Dual-Phase Lock-In Amplifier Based on FPGA for Low-Frequencies Experiments. - Gonzalo Macias-Bobadilla; Juvenal Rodríguez-Reséndiz; Georgina Mota-Valtierra; Genaro M. Soto-Zarazúa; Maurino Méndez-Loyola; Mariano Garduño-Aparicio (Sensors, 2016)