samer@33: % cqedges - Audio Spectrum linear to log frequency map (no checking)
samer@32: %
samer@33: % cqedges ::
samer@32: %    real     ~ 'sampling rate',
samer@32: %    [[2]]    ~ 'requested lower and upper cut-off frequencies',
samer@32: %    real     ~ 'resolution in octaves',
samer@32: %    real     ~ 'origin of frequency grid in Hz (defaut=1kHz)'
samer@33: % -> [[L-1]]  ~ 'frequency bin edges'.
samer@33: % 
samer@33: % Converts a constant-Q filterbank specification into a list of band edges.
samer@32: 
samer@33: function edges=cqedges(fs,range,res,F0)
samer@33: 	% origin of frequnecy grid defaults to 1kHz
samer@33: 	if nargin<4, F0=1000; end
samer@32: 
samer@33: 	% quantise requested edges and represent them in
samer@33: 	% in units of res on a log frequency scale.
samer@33: 	limits = round(log2(range/F0)/res);
samer@32: 
samer@33: 	% convert to normalised frequencies (fs=1)
samer@33: 	edges = (F0/fs)*2.^(res*(limits(1):limits(2)));
samer@33: keyboard
samer@32: 
samer@33: 	% remove any edges above Nyquist rate
samer@33: 	if edges(end)>=0.5, edges = edges(edges<0.5); end
samer@33: end