CAPACITANCE-BASED GUARDING ALARM Russian patent published in 1998 - IPC

FIELD: security, in particular, protection of premises, safes, metal constructions, windows and doors, instrument making industry. SUBSTANCE: sensitive element of device is external capacitor-based antenna. Goal of invention is achieved by additional filtration and amplification channel which input is connected to output of detector and output is connected to signal processing circuits, each of which has serial circuit of comparator, integrator, and Schmidt flip-flop which outputs are connected to actuators. Output of each Schmidt flip-flop in circuit of lesser comparator-firing threshold is connected to input of integrator in circuit of greater comparator-firing threshold. EFFECT: increased stability to noise, device does not react to casual approaches to protected object, to thunder-storms, keeps its operations under weather disturbances, requires no additional tuning of equipment. 3 cl, 2 dwg