kopia lustrzana https://github.com/vsamy/DiFipp
74 wiersze
2.7 KiB
C++
74 wiersze
2.7 KiB
C++
#pragma once
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#include "type_checks.h"
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#include "typedefs.h"
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namespace fratio {
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/*! \brief Transform an analog signal to a discrete signal and vice versa.
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*
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* \see https://en.wikipedia.org/wiki/Bilinear_transform
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* \tparam T Floating (complex) types.
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*/
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template <typename T>
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struct BilinearTransform {
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using SubType = internal::complex_sub_type_t<T>; /*!< Sub-type of the complex if T is complex, T otherwise */
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static_assert(std::is_floating_point<SubType>::value, "This struct can only accept floating point types (real and complex).");
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/*! \brief Transformation from analog to discrete.
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* \param fs Sampling frequency.
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* \param sPlanePole Analog data.
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* \param[out] zPlanePole Resulting discrete data.
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*/
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static void SToZ(SubType fs, const T& sPlanePole, T& zPlanePole);
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/*! \brief Transformation from analog to discrete.
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* \param fs Sampling frequency.
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* \param sPlanePole Analog signal.
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* \param[out] zPlanePole Resulting discrete signal.
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*/
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static void SToZ(SubType fs, const vectX_t<T>& sPlanePoles, Eigen::Ref<vectX_t<T>>& zPlanePoles); // Can be optimized maybe
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/*! \brief Transformation from discrete to analog.
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* \param fs Sampling frequency.
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* \param zPlanePole Discrete data.
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* \param[out] sPlanePole Resulting analog data.
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*/
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static void ZToS(SubType fs, const T& zPlanePole, T& sPlanePole);
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/*! \brief Transformation from discrete to analog.
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* \param fs Sampling frequency.
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* \param zPlanePole Discrete signal.
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* \param[out] sPlanePole Resulting analog signal.
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*/
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static void ZToS(SubType fs, const vectX_t<T>& zPlanePoles, Eigen::Ref<vectX_t<T>>& sPlanePoles); // Can be optimized maybe
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};
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template <typename T>
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void BilinearTransform<T>::SToZ(SubType fs, const T& sPlanePole, T& zPlanePole)
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{
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T scalePole = sPlanePole / (2 * fs);
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zPlanePole = (T(1) + scalePole) / (T(1) - scalePole);
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}
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template <typename T>
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void BilinearTransform<T>::SToZ(SubType fs, const vectX_t<T>& sPlanePoles, Eigen::Ref<vectX_t<T>>& zPlanePoles)
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{
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assert(sPlanePoles.size() == zPlanePoles.size());
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for (Eigen::Index k = 0; k < sPlanePoles.size(); ++k)
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SToZ(fs, sPlanePoles(k), zPlanePoles(k));
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}
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template <typename T>
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void BilinearTransform<T>::ZToS(SubType fs, const T& zPlanePole, T& sPlanePole)
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{
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T invPole = T(1) / zPlanePole;
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sPlanePole = 2 * fs * (T(1) - invPole) / (T(1) + invPole);
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}
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template <typename T>
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void BilinearTransform<T>::ZToS(SubType fs, const vectX_t<T>& zPlanePoles, Eigen::Ref<vectX_t<T>>& sPlanePoles)
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{
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assert(zPlanePoles.size() == sPlanePoles.size());
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for (Eigen::Index k = 0; k < sPlanePoles.size(); ++k)
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ZToS(fs, zPlanePoles(k), sPlanePoles(k));
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}
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} // namespace fratio
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