Re: TSA: Implementing method of Ding et al. "Short-window spectral analysis ..."

From: Alois Schloegl <alois.schloegl ***AT***tugraz.at>
Date: Mon, 11 Apr 2005 19:21:36 +0200
Subject: Re: TSA: Implementing method of Ding et al. "Short-window spectral analysis ..."
Newsgroups: tu-graz.biosig
Organization: Technische Universitaet Graz
Message-id: <425AB220.9010803@tugraz.at>
User-agent: Mozilla Thunderbird 0.9 (Windows/20041103)
References: <200504111343.j3BDht211272@spot.cns.hscbklyn.edu>

David,

there is a simpler solution to this problem. MVAR has been designed in such a way that NaN's are skipped. If you concatanate all "realizations" and insert a sufficient number of NaN's between each realization, and apply this large segment to MVAR, you are all set.

Using BIOSIG.SF.NET you can do:
   [s,sz]=trigg(s, TRIG, ix1, ix2, MOP+1);
   [AR,RC,PE]=mvar(s',MOP);

The result is the esemble average of all segments. You can do this with all modes of MVAR.
See also biosig/t300/TFMVAR.M


Alois




chorlian wrote:

Alois:

	I am planning to implement the MVAR method outlined in Ding et
	al. "Short-window spectral analysis ...", Biol. Cybern. 83,
	35-45 (2000), which determines the covariance matrix by
	averaging over multiple realizations of a process.  Examining
	your code for mvar(), I see that it would be easy to alter the
	section for Mode == 6, as the covariance matrix calculations
	for one loop index are not dependent on those for any
	preceeding loop.  However, for the Nutall-Strand modes, it
	seems like a reaveraging step would be needed for every
	interation of the loop.  Since I am not confident that I could
	modify Mode == 2 without difficulty, I will work with Mode ==
	6.  If I get it to work, I will give you the code for further
	distribution.  Do you have any suggestions before I start this
	project?


David

David B. Chorlian
Senior Scientific Programmer, Neurodynamics Lab, SUNY/HSCB
voice: 718-270-2231; fax: 718-270-4081
chorlian***AT***cns.hscbklyn.edu