1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_nuttall3b_f32.c
4 * Description: Floating-point (f32) Nuttall3b 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 @defgroup WindowNUTTALL3B Nuttall3b window function (71.5 dB)
47
48 */
49
50 /**
51 @ingroup WindowNUTTALL3B
52 */
53
54 /**
55 @brief Nuttall3b window generating function (f32).
56 @param[out] pDst points to the output generated window
57 @param[in] blockSize number of samples in the window
58 @return none
59
60 @par Parameters of the window
61
62 | Parameter | Value |
63 | ------------------------------------: | -----------------: |
64 | Peak sidelobe level | 71.5 dB |
65 | Normalized equivalent noise bandwidth | 1.7037 bins |
66 | 3 dB bandwidth | 1.6162 bins |
67 | Flatness | -1.1352 dB |
68 | Recommended overlap | 59.8 % |
69
70 */
71
72
73
arm_nuttall3b_f32(float32_t * pDst,uint32_t blockSize)74 void arm_nuttall3b_f32(
75 float32_t * pDst,
76 uint32_t blockSize)
77 {
78 float32_t k = 2.0f / ((float32_t) blockSize);
79 float32_t w;
80
81 for(uint32_t i=0;i<blockSize;i++)
82 {
83 w = PI * i * k;
84 w = 0.4243801f - 0.4973406f * cosf (w) + 0.0782793f * cosf (2.f * w);
85
86 pDst[i] = w;
87 }
88 }
89
90 /**
91 @} end of WindowNormal group
92 */
93
94