pm_remez.h

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/* -*- c++ -*- */
/*
 * Copyright 2004,2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */
 
#ifndef INCLUDED_FILTER_PM_REMEZ_H
#define INCLUDED_FILTER_PM_REMEZ_H
 
#include <gnuradio/filter/api.h>
#include <gnuradio/types.h>
#include <string>
#include <vector>
 
namespace gr {
namespace filter {
/*!
 * \brief Parks-McClellan FIR filter design using Remez algorithm.
 * \ingroup filter_design
 *
 * \details
 * Calculates the optimal (in the Chebyshev/minimax sense) FIR
 * filter inpulse response given a set of band edges, the desired
 * response on those bands, and the weight given to the error in
 * those bands.
 *
 * \param order         filter order (number of taps in the returned filter - 1)
 * \param bands         frequency at the band edges [ b1 e1 b2 e2 b3 e3 ...]
 * \param ampl              desired amplitude at the band edges [ a(b1) a(e1) a(b2) a(e2)
 *...] \param error_weight  weighting applied to each band (usually 1) \param filter_type
 *one of "bandpass", "hilbert" or "differentiator"
 * \param grid_density  determines how accurately the filter will be constructed. \
 *                          The minimum value is 16; higher values are slower to compute.
 *
 * Frequency is in the range [0, 1], with 1 being the Nyquist
 * frequency (Fs/2)
 *
 * \returns vector of computed taps
 *
 * \throws std::invalid_argument if args are invalid and std::runtime_error if calculation
 * fails to converge.
 */
 
FILTER_API std::vector<double> pm_remez(int order,
                                        const std::vector<double>& bands,
                                        const std::vector<double>& ampl,
                                        const std::vector<double>& error_weight,
                                        const std::string filter_type = "bandpass",
                                        int grid_density = 16) noexcept(false);
 
} /* namespace filter */
} /* namespace gr */
 
#endif /* INCLUDED_FILTER_PM_REMEZ_H */