2008-03-27 12:12:24 +00:00
|
|
|
/*
|
|
|
|
|
* Copyright (c) 2008, Swedish Institute of Computer Science
|
|
|
|
|
* All rights reserved.
|
|
|
|
|
*
|
|
|
|
|
* Redistribution and use in source and binary forms, with or without
|
|
|
|
|
* modification, are permitted provided that the following conditions
|
|
|
|
|
* are met:
|
|
|
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
|
|
|
* notice, this list of conditions and the following disclaimer.
|
|
|
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
|
|
|
* documentation and/or other materials provided with the distribution.
|
|
|
|
|
* 3. Neither the name of the Institute nor the names of its contributors
|
|
|
|
|
* may be used to endorse or promote products derived from this software
|
|
|
|
|
* without specific prior written permission.
|
|
|
|
|
*
|
|
|
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
|
|
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
|
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
|
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
|
|
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
|
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
|
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
|
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
|
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
|
|
|
* SUCH DAMAGE.
|
|
|
|
|
*
|
|
|
|
|
* -----------------------------------------------------------------
|
|
|
|
|
* ifft - Integer FFT (fast fourier transform) library
|
|
|
|
|
*
|
|
|
|
|
*
|
|
|
|
|
*
|
|
|
|
|
* Author : Joakim Eriksson
|
|
|
|
|
* Created : 2008-03-27
|
2008-04-25 22:12:25 +00:00
|
|
|
* Updated : $Date: 2008/04/25 22:12:25 $
|
|
|
|
|
* $Revision: 1.2 $
|
2008-03-27 12:12:24 +00:00
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
#ifndef IFFT_H
|
|
|
|
|
#define IFFT_H
|
|
|
|
|
#include "contiki-conf.h"
|
|
|
|
|
|
|
|
|
|
/* ifft(xre[], n) - integer (fixpoint) version of Fast Fourier Transform
|
|
|
|
|
An integer version of FFT that takes in-samples in an int16_t array
|
|
|
|
|
and does an fft on n samples in the array.
|
|
|
|
|
The result of the FFT is stored in the same array as the samples
|
|
|
|
|
was stored.
|
|
|
|
|
|
|
|
|
|
Note: This fft is designed to be used with 8 bit values (e.g. not
|
|
|
|
|
16 bit values). The reason for the int16_t array is for keeping some
|
|
|
|
|
'room' for the calculations. It is also designed for doing fairly small
|
|
|
|
|
FFT:s since to large sample arrays might cause it to overflow during
|
|
|
|
|
calculations.
|
|
|
|
|
*/
|
2008-04-25 22:12:25 +00:00
|
|
|
void ifft(int16_t xre[], int16_t xim[], uint16_t n);
|
2008-03-27 12:12:24 +00:00
|
|
|
|
|
|
|
|
#endif /* IFFT_H */
|
