1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_nuttall4c_f32.c
4 * Description: Floating-point (f32) Nuttall4c 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 @defgroup WindowNUTTALL4C Nuttall4c window function (98.1 dB)
46
47 */
48
49 /**
50 @ingroup WindowNUTTALL4C
51 */
52
53 /**
54 @brief Nuttall4c window generating function (f32).
55 @param[out] pDst points to the output generated window
56 @param[in] blockSize number of samples in the window
57
58 @par Parameters of the window
59
60 | Parameter | Value |
61 | ------------------------------------: | -----------------: |
62 | Peak sidelobe level | 98.1 dB |
63 | Normalized equivalent noise bandwidth | 1.9761 bins |
64 | 3 dB bandwidth | 1.8687 bins |
65 | Flatness | -0.8506 dB |
66 | Recommended overlap | 65.6 % |
67
68 */
69
70
71
arm_nuttall4c_f32(float32_t * pDst,uint32_t blockSize)72 ARM_DSP_ATTRIBUTE void arm_nuttall4c_f32(
73 float32_t * pDst,
74 uint32_t blockSize)
75 {
76 float32_t k = 2.0f / ((float32_t) blockSize);
77 float32_t w;
78
79 for(uint32_t i=0;i<blockSize;i++)
80 {
81 w = PI * i * k;
82 w = 0.3635819f - 0.4891775f * cosf (w) +
83 0.1365995f * cosf (2.f * w) - 0.0106411f * cosf (3.f * w);
84
85 pDst[i] = w;
86 }
87 }
88
89 /**
90 @} end of WindowNormal group
91 */
92
93
