Patent ID: 7324800

Claim:
A wake-up system with passive correlators comprising: a) a transmitter, including: a wake-up signal generation unit for generating wake-up signals; a time delay unit for delaying the wake-up signals by a predetermined delay time (Δt) and generating first delayed signals based on a result of the delaying; a first passive correlator for correlating and coding the respective wake-up signals and the respective first delayed signals and synthesizing the coded signals; and a transmission antenna for wirelessly transmitting signals synthesized by the first passive correlator to the air; and b) a receiver, including: a reception antenna for receiving signals transmitted by the transmission antenna; a second passive correlator for delaying the signals received by the reception antenna by a predetermined delay time (Δt), generating second delayed signals based on a result of the delaying, correlating the respective received signals and the respective second delayed signals in the same fashion as the first passive correlator, decoding the correlation result and synthesizing the decoded signals; a signal amplifying unit for amplifying the signals synthesized by the second passive correlator based on a preset gain; an AC/DC converting unit for converting the output signals from the amplifying unit into DC switching voltage; and a switching unit for performing an ON/OFF switching operation according to the DC switching voltage to output a wake-up voltage therefrom to the receiver.