gr_remez.h

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/* -*- c++ -*- */
/*
 * Copyright 2004 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 * 
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 * 
 * GNU Radio 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef INCLUDED_GR_REMEZ_H
#define INCLUDED_GR_REMEZ_H

#include <gr_types.h>
#include <string>
#include <stdexcept>

/*!
 * \brief Parks-McClellan FIR filter design.
 *
 * \ingroup filter_design
 *
 * Calculates the optimal (in the Chebyshev/minimax sense) FIR filter
 * inpulse reponse given a set of band edges, the desired reponse 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::runtime_error if args are invalid or calculation fails to converge.
 */

std::vector<double>
gr_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
          ) throw (std::runtime_error);


#endif /* INCLUDED_GR_REMEZ_H */