/* ----------------------------------------------------------------------
|
* Copyright (C) 2010-2012 ARM Limited. All rights reserved.
|
*
|
* $Date: 17. January 2013
|
* $Revision: V1.4.0
|
*
|
* Project: CMSIS DSP Library
|
* Title: arm_fft_bin_example_f32.c
|
*
|
* Description: Example code demonstrating calculation of Max energy bin of
|
* frequency domain of input signal.
|
*
|
* Target Processor: Cortex-M4/Cortex-M3
|
*
|
* Redistribution and use in source and binary forms, with or without
|
* modification, are permitted provided that the following conditions
|
* are met:
|
* - Redistributions of source code must retain the above copyright
|
* notice, this list of conditions and the following disclaimer.
|
* - Redistributions in binary form must reproduce the above copyright
|
* notice, this list of conditions and the following disclaimer in
|
* the documentation and/or other materials provided with the
|
* distribution.
|
* - Neither the name of ARM LIMITED nor the names of its contributors
|
* may be used to endorse or promote products derived from this
|
* software without specific prior written permission.
|
*
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
* POSSIBILITY OF SUCH DAMAGE.
|
* -------------------------------------------------------------------- */
|
|
/**
|
* @ingroup groupExamples
|
*/
|
|
/**
|
* @defgroup FrequencyBin Frequency Bin Example
|
*
|
* \par Description
|
* \par
|
* Demonstrates the calculation of the maximum energy bin in the frequency
|
* domain of the input signal with the use of Complex FFT, Complex
|
* Magnitude, and Maximum functions.
|
*
|
* \par Algorithm:
|
* \par
|
* The input test signal contains a 10 kHz signal with uniformly distributed white noise.
|
* Calculating the FFT of the input signal will give us the maximum energy of the
|
* bin corresponding to the input frequency of 10 kHz.
|
*
|
* \par Block Diagram:
|
* \image html FFTBin.gif "Block Diagram"
|
* \par
|
* The figure below shows the time domain signal of 10 kHz signal with
|
* uniformly distributed white noise, and the next figure shows the input
|
* in the frequency domain. The bin with maximum energy corresponds to 10 kHz signal.
|
* \par
|
* \image html FFTBinInput.gif "Input signal in Time domain"
|
* \image html FFTBinOutput.gif "Input signal in Frequency domain"
|
*
|
* \par Variables Description:
|
* \par
|
* \li \c testInput_f32_10khz points to the input data
|
* \li \c testOutput points to the output data
|
* \li \c fftSize length of FFT
|
* \li \c ifftFlag flag for the selection of CFFT/CIFFT
|
* \li \c doBitReverse Flag for selection of normal order or bit reversed order
|
* \li \c refIndex reference index value at which maximum energy of bin ocuurs
|
* \li \c testIndex calculated index value at which maximum energy of bin ocuurs
|
*
|
* \par CMSIS DSP Software Library Functions Used:
|
* \par
|
* - arm_cfft_f32()
|
* - arm_cmplx_mag_f32()
|
* - arm_max_f32()
|
*
|
* <b> Refer </b>
|
* \link arm_fft_bin_example_f32.c \endlink
|
*
|
*/
|
|
|
/** \example arm_fft_bin_example_f32.c
|
*/
|
|
|
#include "arm_math.h"
|
#include "arm_const_structs.h"
|
|
#define TEST_LENGTH_SAMPLES 2048
|
|
/* -------------------------------------------------------------------
|
* External Input and Output buffer Declarations for FFT Bin Example
|
* ------------------------------------------------------------------- */
|
extern float32_t testInput_f32_10khz[TEST_LENGTH_SAMPLES];
|
static float32_t testOutput[TEST_LENGTH_SAMPLES/2];
|
|
/* ------------------------------------------------------------------
|
* Global variables for FFT Bin Example
|
* ------------------------------------------------------------------- */
|
uint32_t fftSize = 1024;
|
uint32_t ifftFlag = 0;
|
uint32_t doBitReverse = 1;
|
|
/* Reference index at which max energy of bin ocuurs */
|
uint32_t refIndex = 213, testIndex = 0;
|
|
/* ----------------------------------------------------------------------
|
* Max magnitude FFT Bin test
|
* ------------------------------------------------------------------- */
|
|
int32_t main(void)
|
{
|
|
arm_status status;
|
float32_t maxValue;
|
|
status = ARM_MATH_SUCCESS;
|
|
/* Process the data through the CFFT/CIFFT module */
|
arm_cfft_f32(&arm_cfft_sR_f32_len1024, testInput_f32_10khz, ifftFlag, doBitReverse);
|
|
/* Process the data through the Complex Magnitude Module for
|
calculating the magnitude at each bin */
|
arm_cmplx_mag_f32(testInput_f32_10khz, testOutput, fftSize);
|
|
/* Calculates maxValue and returns corresponding BIN value */
|
arm_max_f32(testOutput, fftSize, &maxValue, &testIndex);
|
|
if (testIndex != refIndex)
|
{
|
status = ARM_MATH_TEST_FAILURE;
|
}
|
|
/* ----------------------------------------------------------------------
|
** Loop here if the signals fail the PASS check.
|
** This denotes a test failure
|
** ------------------------------------------------------------------- */
|
|
if ( status != ARM_MATH_SUCCESS)
|
{
|
while (1);
|
}
|
|
while (1); /* main function does not return */
|
}
|
|
/** \endlink */
|
