scicpp::plots::csd, scicpp::plots::psd¶

Defined in header <scicpp/plots.hpp>

Plot the spectral density.

Return a sciplot::Plot2D object.

Plot scale options:

enum SpectrumPlotScale : int {
    LINEAR,  // Linear scale
    DECIBEL  // Logarithm scale (dB)
};

template<signal::SpectrumScaling scaling = signal::DENSITY, SpectrumPlotScale plot_scale = DECIBEL, typename Array1, typename Array2, typename T = double> auto csd(signal::Spectrum<T> spec, const Array1 &x, const Array2 &y)¶

Plot the cross-spectral density between arrays x and y using a given Spectrum analyzer spec.

template<signal::SpectrumScaling scaling = signal::DENSITY, SpectrumPlotScale plot_scale = DECIBEL, typename Array, typename T = double> auto psd(signal::Spectrum<T> spec, const Array &x)¶

Plot the power spectral density of array x using a given Spectrum analyzer spec.

Example¶

#include <scicpp/core.hpp>
#include <scicpp/plots.hpp>
#include <scicpp/signal.hpp>

namespace sci = scicpp;
namespace plt = sci::plots;

int main() {
    using namespace sci::operators;
    using namespace sci::units::literals;

    const auto N = 1E3;
    const auto fs = 1E2;
    const auto omega0 = 2_rad * sci::pi<double> * 10.0;

    const auto t = sci::arange(0.0, N) / fs;

    // Colored noise
    const auto nse1 = sci::random::randn<double, 2813981405>(t.size() / 2);
    const auto nse2 = sci::random::randn<double, 4130028572>(t.size() / 2);
    const auto r = sci::exp(-sci::arange(0.0, N / 2 + 1) / fs / 0.05);
    const auto cnse1 = sci::signal::fftconvolve(nse1, r) / fs;
    const auto cnse2 = sci::signal::fftconvolve(nse2, r) / fs;

    const auto x = 0.01 * sci::sin(omega0 * t) + cnse1;
    const auto y = 0.01 * sci::sin(omega0 * t) + cnse2;

    auto spec = sci::signal::Spectrum{}.fs(fs).window(
        sci::signal::windows::Hamming, t.size());

    // Plot csd
    auto plot1 = plt::csd(spec, x, y);
    plot1.size(1000, 500);
    plot1.xlabel("FREQUENCY (Hz)");
    plot1.ylabel("CSD (dB / Hz)");
    plot1.show();

    // Plot psd
    auto plot2 = plt::psd(spec, x);
    plot2.size(1000, 500);
    plot2.xlabel("FREQUENCY (Hz)");
    plot2.ylabel("PSD (dB / Hz)");
    plot2.show();
}

See also

Matplotlib documentation

Matplotlib demo