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/*
* Copyright (C) 2004-2010 NXP Software
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/************************************************************************/
/* */
/* Project:: */
/* $Author: beq07716 $*/
/* $Revision: 1000 $*/
/* $Date: 2010-06-28 13:08:20 +0200 (Mon, 28 Jun 2010) $*/
/* */
/************************************************************************/
#include "BIQUAD.h"
#include "FO_1I_D16F16Css_TRC_WRA_01_Private.h"
#include "LVM_Macros.h"
/**************************************************************************
ASSUMPTIONS:
COEFS-
pBiquadState->coefs[0] is A1,
pBiquadState->coefs[1] is A0,
pBiquadState->coefs[2] is -B1, these are in Q15 format
DELAYS-
pBiquadState->pDelays[0] is x(n-1)L in Q0 format
pBiquadState->pDelays[1] is y(n-1)L in Q0 format
***************************************************************************/
void FO_1I_D16F16C15_TRC_WRA_01( Biquad_Instance_t *pInstance,
LVM_INT16 *pDataIn,
LVM_INT16 *pDataOut,
LVM_INT16 NrSamples)
{
LVM_INT32 ynL;
LVM_INT16 ii;
PFilter_State pBiquadState = (PFilter_State) pInstance;
for (ii = NrSamples; ii != 0; ii--)
{
/**************************************************************************
PROCESSING OF THE LEFT CHANNEL
***************************************************************************/
// ynL=A1 (Q15) * x(n-1)L (Q0) in Q15
ynL=(LVM_INT32)pBiquadState->coefs[0]* pBiquadState->pDelays[0];
// ynL+=A0 (Q15) * x(n)L (Q0) in Q15
ynL+=(LVM_INT32)pBiquadState->coefs[1]* (*pDataIn);
// ynL+= (-B1 (Q15) * y(n-1)L (Q0) ) in Q15
ynL+=(LVM_INT32)pBiquadState->coefs[2]*pBiquadState->pDelays[1];
ynL=(LVM_INT16)(ynL>>15); // ynL in Q0 format
/**************************************************************************
UPDATING THE DELAYS
***************************************************************************/
pBiquadState->pDelays[1]=ynL; // Update y(n-1)L in Q0
pBiquadState->pDelays[0]=(*pDataIn++); // Update x(n-1)L in Q0
/**************************************************************************
WRITING THE OUTPUT
***************************************************************************/
*pDataOut++=(LVM_INT16)ynL; // Write Left output in Q0
}
}
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