Using acoustic and electromagnetic induction conditions for the composite, acoustic trigger signal for the induction. Used as the center frequency of 58KHz band width by 57.8KHz - 58.2KHz (0.4KHz) bandwidth for the current principle of all electronic anti-theft system, the narrowest, it is highly unlikely false alarm caused by the interference. Three (DR) composite materials by system impact vibration transmitted signal audio signal fed back to the receiving antenna discrimination identified (There is no principle of sound, and magnetic signals to find sink).