DEVICE FOR SECURITY ALARM ON BASIS OF LEAKAGE CABLE Russian patent published in 2008 - IPC G08B13/22 

FIELD: electric engineering.

SUBSTANCE: device contains high-frequency signal generator, which is modulated by amplitude with pulses of frequency f_mod, leakage cable, mixers, circuit of frequency f_mod isolation, reception cable, approved load, high-frequency amplifier, phase changer of signal for π/2, pulse amplifiers, synchronous detectors, low frequency amplifiers, signals from which are separately squared in processing circuit, summed up, and square root of summed signal is calculated, threshold element, which, in case preset level is exceeded, sends corresponding signal to the circuit of alarm signal generation.

EFFECT: provision of necessary level of sensitivity balancing along borderline of detection facility on the line of leaky wave, high level of detection and noise immunity.

1 dwg