VEHICLE ANTITHEFT DEVICE Russian patent published in 2003 - IPC

FIELD: transport engineering. SUBSTANCE: invention relates to hijacking prevention means. Vehicle is provided with supply source, current limiting resistor, remote change-over switch with two antiphase winding, light- emitting diode, sealed -contact reed relay, ignition key, intermittent signal generator, electromagnetic relay, master generator, phase keyer, transmitter and transmitting antenna. Measurement channel and two position finding channels are provided at receiving point. Measurement channel has receiving antenna, three mixers, search unit, two first intermediate frequency amplifiers, detector, two spectrum width meters, frequency doubler, comparator unit, threshold unit, delay line, three keys, frequency meter, two recording units, second intermediate frequency amplifier, frequency detector, trigger, two 90^o phase shifters, summer, multiplier, narrowband filter and amplitude detector. Position finding channels contain receiving antennas, mixers, first intermediate frequency amplifiers, multipliers, narrowband filters, phase detectors and recording units. EFFECT: improved noise immunity and selectivity of panoramic receiver by suppressing noise received by image and combination channels. 5 dwg