Patent ID: 7747220

Claim:
A system for encoding information on a passive surface acoustic wave device (SAW), comprising: a requesting unit configured to wirelessly transmit an impulse signal; and a SAW device having an interdigital transducer (IDT) that is configured to physically store coded data, the SAW device being configured to receive the impulse signal and in response to receiving the impulse signal, exciting the IDT to generate a coded signal that includes the stored coded data and that includes frequency components at a fundamental frequency; wherein a second IDT is configured to receive the impulse signal and in response to receiving the impulse signal, being further configured to produce a first SAW output that includes frequency components at the fundamental frequency; further comprising: a termination circuit coupled to the IDT and configured to reflect the coded signal generated by the IDT; and wherein the IDT is excited by the first SAW output to generate the coded signal, and the termination circuit re-excites the IDT to generate a coded SAW output that includes the stored coded data.