spectral_metrics.hpp

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// toolboxes/signal/include/nk/signal/spectral_analysis/spectral_metrics.hpp
//
// Spectral measurement functions.
 
#pragma once
 
#include <memory_resource>
#include <tuple>
#include <nk/value/value.hpp>
 
namespace nk::signal {

 


Value bandpower(const Value &x,
                const Value &fs = Value::Empty,
                const Value &freqrange = Value::Empty,
                std::pmr::memory_resource *mr = nullptr);

Value meanfreq(const Value &x, const Value &fs = Value::Empty,
               std::pmr::memory_resource *mr = nullptr);

Value medfreq(const Value &x, const Value &fs = Value::Empty,
              std::pmr::memory_resource *mr = nullptr);

Value enbw(const Value &window, const Value &fs = Value::Empty,
           std::pmr::memory_resource *mr = nullptr);

std::tuple<Value, Value, Value, Value>
obw(const Value &x, const Value &fs = Value::Empty,
    double p = 0.99,
    std::pmr::memory_resource *mr = nullptr);

Value powerbw(const Value &x, const Value &fs = Value::Empty,
              std::pmr::memory_resource *mr = nullptr);

Value spectralcrest(const Value &x, const Value &fs = Value::Empty,
                    std::pmr::memory_resource *mr = nullptr);

Value spectralflatness(const Value &x, const Value &fs = Value::Empty,
                       std::pmr::memory_resource *mr = nullptr);

Value spectralentropy(const Value &x, const Value &fs = Value::Empty,
                      std::pmr::memory_resource *mr = nullptr);

Value spectralkurtosis(const Value &x, const Value &fs = Value::Empty,
                       std::pmr::memory_resource *mr = nullptr);

Value spectralskewness(const Value &x, const Value &fs = Value::Empty,
                       std::pmr::memory_resource *mr = nullptr);
 
// ─────────────────────────────────────────────────────────────────────
// Harmonic / SNR family
//
// All compute fundamental power and noise / harmonic power on the
// periodogram, then return the ratio in dB. Default behaviour treats
// the dominant peak (excluding DC) as the fundamental and uses N = 6
// harmonics.
// ─────────────────────────────────────────────────────────────────────

Value snr(const Value &x, const Value &fs = Value::Empty,
          std::pmr::memory_resource *mr = nullptr);

Value sinad(const Value &x, const Value &fs = Value::Empty,
            std::pmr::memory_resource *mr = nullptr);

Value thd(const Value &x, const Value &fs = Value::Empty,
          std::pmr::memory_resource *mr = nullptr);

Value sfdr(const Value &x, const Value &fs = Value::Empty,
           std::pmr::memory_resource *mr = nullptr);
 
// ─────────────────────────────────────────────────────────────────────
// Analytic-signal-based instantaneous metrics
// ─────────────────────────────────────────────────────────────────────

Value instfreq(const Value &x, const Value &fs = Value::Empty,
               std::pmr::memory_resource *mr = nullptr);

Value instbw(const Value &x, const Value &fs = Value::Empty,
             std::pmr::memory_resource *mr = nullptr);
 

} // namespace nk::signal