1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_nuttall4_f64.c
4 * Description: Floating-point (f64) Nuttall4 window
5 *
6 * $Date: 14 December 2022
7 * $Revision: v1.15.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2022 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/window_functions.h"
30 #include "dsp/fast_math_functions.h"
31 #include <math.h>
32 /**
33 @ingroup groupWindow
34 */
35
36
37
38
39 /**
40 @addtogroup WindowNormal
41 @{
42 */
43
44
45 /**
46 @ingroup WindowNUTTALL4
47 */
48
49 /**
50 @brief Nuttall4 window generating function (f64).
51 @param[out] pDst points to the output generated window
52 @param[in] blockSize number of samples in the window
53
54 @par Parameters of the window
55
56 | Parameter | Value |
57 | ------------------------------------: | -----------------: |
58 | Peak sidelobe level | 60.9 dB |
59 | Normalized equivalent noise bandwidth | 2.31 bins |
60 | 3 dB bandwidth | 2.1884 bins |
61 | Flatness | -0.6184 dB |
62 | Recommended overlap | 70.5 % |
63
64 */
65
66
67
arm_nuttall4_f64(float64_t * pDst,uint32_t blockSize)68 void arm_nuttall4_f64(
69 float64_t * pDst,
70 uint32_t blockSize)
71 {
72 float64_t k = 2. / ((float64_t) blockSize);
73 float64_t w;
74
75 for(uint32_t i=0;i<blockSize;i++)
76 {
77 w = PI_F64 * i * k;
78 w =
79 0.3125 - 0.46875 * cos (w) + 0.1875 * cos (2 * w) -
80 0.03125 * cos (3 * w);
81 pDst[i] = w;
82 }
83 }
84
85 /**
86 @} end of WindowNormal group
87 */
88
89
