tomwalters@0: %
tomwalters@0: %	Taper Window Generator for signal onset/offset
tomwalters@0: %	7 Apr. 1993
tomwalters@0: %	29 Aug. 96
tomwalters@0: %	IRINO Toshio
tomwalters@0: %
tomwalters@0: %	function [TaperWin, TypeTaper] = ...
tomwalters@0: %		TaperWindow(LenWin,TypeTaper,LenTaper,RangeSigma,SwPlot)
tomwalters@0: %	INPUT	LenWin    : Length of Window (Number of points)
tomwalters@0: %		TypeTaper : Type of Taper (KeyWords of 3 letters)
tomwalters@0: %		  (Hamming, Hanning (=cosine^2), Blackman, Gauss, Line)
tomwalters@0: %		LenTaper  : Length of Taper  (Number of points)
tomwalters@0: %		RangeSigma: Range in Sigma (default: 3) for Gauss
tomwalters@0: %		SwPlot    : 0) Omit plotting,  1) Plot Taper
tomwalters@0: %	OUTPUT  TaperWin  : Taper Window Points (max==1);
tomwalters@0: %		TypeTaper : Type of Taper (Full Name)
tomwalters@0: %
tomwalters@0: function [TaperWin, TypeTaper] = ...
tomwalters@0: 	TaperWindow(LenWin,TypeTaper,LenTaper,RangeSigma,SwPlot)
tomwalters@0: 
tomwalters@0: if nargin < 2,
tomwalters@0: help TaperWindow
tomwalters@0: error([ 'Specify Type of Taper : ' ...
tomwalters@0: 	' Hamming, Hanning (=cosine^2), Blackman, Gauss, Line ']);
tomwalters@0: %TaperWin = ones(1,LenWin);
tomwalters@0: %return;
tomwalters@0: end;
tomwalters@0: 
tomwalters@0: if nargin < 3, LenTaper = fix(LenWin/2); end;
tomwalters@0: if nargin < 4, RangeSigma = 3; end;
tomwalters@0: 
tomwalters@0: if  LenTaper*2 >= LenWin, 
tomwalters@0: 	disp('Caution (TaperWindow.m) : No flat part. ');
tomwalters@0: 	if LenTaper ~= fix(LenWin/2),
tomwalters@0: 	disp('Caution (TaperWindow.m) : LenTaper <-- fix(LenWin/2)');
tomwalters@0: 	end;
tomwalters@0: 	LenTaper = fix(LenWin/2); 
tomwalters@0: end;
tomwalters@0: 
tomwalters@0: if nargin < 5, SwPlot = 0; end;	% changing default Swplot 29 Aug. 96
tomwalters@0: 
tomwalters@0: %TypeTaper = lower(TypeTaper(1:3));
tomwalters@0: 
tomwalters@0: if	upper(TypeTaper(1:3)) == 'HAM', 
tomwalters@0: 	Taper = hamming(LenTaper*2)';
tomwalters@0: 	TypeTaper = 'Hamming';
tomwalters@0: elseif	upper(TypeTaper(1:3)) == 'HAN' | upper(TypeTaper(1:3)) == 'COS', 
tomwalters@0: 	Taper = hanning(LenTaper*2)';
tomwalters@0: 	TypeTaper = 'Hanning/Cosine';
tomwalters@0: elseif	upper(TypeTaper(1:3)) == 'BLA', 
tomwalters@0: 	Taper = blackman(LenTaper*2)';
tomwalters@0: 	TypeTaper = 'Blackman';
tomwalters@0: elseif	upper(TypeTaper(1:3)) == 'GAU',  
tomwalters@0: 	if length(RangeSigma) == 0, RangeSigma = 3; end;
tomwalters@0: 	nn = -LenTaper+0.5:1:LenTaper-0.5;
tomwalters@0: 	Taper = exp(-(RangeSigma*nn/LenTaper).^2 /2);
tomwalters@0: 	TypeTaper = 'Gauss';
tomwalters@0: else	Taper = [1:LenTaper LenTaper:-1:1]/LenTaper;  % 'line', 
tomwalters@0: 	TypeTaper = 'Line';
tomwalters@0: end;
tomwalters@0: 
tomwalters@0: %plot(Taper)
tomwalters@0: %size(Taper);
tomwalters@0: LenTaper = fix(LenTaper);
tomwalters@0: TaperWin = [	Taper(1:LenTaper) ones(1,LenWin-LenTaper*2) ...
tomwalters@0: 		Taper(LenTaper+1:LenTaper*2)];
tomwalters@0: 
tomwalters@0: if SwPlot == 1,
tomwalters@0: 
tomwalters@0: plot(TaperWin)
tomwalters@0: xlabel('Points');
tomwalters@0: ylabel('Amplitude');
tomwalters@0: title(['TypeTaper = ' TypeTaper] );
tomwalters@0: 
tomwalters@0: end;
tomwalters@0: