diff --git a/src/sdr/_pll.py b/src/sdr/_pll.py
index 05c7b8f7b..17edc8824 100644
--- a/src/sdr/_pll.py
+++ b/src/sdr/_pll.py
@@ -83,7 +83,7 @@ def __init__(
         K1 = lf.K1
         K2 = lf.K2
 
-        b0 = 0
+        # b0 = 0
         b1 = Kp * K0 * (K1 + K2)
         b2 = -Kp * K0 * K1