ALARM CODE DEVICE Russian patent published in 1996 - IPC

FIELD: alarm devices. SUBSTANCE: device has two parts lock and key which are not connected. Lock has synchronization signal generator 1, synchronization unit 2, encoder 3, OR gate 4, pulse oscillator 5, antenna circuit 6, pulse generator 20, code comparison unit 21, actuating unit 22, D-flip-flop 23, two AND gates 24 and 25. synchronization unit has asynchronous flip- flop which has six NAND gates, three NAND gates, RS-flip-flop which has two NAND gates, binary counter which starts by trailing edge of signal, two inverters, NOR gate, AND gate. Key has antenna circuit 7, which is connected to anodes of rectifying diode 8 and isolating diode 9, accumulating capacitor 10, pulse generator 11, duration pulse selector 12, which output is connected to second input of counter 13, commutator 14, code selection unit 15, key power supply line 16, pulse oscillator 17, breaker 18, load resistor 19, pulse edge generator 26. When key is inserted in area of alternating magnetic current of antenna circuit 6 of lock, codes which are stored in lock encoder 3 and in key selection unit 15 are compared. If they are equal then actuating unit 22 is switched off. Device may be used for car security. EFFECT: increased reliability. 2 cl, 5 dwg