conversions_extras.hpp

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// toolboxes/signal/include/nk/signal/filter_implementation/conversions_extras.hpp
//
// Additional filter-form conversions: sos ↔ tf, sos ↔ zpk, tf ↔ ss,
// sos ↔ ss, zpk ↔ ss, plus tf2zpk (gain-explicit alias of tf2zp).
//
// State-space form is the 4-tuple (A, B, C, D):
//   A : N×N state-transition matrix
//   B : N×1 input vector
//   C : 1×N output vector
//   D : 1×1 direct feed-through scalar
// Single-input single-output controllable canonical form is used.
 
#pragma once
 
#include <memory_resource>
#include <nk/value/value.hpp>
 
#include <tuple>
 
namespace nk::signal {

 

std::tuple<Value, Value>
sos2tf(const Value &                sos,
       double                       g  = 1.0,
       std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, double>
sos2zp(const Value &                sos,
       double                       g  = 1.0,
       std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, double>
tf2zpk(const Value &                b,
       const Value &                a,
       std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, double>
ctf2zp(const Value &                NUM,
       const Value &                DEN,
       const Value &                SV = Value::Empty,
       std::pmr::memory_resource *  mr = nullptr);

Value scaleFilterSections(const Value &                CTFNum,
                          const Value &                SV,
                          std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, Value, Value>
tf2ss(const Value &                b,
      const Value &                a,
      std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value>
ss2tf(const Value &                A,
      const Value &                B,
      const Value &                C,
      double                       D  = 0.0,
      std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, double>
ss2zp(const Value &A, const Value &B, const Value &C, double D = 0.0,
      std::pmr::memory_resource *mr = nullptr);

std::tuple<Value, Value, Value, Value>
zp2ss(const Value &                z,
      const Value &                p,
      double                       k,
      std::pmr::memory_resource *  mr = nullptr);

std::tuple<Value, Value, Value, Value>
sos2ss(const Value &                sos,
       double                       g  = 1.0,
       std::pmr::memory_resource *  mr = nullptr);

Value ss2sos(const Value &A, const Value &B, const Value &C, double D = 0.0,
             std::pmr::memory_resource *mr = nullptr);
 

} // namespace nk::signal