  The standard entanglement test using the Clauser-Horne-Shimony-Holt
inequality is known to fail in mesoscopic junctions at finite temperatures.
Since this is due to the bidirectional particle flow, a similar failure is
expected to occur in an ac-driven contact. We develop a continuous-variable
entanglement test suitable for electrons and holes that are created by the ac
drive. The generalized Bell inequality is violated in junctions with low
conductance or small number of transport channels and with ac voltages which
create few electron-hole pairs per cycle. Our ac-entanglement test depends on
the total number of electron-hole pairs and on the distribution of
probabilities of pair creations similar to the Fano factor.
