如果没有的话，请高手指点下其实现的m文件，不胜感激。

Question

我的版本是matlab7.0，程序中用到这些函数时，系统提示为??? Undefined command/function 'pburg'，用到这些函数都是这种情况。但是看的matlab程序中这些函数都是直接用的？

Answer 1

在命令窗口输入open buttord 即可打开该函数的源代码，并且可以修改该函数修改之后保存在你的工作区间work里面即可调用

Answer 2

function varargout = pburg(x,p,varargin)%PBURG Power Spectral Density (PSD) estimate via Burg's method.% Pxx = PBURG(X,ORDER) returns the PSD of a discrete-time signal vector X% in the vector Pxx. Pxx is the distribution of power per unit frequency.% The frequency is expressed in units of radians/sample. ORDER is the % order of the autoregressive (AR) model used to produce the PSD. PBURG % uses a default FFT length of 256 which determines the length of Pxx.%% For real signals, PBURG returns the one-sided PSD by default; for % complex signals, it returns the two-sided PSD. Note that a one-sided % PSD contains the total power of the input signal.%% Pxx = PBURG(X,ORDER,NFFT) specifies the FFT length used to calculate % the PSD estimates. For real X, Pxx has length (NFFT/2+1) if NFFT is % even, and (NFFT+1)/2 if NFFT is odd. For complex X, Pxx always has % length NFFT. If empty, the default NFFT is 256.%% [Pxx,W] = PBURG(...) returns the vector of normalized angular % frequencies, W, at which the PSD is estimated. W has units of % radians/sample. For real signals, W spans the interval [0,Pi] when % NFFT is even and [0,Pi) when NFFT is odd. For complex signals, W % always spans the interval [0,2*Pi).%% [Pxx,F] = PBURG(...,Fs) specifies a sampling frequency Fs in Hz and% returns the power spectral density in units of power per Hz. F is a% vector of frequencies, in Hz, at which the PSD is estimated. For real % signals, F spans the interval [0,Fs/2] when NFFT is even and [0,Fs/2)% when NFFT is odd. For complex signals, F always spans the interval % [0,Fs). If Fs is empty, [], the sampling frequency defaults to 1 Hz.  %% [Pxx,W] = PBURG(...,'twosided') returns the PSD over the interval% [0,2*Pi), and [Pxx,F] = PBURG(...,Fs,'twosided') returns the PSD over% the interval [0,Fs). Note that 'onesided' may be optionally specified,% but is only valid for real X. The string 'twosided' or 'onesided' may % be placed in any position in the input argument list after ORDER.%% PBURG(...) with no output arguments plots the PSD estimate in dB per % unit frequency in the current figure window.%% EXAMPLE:% randn('state',1); x = randn(100,1); % y = filter(1,[1 1/2 1/3 1/4 1/5],x); % Fourth order AR filter.% pburg(y,4,[],1000); % Uses the default NFFT of 256.%% See also PCOV, PMCOV, PYULEAR, PMTM, PMUSIC, PEIG, PWELCH, PERIODOGRAM, % ARBURG, PRONY, SPECTRUM/BURG, DSPDATA/PSD.% Author(s): R. Losada and P. Pacheco% Copyright 1988-2004 The MathWorks, Inc.% $Revision: 1.26.4.5 $ $Date: 2004/04/13 00:18:07 $error(nargchk(2,5,nargin))method = 'arburg';[Pxx,freq,msg,units,Sxx,options] = arspectra(method,x,p,varargin{:});error(msg);if nargout==0,freq = {freq};if strcmpi(units,'Hz'), freq = {freq{:},'Fs',options.Fs};endhpsd = dspdata.psd(Pxx,freq{:},'SpectrumType',options.range);% Create a spectrum object to store in the PSD object's metadata.hspec = spectrum.burg(p);hpsd.Metadata.setsourcespectrum(hspec);plot(hpsd);else% Assign output arguments.varargout = {Pxx,freq,Sxx}; % Pxx=PSD, Sxx=PSend% [EOF] pburg.m