diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index 62e0f01..32f55c8 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -12,6 +12,7 @@
 from .ch03_ergodic import Ch03ErgodicWindow
 from .ch03_cross import Ch03CrossCorrelationWindow
 from .ch03_psd import Ch03PsdWindow
+from .ch04_sampling import Ch04SamplingWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -21,6 +22,7 @@
         Ch03ErgodicWindow,
         Ch03CrossCorrelationWindow,
         Ch03PsdWindow,
+        Ch04SamplingWindow,
     ]