mha_fftfb.cpp File Reference

Classes
class	MHAOvlFilter::barkscale::hz2bark_t
class	MHAOvlFilter::barkscale::bark2hz_t

Namespaces
	MHAOvlFilter
	Namespace for overlapping FFT based filter bank classes and functions.
	MHAOvlFilter::barkscale
	MHAOvlFilter::FreqScaleFun
	Transform functions from linear scale in Hz to new frequency scales.
	MHAOvlFilter::ShapeFun
	Shape functions for overlapping filters.

Macros
#define	BARKSCALE_ENTRIES   50

Functions
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2hz (mha_real_t x)
	Dummy scale transformation Hz to Hz. More...
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2khz (mha_real_t x)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2octave (mha_real_t x)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2third_octave (mha_real_t x)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2bark (mha_real_t x)
	Transformation to bark scale. More...
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2bark_analytic (mha_real_t)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2erb (mha_real_t)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2erb_glasberg1990 (mha_real_t)
mha_real_t	MHAOvlFilter::FreqScaleFun::hz2log (mha_real_t x)
	Third octave frequency scale. More...
mha_real_t	MHAOvlFilter::FreqScaleFun::inv_scale (mha_real_t, mha_real_t(*)(mha_real_t))
mha_real_t	MHAOvlFilter::ShapeFun::rect (mha_real_t x)
	Filter shape function for rectangular filters. More...
mha_real_t	MHAOvlFilter::ShapeFun::linear (mha_real_t x)
	Filter shape function for sawtooth filters. More...
mha_real_t	MHAOvlFilter::ShapeFun::hann (mha_real_t x)
	Filter shape function for hanning shaped filters. More...
mha_real_t	MHAOvlFilter::ShapeFun::expflt (mha_real_t)
mha_real_t	MHAOvlFilter::ShapeFun::gauss (mha_real_t)
mha_real_t	filtershapefun (mha_real_t f, MHAOvlFilter::band_descriptor_t b, mha_real_t plateau)
	Transform the test frequency into the relative position on the filter flank of the given frequency band. More...

Variables
mha_real_t	MHAOvlFilter::barkscale::vfreq [BARKSCALE_ENTRIES]
mha_real_t	MHAOvlFilter::barkscale::vbark [BARKSCALE_ENTRIES]

Macro Definition Documentation

BARKSCALE_ENTRIES

#define BARKSCALE_ENTRIES   50

Function Documentation

filtershapefun()

mha_real_t filtershapefun	(	mha_real_t	f,
		MHAOvlFilter::band_descriptor_t	b,
		mha_real_t	plateau
	)

Transform the test frequency into the relative position on the filter flank of the given frequency band.

Parameters

f	Test frequency in units corresponding to the chosen frequency scale
b	Descriptor of a single filter bank band: E.g. contains center frequencies of this and the two adjacent bands, and the crossover ("edge") frequencies of this band.
plateau	For non-rectangular filter shapes, specifies what frequency portion of the band around its center frequency should have no attenuation applied.

Precondition

0 <= plateau <= 1

Returns

The position of frequency f on the filter flank as follows: A returned position of 0 means that f is equal to the band's center frequency, or should be treated the same as the center frequency (i.e. is within the band's plateau). A returned position of -1 means that f is <= the lowest frequency of the filter flank (or is an even lower frequency). A returned value of -0.5 means that f is equal to the lower edge frequency. Positive returned values have equivalent meanings for the high half of the filter flank.