.unwrap()

In NumPy, the .unwrap() function is used to unwrap a phase angle array. This function adjusts the phase angles by changing any absolute difference between consecutive angles greater than the specified threshold (default: pi) by their 2*pi complement. It is commonly used in signal processing to correct phase angle discontinuities in wrapped data.

Syntax

numpy.unwrap(p, discont=pi, axis=-1, period=6.283185307179586)

• p: The input array of phase angles to be unwrapped.
• discont (optional): The discontinuity threshold, which defaults to pi. Differences greater than this value will be adjusted by adding or subtracting multiples of 2*pi.
• axis (optional): The axis along which the unwrap operation is applied. Default is the last axis -1.
• period (optional): The period of the phase angles. Default is 2*pi, but it can be set to other values to adjust for different periodicities.

Example 1

This example demonstrates how to use the .unwrap() function to correct phase discontinuities in an array of wrapped phase angles.

# Importing the 'numpy' library as 'np'
import numpy as np

# Creating an array of phase angles with discontinuities
angles = np.array([0, np.pi/2, np.pi, -np.pi/2, -np.pi])

# Applying the unwrap function to correct discontinuities
unwrapped = np.unwrap(angles)

print(unwrapped)

The above example code results in the following output:

[0.         1.57079633 3.14159265 4.71238898 3.14159265]

Note: NumPy outputs phase angles with high precision. For clarity, these examples use rounded values.

Example 2

This example shows how to adjust the discontinuity threshold by setting a custom discont value in .unwrap():

# Importing the 'numpy' library as 'np'
import numpy as np

# Creating an array of phase angles with large discontinuities
angles = np.array([0, np.pi/2, np.pi, 3*np.pi, -np.pi/2])

# Unwrapping with a custom discontinuity threshold of 2*pi
unwrapped = np.unwrap(angles, discont=2*np.pi)

print(unwrapped)

The above example code results in the following output:

[0.         1.57079633 3.14159265 3.14159265 4.71238898]

Codebyte Example

In this Codebyte example, the .unwrap() method corrects discontinuities in an array of phase angles:

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