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39 lines
1.1 KiB
Python
39 lines
1.1 KiB
Python
import numpy as np
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import recv
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import sampling
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import sigproc
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class Filter(object):
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def __init__(self, b, a=()):
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self.b = b
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self.a = a
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self.x = [0] * len(b)
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self.y = [0] * len(a)
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def __call__(self, x):
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self.x = [x] + self.x
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self.x = self.x[:len(self.b)]
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self.y = self.y[:len(self.a)]
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y = np.dot(self.x, self.b) + np.dot(self.y, self.a)
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self.y = [y] + self.y
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return y
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class FreqLoop(object):
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def __init__(self, x, freq):
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self.sampler = sampling.Sampler(x, sampling.Interpolator())
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self.symbols = recv.extract_symbols(self.sampler, freq)
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Kp, Ki = 0.2, 0.01
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b = np.array([1, -1])*Kp + np.array([0.5, 0.5])*Ki
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self.filt = Filter(b=b, a=[1])
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self.correction = 0.0
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def correct(self, actual, expected):
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self.err = np.angle(expected / actual) / np.pi
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self.err = sigproc.clip(self.err, [-0.1, 0.1])
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self.correction = self.filt(self.err)
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self.sampler.correct(offset=self.correction)
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def __iter__(self):
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return iter(self.symbols)
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