Add ZeroPad and Sinusoid signal generators

b_asic/signal_generator.py

@@ -4,8 +4,9 @@ B-ASIC signal generators
 These can be used as input to Simulation to algorithmically provide signal values.
 """
 
+from math import pi, sin
 from numbers import Number
-from typing import Callable
+from typing import Callable, Sequence
 
 
 class SignalGenerator:
@@ -94,6 +95,49 @@ class Constant(SignalGenerator):
         return self._constant
 
 
+class ZeroPad(SignalGenerator):
+    """
+    Signal generator that pads a sequence with zeros.
+
+    Parameters
+    ----------
+    data : 1-D array
+        The data that should be padded.
+    """
+
+    def __init__(self, data: Sequence[complex]) -> Callable[[int], complex]:
+        self._data = data
+        self._len = len(data)
+
+    def __call__(self, time: int) -> complex:
+        if 0 <= time < self._len:
+            return self._data[time]
+        return 0.0
+
+
+class Sinusoid(SignalGenerator):
+    """
+    Signal generator that generates a sinusoid.
+
+    Parameters
+    ----------
+    frequency : float
+        The normalized frequency of the sinusoid. Should normally be in the
+        interval [0, 1], where 1 corresponds to half the sample rate.
+    phase : float, default: 0
+        The normalized phase offset.
+    """
+
+    def __init__(
+        self, frequency: float, phase: float = 0.0
+    ) -> Callable[[int], complex]:
+        self._frequency = frequency
+        self._phase = phase
+
+    def __call__(self, time: int) -> complex:
+        return sin(pi * (self._frequency * time + self._phase))
+
+
 class AddGenerator:
     """
     Signal generator that adds two signals.

test/test_signal_generator.py

-from b_asic.signal_generator import Constant, Impulse, Step
+from math import sqrt
+
+import pytest
+
+from b_asic.signal_generator import Constant, Impulse, Sinusoid, Step, ZeroPad
 
 
 def test_impulse():
     g = Impulse()
+    assert g(-1) == 0
     assert g(0) == 1
     assert g(1) == 0
     assert g(2) == 0
 
     g = Impulse(1)
+    assert g(-1) == 0
     assert g(0) == 0
     assert g(1) == 1
     assert g(2) == 0
@@ -15,11 +21,13 @@ def test_impulse():
 
 def test_step():
     g = Step()
+    assert g(-1) == 0
     assert g(0) == 1
     assert g(1) == 1
     assert g(2) == 1
 
     g = Step(1)
+    assert g(-1) == 0
     assert g(0) == 0
     assert g(1) == 1
     assert g(2) == 1
@@ -27,30 +35,57 @@ def test_step():
 
 def test_constant():
     g = Constant()
+    assert g(-1) == 1
     assert g(0) == 1
     assert g(1) == 1
     assert g(2) == 1
 
     g = Constant(0.5)
+    assert g(-1) == 0.5
     assert g(0) == 0.5
     assert g(1) == 0.5
     assert g(2) == 0.5
 
 
+def test_zeropad():
+    g = ZeroPad([0.4, 0.6])
+    assert g(-1) == 0
+    assert g(0) == 0.4
+    assert g(1) == 0.6
+    assert g(2) == 0
+
+
+def test_sinusoid():
+    g = Sinusoid(0.5)
+    assert g(0) == 0
+    assert g(1) == 1
+    assert g(2) == pytest.approx(0)
+    assert g(3) == -1
+
+    g = Sinusoid(0.5, 0.25)
+    assert g(0) == pytest.approx(sqrt(2) / 2)
+    assert g(1) == pytest.approx(sqrt(2) / 2)
+    assert g(2) == pytest.approx(-sqrt(2) / 2)
+    assert g(3) == pytest.approx(-sqrt(2) / 2)
+
+
 def test_addition():
     g = Impulse() + Impulse(2)
+    assert g(-1) == 0
     assert g(0) == 1
     assert g(1) == 0
     assert g(2) == 1
     assert g(3) == 0
 
     g = 1 + Impulse(2)
+    assert g(-1) == 1
     assert g(0) == 1
     assert g(1) == 1
     assert g(2) == 2
     assert g(3) == 1
 
     g = Impulse(1) + 1
+    assert g(-1) == 1
     assert g(0) == 1
     assert g(1) == 2
     assert g(2) == 1
@@ -59,18 +94,21 @@ def test_addition():
 
 def test_subtraction():
     g = Impulse() - Impulse(2)
+    assert g(-1) == 0
     assert g(0) == 1
     assert g(1) == 0
     assert g(2) == -1
     assert g(3) == 0
 
     g = 1 - Impulse(2)
+    assert g(-1) == 1
     assert g(0) == 1
     assert g(1) == 1
     assert g(2) == 0
     assert g(3) == 1
 
     g = Impulse(2) - 1
+    assert g(-1) == -1
     assert g(0) == -1
     assert g(1) == -1
     assert g(2) == 0
@@ -79,6 +117,13 @@ def test_subtraction():
 
 def test_multiplication():
     g = Impulse() * 0.5
+    assert g(-1) == 0
     assert g(0) == 0.5
     assert g(1) == 0
     assert g(2) == 0
+
+    g = 2 * Sinusoid(0.5, 0.25)
+    assert g(0) == pytest.approx(sqrt(2))
+    assert g(1) == pytest.approx(sqrt(2))
+    assert g(2) == pytest.approx(-sqrt(2))
+    assert g(3) == pytest.approx(-sqrt(2))