CMSIS DSP library
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cmsis_dsp/FilteringFunctions/arm_lms_norm_init_q15.c
- Committer:
- mbed_official
- Date:
- 2015-11-20
- Revision:
- 5:3762170b6d4d
- Parent:
- 3:7a284390b0ce
File content as of revision 5:3762170b6d4d:
/*----------------------------------------------------------------------------- * Copyright (C) 2010-2014 ARM Limited. All rights reserved. * * $Date: 19. March 2015 * $Revision: V.1.4.5 * * Project: CMSIS DSP Library * Title: arm_lms_norm_init_q15.c * * Description: Q15 NLMS initialization function. * * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 * * 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. * ---------------------------------------------------------------------------*/ #include "arm_math.h" #include "arm_common_tables.h" /** * @addtogroup LMS_NORM * @{ */ /** * @brief Initialization function for Q15 normalized LMS filter. * @param[in] *S points to an instance of the Q15 normalized LMS filter structure. * @param[in] numTaps number of filter coefficients. * @param[in] *pCoeffs points to coefficient buffer. * @param[in] *pState points to state buffer. * @param[in] mu step size that controls filter coefficient updates. * @param[in] blockSize number of samples to process. * @param[in] postShift bit shift applied to coefficients. * @return none. * * <b>Description:</b> * \par * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order: * <pre> * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]} * </pre> * The initial filter coefficients serve as a starting point for the adaptive filter. * <code>pState</code> points to the array of state variables and size of array is * <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed * by each call to <code>arm_lms_norm_q15()</code>. */ void arm_lms_norm_init_q15( arm_lms_norm_instance_q15 * S, uint16_t numTaps, q15_t * pCoeffs, q15_t * pState, q15_t mu, uint32_t blockSize, uint8_t postShift) { /* Assign filter taps */ S->numTaps = numTaps; /* Assign coefficient pointer */ S->pCoeffs = pCoeffs; /* Clear state buffer and size is always blockSize + numTaps - 1 */ memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t)); /* Assign post Shift value applied to coefficients */ S->postShift = postShift; /* Assign state pointer */ S->pState = pState; /* Assign Step size value */ S->mu = mu; /* Initialize reciprocal pointer table */ S->recipTable = (q15_t *) armRecipTableQ15; /* Initialise Energy to zero */ S->energy = 0; /* Initialise x0 to zero */ S->x0 = 0; } /** * @} end of LMS_NORM group */