ALARM SIGNALLING SYSTEM Russian patent published in 1995 - IPC

FIELD: signalling systems. SUBSTANCE: system has TV detector, sync generator, commutator, videocontrol unit and memory unit. Signalling device, mixer, analog-to-digital and digital-to-analog converters, unit for forming delayed pulses and digital comparator are introduced into the device additionally. The circuit is separated in the device which limits zone of control in object under observation; information of the object image is memorized in memory unit. In case if information changes in single, two or three parts of the circuit which are set in the frame, the device generates alarm signal. When information changes in all four parts of the circuit simultaneously which is caused by changes in atmosphere, turning lights off and different disturbances, alarm signal does not form. EFFECT: improved noise immunity. 5 cl, 5 dwg