SECURITY ALARM SYSTEM Russian patent published in 1998 - IPC

FIELD: security, in particular, systems for detection of objects which move in monitored space in which or about which large objects are located. SUBSTANCE: device has alarm signal generator, modulation oscillator, amplitude modulator, generator of emitted signal, selector of received signal, signal converter, video amplifier, commutation synchronous filter. Goal of invention is achieved by introduced band-pass filter, two subtraction units, comparator, memory unit, adder and pulse generator. EFFECT: instantaneous compensation of average level of received signal, decreased power of emitted signal, ecological safety, compatibility with adjacent operating devices, increased field of application. 3 dwg