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/**
* Smarc
*
* Copyright (c) 2009-2011 Institut Tlcom - Tlcom Paristech
* Tlcom ParisTech / dept. TSI
*
* Authors : Benoit Mathieu, Jacques Prado
*
* This file is part of Smarc.
*
* Smarc is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Smarc is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef POLYPHASE_DECL_H_
#define POLYPHASE_DECL_H_
#include "filtering.h"
#define FILT(pfilt,m,l) &pfilt->filters[(m*L+l)*K]
#define FILT_STATE(pstate,m) &pstate->yi[m*(K-1)]
/**
* Defines a filter stage.
* - flen: length of remez filter. (L*M*K)
* - L: interpolation factor
* - M: decimation factor
* - K: sub-filter length
* - filters: array of L*M sub filters of length K. (total size is flen)
*/
struct PSFilter {
int flen;
int L;
int M;
int K;
double* filters;
int filter_delay;
};
/**
* Initialize PSFilter struct with given parameters
* - L [IN]: interpolation factor
* - M [IN]: decimation factor
* - fpass [IN]: start of lowpass filter transition band, in normalized form (0<fpass<0.5)
* - fstop [IN]: end of lowpass filter transition band, in normalized form (fpass<fstop<0.5)
* - rp [IN]: accepted ripple factor in pass band (in dB) within global structure.
* - rs [IN]: accepted ripple factor in stop band (in dB)
* - rpFactor [IN]: number of stage in global structure.
*
* Return pointer to PSFilter struct. This pointer must be deleted using destroy_psfilter function.
*/
struct PSFilter* init_psfilter(int L, int M,
double fpass, double fstop,
double rp, double rs, int rpFactor);
/**
* Destroy PSFilter, release memory
*/
void destroy_psfilter(struct PSFilter*);
/**
* Defines a filter stage state.
* - inbuf: input buffer
* - inbuf_size: input buffer allocated size
* - available: available samples in inbuf
* - skip: number of samples to skip (used to handle filter delay)
*/
struct PSState {
int skip;
int phase;
};
/**
* Initialize a filter stage state for the given filter stage
* The returned pointer must be freed by calling destroy_psstate
*/
struct PSState* init_psstate(struct PSFilter*);
/**
* Destroy a filter stage state
*/
void destroy_psstate(struct PSState*);
/**
* Reset a filter stage state so that an other signal can be filtered.
*/
void reset_psstate(struct PSState*, const struct PSFilter*);
#endif /* POLYPHASE_DECL_H_ */
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