Friday, October 3, 2025
HomeLanguagesMatplotlib.axes.Axes.csd() in Python

Matplotlib.axes.Axes.csd() in Python

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.csd() Function

The Axes.csd() function in axes module of matplotlib library is used to plot the cross-spectral density.

Syntax: Axes.csd(self, x, y, NFFT=None, Fs=None, Fc=None, detrend=None, window=None, noverlap=None, pad_to=None, sides=None, scale_by_freq=None, return_line=None, *, data=None, **kwargs)

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

  • x, y: These parameter are the 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.
  • NFFT : This parameter contains the number of data points used in each block for the FFT.
  • detrend : This parameter contains the function applied to each segment before fft-ing, designed to remove the mean or linear trend {‘none’, ‘mean’, ‘linear’}.
  • scale_by_freq : This parameter is allows for integration over the returned frequency values.
  • noverlap : This parameter is the number of points of overlap between blocks.
  • Fc : This parameter is the center frequency of x.
  • return_line : This parameter include the line object plotted in the returned values.

Returns: This returns the following:

  • Pxy:This returns the values for the cross spectrum P_{xy} before scaling.
  • freqs :This returns the frequencies for the elements in Pxy.
  • line :This returns the line created by this function.

The resultant is (Pxy, freqs, line)

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

Example-1:




# Implementation of matplotlib function
import numpy as np
import matplotlib.pyplot as plt
  
dt = 0.01
t = np.arange(0, 30, dt)
nse1 = np.random.randn(len(t))
nse2 = np.random.randn(len(t))
  
s1 = 1.5 * np.sin(2 * np.pi * 10 * t) + nse1
s2 = np.cos(np.pi * t) + nse2
  
fig, ax1 = plt.subplots()
ax1.csd(s1, s2**2, 128, 1./dt)
ax1.set_xlabel('Frequency')
ax1.set_ylabel('CSD(db)')
  
ax1.set_title('matplotlib.axes.Axes.csd() Example')
plt.show()


Output:

Example-2:




# Implementation of matplotlib function
import numpy as np
import matplotlib.pyplot as plt
   
dt = 0.01
t = np.arange(0, 30, dt)
nse1 = np.random.randn(len(t))
nse2 = np.random.randn(len(t))
r = np.exp(-t / 0.05)
   
cnse1 = np.convolve(nse1, r, mode ='same')*dt
cnse2 = np.convolve(nse2, r, mode ='same')*dt
   
s1 = 1.5 * np.sin(2 * np.pi * 10 * t) + cnse1
s2 = np.cos(np.pi * t) + cnse2 + np.sin(2 * np.pi * 10 * t)
   
fig, [ax1, ax2] = plt.subplots(2, 1)
ax1.plot(t, s1, t, s2)
ax1.set_xlim(0, 5)
ax1.set_ylabel('s1 and s2')
ax1.grid(True)
   
ax2.csd(s1, s2, 256, 1./dt)
ax2.set_ylabel('CSD(db)')
ax2.set_xlabel('Frequency')
   
ax1.set_title('matplotlib.axes.Axes.csd() Example')
plt.show()


Output:

Dominic
Dominichttp://wardslaus.com
infosec,malicious & dos attacks generator, boot rom exploit philanthropist , wild hacker , game developer,
RELATED ARTICLES

Most Popular

Dominic
32331 POSTS0 COMMENTS
Milvus
85 POSTS0 COMMENTS
Nango Kala
6703 POSTS0 COMMENTS
Nicole Veronica
11867 POSTS0 COMMENTS
Nokonwaba Nkukhwana
11929 POSTS0 COMMENTS
Shaida Kate Naidoo
6818 POSTS0 COMMENTS
Ted Musemwa
7080 POSTS0 COMMENTS
Thapelo Manthata
6775 POSTS0 COMMENTS
Umr Jansen
6776 POSTS0 COMMENTS