CQDFT - FFT-based filter bank with constant relative bandwidth according

Usage

[cqmag] = cqdft( insig )
[cqmag,fc,cqmaghr,fvec] = cqdft( insig,fs,flow,fhigh,bw )

`insig`	Impulse response or complex spectrum
`fs`	Sampling rate, default is 48kHz.
`flow`	Lowest frequency, minimum: 0.5kHz, default is 2kHz
`fhigh`	Highest frequency, default is, default is 16kHz
`bw`	bandwidth, possible values 3,6,9,12, default is 6.

`cqmag`	mean magnitudes of CQ-bands in dB
`fc`	center frequencies of bands (geo. mean of corners)
`cqmaghr`	same as cqmag but for all freq. bins (high resolution)
`fvec`	freq. vector according to FFT-resolution

cqdft(insig) approximates a constant-Q filter bank by averaging the magnitude bins of a DFT. cqdft results in 'bw' dB-magnitudes per octave.

E. Langendijk and A. Bronkhorst. Contribution of spectral cues to human sound localization. J. Acoust. Soc. Am., 112:1583-1596, 2002.