diff --git a/hera_pspec/noise.py b/hera_pspec/noise.py
index 69a3da78..e0f96a7f 100644
--- a/hera_pspec/noise.py
+++ b/hera_pspec/noise.py
@@ -21,6 +21,8 @@ def calc_P_N(scalar, Tsys, t_int, Ncoherent=1, Nincoherent=None, form='Pk', k=No
 
     Parameters
     ----------
+    scalar : float, Power spectrum normalization factor: X2Y(z) * Omega_P^2 / Omega_PP
+    
     Tsys : float, System temperature in Kelvin
 
     t_int : float, integration time of power spectra in seconds
diff --git a/hera_pspec/pspecdata.py b/hera_pspec/pspecdata.py
index a00c11e3..16883bec 100644
--- a/hera_pspec/pspecdata.py
+++ b/hera_pspec/pspecdata.py
@@ -878,7 +878,7 @@ def units(self, little_h=True):
 
         # set pspec norm units
         if self.primary_beam is None:
-            norm_units = "Hz str [beam normalization not specified]".format(self.dsets[0].vis_units)
+            norm_units = "Hz str [beam normalization not specified]"
         else:
             if little_h:
                 h_unit = "h^-3 "