/* ---------------------------------------------------------------------- 
* Copyright (C) 2010-2012 ARM Limited. All rights reserved.   
*  
* $Date:         17. January 2013
* $Revision:     V1.4.0
*
* Project:       CMSIS DSP Library
*  
* 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 */ 
