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matplotlib.pyplot.magnitude_spectrum(x, Fs=None, Fc=None, window=None, pad_to=None, sides=None, scale=None, *, data=None, **kwargs)[source]

Plot the magnitude spectrum.

Call signature:

magnitude_spectrum(x, Fs=2, Fc=0,  window=mlab.window_hanning,
                   pad_to=None, sides='default', **kwargs)

Compute the magnitude spectrum of x. Data is padded to a length of pad_to and the windowing function window is applied to the signal.

x : 1-D array or sequence

Array or sequence containing the data.

Fs : scalar

The sampling frequency (samples per time unit). It is used to calculate the Fourier frequencies, freqs, in cycles per time unit. The default value is 2.

window : callable or ndarray

A function or a vector of length NFFT. To create window vectors see window_hanning(), window_none(), numpy.blackman(), numpy.hamming(), numpy.bartlett(), scipy.signal(), scipy.signal.get_window(), etc. The default is window_hanning(). If a function is passed as the argument, it must take a data segment as an argument and return the windowed version of the segment.

sides : {'default', 'onesided', 'twosided'}

Specifies which sides of the spectrum to return. Default gives the default behavior, which returns one-sided for real data and both for complex data. 'onesided' forces the return of a one-sided spectrum, while 'twosided' forces two-sided.

pad_to : int

The number of points to which the data segment is padded when performing the FFT. While not increasing the actual resolution of the spectrum (the minimum distance between resolvable peaks), this can give more points in the plot, allowing for more detail. This corresponds to the n parameter in the call to fft(). The default is None, which sets pad_to equal to the length of the input signal (i.e. no padding).

scale : {'default', 'linear', 'dB'}

The scaling of the values in the spec. 'linear' is no scaling. 'dB' returns the values in dB scale, i.e., the dB amplitude (20 * log10). 'default' is 'linear'.

Fc : int

The center frequency of x (defaults to 0), which offsets the x extents of the plot to reflect the frequency range used when a signal is acquired and then filtered and downsampled to baseband.

spectrum : 1-D array

The values for the magnitude spectrum before scaling (real valued).

freqs : 1-D array

The frequencies corresponding to the elements in spectrum.

line : a Line2D instance

The line created by this function.

Other Parameters:
**kwargs :

Keyword arguments control the Line2D properties:

Property Description
agg_filter a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array
alpha float
animated bool
antialiased bool
clip_box Bbox
clip_on bool
clip_path [(Path, Transform) | Patch | None]
color color
contains callable
dash_capstyle {'butt', 'round', 'projecting'}
dash_joinstyle {'miter', 'round', 'bevel'}
dashes sequence of floats (on/off ink in points) or (None, None)
drawstyle {'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'}
figure Figure
fillstyle {'full', 'left', 'right', 'bottom', 'top', 'none'}
gid str
in_layout bool
label object
linestyle {'-', '--', '-.', ':', '', (offset, on-off-seq), ...}
linewidth float
marker unknown
markeredgecolor color
markeredgewidth float
markerfacecolor color
markerfacecoloralt color
markersize float
markevery unknown
path_effects AbstractPathEffect
picker float or callable[[Artist, Event], Tuple[bool, dict]]
pickradius float
rasterized bool or None
sketch_params (scale: float, length: float, randomness: float)
snap bool or None
solid_capstyle {'butt', 'round', 'projecting'}
solid_joinstyle {'miter', 'round', 'bevel'}
transform matplotlib.transforms.Transform
url str
visible bool
xdata 1D array
ydata 1D array
zorder float

See also

psd() plots the power spectral density.`.
angle_spectrum() plots the angles of the corresponding frequencies.
phase_spectrum() plots the phase (unwrapped angle) of the corresponding frequencies.
specgram() can plot the magnitude spectrum of segments within the signal in a colormap.



In addition to the above described arguments, this function can take a data keyword argument. If such a data argument is given, the following arguments are replaced by data[<arg>]:

  • All arguments with the following names: 'x'.

Objects passed as data must support item access (data[<arg>]) and membership test (<arg> in data).