diff --git a/simulations/lib/signals/digitisedsignal.py b/simulations/lib/signals/digitisedsignal.py
index a618b2a..f77c792 100755
--- a/simulations/lib/signals/digitisedsignal.py
+++ b/simulations/lib/signals/digitisedsignal.py
@@ -82,11 +82,14 @@ class DigitisedSignal(Signal):
     def __len__(self):
         return self.sample_length
 
+    def raw_time(self):
+        return np.arange(0, self.time_length, 1/self.sample_rate)
+
     def _translate(self, t_f = None, x_f = None, t_0 = None, x_0 = None, velocity = None):
         """
         Translate the signal from (t_0, x_0) to (t_f, x_f) with optional velocity.
 
-        Returns the signal at (t_f, x_f)
+        Returns the signal at (t_f, x_f) and the total time offset
         """
 
         total_time_offset = self.total_time_offset(t_f=t_f, x_f=x_f, t_0=t_0, x_0=x_0, velocity=velocity)
@@ -137,7 +140,7 @@ class DigitisedSignal(Signal):
                     amplitude = self.raw[n_offset_int]
 
             if not self.periodic:
-                if hasattr(amplitude, 'ndim'):
+                if hasattr(amplitude, 'ndim') and amplitude.ndim > 0:
                     amplitude[mask_idx] = 0
 
         return amplitude, total_time_offset