CMSIS DSP library
Dependents: KL25Z_FFT_Demo Hat_Board_v5_1 KL25Z_FFT_Demo_tony KL25Z_FFT_Demo_tony ... more
Fork of mbed-dsp by
Diff: cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c Wed Nov 28 12:30:09 2012 +0000 @@ -0,0 +1,97 @@ +/*----------------------------------------------------------------------------- +* Copyright (C) 2010 ARM Limited. All rights reserved. +* +* $Date: 15. February 2012 +* $Revision: V1.1.0 +* +* Project: CMSIS DSP Library +* Title: arm_biquad_cascade_df2T_init_f32.c +* +* Description: Initialization function for the floating-point transposed +* direct form II Biquad cascade filter. +* +* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 +* +* Version 1.1.0 2012/02/15 +* Updated with more optimizations, bug fixes and minor API changes. +* +* Version 1.0.10 2011/7/15 +* Big Endian support added and Merged M0 and M3/M4 Source code. +* +* 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 BiquadCascadeDF2T + * @{ + */ + +/** + * @brief Initialization function for the floating-point transposed direct form II Biquad cascade filter. + * @param[in,out] *S points to an instance of the filter data structure. + * @param[in] numStages number of 2nd order stages in the filter. + * @param[in] *pCoeffs points to the filter coefficients. + * @param[in] *pState points to the state buffer. + * @return none + * + * <b>Coefficient and State Ordering:</b> + * \par + * The coefficients are stored in the array <code>pCoeffs</code> in the following order: + * <pre> + * {b10, b11, b12, a11, a12, b20, b21, b22, a21, a22, ...} + * </pre> + * + * \par + * where <code>b1x</code> and <code>a1x</code> are the coefficients for the first stage, + * <code>b2x</code> and <code>a2x</code> are the coefficients for the second stage, + * and so on. The <code>pCoeffs</code> array contains a total of <code>5*numStages</code> values. + * + * \par + * The <code>pState</code> is a pointer to state array. + * Each Biquad stage has 2 state variables <code>d1,</code> and <code>d2</code>. + * The 2 state variables for stage 1 are first, then the 2 state variables for stage 2, and so on. + * The state array has a total length of <code>2*numStages</code> values. + * The state variables are updated after each block of data is processed; the coefficients are untouched. + */ + +void arm_biquad_cascade_df2T_init_f32( + arm_biquad_cascade_df2T_instance_f32 * S, + uint8_t numStages, + float32_t * pCoeffs, + float32_t * pState) +{ + /* Assign filter stages */ + S->numStages = numStages; + + /* Assign coefficient pointer */ + S->pCoeffs = pCoeffs; + + /* Clear state buffer and size is always 2 * numStages */ + memset(pState, 0, (2u * (uint32_t) numStages) * sizeof(float32_t)); + + /* Assign state pointer */ + S->pState = pState; +} + +/** + * @} end of BiquadCascadeDF2T group + */