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 <stddef.h> 23 #include <stdint.h> 24 25 /*------------------------------------------------------------------* 26 * Calculate the Chevyshev polynomial series 27 * F(w) = 2*exp(-j5w)*C(x) 28 * C(x) = (T_0(x) + f(1)T_1(x) + ... + f(4)T_1(x) + f(5)/2) 29 * T_i(x) is the i:th order Chebyshev polynomial 30 *------------------------------------------------------------------*/ 31 32 int16_t WebRtcIlbcfix_Chebyshev( 33 /* (o) Result of C(x) */ 34 int16_t x, /* (i) Value to the Chevyshev polynomial */ 35 int16_t* f /* (i) The coefficients in the polynomial */ 36 ); 37 38 #endif 39