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94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_blackman_harris_92db_f32.c
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* Description: Floating-point (f32) 92 dB Blackman Harris window
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*
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* $Date: 14 December 2022
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* $Revision: v1.15.0
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*
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* Target Processor: Cortex-M and Cortex-A cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2022 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "dsp/window_functions.h"
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#include "dsp/fast_math_functions.h"
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#include <math.h>
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/**
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@ingroup groupWindow
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*/
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/**
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@addtogroup WindowNormal
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@{
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*/
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/**
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@defgroup WindowBLACKMAN_HARRIS_92DB Blackman Harris window function (92 dB)
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*/
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/**
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@ingroup WindowBLACKMAN_HARRIS_92DB
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*/
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/**
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@brief 92 dB Blackman Harris window generating function (f32).
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@param[out] pDst points to the output generated window
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@param[in] blockSize number of samples in the window
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@return none
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@par Parameters of the window
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| Parameter | Value |
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| ------------------------------------: | -----------------: |
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| Peak sidelobe level | 92.0 dB |
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| Normalized equivalent noise bandwidth | 2.0044 bins |
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| 3 dB bandwidth | 1.8962 bins |
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| Flatness | -0.8256 dB |
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| Recommended overlap | 66.1 % |
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*/
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void arm_blackman_harris_92db_f32(
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float32_t * pDst,
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uint32_t blockSize)
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{
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float32_t k = 2.0f / ((float32_t) blockSize);
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float32_t w;
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for(uint32_t i=0;i<blockSize;i++)
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{
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w = PI * i * k;
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w = 0.35875f - 0.48829f * cosf (w) +
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0.14128f * cosf (2.f * w) - 0.01168f * cosf (3.f * w);
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pDst[i] = w;
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}
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}
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/**
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@} end of WindowNormal group
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*/
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