def test_init_from_attenuation_VF_array_att(self):
"""
Test passing array as attenuation in the Coaxial classmethod
`from_attenuation_VF_units`.
"""
# create a Coaxial media for frequency-dependant attenuation and
# test the resulting alpha values (real part of gamma)
frequency = rf.Frequency(start=1, stop=2, unit='GHz', npoints=101)
# k0k1k2 attenuation model
# values taken for HUBER+SUHNER DATA SHEET Coaxial Cable S_10172_B-1
# attenuation in dB/m for frequency in GHz
att = 0 + 0.0826 * npy.sqrt(
frequency.f_scaled) + 0.0129 * frequency.f_scaled
coax = Coaxial.from_attenuation_VF(frequency=frequency,
att=att,
unit='dB/m')
# check alpha in gamma
assert_array_almost_equal(rf.db_2_np(att), coax.gamma.real)
# if the attenuation array length does not match the frequency,
# should raise a ValueError
frequency2 = rf.Frequency(start=1, stop=2, unit='GHz', npoints=10)
with self.assertRaises(ValueError):
coax = Coaxial.from_attenuation_VF(frequency=frequency2, att=att)
def test_init_from_attenuation_VF_units(self):
"""
Test the attenuation unit conversions in the Coaxial classmethod
`from_attenuation_VF_units`.
"""
# create a dummy Coaxial media for various attenuation and test the
# resulting alpha values (real part of gamma)
frequency = rf.Frequency(npy.random.rand(), unit='GHz', npoints=1)
_att = npy.random.rand()
# dB/m
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='dB/m')
assert_almost_equal(coax.gamma.real, rf.db_2_np(_att))
# dB/100m
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='dB/100m')
assert_almost_equal(coax.gamma.real, rf.db_2_np(_att) / 100)
# dB/feet
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='dB/feet')
assert_almost_equal(coax.gamma.real,
rf.db_2_np(_att) * rf.meter_2_feet())
# dB/100m
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='dB/100feet')
assert_almost_equal(coax.gamma.real,
rf.db_2_np(_att) / 100 * rf.meter_2_feet())
# Neper/m
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='Np/m')
assert_almost_equal(coax.gamma.real, _att)
# Neper/feet
coax = Coaxial.from_attenuation_VF(frequency=frequency,
VF=1,
att=_att,
unit='Np/feet')
assert_almost_equal(coax.gamma.real, _att * rf.meter_2_feet())
def test_db_2_np(self):
"""
Test dB to Np conversion with:
1 [dB] = ln(10)/20 [Np]
"""
assert_almost_equal(rf.db_2_np(1), log(10) / 20)