Matplotlib.axes.Axes.magnitude_spectrum() in Python

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Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. The Axes Class contains most of the figure elements: Axis, Tick, Line2D, Text, Polygon, etc., and sets the coordinate system. And the instances of Axes supports callbacks through a callbacks attribute.

matplotlib.axes.Axes.magnitude_spectrum() Function

The Axes.magnitude_spectrum() function in axes module of matplotlib library is used to plot the magnitude spectrum.

Syntax: Axes.magnitude_spectrum(self, x, Fs=None, Fc=None, window=None, pad_to=None, sides=None, *, data=None, **kwargs)

Parameters: This method accept the following parameters that are described below:

x: This parameter is a sequence of data.

Fs : This parameter is a scalar. Its default value is 2.

window: This parameter take a data segment as an argument and return the windowed version of the segment. Its default value is window_hanning()

sides: This parameter specifies which sides of the spectrum to return. This can have following values : ‘default’, ‘onesided’ and ‘twosided’.

pad_to : This parameter contains the integer value to which the data segment is padded.

Fc: This parameter is also contains the integer value to offsets the x extents of the plot to reflect the frequency range. Its default value is 0

Returns: This returns the following:

spectrum :This returns the angle spectrum in radians.

freqs :This returns the frequencies corresponding to the elements in spectrum.

line : This returns the line created by this function.

The resultant is (spectrum, freqs, line)

Below examples illustrate the matplotlib.axes.Axes.magnitude_spectrum() function in matplotlib.axes:

Example 1:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import numpy as np 
np.random.seed(10**5) 
   
dt = 0.0001
Fs = 1 / dt 
zambiatek = np.array([22.00, 61.90, 7.80, 
                  24.40, 110.25, 20.05, 
                  15.00, 22.80, 34.90, 
                  57.30]) 
  
nse = np.random.randn(len(zambiatek)) 
r = np.exp(-zambiatek / 0.05) 
   
s = 0.5 * np.sin(1.5 * np.pi * zambiatek) + nse 
   
# plot magnitude_spectrum 
fig, ax = plt.subplots() 
ax.magnitude_spectrum(s, Fs = Fs,  
                      color ="green") 
  
ax.set_title('matplotlib.axes.Axes.magnitude_spectrum()\ 
Example') 
  
plt.show() 

Output:

Example 2:

# Implementation of matplotlib function 
import matplotlib.pyplot as plt 
import numpy as np 
np.random.seed(0) 
   
dt = 0.01
Fs = 1 / dt 
t = np.arange(0, 10, dt) 
res = np.random.randn(len(t)) 
r = np.exp(-t / 0.05) 
   
cres = np.convolve(res, r)*dt 
cres = cres[:len(t)] 
s = 0.5 * np.sin(1.5 * np.pi * t) + cres 
   
# plot simple spectrum 
fig, (ax1, ax2) = plt.subplots(2, 1) 
ax1.plot(t, s, color ="green") 
   
# plot magnitude_spectrum 
ax2.magnitude_spectrum(s, Fs = Fs,  
                       color ="green") 
   
ax1.set_title('matplotlib.axes.Axes.magnitude_spectrum()\ 
Example') 
  
plt.show() 