How do you make a spectrogram in Python?

 Question:-

How do you make a spectrogram in Python?

Plot spectrogram in Python

A spectrogram is like a photograph of a signal on the x-axis and y-axis. To plot this photograph we have to import a module named as Matplotlib.pyplot. this module provides specgram() method which takes signal as input and plot the spectrogram. So let’s see its Solution.

Example :-

# import the libraries 
import matplotlib.pyplot as plot 
import numpy as np 
# Define the list of frequencies 
frequencies  = np.arange(5,105,5) 
# Sampling Frequency 
samplingFrequency  = 400 
# Create two ndarrays 
s1 = np.empty([0]) # For samples 
s2 = np.empty([0]) # For signal 
# Start Value of the sample 
start  = 1 
# Stop Value of the sample 
stop  = samplingFrequency+1 
for frequency in frequencies: 
  sub1 = np.arange(start, stop, 1) 
  # Signal - Sine wave with varying frequency + Noise 
  sub2 = np.sin(2*np.pi*sub1*frequency*1/samplingFrequency)+np.random.randn(len(sub1)) 
  s1  = np.append(s1, sub1) 
  s2  = np.append(s2, sub2) 
  start  = stop+1 
  stop  = start+samplingFrequency 
# Plot the signal 
plot.subplot(211) 
plot.plot(s1,s2) 
plot.xlabel('Sample') 
plot.ylabel('Amplitude') 
# Plot the spectrogram 
plot.subplot(212) 
powerSpectrum, freqenciesFound, time, imageAxis = plot.specgram(s2, Fs=samplingFrequency) 
plot.xlabel('Time') 
plot.ylabel('Frequency') 
plot.show()