feat: Ch06 Digital Filters

Signed-off-by: Philipp Le <philipp@philipple.de>
Change-Id: I2dce67a8fe4409865369146eba8be7f60ec52b11
diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index 82c94ce..75d062e 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -18,6 +18,7 @@
 from .ch05_modulation import Ch05ModulationWindow
 from .ch05_iq import Ch05IqWindow
 from .ch05_qam import Ch05QamWindow
+from .ch06_filter import Ch06FilterWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -33,6 +34,7 @@
         Ch05ModulationWindow,
         Ch05IqWindow,
         Ch05QamWindow,
+        Ch06FilterWindow,
     ]