SYSTEM OF PROTECTION AGAINST UNAUTHORIZED ACCESS TO VEHICLES Russian patent published in 2013 - IPC B60R25/00 

FIELD: transport.

SUBSTANCE: invention relates to automotive industry and can be used for prevention of unauthorized access to automobiles. Proposed system comprises logical module 1, transponder reader 2, transponder 3, memory 4 of individual service settings, user warning unit 5, immobiliser relay component 6, and setting state signal converter 7. Transponder reader 2 incorporates oscillator 8, modulation code oscillator 9, phase-shift modulator 10, power amplifier 11, duplexer 12, transceiving antenna 13, HF amplifier 14, 1^st, 2^nd, 3^rd and 4^th multipliers 15, 16, 28 and 29, respectively, first and second narrowband filters 17 and 50, first and second LF filters 18 and 31, first and second demodulators 19 and 34 of FM-signals, memory 20, comparator 21, first and second phase inverters 32 and 33, and subtractor 35. Transponder 3 consists of piezocrystal 22, microstrip antenna 23, electrodes 24, first and second busses 25 and 26, and unit of reflectors 27. Technical effect is ensured by attenuation of narrowband interferences, increasing SNR at subtractor output by two universal demodulators with their inverses output voltages summed up in absolute value while unipolar interference voltages are mutually subtracted.

EFFECT: higher noise immunity, validity of complex signals reception.

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