diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index 2284b9a..62e0f01 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -11,6 +11,7 @@
 from .ch02_fourier import Ch02FourierWindow
 from .ch03_ergodic import Ch03ErgodicWindow
 from .ch03_cross import Ch03CrossCorrelationWindow
+from .ch03_psd import Ch03PsdWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -19,6 +20,7 @@
         Ch02FourierWindow,
         Ch03ErgodicWindow,
         Ch03CrossCorrelationWindow,
+        Ch03PsdWindow,
     ]