SAFEGUARD SIGNALLING DEVICE Russian patent published in 1998 - IPC

FIELD: safeguard signalling equipment using a radio beam for producing the line of detection in protected zone of the object, applicable in moving objects registration (count) systems. SUBSTANCE: the safeguard signalling device uses a transmitter and a microwave receiver, receiving and transmitting antennas; the radio beam produced by the transmitter antenna is directed towards the receiver antenna and produces a detection zone between them. The device operating frequency is within a frequency band at which the coefficient of shading of the first Fresnel zone by a man increases by 2-3 times; the transmitter operating frequency in the band is selected proceeding from the condition of maximum absorption of electromagnetic energy by air oxygen; besides, the transmitter operates in the condition of modulation at a frequency determined by minimum noise of the receiver microwave discriminator, and with a relative duration ratio at which the level of average power ensures the receiver sensitivity at a preset distance. EFFECT: enhanced detection characteristics, enhanced concealment and electromagnetic compatibility, reduced power consumption and mass and dimensional characteristics of the device. 2 dwg