/* ----------------------------------------------------------------------
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* Copyright (C) 2010-2012 ARM Limited. All rights reserved.
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*
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* $Date: 17. January 2013
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* $Revision: V1.4.0
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*
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* Project: CMSIS DSP Library
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* Title: arm_signal_converge_example_f32.c
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*
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* Description: Example code demonstrating convergence of an adaptive
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* filter.
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*
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* Target Processor: Cortex-M4/Cortex-M3
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of ARM LIMITED nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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* -------------------------------------------------------------------- */
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/**
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* @ingroup groupExamples
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*/
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/**
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* @defgroup SignalConvergence Signal Convergence Example
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*
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* \par Description:
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* \par
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* Demonstrates the ability of an adaptive filter to "learn" the transfer function of
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* a FIR lowpass filter using the Normalized LMS Filter, Finite Impulse
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* Response (FIR) Filter, and Basic Math Functions.
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*
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* \par Algorithm:
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* \par
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* The figure below illustrates the signal flow in this example. Uniformly distributed white
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* noise is passed through an FIR lowpass filter. The output of the FIR filter serves as the
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* reference input of the adaptive filter (normalized LMS filter). The white noise is input
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* to the adaptive filter. The adaptive filter learns the transfer function of the FIR filter.
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* The filter outputs two signals: (1) the output of the internal adaptive FIR filter, and
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* (2) the error signal which is the difference between the adaptive filter and the reference
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* output of the FIR filter. Over time as the adaptive filter learns the transfer function
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* of the FIR filter, the first output approaches the reference output of the FIR filter,
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* and the error signal approaches zero.
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* \par
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* The adaptive filter converges properly even if the input signal has a large dynamic
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* range (i.e., varies from small to large values). The coefficients of the adaptive filter
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* are initially zero, and then converge over 1536 samples. The internal function test_signal_converge()
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* implements the stopping condition. The function checks if all of the values of the error signal have a
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* magnitude below a threshold DELTA.
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*
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* \par Block Diagram:
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* \par
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* \image html SignalFlow.gif
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*
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*
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* \par Variables Description:
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* \par
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* \li \c testInput_f32 points to the input data
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* \li \c firStateF32 points to FIR state buffer
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* \li \c lmsStateF32 points to Normalised Least mean square FIR filter state buffer
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* \li \c FIRCoeff_f32 points to coefficient buffer
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* \li \c lmsNormCoeff_f32 points to Normalised Least mean square FIR filter coefficient buffer
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* \li \c wire1, wir2, wire3 temporary buffers
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* \li \c errOutput, err_signal temporary error buffers
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*
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* \par CMSIS DSP Software Library Functions Used:
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* \par
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* - arm_lms_norm_init_f32()
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* - arm_fir_init_f32()
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* - arm_fir_f32()
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* - arm_lms_norm_f32()
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* - arm_scale_f32()
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* - arm_abs_f32()
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* - arm_sub_f32()
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* - arm_min_f32()
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* - arm_copy_f32()
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*
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* <b> Refer </b>
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* \link arm_signal_converge_example_f32.c \endlink
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*
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*/
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/** \example arm_signal_converge_example_f32.c
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*/
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#include "arm_math.h"
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#include "math_helper.h"
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/* ----------------------------------------------------------------------
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** Global defines for the simulation
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* ------------------------------------------------------------------- */
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#define TEST_LENGTH_SAMPLES 1536
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#define NUMTAPS 32
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#define BLOCKSIZE 32
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#define DELTA_ERROR 0.000001f
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#define DELTA_COEFF 0.0001f
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#define MU 0.5f
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#define NUMFRAMES (TEST_LENGTH_SAMPLES / BLOCKSIZE)
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/* ----------------------------------------------------------------------
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* Declare FIR state buffers and structure
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* ------------------------------------------------------------------- */
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float32_t firStateF32[NUMTAPS + BLOCKSIZE];
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arm_fir_instance_f32 LPF_instance;
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/* ----------------------------------------------------------------------
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* Declare LMSNorm state buffers and structure
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* ------------------------------------------------------------------- */
