samer@0: % ainvmel - arrow to warp mel scale spectrum to linear freq spectrum
samer@0: %
samer@0: % ainvmel :: 
samer@0: %    N:natural ~'block size of original audio frames',
samer@0: %    nonneg    ~'audio sampling frequency in Hz',
samer@0: %    [[1,2]]   ~'frequency limits in Hz',
samer@0: %    L:natural ~'number of bands in mel spectrum'
samer@0: % -> arrow( {[[L]]}, {[[dftbins(N)]]}, empty).
samer@0: 
samer@0: function o=ainvmel(N,fs,flim,L)
samer@0: 	o=amult(tri_filterbank_aa(melspace(flim(1),min(flim(2),fs/2),L+2),binmap(0,fs/2,dftbins(N)))');
samer@0: end