diff --git a/src/cbadc/analog_signal/_analog_signal.py b/src/cbadc/analog_signal/_analog_signal.py
index 045c53b..081f6b4 100644
--- a/src/cbadc/analog_signal/_analog_signal.py
+++ b/src/cbadc/analog_signal/_analog_signal.py
@@ -68,6 +68,11 @@ def __div__(self, other):
 class ModulatedSignal(_AnalogSignal):
     def __init__(self, *signals: _AnalogSignal):
         self._signals = signals
+        # Check if piecewise constant
+        self.piecewise_constant = True
+        for signal in self._signals:
+            if not signal.piecewise_constant:
+                self.piecewise_constant = False
 
     def evaluate(self, t: float) -> float:
         """Evaluate the signal at time :math:`t`.
@@ -98,6 +103,11 @@ class SuperpositionSignal(_AnalogSignal):
 
     def __init__(self, *signals: _AnalogSignal):
         self._signals = signals
+        # Check if piecewise constant
+        self.piecewise_constant = True
+        for signal in self._signals:
+            if not signal.piecewise_constant:
+                self.piecewise_constant = False
 
     def evaluate(self, t: float) -> float:
         """Evaluate the signal at time :math:`t`.
diff --git a/src/cbadc/analog_signal/impulse_responses.py b/src/cbadc/analog_signal/impulse_responses.py
index 234e9dd..2ab87de 100644
--- a/src/cbadc/analog_signal/impulse_responses.py
+++ b/src/cbadc/analog_signal/impulse_responses.py
@@ -1,4 +1,5 @@
 """Analog impulse response signals from common linear systems."""
+
 from typing import Union
 import numpy as np
 import sympy as sp
@@ -10,6 +11,7 @@ class _ImpulseResponse(_AnalogSignal):
     def __init__(self):
         super().__init__()
         self.t0 = 0.0
+        self.piecewise_constant = True
 
 
 class StepResponse(_ImpulseResponse):
diff --git a/src/cbadc/simulator/numerical_simulator.py b/src/cbadc/simulator/numerical_simulator.py
index 046836e..c83e06b 100644
--- a/src/cbadc/simulator/numerical_simulator.py
+++ b/src/cbadc/simulator/numerical_simulator.py
@@ -375,7 +375,9 @@ def _pre_computations(self):
             tf = self.analog_system.transfer_function_matrix(
                 np.array([analog_signal.angularFrequency])
             )
-            self._pre_computed_transfer_function[0, :, l] = np.abs(tf[:, l_index, 0])
+            self._pre_computed_transfer_function[0, :, l] = (
+                np.abs(tf[:, l_index, 0]) * analog_signal.amplitude
+            )
             self._pre_computed_transfer_function[1, :, l] = (
                 np.angle(tf[:, l_index, 0]) + analog_signal.phase
             )