scipy.signal¶
This module defines the single function:
sosfilt¶
scipy:
https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.sosfilt.html
Filter data along one dimension using cascaded second-order sections.
The function takes two positional arguments, sos, the filter
segments of length 6, and the one-dimensional, uniformly sampled data
set to be filtered. Returns the filtered data, or the filtered data and
the final filter delays, if the zi keyword arguments is supplied.
The keyword argument must be a float ndarray of shape
(n_sections, 2). If zi is not passed to the function, the
initial values are assumed to be 0.
# code to be run in micropython
from ulab import numpy as np
from ulab import scipy as spy
x = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
sos = [[1, 2, 3, 1, 5, 6], [1, 2, 3, 1, 5, 6]]
y = spy.signal.sosfilt(sos, x)
print('y: ', y)
y: array([0.0, 1.0, -4.0, 24.0, -104.0, 440.0, -1728.0, 6532.000000000001, -23848.0, 84864.0], dtype=float)
# code to be run in micropython
from ulab import numpy as np
from ulab import scipy as spy
x = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
sos = [[1, 2, 3, 1, 5, 6], [1, 2, 3, 1, 5, 6]]
# initial conditions of the filter
zi = np.array([[1, 2], [3, 4]])
y, zf = spy.signal.sosfilt(sos, x, zi=zi)
print('y: ', y)
print('\n' + '='*40 + '\nzf: ', zf)
y: array([4.0, -16.0, 63.00000000000001, -227.0, 802.9999999999999, -2751.0, 9271.000000000001, -30775.0, 101067.0, -328991.0000000001], dtype=float)
========================================
zf: array([[37242.0, 74835.0],
[1026187.0, 1936542.0]], dtype=float)