1/*
2 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11/******************************************************************
12
13 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_Chebyshev.h
16
17******************************************************************/
18
19#ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_CHEBYSHEV_H_
20#define WEBRTC_MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_CHEBYSHEV_H_
21
22#include "defines.h"
23
24/*------------------------------------------------------------------*
25 *  Calculate the Chevyshev polynomial series
26 *  F(w) = 2*exp(-j5w)*C(x)
27 *   C(x) = (T_0(x) + f(1)T_1(x) + ... + f(4)T_1(x) + f(5)/2)
28 *   T_i(x) is the i:th order Chebyshev polynomial
29 *------------------------------------------------------------------*/
30
31int16_t WebRtcIlbcfix_Chebyshev(
32    /* (o) Result of C(x) */
33    int16_t x,  /* (i) Value to the Chevyshev polynomial */
34    int16_t *f  /* (i) The coefficients in the polynomial */
35                                      );
36
37#endif
38