matplotlib.pyplot.magnitude_spectrum#

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.

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.

Parameters
x1-D array or sequence

Array or sequence containing the data.

Fsfloat, default: 2

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

windowcallable or ndarray, default: window_hanning

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. 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'}, optional

Which sides of the spectrum to return. 'default' is one-sided for real data and two-sided for complex data. 'onesided' forces the return of a one-sided spectrum, while 'twosided' forces two-sided.

pad_toint, optional

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'.

Fcint, default: 0

The center frequency of x, 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.

Returns
spectrum1-D array

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

freqs1-D array

The frequencies corresponding to the elements in spectrum.

lineLine2D

The line created by this function.

Other Parameters
dataindexable object, optional

If given, the following parameters also accept a string s, which is interpreted as data[s] (unless this raises an exception):

x

**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

scalar or None

animated

bool

antialiased or aa

bool

clip_box

Bbox

clip_on

bool

clip_path

Patch or (Path, Transform) or None

color or c

color

dash_capstyle

CapStyle or {'butt', 'projecting', 'round'}

dash_joinstyle

JoinStyle or {'miter', 'round', 'bevel'}

dashes

sequence of floats (on/off ink in points) or (None, None)

data

(2, N) array or two 1D arrays

drawstyle or ds

{'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'}, default: 'default'

figure

Figure

fillstyle

{'full', 'left', 'right', 'bottom', 'top', 'none'}

gid

str

in_layout

bool

label

object

linestyle or ls

{'-', '--', '-.', ':', '', (offset, on-off-seq), ...}

linewidth or lw

float

marker

marker style string, Path or MarkerStyle

markeredgecolor or mec

color

markeredgewidth or mew

float

markerfacecolor or mfc

color

markerfacecoloralt or mfcalt

color

markersize or ms

float

markevery

None or int or (int, int) or slice or list[int] or float or (float, float) or list[bool]

mouseover

bool

path_effects

AbstractPathEffect

picker

float or callable[[Artist, Event], tuple[bool, dict]]

pickradius

float

rasterized

bool

sketch_params

(scale: float, length: float, randomness: float)

snap

bool or None

solid_capstyle

CapStyle or {'butt', 'projecting', 'round'}

solid_joinstyle

JoinStyle or {'miter', 'round', 'bevel'}

transform

unknown

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.