| 摘要 |
An ultrasonic recognition system on digital communication comprises an identification card, a detail communication device attached to a detail computer, and a master communication device attached to a master computer. The identification card consists of a first piezoelectric substrate, an individual coded IDT, and a first intermediary IDT. The detail communication device consists of a second piezoelectric substrate and transmitting- and receiving sections. The transmitting section is composed of a bipolar-pulse generator, a first coded IDT, a second coded IDT, a second intermediary IDT, an electrode group, a synchronizing device, an envelope detecting device, and a monopolar-pulse generator. The receiving section is composed of a third intermediary IDT, a third coded IDT, a fourth coded IDT, and a detecting device. If the identification card is set in the detail communication device, a pulse is generated at the bipolar-pulse generator at regular intervals. When the pulse is applied to the individual coded IDT, an individual SAW is excited on the first piezoelectric substrate. The individual SAW is detected at the first intermediary IDT as an individual coded burst-signal, which is received at the electrode group and is converted into an individual coded digital-signal at the monopolar-pulse generator. The individual coded digital-signal is delivered into a digital network. When the individual coded digital-signal is received by the master communication device, the signal decoding is achieved, so that the identification-card singularity is recognized by the master communication device.
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