diff --git a/pyproject.toml b/pyproject.toml
index 6fc07d9..1ea2aad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "backscattering_simulation_data"
-version = "0.1.1"
+version = "0.1.2"
 authors = [{ name = "linarphy", email = "linarphy@linarphy.net" }]
 description = "Simulation data management for the measurement of backscattered light in the Virgo interferometer"
 readme = "README.md"
diff --git a/src/backscattering_simulation_data/utils.py b/src/backscattering_simulation_data/utils.py
index 72258a9..f421737 100644
--- a/src/backscattering_simulation_data/utils.py
+++ b/src/backscattering_simulation_data/utils.py
@@ -71,18 +71,18 @@ def frequencyseries_to_dataset(
     dataset = store.create_dataset(name, data=frequencyseries.data)
     if frequencyseries.unit is not None:
         dataset.attrs["units"] = frequencyseries.unit.to_string()
-    if not isinstance(frequencyseries.t0, Quantity):
+    if not isinstance(frequencyseries.f0, Quantity):
         raise ValueError(
-            "t0 must be a quantity, not {}".format(
+            "f0 must be a quantity, not {}".format(
                 type(frequencyseries.f0)
             )
         )
-    if not isinstance(frequencyseries.dt, Quantity):
+    if not isinstance(frequencyseries.df, Quantity):
         raise ValueError(
-            "t0 must be a quantity, not {}".format(
+            "f0 must be a quantity, not {}".format(
                 type(frequencyseries.df)
             )
         )
-    dataset.attrs["f0"] = frequencyseries.t0.to_string()
-    dataset.attrs["df"] = frequencyseries.dt.to_string()
+    dataset.attrs["f0"] = frequencyseries.f0.to_string()
+    dataset.attrs["df"] = frequencyseries.df.to_string()
     return dataset