1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2012 ARM Limited. All rights reserved.
3 *
4 * $Date: 17. January 2013
5 * $Revision: V1.4.0
6 *
7 * Project: CMSIS DSP Library
8 * Title: arm_fft_bin_example_f32.c
9 *
10 * Description: Example code demonstrating calculation of Max energy bin of
11 * frequency domain of input signal.
12 *
13 * Target Processor: Cortex-M4/Cortex-M3
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * - Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * - Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 * - Neither the name of ARM LIMITED nor the names of its contributors
25 * may be used to endorse or promote products derived from this
26 * software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
31 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
32 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
34 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
35 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
36 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
38 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39 * POSSIBILITY OF SUCH DAMAGE.
40 * -------------------------------------------------------------------- */
41
42 /**
43 * @addtogroup groupExamples
44 * @{
45 *
46 * @defgroup FrequencyBin Frequency Bin Example
47 *
48 * \par Description
49 * \par
50 * Demonstrates the calculation of the maximum energy bin in the frequency
51 * domain of the input signal with the use of Complex FFT, Complex
52 * Magnitude, and Maximum functions.
53 *
54 * \par Algorithm:
55 * \par
56 * The input test signal contains a 10 kHz signal with uniformly distributed white noise.
57 * Calculating the FFT of the input signal will give us the maximum energy of the
58 * bin corresponding to the input frequency of 10 kHz.
59 *
60 * \par Block Diagram:
61 * \image html FFTBin.gif "Block Diagram"
62 * \par
63 * The figure below shows the time domain signal of 10 kHz signal with
64 * uniformly distributed white noise, and the next figure shows the input
65 * in the frequency domain. The bin with maximum energy corresponds to 10 kHz signal.
66 * \par
67 * \image html FFTBinInput.gif "Input signal in Time domain"
68 * \image html FFTBinOutput.gif "Input signal in Frequency domain"
69 *
70 * \par Variables Description:
71 * \par
72 * \li \c testInput_f32_10khz points to the input data
73 * \li \c testOutput points to the output data
74 * \li \c fftSize length of FFT
75 * \li \c ifftFlag flag for the selection of CFFT/CIFFT
76 * \li \c doBitReverse Flag for selection of normal order or bit reversed order
77 * \li \c refIndex reference index value at which maximum energy of bin ocuurs
78 * \li \c testIndex calculated index value at which maximum energy of bin ocuurs
79 *
80 * \par CMSIS DSP Software Library Functions Used:
81 * \par
82 * - arm_cfft_f32()
83 * - arm_cmplx_mag_f32()
84 * - arm_max_f32()
85 *
86 * <b> Refer </b>
87 * \link arm_fft_bin_example_f32.c \endlink
88 *
89 * \example arm_fft_bin_example_f32.c
90 *
91 * @}*/
92
93 #include "arm_math.h"
94 #include "arm_const_structs.h"
95
96 #if defined(SEMIHOSTING)
97 #include <stdio.h>
98 #endif
99
100 #define TEST_LENGTH_SAMPLES 2048
101
102 /* -------------------------------------------------------------------
103 * External Input and Output buffer Declarations for FFT Bin Example
104 * ------------------------------------------------------------------- */
105 extern float32_t testInput_f32_10khz[TEST_LENGTH_SAMPLES];
106 static float32_t testOutput[TEST_LENGTH_SAMPLES/2];
107
108 /* ------------------------------------------------------------------
109 * Global variables for FFT Bin Example
110 * ------------------------------------------------------------------- */
111 uint32_t fftSize = 1024;
112 uint32_t ifftFlag = 0;
113 uint32_t doBitReverse = 1;
114 arm_cfft_instance_f32 varInstCfftF32;
115
116 /* Reference index at which max energy of bin ocuurs */
117 uint32_t refIndex = 213, testIndex = 0;
118
119 /* ----------------------------------------------------------------------
120 * Max magnitude FFT Bin test
121 * ------------------------------------------------------------------- */
122
main(void)123 int32_t main(void)
124 {
125
126 arm_status status;
127 float32_t maxValue;
128
129 status = ARM_MATH_SUCCESS;
130
131 status=arm_cfft_init_1024_f32(&varInstCfftF32);
132
133 /* Process the data through the CFFT/CIFFT module */
134 arm_cfft_f32(&varInstCfftF32, testInput_f32_10khz, ifftFlag, doBitReverse);
135
136 /* Process the data through the Complex Magnitude Module for
137 calculating the magnitude at each bin */
138 arm_cmplx_mag_f32(testInput_f32_10khz, testOutput, fftSize);
139
140 /* Calculates maxValue and returns corresponding BIN value */
141 arm_max_f32(testOutput, fftSize, &maxValue, &testIndex);
142
143 status = (testIndex != refIndex) ? ARM_MATH_TEST_FAILURE : ARM_MATH_SUCCESS;
144
145 if (status != ARM_MATH_SUCCESS)
146 {
147 #if defined (SEMIHOSTING)
148 printf("FAILURE\n");
149 #else
150 while (1); /* main function does not return */
151 #endif
152 }
153 else
154 {
155 #if defined (SEMIHOSTING)
156 printf("SUCCESS\n");
157 #else
158 while (1); /* main function does not return */
159 #endif
160 }
161 }
162
163 /** \endlink */
164
