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Plot Frequency Spectrum ​

This demo shows how to plot power spectra from SpectrumData objects.

When to Use plot_frequency_spectrum vs plot_channel_spectrum? ​

FunctionInputBest For
plot_channel_spectrum(dat)Raw/preprocessed dataQuick interactive inspection with Welch's method
plot_frequency_spectrum(spectrum)SpectrumDataPlotting pre-computed spectra with full control

Key Parameters ​

ParameterDefaultDescription
channel_selectionchannels()Which channels to plot
x_scale:linear:linear or :log10
y_scale:linear:linear or :log10
unit:linear:linear (μV²/Hz) or :dB
max_freqnothingMaximum frequency to display
show_legendtrueShow channel name legend

What You'll Learn ​

  1. Plotting spectra for all or selected channels

  2. Switching between linear and log scales

  3. Using decibel units

  4. Limiting the frequency range

Code Examples ​

Show Code
julia
# Demo: Plotting Power Spectrum from SpectrumData
# Shows how to visualise frequency spectra computed by freq_spectrum,
# with options for channel selection, axis scaling, and dB units.

using EegFun
# Note: EegFun.example_path() resolves bundled example data paths.
# When using your own data, simply pass the file path directly, e.g.:
# dat = EegFun.read_raw_data("/path/to/your/data.bdf")

#######################################################################
# LOAD DATA
#######################################################################

dat = EegFun.read_raw_data(EegFun.example_path("data/bdf/example1.bdf"))
layout = EegFun.read_layout(EegFun.example_path("layouts/biosemi/biosemi72.csv"))
EegFun.polar_to_cartesian_xy!(layout)
dat = EegFun.create_eegfun_data(dat, layout)

EegFun.highpass_filter!(dat, 0.5)

#######################################################################
# COMPUTE SPECTRUM
#######################################################################

spectrum = EegFun.freq_spectrum(dat)

#######################################################################
# BASIC SPECTRUM PLOT — ALL CHANNELS
#######################################################################

EegFun.plot_frequency_spectrum(spectrum)

#######################################################################
# SINGLE CHANNEL
#######################################################################

EegFun.plot_frequency_spectrum(spectrum, channel_selection = EegFun.channels(:Cz))

#######################################################################
# LOG SCALE AXES
#######################################################################

EegFun.plot_frequency_spectrum(spectrum, channel_selection = EegFun.channels(:Cz), x_scale = :log10, y_scale = :log10)

#######################################################################
# DECIBEL UNITS
#######################################################################

EegFun.plot_frequency_spectrum(spectrum, channel_selection = EegFun.channels([:Cz, :Pz]), unit = :dB, max_freq = 100.0)

#######################################################################
# CUSTOM STYLING
#######################################################################

EegFun.plot_frequency_spectrum(
    spectrum,
    channel_selection = EegFun.channels([:Cz, :Oz]),
    linewidth = 3,
    line_alpha = 0.6,
    title = "Power Spectrum",
)

See Also ​