square — SciPy v1.15.3 Manual (original) (raw)

scipy.signal.

scipy.signal.square(t, duty=0.5)[source]#

Return a periodic square-wave waveform.

The square wave has a period 2*pi, has value +1 from 0 to2*pi*duty and -1 from 2*pi*duty to 2*pi. duty must be in the interval [0,1].

Note that this is not band-limited. It produces an infinite number of harmonics, which are aliased back and forth across the frequency spectrum.

Parameters:

tarray_like

The input time array.

dutyarray_like, optional

Duty cycle. Default is 0.5 (50% duty cycle). If an array, causes wave shape to change over time, and must be the same length as t.

Returns:

yndarray

Output array containing the square waveform.

Examples

A 5 Hz waveform sampled at 500 Hz for 1 second:

import numpy as np from scipy import signal import matplotlib.pyplot as plt t = np.linspace(0, 1, 500, endpoint=False) plt.plot(t, signal.square(2 * np.pi * 5 * t)) plt.ylim(-2, 2)

A pulse-width modulated sine wave:

plt.figure() sig = np.sin(2 * np.pi * t) pwm = signal.square(2 * np.pi * 30 * t, duty=(sig + 1)/2) plt.subplot(2, 1, 1) plt.plot(t, sig) plt.subplot(2, 1, 2) plt.plot(t, pwm) plt.ylim(-1.5, 1.5)