mspc.m

最新的HHT时频分析程序By Huang and Wu

function ms=mspc(x,f)
 
% The function MSPC calculates a normalized marginal damping spectrum
% of x(k,n), where k specifies the number of frequencies, and 
% n is the number of time values.
%
% An input matrix can be generated by calling a function that generates
% the spectrum, for example NSP or NSPAB.
% Function PLOT can be used to view the marginal spectrum,
%    for example, plot(f,ms).
%
% Calling sequence-
% ms=mspc(x,f)
%
% Input-
%	x	- 2-D matrix x(k,n) of the HHT spectrum
%	f	- vector f(k) that specifies the frequency-axis values
%
% Output-
%	ms	- vector ms(k) that specifies the marginal spectrum	
 
% Z. Shen (JHU)		March, 1996 Initial
% J. Marshak (NASA GSFC)	Feb.24, 2004 Modified
%				(removed frequency from being returned).
%
% Xianyao Chen, September, 2008
%   remove the bug of x = x.*x
%   add /2 when calculate ms, read the paper "On the marginal spectrum" for the details