fft.hcc File Reference

#include <stdlib.hch>
#include "pal_master.hch"
#include "audio.hch"
#include "weights_256.hch"
#include "configuration.hch"
#include "xilinxmult.hch"
#include "fft.hch"

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Defines
#define	DC_COMPONENT   8470527
Functions
macro proc	multiply (result, op_a, op_b)
	Procedure used for multiply-ing.
void	calculate_fft (unsigned 1 select_inverse)
	This routine performs the Fast Fourier Transform for calculation of the frequency spectrum.
void	perform_fft (signed 16 *pcm_audio)
void	perform_ifft (signed 16 *modified_audio, unsigned 6 *ifft_info)
void	equalize_audio (audiodata_t *audiodata)
	This routine equalizes the frequencies derived by the FFT calculation, according to the settings of the equalizer bars.
Variables
ram signed	eq_settings [16] = {0,2,4,7,10,13,16,19,22,26,30,35,41,48,55,63}

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Detailed Description

Graphic Equalizer API

on the samples. Besides the FFT this module also will equalize the audio signal according to the setting made by the user.

Project information.

Project Graphic Equalizer

Author:

M. Lauwerijssen

Date:

20041110

Version:

0.1

Copyright

Copyright ©2004 Koninklijke Philips Electronics N.V. All rights reserved

Change history

20041110: M. Lauwerijssen
Initial version

Definition in file fft.hcc.

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Define Documentation

#define DC_COMPONENT   8470527

Definition at line 69 of file fft.hcc.

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Function Documentation

macro proc multiply (  result  , op_a  , op_b  )

Procedure used for multiply-ing. Parameters: result  variable containing the result of the multiply procedure op_a  integer value to be multiplied. op_b  integer value to be multiplied. Returns: Procedure returns through variable. Return values: signed  36 Definition at line 82 of file fft.hcc. Referenced by calculate_fft(), and equalize_audio().

void calculate_fft (  unsigned 1  select_inverse  )

This routine performs the Fast Fourier Transform for calculation of the frequency spectrum. Parameters: select_inverse  determines if a FFT or iFFT has to be calculated Returns: nothing Return values: void  cost 12391 cycles Definition at line 104 of file fft.hcc. References multiply(), NUMBER_OF_COLUMNS, NUMBER_OF_POINTS, weight_im, and weight_re. Referenced by perform_fft(), and perform_ifft().

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void perform_fft (  signed 16 *  pcm_audio  )

Definition at line 259 of file fft.hcc. References calculate_fft().

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void perform_ifft (  signed 16 *  modified_audio, unsigned 6 *  ifft_info )

Definition at line 324 of file fft.hcc. References calculate_fft().

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void equalize_audio (  audiodata_t *  audiodata  )

This routine equalizes the frequencies derived by the FFT calculation, according to the settings of the equalizer bars. Note: Cost: 3844 clock cycles (Maximum) Parameters: *audiodata  pointer to the audiodata struct, containing the eq_info, etc. Returns: void Return values: void  Definition at line 398 of file fft.hcc. References audiodata_t::display_log, eq_settings, audiodata_t::equalizer_levels_ptr, multiply(), and NUMBER_OF_POINTS.

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Variable Documentation

ram signed eq_settings[16] = {0,2,4,7,10,13,16,19,22,26,30,35,41,48,55,63}

Definition at line 64 of file fft.hcc. Referenced by equalize_audio().

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