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/* ----------------------------------------------------------------------
* Copyright (C) 2010-2012 ARM Limited. All rights reserved.
*
* $Date: 17. January 2013
* $Revision: V1.4.0
*
* Project: CMSIS DSP Library
* Title: arm_signal_converge_example_f32.c
*
* Description: Example code demonstrating convergence of an adaptive
* filter.
*
* 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 SignalConvergence Signal Convergence Example
*
* \par Description:
* \par
* Demonstrates the ability of an adaptive filter to "learn" the transfer function of
* a FIR lowpass filter using the Normalized LMS Filter, Finite Impulse
* Response (FIR) Filter, and Basic Math Functions.
*
* \par Algorithm:
* \par
* The figure below illustrates the signal flow in this example. Uniformly distributed white
* noise is passed through an FIR lowpass filter. The output of the FIR filter serves as the
* reference input of the adaptive filter (normalized LMS filter). The white noise is input
* to the adaptive filter. The adaptive filter learns the transfer function of the FIR filter.
* The filter outputs two signals: (1) the output of the internal adaptive FIR filter, and
* (2) the error signal which is the difference between the adaptive filter and the reference
* output of the FIR filter. Over time as the adaptive filter learns the transfer function
* of the FIR filter, the first output approaches the reference output of the FIR filter,
* and the error signal approaches zero.
* \par
* The adaptive filter converges properly even if the input signal has a large dynamic
* range (i.e., varies from small to large values). The coefficients of the adaptive filter
* are initially zero, and then converge over 1536 samples. The internal function test_signal_converge()
* implements the stopping condition. The function checks if all of the values of the error signal have a
* magnitude below a threshold DELTA.
*
* \par Block Diagram:
* \par
* \image html SignalFlow.gif
*
*
* \par Variables Description:
* \par
* \li \c testInput_f32 points to the input data
* \li \c firStateF32 points to FIR state buffer
* \li \c lmsStateF32 points to Normalised Least mean square FIR filter state buffer
* \li \c FIRCoeff_f32 points to coefficient buffer
* \li \c lmsNormCoeff_f32 points to Normalised Least mean square FIR filter coefficient buffer
* \li \c wire1, wir2, wire3 temporary buffers
* \li \c errOutput, err_signal temporary error buffers
*
* \par CMSIS DSP Software Library Functions Used:
* \par
* - arm_lms_norm_init_f32()
* - arm_fir_init_f32()
* - arm_fir_f32()
* - arm_lms_norm_f32()
* - arm_scale_f32()
* - arm_abs_f32()
* - arm_sub_f32()
* - arm_min_f32()
* - arm_copy_f32()
*
* <b> Refer </b>
* \link arm_signal_converge_example_f32.c \endlink
*
*/
/** \example arm_signal_converge_example_f32.c
*/
#include "arm_math.h"
#include "math_helper.h"
/* ----------------------------------------------------------------------
** Global defines for the simulation
* ------------------------------------------------------------------- */
#define TEST_LENGTH_SAMPLES 1536
#define NUMTAPS 32
#define BLOCKSIZE 32
#define DELTA_ERROR 0.000001f
#define DELTA_COEFF 0.0001f
#define MU 0.5f
#define NUMFRAMES (TEST_LENGTH_SAMPLES / BLOCKSIZE)
/* ----------------------------------------------------------------------
* Declare FIR state buffers and structure
* ------------------------------------------------------------------- */
float32_t firStateF32[NUMTAPS + BLOCKSIZE];
arm_fir_instance_f32 LPF_instance;
/* ----------------------------------------------------------------------
* Declare LMSNorm state buffers and structure
* ------------------------------------------------------------------- */
float32_t lmsStateF32[NUMTAPS + BLOCKSIZE];
float32_t errOutput[TEST_LENGTH_SAMPLES];
arm_lms_norm_instance_f32 lmsNorm_instance;
/* ----------------------------------------------------------------------
