filters.hpp

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//
// Copyright 2015 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
 
#pragma once
 
#include <uhd/config.hpp>
#include <uhd/utils/log.hpp>
#include <stdint.h>
#include <cstddef>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
 
namespace uhd {
 
class UHD_API filter_info_base
{
public:
    typedef std::shared_ptr<filter_info_base> sptr;
    enum filter_type { ANALOG_LOW_PASS, ANALOG_BAND_PASS, DIGITAL_I16, DIGITAL_FIR_I16 };
 
    filter_info_base(filter_type type, bool bypass, size_t position_index)
        : _type(type), _bypass(bypass), _position_index(position_index)
    {
        // NOP
    }
 
    UHD_INLINE virtual bool is_bypassed()
    {
        return _bypass;
    }
 
    UHD_INLINE filter_type get_type()
    {
        return _type;
    }
 
    virtual ~filter_info_base()
    {
        // NOP
    }
 
    virtual std::string to_pp_string();
 
protected:
    filter_type _type;
    bool _bypass;
    size_t _position_index;
};
 
UHD_API_HEADER std::ostream& operator<<(std::ostream& os, filter_info_base& f);
 
class UHD_API analog_filter_base : public filter_info_base
{
    std::string _analog_type;
 
public:
    typedef std::shared_ptr<analog_filter_base> sptr;
    analog_filter_base(filter_type type,
        bool bypass,
        size_t position_index,
        const std::string& analog_type)
        : filter_info_base(type, bypass, position_index), _analog_type(analog_type)
    {
        // NOP
    }
 
    UHD_INLINE const std::string& get_analog_type()
    {
        return _analog_type;
    }
 
    std::string to_pp_string() override;
};
 
class UHD_API analog_filter_lp : public analog_filter_base
{
    double _cutoff;
    double _rolloff;
 
public:
    typedef std::shared_ptr<analog_filter_lp> sptr;
    analog_filter_lp(filter_type type,
        bool bypass,
        size_t position_index,
        const std::string& analog_type,
        double cutoff,
        double rolloff)
        : analog_filter_base(type, bypass, position_index, analog_type)
        , _cutoff(cutoff)
        , _rolloff(rolloff)
    {
        // NOP
    }
 
    UHD_INLINE double get_cutoff()
    {
        return _cutoff;
    }
 
    UHD_INLINE double get_rolloff()
    {
        return _rolloff;
    }
 
    UHD_INLINE void set_cutoff(const double cutoff)
    {
        _cutoff = cutoff;
    }
 
    std::string to_pp_string() override;
};
 
template <typename tap_t>
class UHD_API_HEADER digital_filter_base : public filter_info_base
{
protected:
    double _rate;
    uint32_t _interpolation;
    uint32_t _decimation;
    tap_t _tap_full_scale;
    uint32_t _max_num_taps;
    std::vector<tap_t> _taps;
 
public:
    typedef std::shared_ptr<digital_filter_base> sptr;
    digital_filter_base(filter_type type,
        bool bypass,
        size_t position_index,
        double rate,
        uint32_t interpolation,
        uint32_t decimation,
        tap_t tap_full_scale,
        uint32_t max_num_taps,
        const std::vector<tap_t>& taps)
        : filter_info_base(type, bypass, position_index)
        , _rate(rate)
        , _interpolation(interpolation)
        , _decimation(decimation)
        , _tap_full_scale(tap_full_scale)
        , _max_num_taps(max_num_taps)
        , _taps(taps)
    {
        // NOP
    }
 
    UHD_INLINE double get_output_rate()
    {
        return (_bypass ? _rate : (_rate / _decimation * _interpolation));
    }
 
    UHD_INLINE double get_input_rate()
    {
        return _rate;
    }
 
    UHD_INLINE uint32_t get_interpolation()
    {
        return _interpolation;
    }
 
    UHD_INLINE uint32_t get_decimation()
    {
        return _decimation;
    }
 
    UHD_INLINE uint32_t get_tap_full_scale()
    {
        return _tap_full_scale;
    }
 
    UHD_INLINE std::vector<tap_t>& get_taps()
    {
        return _taps;
    }
 
    std::string to_pp_string() override
    {
        std::ostringstream os;
        os << filter_info_base::to_pp_string() << "\t[digital_filter_base]" << std::endl
           << "\tinput rate: " << _rate << std::endl
           << "\tinterpolation: " << _interpolation << std::endl
           << "\tdecimation: " << _decimation << std::endl
           << "\tfull-scale: " << _tap_full_scale << std::endl
           << "\tmax num taps: " << _max_num_taps << std::endl
           << "\ttaps: " << std::endl;
 
        os << "\t\t";
        for (size_t i = 0; i < _taps.size(); i++) {
            os << "(tap " << i << ": " << _taps[i] << ")";
            if (((i % 10) == 0) && (i != 0)) {
                os << std::endl << "\t\t";
            }
        }
        os << std::endl;
        return std::string(os.str());
    }
};
 
template <typename tap_t>
class UHD_API_HEADER digital_filter_fir : public digital_filter_base<tap_t>
{
public:
    typedef std::shared_ptr<digital_filter_fir<tap_t>> sptr;
 
    digital_filter_fir(filter_info_base::filter_type type,
        bool bypass,
        size_t position_index,
        double rate,
        uint32_t interpolation,
        uint32_t decimation,
        tap_t tap_bit_width,
        uint32_t max_num_taps,
        const std::vector<tap_t>& taps)
        : digital_filter_base<tap_t>(type,
            bypass,
            position_index,
            rate,
            interpolation,
            decimation,
            tap_bit_width,
            max_num_taps,
            taps)
    {
        // NOP
    }
 
    void set_taps(const std::vector<tap_t>& taps)
    {
        std::size_t num_taps = taps.size();
        if (num_taps < this->_max_num_taps) {
            UHD_LOGGER_WARNING("FILTERS") << "digital_filter_fir::set_taps not enough "
                                             "coefficients. Appending zeros";
            std::vector<tap_t> coeffs;
            for (size_t i = 0; i < this->_max_num_taps; i++) {
                if (i < num_taps) {
                    coeffs.push_back(taps[i]);
                } else {
                    coeffs.push_back(0);
                }
            }
            this->_taps = coeffs;
        } else {
            this->_taps = taps;
        }
    }
};
 
} // namespace uhd