/Users/richardeakin/projects/libsms/trunk/src/spectrum.c File Reference

functions to convert between frequency (spectrum) and time (wavefrom) domain More...

#include "sms.h"

Include dependency graph for spectrum.c:

Functions
int	sms_spectrum (int sizeWindow, sfloat *pWaveform, sfloat *pWindow, int sizeMag, sfloat *pMag, sfloat *pPhase)
	compute a complex spectrum from a waveform
int	sms_spectrumMag (int sizeWindow, sfloat *pWaveform, sfloat *pWindow, int sizeMag, sfloat *pMag)
	compute the spectrum Magnitude of a waveform
int	sms_invSpectrum (int sizeWaveform, sfloat *pWaveform, sfloat *pWindow, int sizeMag, sfloat *pMag, sfloat *pPhase)
	function for a quick inverse spectrum, windowed
int	sms_invQuickSpectrumW (sfloat *pFMagSpectrum, sfloat *pFPhaseSpectrum, int sizeFft, sfloat *pFWaveform, int sizeWave, sfloat *pFWindow)
	function for a quick inverse spectrum, windowed function to perform the inverse FFT, windowing the output sfloat *pFMagSpectrum input magnitude spectrum sfloat *pFPhaseSpectrum input phase spectrum int sizeFft size of FFT sfloat *pFWaveform output waveform int sizeWave size of output waveform sfloat *pFWindow synthesis window
void	sms_RectToPolar (int sizeMag, sfloat *pRect, sfloat *pMag, sfloat *pPhase)
	convert spectrum from Rectangular to Polar form
void	sms_PolarToRect (int sizeSpec, sfloat *pRect, sfloat *pMag, sfloat *pPhase)
	convert spectrum from Rectangular to Polar form
void	sms_spectrumRMS (int sizeMag, sfloat *pInRect, sfloat *pOutMag)
	compute magnitude spectrum of a DFT in rectangular coordinates

---

Detailed Description

functions to convert between frequency (spectrum) and time (wavefrom) domain

---

Function Documentation

int sms_invQuickSpectrumW	(	sfloat *	pFMagSpectrum,
		sfloat *	pFPhaseSpectrum,
		int	sizeFft,
		sfloat *	pFWaveform,
		int	sizeWave,
		sfloat *	pFWindow
	)

function for a quick inverse spectrum, windowed function to perform the inverse FFT, windowing the output sfloat *pFMagSpectrum input magnitude spectrum sfloat *pFPhaseSpectrum input phase spectrum int sizeFft size of FFT sfloat *pFWaveform output waveform int sizeWave size of output waveform sfloat *pFWindow synthesis window

References sfloat, and sms_ifft().

Here is the call graph for this function:

int sms_invSpectrum	(	int	sizeWaveform,
		sfloat *	pWaveform,
		sfloat *	pWindow,
		int	sizeMag,
		sfloat *	pMag,
		sfloat *	pPhase
	)

function for a quick inverse spectrum, windowed

Not done yet, but this will be a function that is the inverse of sms_spectrum above.

function to perform the inverse FFT, windowing the output sfloat *pFMagSpectrum input magnitude spectrum sfloat *pFPhaseSpectrum input phase spectrum int sizeFft size of FFT sfloat *pFWaveform output waveform int sizeWave size of output waveform sfloat *pFWindow synthesis window

References sfloat, sms_error(), sms_ifft(), sms_PolarToRect(), and sms_power2().

Here is the call graph for this function:

void sms_PolarToRect	(	int	sizeSpec,
		sfloat *	pRect,
		sfloat *	pMag,
		sfloat *	pPhase
	)

convert spectrum from Rectangular to Polar form

Parameters:

	sizeSpec	size of spectrum (pMag and pPhase arrays)
	pRect	pointer output spectrum in rectangular form (2x sizeSpec)
	pMag	pointer to sfloat array of magnitude spectrum
	pPhase	pointer to sfloat array of phase spectrum

References sfloat.

void sms_RectToPolar	(	int	sizeMag,
		sfloat *	pRect,
		sfloat *	pMag,
		sfloat *	pPhase
	)

convert spectrum from Rectangular to Polar form

Parameters:

	sizeMag	size of spectrum (pMag and pPhase arrays)
	pRect	pointer output spectrum in rectangular form (2x sizeSpec)
	pMag	pointer to sfloat array of magnitude spectrum
	pPhase	pointer to sfloat array of phase spectrum

References sfloat.

int sms_spectrum	(	int	sizeWindow,
		sfloat *	pWaveform,
		sfloat *	pWindow,
		int	sizeMag,
		sfloat *	pMag,
		sfloat *	pPhase
	)

compute a complex spectrum from a waveform

Parameters:

	sizeWindow	size of analysis window
	pWaveform	pointer to input waveform
	pWindow	pointer to input window
	sizeMag	size of output magnitude and phase spectrums
	pMag	pointer to output magnitude spectrum
	pPhase	pointer to output phase spectrum

Returns:

sizeFft, -1 on error

Todo:

remove this return

References sfloat, sms_error(), sms_fft(), sms_power2(), and sms_windowCentered().

Here is the call graph for this function:

int sms_spectrumMag	(	int	sizeWindow,
		sfloat *	pWaveform,
		sfloat *	pWindow,
		int	sizeMag,
		sfloat *	pMag
	)

compute the spectrum Magnitude of a waveform

This function windows the waveform with pWindow and performs a zero-padded FFT (if sizeMag*2 > sizeWindow). The spectra is then converted magnitude (RMS).

Parameters:

	sizeWindow	size of analysis window / input wavefrom
	pWaveform	pointer to input waveform
	pWindow	pointer to analysis window
	sizeMag	size of output magnitude spectrum
	pMag	pointer to output magnitude spectrum

Returns:

0 on success, -1 on error

References sfloat, sms_error(), sms_fft(), and sms_power2().

Here is the call graph for this function:

void sms_spectrumRMS	(	int	sizeMag,
		sfloat *	pInRect,
		sfloat *	pOutMag
	)

compute magnitude spectrum of a DFT in rectangular coordinates

Parameters:

	sizeMag	size of output Magnitude (half of input real FFT)
	pInRect	pointer to input DFT array (real/imag sfloats)
	pOutMag	pointer to of magnitude spectrum array

References sfloat.