class LowPassFilterTest(unittest.TestCase):
def setUp(self):
self.p1 = LowPassFilter()
self.s1 = DiracSource()
self.p2 = LowPassFilter()
self.s2 = SineSource(freq=400, amp=1.0)
self.p3 = LowPassFilter()
self.s3 = SineSource(freq=40, amp=1.0)
def test_on_dirac(self):
chunk = list(islice(self.s1.read(), 0, 100))
proc = self.p1.process(chunk)
# Lets check if IIR filter is really infinite.
self.assertTrue(abs(proc[-1][0]) > 0.001)
def test_on_sin(self):
# A bit weird way to check if LP filter passing low frequences
# Freq for filter is 150 Hz, so:
# 400 Hz freq should be dimmed
chunk_len = self.s2.rate / 400
chunk = list(islice(self.s2.read(), 0, chunk_len * 2))
proc = self.p2.process(chunk)
self.assertTrue(max(map(lambda x: abs(x[0]), proc)) < 0.3)
# 40 Hz should be pretty much left intact
chunk_len = self.s2.rate / 40
chunk = list(islice(self.s3.read(), 0, chunk_len * 2))
proc = self.p3.process(chunk)
self.assertTrue(max(map(lambda x: abs(x[0]), proc)) > 0.8)
def setUp(self):
self.p1 = LowPassFilter()
self.s1 = DiracSource()
self.p2 = LowPassFilter()
self.s2 = SineSource(freq=400, amp=1.0)
self.p3 = LowPassFilter()
self.s3 = SineSource(freq=40, amp=1.0)