diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index f365349..1172ee0 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -14,6 +14,7 @@
 from .ch03_psd import Ch03PsdWindow
 from .ch04_sampling import Ch04SamplingWindow
 from .ch04_window import Ch04WindowWindow
+from .ch04_quantization_noise import Ch04QuantizationNoiseWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -25,6 +26,7 @@
         Ch03PsdWindow,
         Ch04SamplingWindow,
         Ch04WindowWindow,
+        Ch04QuantizationNoiseWindow,
     ]