diff --git a/docs/notebooks b/docs/notebooks
index 43ba05942..d3a039c52 160000
--- a/docs/notebooks
+++ b/docs/notebooks
@@ -1 +1 @@
-Subproject commit 43ba0594276c66e27a877488ec333b5c3e0b56b3
+Subproject commit d3a039c52a4b16724340de5af46c3f158209d03f
diff --git a/stingray/pulse/modeling.py b/stingray/pulse/modeling.py
index dc864d33f..2934b0935 100644
--- a/stingray/pulse/modeling.py
+++ b/stingray/pulse/modeling.py
@@ -89,14 +89,16 @@ def sinc_square_deriv(x, amplitude=1.0, mean=0.0, width=1.0):
     >>> assert np.allclose(sinc_square_deriv(0, amplitude=2.), [1., 0., 0.])
     """
     x_is_zero = x == mean
-
+    denominator = (x - mean) / width
+    denominator_squared = np.where(denominator == 0, 1e-10, denominator**2)  # Avoid division by 0
     d_x = (
         2
         * amplitude
         * sinc((x - mean) / width)
         * (x * np.cos((x - mean) / width) - np.sin((x - mean) / width))
-        / ((x - mean) / width) ** 2
+        / denominator_squared
     )
+
     d_x = np.asanyarray(d_x)
     d_amplitude = sinc((x - mean) / width) ** 2
     d_x[x_is_zero] = 0