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arm_lms_init_f32.c 3.6KB

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  1. /*-----------------------------------------------------------------------------
  2. * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
  3. *
  4. * $Date: 17. January 2013
  5. * $Revision: V1.4.1
  6. *
  7. * Project: CMSIS DSP Library
  8. * Title: arm_lms_init_f32.c
  9. *
  10. * Description: Floating-point LMS filter initialization function.
  11. *
  12. * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13. *
  14. * Redistribution and use in source and binary forms, with or without
  15. * modification, are permitted provided that the following conditions
  16. * are met:
  17. * - Redistributions of source code must retain the above copyright
  18. * notice, this list of conditions and the following disclaimer.
  19. * - Redistributions in binary form must reproduce the above copyright
  20. * notice, this list of conditions and the following disclaimer in
  21. * the documentation and/or other materials provided with the
  22. * distribution.
  23. * - Neither the name of ARM LIMITED nor the names of its contributors
  24. * may be used to endorse or promote products derived from this
  25. * software without specific prior written permission.
  26. *
  27. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35. * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38. * POSSIBILITY OF SUCH DAMAGE.
  39. * ---------------------------------------------------------------------------*/
  40. #include "arm_math.h"
  41. /**
  42. * @addtogroup LMS
  43. * @{
  44. */
  45. /**
  46. * @brief Initialization function for floating-point LMS filter.
  47. * @param[in] *S points to an instance of the floating-point LMS filter structure.
  48. * @param[in] numTaps number of filter coefficients.
  49. * @param[in] *pCoeffs points to the coefficient buffer.
  50. * @param[in] *pState points to state buffer.
  51. * @param[in] mu step size that controls filter coefficient updates.
  52. * @param[in] blockSize number of samples to process.
  53. * @return none.
  54. */
  55. /**
  56. * \par Description:
  57. * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
  58. * <pre>
  59. * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
  60. * </pre>
  61. * The initial filter coefficients serve as a starting point for the adaptive filter.
  62. * <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_f32()</code>.
  63. */
  64. void arm_lms_init_f32(
  65. arm_lms_instance_f32 * S,
  66. uint16_t numTaps,
  67. float32_t * pCoeffs,
  68. float32_t * pState,
  69. float32_t mu,
  70. uint32_t blockSize)
  71. {
  72. /* Assign filter taps */
  73. S->numTaps = numTaps;
  74. /* Assign coefficient pointer */
  75. S->pCoeffs = pCoeffs;
  76. /* Clear state buffer and size is always blockSize + numTaps */
  77. memset(pState, 0, (numTaps + (blockSize - 1)) * sizeof(float32_t));
  78. /* Assign state pointer */
  79. S->pState = pState;
  80. /* Assign Step size value */
  81. S->mu = mu;
  82. }
  83. /**
  84. * @} end of LMS group
  85. */