diff --git a/CHANGELOG.md b/CHANGELOG.md
index 644f3224adedb50addd4a7b8b790aac76fe1e917..f00514e2947b66039f975bcca8d71110119dc622 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ Changes currently on master, but not under a tag.
 - Added method to result to get injection recovery credible levels
 - Added function to generate a pp-plot from many results to core/result.py
 - Fixed a bug which caused `Interferometer.detector_tensor` not to update when `latitude`, `longitude`, `xarm_azimuth`, `yarm_azimuth`, `xarm_tilt`, `yarm_tilt` were updated.
+- Extracted time and frequency series behaviour from `WaveformGenerator` and `InterferometerStrainData` and moved it to `series.gw.CoupledTimeAndFrequencySeries`
 
 ### Changes
 - Switch the ordering the key-word arguments in `result.read_in_result` to put