('Property','Value',...) creates a new SSBFORM or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before SsbForm_OpeningFunction gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to SsbForm_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 SsbForm

% Last Modified by GUIDE v2.5 07-Dec-2008 11:26:04

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @SsbForm_OpeningFcn, ...
                   'gui_OutputFcn',  @SsbForm_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 SsbForm is made visible.
function SsbForm_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 SsbForm (see VARARGIN)

% Choose default command line output for SsbForm
bg=imread('P6.bmp');
axes(handles.axes1);
imshow(bg);
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes SsbForm wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = SsbForm_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 selection change in popupmenu1.
function popupmenu1_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = get(hObject,'String') returns popupmenu1 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu1


% --- Executes during object creation, after setting all properties.
function popupmenu1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to popupmenu1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: popupmenu controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc
    set(hObject,'BackgroundColor','white');
else
    set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end


% --- Executes on selection change in popupmenu2.
function popupmenu2_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = get(hObject,'String') returns popupmenu2 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu2


% --- Executes during object creation, after setting all properties.
function popupmenu2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to popupmenu2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: popupmenu controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc
    set(hObject,'BackgroundColor','white');
else
    set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end


% --- Executes on selection change in popupmenu3.
function popupmenu3_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = get(hObject,'String') returns popupmenu3 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu3


% --- Executes during object creation, after setting all properties.
function popupmenu3_CreateFcn(hObject, eventdata, handles)
% hObject    handle to popupmenu3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: popupmenu controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc
    set(hObject,'BackgroundColor','white');
else
    set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end


% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global BW CW F t ts
t=[-pi:ts:pi];
ts=0.01;
if get(handles.popupmenu1,'value')==1
 elseif get(handles.popupmenu1,'value')==2
   BW='5*sin(t)'
 elseif get(handles.popupmenu1,'value')==3
   BW='10*sin(t)'
 elseif get(handles.popupmenu1,'value')==4
   BW='15*sin(t)'
end
if get(handles.popupmenu3,'value')==1
elseif get(handles.popupmenu3,'value')==2
     F=5
elseif get(handles.popupmenu3,'value')==3
     F=10
 elseif get(handles.popupmenu3,'value')==4
     F=15
end
if get(handles.popupmenu2,'value')==1
elseif get(handles.popupmenu2,'value')==2
    CW='cos(2*pi*F*t)'
elseif get(handles.popupmenu2,'value')==3
    CW='sin(2*pi*F*t)'
end
if get(handles.popupmenu1,'value')==1  | get(handles.popupmenu2,'value')==1|get(handles.popupmenu3,'value')==1
    warndlg('Unfilled Parameter !!!')
else
if   get(handles.popupmenu1,'value')==2
      set(handles.edit1,'string','BW=5*sin(t)');
elseif  get(handles.popupmenu1,'value')==3
      set(handles.edit1,'string','BW=10*sin(t)');
elseif  get(handles.popupmenu1,'value')==4
      set(handles.edit1,'string','BW=15*sin(t)');
 end
 if     CW=='sin(2*pi*F*t)'
      set(handles.edit2,'string','CW=sin(2*pi*F*t)');
 elseif CW=='cos(2*pi*F*t)'
       set(handles.edit2,'string','CW=cos(2*pi*F*t)');
 end
 if     F==5
     set(handles.edit3,'string','FC=5');
 elseif F==10
       set(handles.edit3,'string','FC=10')
 elseif F==15
          set(handles.edit3,'string','FC=15')
 end
end
% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
close all
SsbForm

% --- 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)
close
SysFirstF


function edit1_Callback(hObject, eventdata, handles)
% hObject    handle to edit1 (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 edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double


% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit1 (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
    set(hObject,'BackgroundColor','white');
else
    set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end

三、运行结果

四、备注

码农公寓

一、简介

二、源代码

三、运行结果

四、备注

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