Fpeak2Fr.m

%
%    Estimate fr from fpeak 
%    Toshio IRINO
%    Created: 10 June 98
%    Modified: 17 Nov. 2006
%
%  function [fr, ERBw] = Fpeak2Fr(n,b,c,fpeak)
%    INPUT:  n,b,c : gammachirp param.
%            fpeak : peak freq.
%    OUTPUT: fr    : fr
%            ERBw  : ERBw(fr)
%
function [fr, ERBw] = Fpeak2Fr(n,b,c,fpeak)

if nargin < 4; help Fpeak2Fr; end;

n = n(:);
b = b(:);
c = c(:);
fpeak = fpeak(:);

%    fpeak = fr + c*b*ERBw(fr)/n 
%    ERBw(fr) = 24.7*(4.37*fr/1000 + 1) = k1*fr + k2  % M&G 1990
%
%  k1 = 24.7*4.37/1000; 
%  k2 = 24.7;
%  use Freq2ERB for software consistency (17 Dec 2006)

[dummy k2] = Freq2ERB(0);
[dummy w1] = Freq2ERB(1);
k1 = w1-k2;

fr = (fpeak - c.*b./n * k2)./(1 + c.*b./n * k1);
[dummy ERBw] = Freq2ERB(fr);