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/* -*- c++ -*- */
/*
* Copyright 2004,2012,2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_IIR_FILTER_CCZ_H
#define INCLUDED_IIR_FILTER_CCZ_H
#include <gnuradio/filter/api.h>
#include <gnuradio/sync_block.h>
namespace gr {
namespace filter {
/*!
* \brief IIR filter with complex input, complex output, and
* complex (double) taps.
* \ingroup filter_blk
*
* \details
* This filter uses the Direct Form I implementation, where \p
* fftaps contains the feed-forward taps, and \p fbtaps the
* feedback ones.
*
* \p oldstyle: The old style of the IIR filter uses feedback
* taps that are negative of what most definitions use (scipy
* and Matlab among them). This parameter keeps using the old
* GNU Radio style and is set to TRUE by default. When taps
* generated from scipy, Matlab, or gr_filter_design, use the
* new style by setting this to FALSE.
*
* The input and output satisfy a difference equation of the form
\f[
y[n] - \sum_{k=1}^{M} a_k y[n-k] = \sum_{k=0}^{N} b_k x[n-k]
\f]
\xmlonly
y[n] - \sum_{k=1}^{M} a_k y[n-k] = \sum_{k=0}^{N} b_k x[n-k]
\endxmlonly
* with the corresponding rational system function
\f[
H(z) = \frac{\sum_{k=0}^{M} b_k z^{-k}}{1 - \sum_{k=1}^{N} a_k z^{-k}}
\f]
\xmlonly
H(z) = \ frac{\sum_{k=0}^{M} b_k z^{-k}}{1 - \sum_{k=1}^{N} a_k z^{-k}}
\endxmlonly
*/
class FILTER_API iir_filter_ccz : virtual public sync_block
{
public:
// gr::filter::iir_filter_ccz::sptr
typedef boost::shared_ptr<iir_filter_ccz> sptr;
static sptr make(const std::vector<gr_complexd>& fftaps,
const std::vector<gr_complexd>& fbtaps,
bool oldstyle = true);
virtual void set_taps(const std::vector<gr_complexd>& fftaps,
const std::vector<gr_complexd>& fbtaps) = 0;
};
} /* namespace filter */
} /* namespace gr */
#endif /* INCLUDED_IIR_FILTER_CCZ_H */
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