arm_biquad_cascade_df2T_init_f32.c
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| text/x-c
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CLexer
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r16 | /*----------------------------------------------------------------------------- | ||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 29. November 2010 | ||||
* $Revision: V1.0.3 | ||||
* | ||||
* 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 | ||||
* | ||||
* 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 | ||||
*/ | ||||