diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index 1172ee0..0aa1b95 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -15,6 +15,7 @@
 from .ch04_sampling import Ch04SamplingWindow
 from .ch04_window import Ch04WindowWindow
 from .ch04_quantization_noise import Ch04QuantizationNoiseWindow
+from .ch05_modulation import Ch05ModulationWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -27,6 +28,7 @@
         Ch04SamplingWindow,
         Ch04WindowWindow,
         Ch04QuantizationNoiseWindow,
+        Ch05ModulationWindow,
     ]