samer@32: function [y,f] = realfft(x,nfft)
samer@32: % realfft - Do FFT assuming real data, returning complex half spectrum
samer@32: %
samer@32: % realfft ::
samer@32: %    [[L,T]->real]     ~'sequence of T L-point frames',
samer@32: %    N:natural         ~'FFT size'
samer@32: % -> [[M,T]->complex]  ~'sequence of T M-point complex spectra',
samer@32: %    [[M]]             ~'normalised centre frequency for each bin'.
samer@32: %      
samer@32: % Note that M=dftbins(N).
samer@32: 
samer@32: % apply the window and do FFT on each column, then
samer@32: % assume it's a real signal and discard half the bins
samer@32: y = fft(x,nfft);
samer@32: select=1:dftbins(nfft);
samer@32: y = y(select,:);
samer@32: % compute the normalised frequency for each bin
samer@32: f=(select-1)/nfft;