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74 lines
1.8 KiB
Python
74 lines
1.8 KiB
Python
from amodem import dsp
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from amodem import sampling
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from amodem import config
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import numpy as np
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import random
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import itertools
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config = config.fastest()
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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_demux():
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freqs = np.array([1e3, 2e3])
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omegas = 2 * np.pi * freqs / config.Fs
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carriers = [dsp.exp_iwt(2*np.pi*f/config.Fs, config.Nsym) for f in freqs]
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syms = [3, 2j]
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sig = np.dot(syms, carriers)
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res = dsp.Demux(sampling.Sampler(sig.real), omegas, config.Nsym)
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res = np.array(list(res))
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assert np.max(np.abs(res - syms)) < 1e-12
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def test_qam():
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q = dsp.MODEM(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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def noise(A):
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return 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.MODEM(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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