/* -*- c++ -*- */

/*

 * Copyright 2002,2007 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 _GRI_MMSE_FIR_INTERPOLATOR_CC_H_

#define _GRI_MMSE_FIR_INTERPOLATOR_CC_H_

#include <gr_complex.h>

#include <vector>

class gr_fir_ccf;

/*!

 * \brief Compute intermediate samples between signal samples x(k*Ts)

 * \ingroup filter_primitive

 *

 * This implements a Mininum Mean Squared Error interpolator with 8 taps.

 * It is suitable for signals where the bandwidth of interest B = 1/(4*Ts)

 * Where Ts is the time between samples.

 *

 * Although mu, the fractional delay, is specified as a float, it is actually

 * quantized.  0.0 <= mu <= 1.0.  That is, mu is quantized in the interpolate 

 * method to 32nd's of a sample.

 */

class gri_mmse_fir_interpolator_cc {

public:

  gri_mmse_fir_interpolator_cc ();

  ~gri_mmse_fir_interpolator_cc ();

  unsigned ntaps () const;

  unsigned nsteps () const;

  /*!

   * \brief compute a single interpolated output value.

   *

   * \p input must have ntaps() valid entries and be 8-byte aligned.

   * input[0] .. input[ntaps() - 1] are referenced to compute the output value.

   * \throws std::invalid_argument if input is not 8-byte aligned.

   *

   * \p mu must be in the range [0, 1] and specifies the fractional delay.

   *

   * \returns the interpolated input value.

   */

  gr_complex interpolate (const gr_complex input[], float mu);

protected:

  std::vector<gr_fir_ccf *>        filters;

};

#endif /* _GRI_MMSE_FIR_INTERPOLATOR_CC_H_ */