diff --git a/gprMax/waveforms.py b/gprMax/waveforms.py
index ebb278b6..9da54d16 100644
--- a/gprMax/waveforms.py
+++ b/gprMax/waveforms.py
@@ -45,11 +45,11 @@ class Waveform:
         """
         
         # Coefficients for certain waveforms
-        if self.type == 'gaussian' or self.type == 'gaussiandot' or self.type == 'gaussiandotnorm':
+        if self.type == 'gaussian' or self.type == 'gaussiandot' or self.type == 'gaussiandotdot':
             chi = 1 / self.freq
             zeta = 2 * np.pi * np.pi * self.freq * self.freq
             delay = time - chi
-        elif self.type == 'gaussiandotdot' or self.type == 'gaussiandotdotnorm' or self.type == 'ricker':
+        elif self.type == 'gaussiandotnorm' or self.type == 'gaussiandotdotnorm' or self.type == 'ricker':
             chi = np.sqrt(2) / self.freq
             zeta = np.pi * np.pi * self.freq * self.freq
             delay = time - chi