Signal Processing

Signal processing basics and EEG.

Summing Sine Waves


import numpy as np                   # for multi-dimensional containers
import pandas as pd                  # for DataFrames
import plotly.graph_objects as go    # for data visualisation
from plotly.subplots import make_subplots

Creating Multiple Sine Wave

Let's create and plot five sine waves, similar to the ones from the previous section. Let's start by defining our time window and sample rate.

sample_rate = 1000
start_time = 0
end_time = 10
theta = 0

time = np.arange(start_time, end_time, 1/sample_rate)

Now we'll store their frequencies in a list named frequency, and their amplitudes in a list named amplitude.

frequency = [3, 5, 2, 1, 10]
amplitude = [1, 2, 7, 3, 0.1]

Finally, let's loop through our five frequency/amplitude values and use them to calculate and visualise the sine waves using subplots.

fig = make_subplots(rows=5, cols=1, shared_xaxes=True)

for i in range(5):
    sinewave = amplitude[i] * np.sin(2 * np.pi * frequency[i] * time + theta)
    fig.add_scatter(x=time, y=sinewave, row=i+1, col=1, name=f"wave {i+1}")