spectrum_plot¶

MATLAB equivalent: sidSpectrumPlot

spectrum_plot ¶

Power spectrum plot with confidence bands.

spectrum_plot ¶

spectrum_plot(result: FreqResult, *, confidence: float = 3.0, frequency_unit: str = 'rad/s', color: str | tuple = None, line_width: float = 1.5, ax=None) -> dict

Power spectrum plot with shaded confidence bands.

This is the Python port of sidSpectrumPlot.m.

Plots the noise spectrum (or output spectrum in time-series mode) in dB with an optional shaded +/- confidence-sigma band.

Parameters:

Name	Type	Description	Default
`result`	`FreqResult`	Result struct returned by :func:`sid.freq_bt`, :func:`sid.freq_etfe`, or :func:`sid.freq_btfdr`.	required
`confidence`	`float`	Number of standard deviations for the shaded confidence band. Set to `0` to hide the bands. Default is `3.0`.	`3.0`
`frequency_unit`	`str`	`'rad/s'` (default) or `'Hz'`.	`'rad/s'`
`color`	`str or tuple`	Line and fill colour. Default is `'#D95319'` (MATLAB orange).	`None`
`line_width`	`float`	Line width. Default is `1.5`.	`1.5`
`ax`	`matplotlib Axes or None`	Existing axes to plot into. If `None`, a new figure is created.	`None`

Returns:

Type	Description
`dict`	Dictionary with the following keys: `'fig'` -- matplotlib Figure handle. `'ax'` -- Axes handle. `'line'` -- Line2D handle for the spectrum trace.

Examples:

>>> import numpy as np
>>> import sid
>>> y = np.random.randn(500)
>>> result = sid.freq_bt(y, None)
>>> h = sid.spectrum_plot(result, confidence=3)

Notes

Specification: (Spectrum plotting -- not yet in SPEC.md)

For MIMO systems only the first output channel is plotted.