sdrangel/wdsp/anf.cpp

/*  anf.c

This file is part of a program that implements a Software-Defined Radio.

Copyright (C) 2012, 2013 Warren Pratt, NR0V
Copyright (C) 2024 Edouard Griffiths, F4EXB Adapted to SDRangel

This program 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
of the License, or (at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

The author can be reached by email at

warren@wpratt.com

*/

#include "comm.hpp"
#include "amd.hpp"
#include "snba.hpp"
#include "emnr.hpp"
#include "anr.hpp"
#include "anf.hpp"
#include "bandpass.hpp"
#include "RXA.hpp"

namespace WDSP {

ANF::ANF(
    int _run,
    int _position,
    int _buff_size,
    float *_in_buff,
    float *_out_buff,
    int _dline_size,
    int _n_taps,
    int _delay,
    double _two_mu,
    double _gamma,
    double _lidx,
    double _lidx_min,
    double _lidx_max,
    double _ngamma,
    double _den_mult,
    double _lincr,
    double _ldecr
)
{
    run = _run;
    position = _position;
    buff_size = _buff_size;
    in_buff = _in_buff;
    out_buff = _out_buff;
    dline_size = _dline_size;
    mask = _dline_size - 1;
    n_taps = _n_taps;
    delay = _delay;
    two_mu = _two_mu;
    gamma = _gamma;
    in_idx = 0;
    lidx = _lidx;
    lidx_min = _lidx_min;
    lidx_max = _lidx_max;
    ngamma = _ngamma;
    den_mult = _den_mult;
    lincr = _lincr;
    ldecr = _ldecr;

    std::fill(d.begin(), d.end(), 0);
    std::fill(w.begin(), w.end(), 0);
}

void ANF::execute(int _position)
{
    int i, j, idx;
    double c0, c1;
    double y, error, sigma, inv_sigp;
    double nel, nev;

    if (run && (position == _position))
    {
        for (i = 0; i < buff_size; i++)
        {
            d[in_idx] = in_buff[2 * i + 0];

            y = 0;
            sigma = 0;

            for (j = 0; j < n_taps; j++)
            {
                idx = (in_idx + j + delay) & mask;
                y += w[j] * d[idx];
                sigma += d[idx] * d[idx];
            }

            inv_sigp = 1.0 / (sigma + 1e-10);
            error = d[in_idx] - y;

            out_buff[2 * i + 0] = error;
            out_buff[2 * i + 1] = 0.0;

            if ((nel = error * (1.0 - two_mu * sigma * inv_sigp)) < 0.0)
                nel = -nel;

            if ((nev = d[in_idx] - (1.0 - two_mu * ngamma) * y - two_mu * error * sigma * inv_sigp) < 0.0)
                nev = -nev;

            if (nev < nel)
            {
                if ((lidx += lincr) > lidx_max) lidx = lidx_max;
            }
            else
            {
                if ((lidx -= ldecr) < lidx_min) lidx = lidx_min;
            }

            ngamma = gamma * (lidx * lidx) * (lidx * lidx) * den_mult;

            c0 = 1.0 - two_mu * ngamma;
            c1 = two_mu * error * inv_sigp;

            for (j = 0; j < n_taps; j++)
            {
                idx = (in_idx + j + delay) & mask;
                w[j] = c0 * w[j] + c1 * d[idx];
            }

            in_idx = (in_idx + mask) & mask;
        }
    }
    else if (in_buff != out_buff)
    {
        std::copy(in_buff, in_buff + buff_size * 2, out_buff);
    }
}

void ANF::flush()
{
    std::fill(d.begin(), d.end(), 0);
    std::fill(w.begin(), w.end(), 0);
    in_idx = 0;
}

void ANF::setBuffers(float* _in, float* _out)
{
    in_buff = _in;
    out_buff = _out;
}

void ANF::setSamplerate(int)
{
    flush();
}

void ANF::setSize(int _size)
{
    buff_size = _size;
    flush();
}

/********************************************************************************************************
*                                                                                                       *
*                                           RXA Properties                                              *
*                                                                                                       *
********************************************************************************************************/

void ANF::setVals(int _taps, int _delay, double _gain, double _leakage)
{
    n_taps = _taps;
    delay = _delay;
    two_mu = _gain;          //try two_mu = 1e-4
    gamma = _leakage;        //try gamma = 0.10
    flush();
}

void ANF::setTaps(int _taps)
{
    n_taps = _taps;
    flush();
}

void ANF::setDelay(int _delay)
{
    delay = _delay;
    flush();
}

void ANF::setGain(double _gain)
{
    two_mu = _gain;
    flush();
}

void ANF::setLeakage(double _leakage)
{
    gamma = _leakage;
    flush();
}

} // namespace WDSP