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108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_hft95_f64.c
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* Description: Floating-point (f64) Hft95 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 WindowFlat
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@{
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*/
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/**
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@ingroup WindowHFT95
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*/
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/**
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@brief Hft95 window generating function (f64).
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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 | 95.0 dB |
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| Normalized equivalent noise bandwidth | 3.8112 bins |
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| 3 dB bandwidth | 3.7590 bins |
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| Flatness | 0.0044 dB |
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| Recommended overlap | 75.6 % |
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Included in CMSIS-DSP with authorization from professor
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Gerhard Heinzel.
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@par Original article:
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Spectrum and spectral density estimation by the Discrete Fourier
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transform (DFT), including a comprehensive list of window
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functions and some new
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flat-top windows.
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@par Authors:
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G. Heinzel, A. Rudiger and R. Schilling,
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Max-Planck-Institut fur Gravitationsphysik
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(Albert-Einstein-Institut)
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Teilinstitut Hannover
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*/
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void arm_hft95_f64(
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float64_t * pDst,
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uint32_t blockSize)
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{
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float64_t k = 2. / ((float64_t) blockSize);
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float64_t w;
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for(uint32_t i=0;i<blockSize;i++)
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{
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w = PI_F64 * (i * k);
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w =
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(1.0 -
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1.9383379 * cos (w) +
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1.3045202 * cos (2 * w) -
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0.4028270 * cos (3 * w) + 0.0350665 * cos (4 * 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 WindowFlat group
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*/
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