* Function Declarations for Signal Convergence Example
* ------------------------------------------------------------------- */
arm_status test_signal_converge_example( void );
/* ----------------------------------------------------------------------
* Internal functions
* ------------------------------------------------------------------- */
arm_status test_signal_converge(float32_t* err_signal,
uint32_t blockSize);
void getinput(float32_t* input,
uint32_t fr_cnt,
uint32_t blockSize);
/* ----------------------------------------------------------------------
* External Declarations for FIR F32 module Test
* ------------------------------------------------------------------- */
extern float32_t testInput_f32[TEST_LENGTH_SAMPLES];
extern float32_t lmsNormCoeff_f32[32];
extern const float32_t FIRCoeff_f32[32];
extern arm_lms_norm_instance_f32 lmsNorm_instance;
/* ----------------------------------------------------------------------
* Declare I/O buffers
* ------------------------------------------------------------------- */
float32_t wire1[BLOCKSIZE];
float32_t wire2[BLOCKSIZE];
float32_t wire3[BLOCKSIZE];
float32_t err_signal[BLOCKSIZE];
/* ----------------------------------------------------------------------
* Signal converge test
* ------------------------------------------------------------------- */
int32_t main(void)
{
uint32_t i;
arm_status status;
uint32_t index;
float32_t minValue;
/* Initialize the LMSNorm data structure */
arm_lms_norm_init_f32(&lmsNorm_instance, NUMTAPS, lmsNormCoeff_f32, lmsStateF32, MU, BLOCKSIZE);
/* Initialize the FIR data structure */
arm_fir_init_f32(&LPF_instance, NUMTAPS, (float32_t *)FIRCoeff_f32, firStateF32, BLOCKSIZE);
/* ----------------------------------------------------------------------
* Loop over the frames of data and execute each of the processing
* functions in the system.
* ------------------------------------------------------------------- */
for(i=0; i < NUMFRAMES; i++)
{
/* Read the input data - uniformly distributed random noise - into wire1 */
arm_copy_f32(testInput_f32 + (i * BLOCKSIZE), wire1, BLOCKSIZE);
/* Execute the FIR processing function. Input wire1 and output wire2 */
arm_fir_f32(&LPF_instance, wire1, wire2, BLOCKSIZE);
/* Execute the LMS Norm processing function*/
arm_lms_norm_f32(&lmsNorm_instance, /* LMSNorm instance */
wire1, /* Input signal */
wire2, /* Reference Signal */
wire3, /* Converged Signal */
err_signal, /* Error Signal, this will become small as the signal converges */
BLOCKSIZE); /* BlockSize */
/* apply overall gain */
arm_scale_f32(wire3, 5, wire3, BLOCKSIZE); /* in-place buffer */
}
status = ARM_MATH_SUCCESS;
/* -------------------------------------------------------------------------------
* Test whether the error signal has reached towards 0.
* ----------------------------------------------------------------------------- */
arm_abs_f32(err_signal, err_signal, BLOCKSIZE);
arm_min_f32(err_signal, BLOCKSIZE, &minValue, &index);
if (minValue > DELTA_ERROR)
{
status = ARM_MATH_TEST_FAILURE;
}
/* ----------------------------------------------------------------------
* Test whether the filter coefficients have converged.
* ------------------------------------------------------------------- */
arm_sub_f32((float32_t *)FIRCoeff_f32, lmsNormCoeff_f32, lmsNormCoeff_f32, NUMTAPS);
arm_abs_f32(lmsNormCoeff_f32, lmsNormCoeff_f32, NUMTAPS);
arm_min_f32(lmsNormCoeff_f32, NUMTAPS, &minValue, &index);
if (minValue > DELTA_COEFF)
{
status = ARM_MATH_TEST_FAILURE;
}
/* ----------------------------------------------------------------------
* Loop here if the signals did not pass the convergence check.
* This denotes a test failure
* ------------------------------------------------------------------- */
if ( status != ARM_MATH_SUCCESS)
{
while (1);
}
while (1); /* main function does not return */
}
/** \endlink */
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