| /* ---------------------------------------------------------------------- |
| * 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 */ |