/*----------------------------------------------------------------------------- * Copyright (C) 2010 ARM Limited. All rights reserved. * * $Date: 29. November 2010 * $Revision: V1.0.3 * * Project: CMSIS DSP Library * Title: arm_lms_init_q31.c * * Description: Q31 LMS filter initialization function. * * Target Processor: Cortex-M4/Cortex-M3 * * Version 1.0.3 2010/11/29 * Re-organized the CMSIS folders and updated documentation. * * Version 1.0.2 2010/11/11 * Documentation updated. * * Version 1.0.1 2010/10/05 * Production release and review comments incorporated. * * Version 1.0.0 2010/09/20 * Production release and review comments incorporated * * Version 0.0.7 2010/06/10 * Misra-C changes done * ---------------------------------------------------------------------------*/ #include "arm_math.h" /** * @ingroup groupFilters */ /** * @addtogroup LMS * @{ */ /** * @brief Initialization function for Q31 LMS filter. * @param[in] *S points to an instance of the Q31 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. * * \par Description: * pCoeffs points to the array of filter coefficients stored in time reversed order: *
  
 *    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}  
 * 
* The initial filter coefficients serve as a starting point for the adaptive filter. * pState points to an array of length numTaps+blockSize-1samples, * where blockSize is the number of input samples processed by each call to * arm_lms_q31(). */ void arm_lms_init_q31( arm_lms_instance_q31 * S, uint16_t numTaps, q31_t * pCoeffs, q31_t * pState, q31_t mu, uint32_t blockSize, uint32_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, ((uint32_t) numTaps + (blockSize - 1u)) * sizeof(q31_t)); /* Assign state pointer */ S->pState = pState; /* Assign Step size value */ S->mu = mu; /* Assign postShift value to be applied */ S->postShift = postShift; } /** * @} end of LMS group */