text: /* ----------------------------------------------------------------------
  * 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 */
  