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Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c')
-rw-r--r-- | DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c b/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c new file mode 100644 index 0000000..d9011fe --- /dev/null +++ b/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c @@ -0,0 +1,102 @@ +/*----------------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* 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 +* +* 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" + +/** + * @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 + */ |