Transfer Function Library

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Overview

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This is C++ library which provides set of opertions on transfer functions. Those are operations like:

• calculate transfer functions of series/parrallel/feedback connection,
• discretize transfer function,
• analyse stability,
• calculate step/impulse response,
• calculate Bode/Nyquist plot,
• simulation of discrete transfer function.

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Development enironment

• Programming language:
  • C++20 standard - g++10.3 or higher
• Build system:
  • CMake 3.12 or higher
• Static code analysis:
  • cppcheck 1.90 or higher
  • pygments
• Test coverage:
  • gcov
  • lcov
• Coding style check
  • cpplint 1.5.5 or higher

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Usage

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Create Transfer Function

// Prepare num and den of TF, where tf_core::TransferFunction::CoefficientsVector = std::vector<float>
tf_core::TransferFunction::CoefficientsVector num = {1.0f};
tf_core::TransferFunction::CoefficientsVector den = {1.0f, 2.0f};

auto tf = tf_core::TransferFunction(num, den);

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Connect Transfer Functions

• Parallel

// Prepare TF
auto G = tf_core::TransferFunction(num_g, den_g);
auto H = tf_core::TransferFunction(num_h, den_h);

auto parallel_connection = G + H;
//Or
auto parallel_connection = G.Parallel(H);

• Serial

// Prepare TF
auto G = tf_core::TransferFunction(num_g, den_g);
auto H = tf_core::TransferFunction(num_h, den_h);

auto serial_connection = G * H;
//Or
auto serial_connection = G.Serial(H);

• Feedback

// Prepare TF
auto G = tf_core::TransferFunction(num_g, den_g);
auto H = tf_core::TransferFunction(num_h, den_h);

auto feedback_connection = G.Feedback(H);
// Or positive feedback
auto feedback_connection = G.Feedback(H, true);

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Discretize

//Define TF
auto G = tf_core::TransferFunction(num_g, den_g);

// Define discretization time and method
float sampling_time = 0.01f;
auto discretization_method = tf_core::DiscretizationMethod::Tustin;

// Discretize
auto discrete_G = G.Discretize(sampling_time, discretization_method);

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Simulate

//Define TF
auto G = tf_core::TransferFunction(num_g, den_g);

// Define signal, where using Signal = std::vector<float>;
Signal input_signal = {...};

// Simulate
auto output_signal = G.Simulate(input_signal);