00001 /*This file is prepared for Doxygen automatic documentation generation.*/ 00015 /* Copyright (c) 2009 Atmel Corporation. All rights reserved. 00016 * 00017 * Redistribution and use in source and binary forms, with or without 00018 * modification, are permitted provided that the following conditions are met: 00019 * 00020 * 1. Redistributions of source code must retain the above copyright notice, this 00021 * list of conditions and the following disclaimer. 00022 * 00023 * 2. Redistributions in binary form must reproduce the above copyright notice, 00024 * this list of conditions and the following disclaimer in the documentation 00025 * and/or other materials provided with the distribution. 00026 * 00027 * 3. The name of Atmel may not be used to endorse or promote products derived 00028 * from this software without specific prior written permission. 00029 * 00030 * 4. This software may only be redistributed and used in connection with an Atmel 00031 * AVR product. 00032 * 00033 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED 00034 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00035 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE 00036 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR 00037 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 00038 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 00039 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 00040 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00041 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 00042 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE 00043 * 00044 */ 00045 00046 #include "dsp.h" 00047 00048 #define WIN_HAMM_A0 0.53836 00049 #define WIN_HAMM_A1 0.46164 00050 00051 #if defined(FORCE_ALL_GENERICS) || \ 00052 defined(FORCE_GENERIC_WIN16_HAMM) || \ 00053 !defined(TARGET_SPECIFIC_WIN16_HAMM) 00054 00055 // Hamming 00056 // w(n) = 0.53836 - 0.46164*cos(2*PI*n/(N-1)) 00057 // avec 00058 // N = signal width 00059 // Constraints: size > 1 00060 void dsp16_win_hamm(dsp16_t *vect1, int size) 00061 { 00062 dsp16_t s, t, w; 00063 int i; 00064 00065 // Initialization 00066 t = DSP16_Q(0.); 00067 // Calculation of 2/(N-1) <- because a cos is in the range [-1; 1], 00068 // therefore -1 equals -PI and 1, PI. 00069 s = (DSP16_Q(1.)/(size - 1)) << 1; 00070 00071 // Compute the window 00072 for(i=0; i<(size >> 1); i++) 00073 { 00074 w = DSP16_Q(WIN_HAMM_A0); 00075 w -= (((S32) DSP16_Q(WIN_HAMM_A1))*((S32) dsp16_op_cos(t))) >> DSP16_QB; 00076 vect1[i] = w; 00077 vect1[size-i-1] = w; 00078 t += s; 00079 } 00080 00081 // If the size is odd 00082 if (size & 1) 00083 vect1[size >> 1] = DSP16_Q(1.); 00084 } 00085 00086 #endif 00087 00088 #if defined(FORCE_ALL_GENERICS) || \ 00089 defined(FORCE_GENERIC_WIN32_HAMM) || \ 00090 !defined(TARGET_SPECIFIC_WIN32_HAMM) 00091 00092 void dsp32_win_hamm(dsp32_t *vect1, int size) 00093 { 00094 dsp32_t s, t, w; 00095 int i; 00096 00097 // Initialization 00098 t = DSP32_Q(0.); 00099 // Calculation of 2/(N-1) <- because a cos is in the range [-1; 1], 00100 // therefore -1 equals -PI and 1, PI. 00101 s = (DSP32_Q(1.)/(size - 1)) << 1; 00102 00103 // Compute the window 00104 for(i=0; i<(size >> 1); i++) 00105 { 00106 w = DSP32_Q(WIN_HAMM_A0); 00107 w -= (((S64) DSP32_Q(WIN_HAMM_A1))*((S64) dsp32_op_cos(t))) >> DSP32_QB; 00108 vect1[i] = w; 00109 vect1[size-i-1] = w; 00110 t += s; 00111 } 00112 00113 // If the size is odd 00114 if (size & 1) 00115 vect1[size >> 1] = DSP32_Q(1.); 00116 } 00117 00118 #endif