filter.h

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 /******************************************************************

 iLBC Speech Coder ANSI-C Source Code

 filter.h

 Copyright (C) The Internet Society (2004).
 All Rights Reserved.

 ******************************************************************/






 #ifndef __iLBC_FILTER_H
 #define __iLBC_FILTER_H

 void AllPoleFilter(
 float *InOut, /* (i/o) on entrance InOut[-orderCoef] to
 InOut[-1] contain the state of the
 filter (delayed samples). InOut[0] to
 InOut[lengthInOut-1] contain the filter
 input, on en exit InOut[-orderCoef] to
 InOut[-1] is unchanged and InOut[0] to
 InOut[lengthInOut-1] contain filtered
 samples */
 float *Coef,/* (i) filter coefficients, Coef[0] is assumed
 to be 1.0 */
 int lengthInOut,/* (i) number of input/output samples */
 int orderCoef /* (i) number of filter coefficients */
 );

 void AllZeroFilter(
 float *In, /* (i) In[0] to In[lengthInOut-1] contain
 filter input samples */
 float *Coef,/* (i) filter coefficients (Coef[0] is assumed
 to be 1.0) */
 int lengthInOut,/* (i) number of input/output samples */
 int orderCoef, /* (i) number of filter coefficients */
 float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
 contain the filter state, on exit Out[0]
 to Out[lengthInOut-1] contain filtered
 samples */
 );

 void ZeroPoleFilter(
 float *In, /* (i) In[0] to In[lengthInOut-1] contain filter
 input samples In[-orderCoef] to In[-1]
 contain state of all-zero section */
 float *ZeroCoef,/* (i) filter coefficients for all-zero
 section (ZeroCoef[0] is assumed to
 be 1.0) */
 float *PoleCoef,/* (i) filter coefficients for all-pole section
 (ZeroCoef[0] is assumed to be 1.0) */
 int lengthInOut,/* (i) number of input/output samples */
 int orderCoef, /* (i) number of filter coefficients */
 float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
 contain state of all-pole section. On
 exit Out[0] to Out[lengthInOut-1]
 contain filtered samples */
 );






 void DownSample (
 float *In, /* (i) input samples */
 float *Coef, /* (i) filter coefficients */
 int lengthIn, /* (i) number of input samples */
 float *state, /* (i) filter state */
 float *Out /* (o) downsampled output */
 );

 #endif