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 #if defined(FORCE_ALL_GENERICS) || \ 00049 defined(FORCE_GENERIC_WIN16_WELCH) || \ 00050 !defined(TARGET_SPECIFIC_WIN16_WELCH) 00051 00052 // w = 1-((n - N/2)/(N/2))^2 00053 void dsp16_win_welch(dsp16_t *vect1, int size) 00054 { 00055 dsp16_t s, t, w; 00056 int i; 00057 00058 // Initialization 00059 t = DSP16_Q(0.); 00060 // Increment 1/(size*0.5) 00061 s = (DSP16_Q(1.) / size) << 1; 00062 // Compute the 1st half 00063 for(i=0; i<(size >> 1); i++) 00064 { 00065 w = t - DSP16_Q(1.); 00066 w = (((S32) w)*((S32) w)) >> DSP16_QB; 00067 w = DSP16_Q(1.) - w; 00068 vect1[i] = w; 00069 vect1[size-i-1] = w; 00070 t += s; 00071 } 00072 00073 // If the size is odd 00074 if (size & 1) 00075 vect1[size >> 1] = DSP16_Q(1.); 00076 } 00077 00078 #endif 00079 00080 #if defined(FORCE_ALL_GENERICS) || \ 00081 defined(FORCE_GENERIC_WIN32_WELCH) || \ 00082 !defined(TARGET_SPECIFIC_WIN32_WELCH) 00083 00084 void dsp32_win_welch(dsp32_t *vect1, int size) 00085 { 00086 dsp32_t s, t, w; 00087 int i; 00088 00089 // Initialization 00090 t = DSP32_Q(0.); 00091 // Increment 1/(size*0.5) 00092 s = (DSP32_Q(1.) / size) << 1; 00093 // Compute the 1st half 00094 for(i=0; i<(size >> 1); i++) 00095 { 00096 w = t - DSP32_Q(1.); 00097 w = (((S64) w)*((S64) w)) >> DSP32_QB; 00098 w = DSP32_Q(1.) - w; 00099 vect1[i] = w; 00100 vect1[size-i-1] = w; 00101 t += s; 00102 } 00103 00104 // If the size is odd 00105 if (size & 1) 00106 vect1[size >> 1] = DSP32_Q(1.); 00107 } 00108 00109 #endif