blob: 539206de7fb7be94a4c88f731115eebbfbaf38f4 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cfft_radix4_init_f32.c
* Description: Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT Initialization function
*
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "arm_math.h"
#include "arm_common_tables.h"
/**
@ingroup groupTransforms
*/
/**
@addtogroup ComplexFFT
@{
*/
/**
@brief Initialization function for the floating-point CFFT/CIFFT.
@deprecated Do not use this function. It has been superceded by \ref arm_cfft_f32 and will be removed in the future.
@param[in,out] S points to an instance of the floating-point CFFT/CIFFT structure
@param[in] fftLen length of the FFT
@param[in] ifftFlag flag that selects transform direction
- value = 0: forward transform
- value = 1: inverse transform
@param[in] bitReverseFlag flag that enables / disables bit reversal of output
- value = 0: disables bit reversal of output
- value = 1: enables bit reversal of output
@return execution status
- \ref ARM_MATH_SUCCESS : Operation successful
- \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
@par Details
The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
@par
The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
@par
The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
@par
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
*/
arm_status arm_cfft_radix4_init_f32(
arm_cfft_radix4_instance_f32 * S,
uint16_t fftLen,
uint8_t ifftFlag,
uint8_t bitReverseFlag)
{
/* Initialise the default arm status */
arm_status status = ARM_MATH_SUCCESS;
/* Initialise the FFT length */
S->fftLen = fftLen;
/* Initialise the Twiddle coefficient pointer */
S->pTwiddle = (float32_t *) twiddleCoef;
/* Initialise the Flag for selection of CFFT or CIFFT */
S->ifftFlag = ifftFlag;
/* Initialise the Flag for calculation Bit reversal or not */
S->bitReverseFlag = bitReverseFlag;
/* Initializations of structure parameters depending on the FFT length */
switch (S->fftLen)
{
case 4096U:
/* Initializations of structure parameters for 4096 point FFT */
/* Initialise the twiddle coef modifier value */
S->twidCoefModifier = 1U;
/* Initialise the bit reversal table modifier */
S->bitRevFactor = 1U;
/* Initialise the bit reversal table pointer */
S->pBitRevTable = (uint16_t *) armBitRevTable;
/* Initialise the 1/fftLen Value */
S->onebyfftLen = 0.000244140625;
break;
case 1024U:
/* Initializations of structure parameters for 1024 point FFT */
/* Initialise the twiddle coef modifier value */
S->twidCoefModifier = 4U;
/* Initialise the bit reversal table modifier */
S->bitRevFactor = 4U;
/* Initialise the bit reversal table pointer */
S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
/* Initialise the 1/fftLen Value */
S->onebyfftLen = 0.0009765625f;
break;
case 256U:
/* Initializations of structure parameters for 256 point FFT */
S->twidCoefModifier = 16U;
S->bitRevFactor = 16U;
S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
S->onebyfftLen = 0.00390625f;
break;
case 64U:
/* Initializations of structure parameters for 64 point FFT */
S->twidCoefModifier = 64U;
S->bitRevFactor = 64U;
S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
S->onebyfftLen = 0.015625f;
break;
case 16U:
/* Initializations of structure parameters for 16 point FFT */
S->twidCoefModifier = 256U;
S->bitRevFactor = 256U;
S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
S->onebyfftLen = 0.0625f;
break;
default:
/* Reporting argument error if fftSize is not valid value */
status = ARM_MATH_ARGUMENT_ERROR;
break;
}
return (status);
}
/**
@} end of ComplexFFT group
*/
|
