MHAFilter::fftfilterbank_t Class Reference

FFT based FIR filterbank implementation. More...

Inheritance diagram for MHAFilter::fftfilterbank_t:

Public Member Functions
	fftfilterbank_t (unsigned int fragsize, unsigned int inputchannels, unsigned int firchannels, unsigned int fftlen)
	Constructor. More...
	~fftfilterbank_t ()
void	update_coeffs (const mha_wave_t *h)
	Update the set of coefficients. More...
void	filter (const mha_wave_t *s_in, mha_wave_t **s_out, const mha_wave_t *h)
	Apply filter with changing coefficients to a waveform fragment. More...
void	filter (const mha_wave_t *s_in, mha_wave_t **s_out)
	Apply filter to waveform fragment, without changing the coefficients. More...
const mha_wave_t *	get_irs () const
	Return the current IRS. More...

Private Attributes
unsigned int	fragsize
unsigned int	inputchannels
unsigned int	firchannels
unsigned int	outputchannels
unsigned int	fftlen
MHASignal::waveform_t	hw
MHASignal::spectrum_t	Hs
MHASignal::waveform_t	xw
MHASignal::spectrum_t	Xs
MHASignal::waveform_t	yw
MHASignal::spectrum_t	Ys
MHASignal::waveform_t	yw_temp
MHASignal::waveform_t	tail
mha_fft_t	fft

Detailed Description

FFT based FIR filterbank implementation.

This class convolves n input channels with m filter coefficient sets and returns n*m output channels.

The maximal number of coefficients can be FFT length - fragsize + 1.

Constructor & Destructor Documentation

fftfilterbank_t()

MHAFilter::fftfilterbank_t::fftfilterbank_t	(	unsigned int	fragsize,
		unsigned int	inputchannels,
		unsigned int	firchannels,
		unsigned int	fftlen
	)

Constructor.

Parameters

fragsize	Number of frames expected in input signal (each cycle).
inputchannels	Number of channels expected in input signal.
firchannels	Number of channels expected in FIR filter coefficients (= number of bands).
fftlen	FFT length of filter.

The number of output channels is inputchannels*firchannels.

~fftfilterbank_t()

MHAFilter::fftfilterbank_t::~fftfilterbank_t

(

)

Member Function Documentation

update_coeffs()

void MHAFilter::fftfilterbank_t::update_coeffs

(

const mha_wave_t *

h

)

Update the set of coefficients.

Parameters

h	Coefficients structure

Note

The number of channels in h must match the number of channels given in the constructor, and the number of frames can not be more than fftlen-fragsize+1.

filter() [1/2]

void MHAFilter::fftfilterbank_t::filter	(	const mha_wave_t *	s_in,
		mha_wave_t **	s_out,
		const mha_wave_t *	h
	)

Apply filter with changing coefficients to a waveform fragment.

Parameters

s_in	Input signal pointer.

Return values

s_out

Pointer to output signal pointer, will be set to a valid signal

Parameters

h	FIR coefficients

filter() [2/2]

void MHAFilter::fftfilterbank_t::filter	(	const mha_wave_t *	s_in,
		mha_wave_t **	s_out
	)

Apply filter to waveform fragment, without changing the coefficients.

Parameters

s_in	Input signal pointer.

Return values

s_out

Pointer to output signal pointer, will be set to a valid signal

get_irs()

const mha_wave_t* MHAFilter::fftfilterbank_t::get_irs ( ) const

inline

Return the current IRS.

Member Data Documentation

fragsize

unsigned int MHAFilter::fftfilterbank_t::fragsize

private

inputchannels

unsigned int MHAFilter::fftfilterbank_t::inputchannels

private

firchannels

unsigned int MHAFilter::fftfilterbank_t::firchannels

private

outputchannels

unsigned int MHAFilter::fftfilterbank_t::outputchannels

private

fftlen

unsigned int MHAFilter::fftfilterbank_t::fftlen

private

hw

MHASignal::waveform_t MHAFilter::fftfilterbank_t::hw

private

Hs

MHASignal::spectrum_t MHAFilter::fftfilterbank_t::Hs

private

xw

MHASignal::waveform_t MHAFilter::fftfilterbank_t::xw

private

Xs

MHASignal::spectrum_t MHAFilter::fftfilterbank_t::Xs

private

yw

MHASignal::waveform_t MHAFilter::fftfilterbank_t::yw

private

Ys

MHASignal::spectrum_t MHAFilter::fftfilterbank_t::Ys

private

yw_temp

MHASignal::waveform_t MHAFilter::fftfilterbank_t::yw_temp

private

tail

MHASignal::waveform_t MHAFilter::fftfilterbank_t::tail

private

fft

mha_fft_t MHAFilter::fftfilterbank_t::fft

private

---

The documentation for this class was generated from the following files:

• mha_filter.hh
• mha_filter.cpp