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 MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_CHEBYSHEV_H_
20 #define 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 
31 int16_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