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scipy.signal.

# bode

scipy.signal.bode(system, w=None, n=100)

  Calculate Bode magnitude and phase data of a continuous-time system.

  Parameters:
    system an instance of the LTI class or a tuple describing the system.

      The following gives the number of elements in the tuple and the interpretation:

      > - 1 (instance of `lti`)

      > - 2 (num, den)

      > - 3 (zeros, poles, gain)

      > - 4 (A, B, C, D)

    w array_like, optional

      Array of frequencies (in rad/s). Magnitude and phase data is calculated for every value in this array. If not given a reasonable set will be calculated.

    n int, optional

      Number of frequency points to compute if w is not given. The n frequencies are logarithmically spaced in an interval chosen to include the influence of the poles and zeros of the system.

  Returns:
    w 1D ndarray

      Frequency array [rad/s]

    mag 1D ndarray

      Magnitude array [dB]

    phase 1D ndarray

      Phase array [deg]

  Notes

  If (num, den) is passed in for `system`, coefficients for both the numerator and denominator should be specified in descending exponent order (e.g. `s^2 + 3s + 5` would be represented as `[1, 3, 5]`).

  Added in version 0.11.0.

  Array API Standard Support

  `bode` 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

      >>> from scipy import signal
      >>> import matplotlib.pyplot as plt

      >>> sys = signal.TransferFunction([1], [1, 1])
      >>> w, mag, phase = signal.bode(sys)

      >>> plt.figure()
      >>> plt.semilogx(w, mag)    # Bode magnitude plot
      >>> plt.figure()
      >>> plt.semilogx(w, phase)  # Bode phase plot
      >>> plt.show()