Patent ID: 6215437
Filing Date: 2001-04-10
Classification: G01S,G06K

Abstract:
A method of remote communication in a noisy environment, within a predetermined frequency band, between an interrogator and a transponder wherein an interrogator transmits an interrogation signal and the transponder responds with data, stored therein, modulating a transponder response signal, comprising:receiving background noise, having frequency components, within said predetermined frequency band during a time when neither said interrogation signal nor said transponder response signal are being transmitted or received;converting said background noise into a digital signal;identifying said frequency components of said background noise which have an amplitude exceeding a predetermined threshold;computing coefficients of an adaptive filter, having a passband characteristic, in dependence upon said identified frequency components such that said passband characteristic suppresses said identified frequency components;transmitting said interrogation signal;receiving said transponder response signal and superimposed background noise;converting said transponder response signal and said superimposed noise into a digital signal;routing said digital signal through said adaptive filter; anddemodulating the output of said adaptive filter and yielding said data stored therein.