Use rms in welch

qutil/signal_processing/real_space.py

@@ -229,9 +229,8 @@ def welch(x, fourier_procfn: Optional[Union[Callable, Sequence[Callable]]] = Non
             return d
     elif not callable(normalize):
         def normalize_func(d):
-            # RMS normalization. Assumes detrend has already removed a constant trend, which means
-            # we divide by the standard deviation.
-            return d / d.std(axis=-1)[..., None]
+            # RMS normalization. Assumes detrend has already removed a constant trend.
+            return d / rms(d, axis=-1, keepdims=True)
     elif axis != -1:
         def normalize_func(d):
             d = np.moveaxis(d, -1, axis)