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scipy.signal.

# square

scipy.signal.square(t, duty=0.5)

  Return a periodic square-wave waveform.

  The square wave has a period `2*pi`, has value +1 from 0 to `2*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:
    t array_like

      The input time array.

    duty array_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:
    y ndarray

      Output array containing the square waveform.

  Notes

  Array API Standard Support

  `square` has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable `SCIPY_ARRAY_API=1` and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

  Library | CPU | GPU
  --- | --- | ---
  NumPy | ✅ | n/a
  CuPy | n/a | ⛔
  PyTorch | ⛔ | ⛔
  JAX | ⛔ | ⛔
  Dask | ⛔ | n/a

  > See Support for the array API standard for more information.

  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)