18 lines
420 B
18 lines
420 B
9 years ago
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"""Classes for filtering discrete time signals."""
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import numpy as np
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class FirstOrderLowpassFilter(object):
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def __init__(self, fc, dt, x1=0):
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self.kf = 2 * np.pi * fc * dt / (1 + 2 * np.pi * fc * dt)
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self.x1 = x1
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def __call__(self, x):
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self.x1 = (1 - self.kf) * self.x1 + self.kf * x
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# If previous or current is NaN, reset filter.
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if np.isnan(self.x1):
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self.x1 = x
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return self.x1
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