lpf_1.h

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 * @details
 * This file defines the @ref filter::low_pass::LPF_1 class, which
 * implements a first-order low-pass filter for attenuating high-frequency
 * components of an input signal.
 *
 * The filter is parameterized by its cutoff frequency and sampling time.
 * The implementation maintains the previous output value as its internal
 * state.
 *
 * The class is templated to support different numeric types such as
 * @c float and @c double.
 *
 * @tparam T Numeric data type used for the filter calculations.
 *
 * @author Abhinay Kumar
 * @version 1.0.0
 *
 * @copyright
 * Copyright (c) 2026 Abhinay Kumar
 */
 
#ifndef FILTER_LPF_1
#define FILTER_LPF_1
 
namespace filter
{
 
    namespace low_pass
    {

         * @class LPF_1
         * @brief First-order low-pass filter.
         *
         * @details
         * The LPF_1 class implements a discrete-time first-order
         * low-pass filter.
         *
         * The filter attenuates high-frequency components while allowing
         * low-frequency components of the input signal to pass.
         *
         * The filter can be configured using the cutoff frequency and
         * sampling time. Alternatively, individual filter parameters such
         * as the cutoff frequency, time constant, sampling time, and
         * filter coefficient can be configured directly.
         *
         * @tparam T Numeric data type used for the filter.
         *
         * @par Example
         * @code{.cpp}
         * filter::low_pass::LPF_1<double> filter;
         *
         * filter.config(10.0, 0.001);
         *
         * double output = filter.update(input);
         * @endcode
         */
        template <typename T>
        class LPF_1
        {
        public:

             * their default values.
             */
            LPF_1();


             *
             * @param[in] fc_ Cutoff frequency of the filter in Hz.
             * @param[in] dt_ Sampling time of the filter in seconds.
             *
             * @details
             * Configures the filter using the cutoff frequency and
             * sampling time.
             */
            void config(T fc_, T dt_);


             *
             * @param[in] fc_ Cutoff frequency of the filter in Hz.
             * @param[in] dt_ Sampling time of the filter in seconds.
             *
             * @details
             * Updates the cutoff frequency and sampling time used by
             * the filter.
             */
            void set_param(T fc_, T dt_);


            T update(T x_k);

            void reset();

            void set_fc(T fc_);

            void set_tau(T tau_);

            void set_dt(T dt_);

            void set_alpha(T alpha_);

            T get_fc();

            T get_tau();

            T get_dt();

            T get_alpha();

            T get_fs();
 
        private:
            T fc = 0.0;

            T tau = 0.0;

            T dt = 0.0;

            T alpha = 0.0;

            T y_k_1 = 0.0;

            bool start = false;
        };
 
#include "../../src/low_pass/lpf_1.tpp"
    } // namespace low_pass
 
} // namespace filter
 
#endif // FILTER_LPF_1