GUARDING ALARM DEVICE Russian patent published in 1998 - IPC

FIELD: fence guarding. SUBSTANCE: device has sensitive element which is designed as coaxial cable which inner conductor is connected to input of amplifier, which output is connected to input of band-pass filter, which output is connected to input of first detector, which output is connected to input of first threshold gate, which output is connected to first input of generator of alarm pulses. Goal of invention is achieved by introduced measuring bridge, differential amplifier, second detector, second threshold gate. Inner and outer conductors of coaxial cable are connected to inputs of measuring bridge, which outputs are connected to inputs of differential amplifier, which output is connected to input of second detector, which output is connected to input of second threshold gate, which output is connected to second input of alarm pulse generator. EFFECT: increased functional reliability. 1 dwg