(semi-)revert ab20db4: Antenna encapsulates a digitizer

Antenna should not encapsulate a Digitizer in this way.
Maybe it can be added later, but I see mostly complexiy in that
design.

simulations/lib/location/antenna.py

@@ -1,7 +1,6 @@
 from functools import partial
 
 from .location import Location
-from ..sampling import Digitizer
 
 class Antenna(Location):
     """
@@ -12,56 +11,27 @@ class Antenna(Location):
     Optionally uses digitizer to transform the signal
     when receiving.
     """
-    def __init__(self, x, digitizer=None):
+    def __init__(self, x):
         super().__init__(x)
 
-        self.digitizer = digitizer
-
     def __repr__(self):
         return "Antenna({}, {})".format(repr(self.x), repr(self.x))
 
-    def _digitise_partial(self, signal: callable, *args, digitise=True, **kwargs) -> callable:
-        """
-        A wrapper around functools.partial to support optionally
-        digitising the returned signal.
-        """
-        if self.digitizer and digitise:
-            signal = self.digitizer.digitise(signal)
-
-        return partial(signal, *args, **kwargs)
-
-
-    def emit(self, signal: callable, digitise=False) -> callable:
+    def emit(self, signal: callable) -> callable:
         """
         Return a function that emits a signal from the antenna's location
         """
-        return self._digitise_partial(signal, x_0=self.x, digitise=digitise)
+        return partial(signal, x_0=self.x)
 
-    def recv(self, signal: callable, digitise=True) -> callable:
+    def recv(self, signal: callable) -> callable:
         """
         Return a function that traces the signal as a function of time
         at the antenna's location
         """
-        return self._digitise_partial(signal, x_f=self.x, digitise=digitise)
+        return partial(signal, x_f=self.x)
 
     receive = recv
 
-    # math
-    def __add__(self, other):
-        if isinstance(other, Location):
-            other = other.x
-
-        return self.__class__(self.x + other, self.digitizer)
-
-    def __sub__(self, other):
-        if isinstance(other, Location):
-            other = other.x
-
-        return self.__class__(self.x - other, self.digitizer)
-
-    def __mul__(self, other):
-        return self.__class__(self.x * other, self.digitizer)
-
 class Receiver(Antenna):
     """
     An antenna which main purpose is to trace a signal over time.