Patent ID: 6690261
Filing Date: 2004-02-10
Classification: G06K

Abstract:
An ultrasonic recognition system on digital communication comprising:an identification card consisting of a first piezoelectric substrate, an individual coded IDT having an individual coded pattern, a first intermediary IDT; a detail communication device attached to a detail computer and consisting of a second piezoelectric substrate and transmitting- and receiving sections, said transmitting section being composed of a bipolar-pulse generator, a first coded IDT having a first coded pattern, a second coded IDT having a second coded pattern, a second intermediary IDT, an electrode group consisting of first- and second side IDTs and a central IDT between said first- and second side IDTs, a synchronizing device connected between said second intermediary IDT and said first side IDT, an envelope detecting device connected with said central IDT a monopolar-pulse generator; and a master communication device attached to a master computer and having the same construction as said detail communication device, and consisting of a third piezoelectric substrate and transmitting- and receiving sections, said receiving section being composed of a third intermediary IDT, a third coded IDT having a third coded pattern, a fourth coded IDT having a fourth coded pattern, and a detecting device, said bipolar-pulse generator generating a pulse while said identification card is set in said detail communication device, said individual coded IDT exciting an individual SAW on said first piezoelectric substrate when receiving said pulse, said first intermediary IDT detecting an individual coded burst-signal corresponding to said individual coded pattern, said first- and second side IDTs receiving said individual coded burst-signal, simultaneously, and exciting first- and second SAWs on said second piezoelectric substrate, said central IDT receiving said first- and second SAWs simultaneously, said monopolar-pulse generator causing an individual coded digital-signal via said envelope detecting device, and delivering said individual coded digital-signal into a digital network, said third intermediary IDT receiving said individual coded digital-signal from said digital network, and exciting a third SAW composed of an individual coded row of burst-wave groups on said third piezoelectric substrate, said third- and fourth coded IDTs detecting first- and second decoded pulses, respectively, when each of said burst-wave groups correlates to said third- and fourth coded patterns, respectively, said detecting device detecting an output digital-signal, which is based on said first- and second decoded pulses and is equivalent to said individual coded pattern, and recognizing the identification-card singularity from said output digital-signal.