1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_nuttall4a_f64.c
4 * Description: Floating-point (f64) Nuttall4a 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 /**
34 @ingroup groupWindow
35 */
36
37
38
39
40 /**
41 @addtogroup WindowNormal
42 @{
43 */
44
45
46 /**
47 @ingroup WindowNUTTALL4A
48 */
49
50 /**
51 @brief Nuttall4a window generating function (f64).
52 @param[out] pDst points to the output generated window
53 @param[in] blockSize number of samples in the window
54
55 @par Parameters of the window
56
57 | Parameter | Value |
58 | ------------------------------------: | -----------------: |
59 | Peak sidelobe level | 82.6 dB |
60 | Normalized equivalent noise bandwidth | 2.1253 bins |
61 | 3 dB bandwidth | 2.0123 bins |
62 | Flatness | -0.7321 dB |
63 | Recommended overlap | 68.0 % |
64
65 */
66
67
68
arm_nuttall4a_f64(float64_t * pDst,uint32_t blockSize)69 void arm_nuttall4a_f64(
70 float64_t * pDst,
71 uint32_t blockSize)
72 {
73 float64_t k = 2. / ((float64_t) blockSize);
74 float64_t w;
75
76 for(uint32_t i=0;i<blockSize;i++)
77 {
78 w = PI_F64 * i * k;
79 w = 0.338946 - 0.481973 * cos (w) +
80 0.161054 * cos (2 * w) - 0.018027 * cos (3 * w);
81
82 pDst[i] = w;
83 }
84 }
85
86 /**
87 @} end of WindowNormal group
88 */
89
90
