Patent ID: 7528743
Filing Date: 2009-05-05
Classification: G06F,H04B

Abstract:
1. A sensor circuit for transmission of information to an external communications device, the sensor circuit comprising: a resonant circuit; a power extracting circuit for extracting power for driving components of the sensor circuit from an induced voltage which is generated in the resonant circuit due to externally transmitted electromagnetic waves; a first of said components comprising a digital information generator for detecting analog information from interaction between a wireless position indicator and a digitizer tablet and generating digital information which corresponds to the analog information and which includes a binary code of two bits or more; and a second of said components comprising a resonance characteristic controller for bringing the resonant circuit into a short-circuited state in accordance with any one of ‘0’ and ‘1’ of the binary code in synchronization with at least part of the electromagnetic waves, wherein, by transmitting the digital information including the binary code, only one bit of the binary code changes when the corresponding analog information changes, a variation in the power supply voltage is suppressed and the analog information is stably detected.