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float32_t lmsStateF32[NUMTAPS + BLOCKSIZE];
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float32_t errOutput[TEST_LENGTH_SAMPLES];
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arm_lms_norm_instance_f32 lmsNorm_instance;
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/* ----------------------------------------------------------------------
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* Function Declarations for Signal Convergence Example
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* ------------------------------------------------------------------- */
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arm_status test_signal_converge_example( void );
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/* ----------------------------------------------------------------------
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* Internal functions
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* ------------------------------------------------------------------- */
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arm_status test_signal_converge(float32_t* err_signal,
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uint32_t blockSize);
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void getinput(float32_t* input,
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uint32_t fr_cnt,
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uint32_t blockSize);
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/* ----------------------------------------------------------------------
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* External Declarations for FIR F32 module Test
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* ------------------------------------------------------------------- */
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extern float32_t testInput_f32[TEST_LENGTH_SAMPLES];
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extern float32_t lmsNormCoeff_f32[32];
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extern const float32_t FIRCoeff_f32[32];
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extern arm_lms_norm_instance_f32 lmsNorm_instance;
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/* ----------------------------------------------------------------------
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* Declare I/O buffers
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* ------------------------------------------------------------------- */
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float32_t wire1[BLOCKSIZE];
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float32_t wire2[BLOCKSIZE];
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float32_t wire3[BLOCKSIZE];
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float32_t err_signal[BLOCKSIZE];
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/* ----------------------------------------------------------------------
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* Signal converge test
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* ------------------------------------------------------------------- */
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int32_t main(void)
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{
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uint32_t i;
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arm_status status;
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uint32_t index;
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float32_t minValue;
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/* Initialize the LMSNorm data structure */
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arm_lms_norm_init_f32(&lmsNorm_instance, NUMTAPS, lmsNormCoeff_f32, lmsStateF32, MU, BLOCKSIZE);
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/* Initialize the FIR data structure */
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arm_fir_init_f32(&LPF_instance, NUMTAPS, (float32_t *)FIRCoeff_f32, firStateF32, BLOCKSIZE);
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/* ----------------------------------------------------------------------
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* Loop over the frames of data and execute each of the processing
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* functions in the system.
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* ------------------------------------------------------------------- */
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for(i=0; i < NUMFRAMES; i++)
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{
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/* Read the input data - uniformly distributed random noise - into wire1 */
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arm_copy_f32(testInput_f32 + (i * BLOCKSIZE), wire1, BLOCKSIZE);
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/* Execute the FIR processing function. Input wire1 and output wire2 */
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arm_fir_f32(&LPF_instance, wire1, wire2, BLOCKSIZE);
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/* Execute the LMS Norm processing function*/
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arm_lms_norm_f32(&lmsNorm_instance, /* LMSNorm instance */
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wire1, /* Input signal */
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wire2, /* Reference Signal */
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wire3, /* Converged Signal */
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err_signal, /* Error Signal, this will become small as the signal converges */
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BLOCKSIZE); /* BlockSize */
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/* apply overall gain */
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arm_scale_f32(wire3, 5, wire3, BLOCKSIZE); /* in-place buffer */
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}
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status = ARM_MATH_SUCCESS;
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/* -------------------------------------------------------------------------------
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* Test whether the error signal has reached towards 0.
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* ----------------------------------------------------------------------------- */
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arm_abs_f32(err_signal, err_signal, BLOCKSIZE);
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arm_min_f32(err_signal, BLOCKSIZE, &minValue, &index);
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if (minValue > DELTA_ERROR)
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{
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status = ARM_MATH_TEST_FAILURE;
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}
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/* ----------------------------------------------------------------------
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* Test whether the filter coefficients have converged.
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* ------------------------------------------------------------------- */
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arm_sub_f32((float32_t *)FIRCoeff_f32, lmsNormCoeff_f32, lmsNormCoeff_f32, NUMTAPS);
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arm_abs_f32(lmsNormCoeff_f32, lmsNormCoeff_f32, NUMTAPS);
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arm_min_f32(lmsNormCoeff_f32, NUMTAPS, &minValue, &index);
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if (minValue > DELTA_COEFF)
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{
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status = ARM_MATH_TEST_FAILURE;
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}
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/* ----------------------------------------------------------------------
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* Loop here if the signals did not pass the convergence check.
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* This denotes a test failure
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* ------------------------------------------------------------------- */
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if ( status != ARM_MATH_SUCCESS)
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{
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while (1);
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}
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while (1); /* main function does not return */
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}
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/** \endlink */
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