tomwalters@0: %
tomwalters@0: %       Calculation of Equal Frequency scale on ERB/Mel/Log/Linear scale
tomwalters@0: %       Toshio IRINO
tomwalters@0: %       5 Oct 2001
tomwalters@0: %
tomwalters@0: %    function [Frs] = EqualFreqScale(NameScale,NumCh,RangeFreq),
tomwalters@0: %      INPUT:  NameScale: 'ERB', 'mel', 'log', 'linear'
tomwalters@0: %	       NumCh:  Number of channels
tomwalters@0: %              RangeFreq: Frequency Range
tomwalters@0: %      OUTPUT: Frs:    Fr vector
tomwalters@0: %     	       WFval: Warped Freq. value
tomwalters@0: %
tomwalters@0: function [Frs, WFvals] = EqualFreqScale(NameScale,NumCh,RangeFreq),
tomwalters@0: 
tomwalters@0: if nargin <3, help EqualFreqScale; end;
tomwalters@0: if diff(RangeFreq) < 0, 
tomwalters@0: 	help  EqualFreqScale; 
tomwalters@0: 	error('RangeFreq(1) should be less than RangeFreq(2).');  
tomwalters@0: end;
tomwalters@0: 
tomwalters@0: if strcmp(lower(NameScale),'linear') == 1, 
tomwalters@0: 	RangeWF = RangeFreq;
tomwalters@0: 	dWF = diff(RangeWF)/(NumCh-1);
tomwalters@0: 	WFvals = RangeWF(1):dWF:RangeWF(2)+eps*1000;
tomwalters@0: 	Frs = WFvals;
tomwalters@0: 
tomwalters@0: elseif 	strcmp(lower(NameScale),'mel') == 1,
tomwalters@0: 	RangeWF = Freq2Mel(RangeFreq);
tomwalters@0: 	dWF = diff(RangeWF)/(NumCh-1);
tomwalters@0: 	WFvals = RangeWF(1):dWF:RangeWF(2)+eps*1000;
tomwalters@0: 	Frs = Mel2Freq(WFvals);
tomwalters@0: 
tomwalters@0: elseif 	strcmp(lower(NameScale),'erb') == 1,
tomwalters@0: 	RangeWF = Freq2ERB(RangeFreq);
tomwalters@0: 	dWF = diff(RangeWF)/(NumCh-1);
tomwalters@0: 	WFvals = RangeWF(1):dWF:RangeWF(2)+eps*1000;
tomwalters@0: 	Frs = ERB2Freq(WFvals);
tomwalters@0: 
tomwalters@0: elseif  strcmp(lower(NameScale),'log') == 1, 
tomwalters@0: 	if min(RangeFreq) < 50,
tomwalters@0: 	  disp([ 'min(RangeFreq) < 50. Replaced by 50.' ]);
tomwalters@0: 	  RangeFreq(1) = 50;
tomwalters@0: 	end;
tomwalters@0: 	RangeWF = log10(RangeFreq);
tomwalters@0: 	dWF = diff(RangeWF)/(NumCh-1);
tomwalters@0: 	WFvals = RangeWF(1):dWF:RangeWF(2)+eps*1000;
tomwalters@0: 	Frs = 10.^WFvals;
tomwalters@0: 
tomwalters@0: else
tomwalters@0: 	help EqualFreqScale;
tomwalters@0: 	error('Specify NameScale correctly');
tomwalters@0: end;
tomwalters@0: