Patent ID: 6404338
Filing Date: 2002-06-11
Classification: G01S,G08B

Abstract:
Security system for detection of an object in an area, comprising:at least a first and a second transmission system coupled by a wireless connection; wherein one transmission system is attached to the object; a signal source located in one of the transmission systems that generates a signal of output pulses having, during the duration of the pulses, a monotonically changing frequency; wherein the second transmission system transmits a control signal to the first transmission system, and upon receipt of the control signal, the first transmission system transmits an acknowledgement signal to the second transmission system; a dispersion filter located in one of the transmission systems that is matched to the signal source and has a predetermined frequency-dependent signal transit time such that the spectral signal portions of the pulses appear at the output of the dispersion filter with slight temporal imprecision essentially coincidentally; a time-measuring device located in the second transmission system that measures the signal transit time between emission of the control signal and receipt of the acknowledgement signal; a calculating unit connected with the time-measuring device that calculates a measurement and generates an alarm signal as a function of signal transit time.