diff --git a/qbiocode/embeddings/embed.py b/qbiocode/embeddings/embed.py
index 3b6b087..af306ae 100644
--- a/qbiocode/embeddings/embed.py
+++ b/qbiocode/embeddings/embed.py
@@ -66,7 +66,13 @@ def data_map_func(x: np.ndarray) -> float:
                 float: the mapped value
             """
             coeff = x[0] / 2 if len(x) == 1 else reduce(lambda m, n: (m * n) / 2, x)
-            return float(coeff)
+            try:
+                return float(coeff)
+            except TypeError:
+                # coeff is a symbolic ParameterExpression during circuit
+                # construction (unbound parameters) — return it unevaluated
+                # and let Qiskit bind real values later.
+                return coeff
 
     else:
         data_map_func = None