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https://github.com/romanz/amodem.git
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89 lines
2.1 KiB
Python
89 lines
2.1 KiB
Python
import random
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import itertools
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import numpy as np
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from numpy.linalg import norm
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from amodem import dsp
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from amodem import config
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def test_qam():
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q = dsp.QAM(config.symbols)
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r = random.Random(0)
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m = q.bits_per_symbol
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bits = [tuple(r.randint(0, 1) for j in range(m)) for i in range(1024)]
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stream = itertools.chain(*bits)
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S = list(q.encode(list(stream)))
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decoded = list(q.decode(S))
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assert decoded == bits
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noise = lambda A: A*(r.uniform(-1, 1) + 1j*r.uniform(-1, 1))
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noised_symbols = [(s + noise(1e-3)) for s in S]
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decoded = list(q.decode(noised_symbols))
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assert decoded == bits
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def quantize(q, s):
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bits, = list(q.decode([s]))
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r, = q.encode(bits)
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index = np.argmin(np.abs(s - q.symbols))
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expected = q.symbols[index]
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assert r == expected
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def test_overflow():
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q = dsp.QAM(config.symbols)
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r = np.random.RandomState(seed=0)
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for i in range(10000):
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s = 10*(r.normal() + 1j * r.normal())
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quantize(q, s)
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def test_linreg():
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x = np.array([1, 3, 2, 8, 4, 6, 9, 7, 0, 5])
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a, b = 12.3, 4.56
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y = a * x + b
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a_, b_ = dsp.linear_regression(x, y)
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assert abs(a - a_) < 1e-10
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assert abs(b - b_) < 1e-10
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def test_filter():
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x = range(10)
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y = dsp.lfilter(b=[1], a=[1], x=x)
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assert (np.array(x) == y).all()
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x = [1] + [0] * 10
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y = dsp.lfilter(b=[0.5], a=[1, -0.5], x=x)
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assert list(y) == [0.5 ** (i+1) for i in range(len(x))]
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def test_estimate():
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r = np.random.RandomState(seed=0)
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x = r.uniform(-1, 1, [1000])
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x[:10] = 0
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x[len(x)-10:] = 0
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c = 1.23
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y = c * x
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c_, = dsp.estimate(x=x, y=y, order=1)
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assert abs(c - c_) < 1e-12
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h = [1, 1]
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y = dsp.lfilter(b=h, a=[1], x=x)
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h_ = dsp.estimate(x=x, y=y, order=len(h))
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assert norm(h - h_) < 1e-12
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h = [0.1, 0.6, 0.9, 0.7, -0.2]
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L = len(h) // 2
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y = dsp.lfilter(b=h, a=[1], x=x)
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h_ = dsp.estimate(
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x=x[:len(x)-L], y=y[L:],
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order=len(h), lookahead=L
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)
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assert norm(h - h_) < 1e-12
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y_ = dsp.lfilter(b=h_, a=[1], x=x)
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assert norm(y - y_) < 1e-12
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