/* -*- 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 2, 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_PLL_FREQDET_CF_H

#define INCLUDED_GR_PLL_FREQDET_CF_H

#include <gr_sync_block.h>

class gr_pll_freqdet_cf;

typedef boost::shared_ptr<gr_pll_freqdet_cf> gr_pll_freqdet_cf_sptr;

gr_pll_freqdet_cf_sptr gr_make_pll_freqdet_cf (float alpha, float beta,

                                               float max_freq, float min_freq);

/*!

 * \brief Implements a PLL which locks to the input frequency and outputs 

 * an estimate of that frequency.  Useful for FM Demod.

 * \ingroup block

 *

 * input: stream of complex; output: stream of floats

 *

 * This PLL locks onto a [possibly noisy] reference carrier on

 * the input and outputs an estimate of that frequency in radians per sample.

 * All settings max_freq and min_freq are in terms of radians per sample, 

 * NOT HERTZ.  Alpha is the phase gain (first order, units of radians per radian) 

 * and beta is the frequency gain (second order, units of radians per sample per radian)

 * \sa gr_pll_refout_cc, gr_pll_carriertracking_cc

 */

class gr_pll_freqdet_cf : public gr_sync_block

{

  friend gr_pll_freqdet_cf_sptr gr_make_pll_freqdet_cf (float alpha, float beta,

                                                        float max_freq, float min_freq);

  float d_alpha,d_beta,d_max_freq,d_min_freq,d_phase,d_freq;

  gr_pll_freqdet_cf (float alpha, float beta, float max_freq, float min_freq);

  int work (int noutput_items,

            gr_vector_const_void_star &input_items,

            gr_vector_void_star &output_items);

private:

  float mod_2pi (float in);

  float phase_detector(gr_complex sample,float ref_phase);

};

#endif