Patent ID: 7994923
Filing Date: 2011-08-09
Classification: G06K

Abstract:
1. A contactless electronic device, the contactless electronic device comprising a semiconductor integrated circuit, a first antenna to receive frequencies of a first frequency band, and a second antenna to receive frequencies of a second frequency band lower than the first frequency band, wherein the semiconductor integrated circuit includes: terminals connected to the first and second antennas, a power supply circuit, an interface judgment circuit, a clock circuit, a data transceiver circuit, a signal processing circuit, a filter circuit to extract a high-frequency signal of a predetermined frequency range from a received high-frequency signal from one of the first and second antennas, and a binarization circuit to perform a binary judgment of an output of the filter circuit, wherein the interface judgment circuit judges if the received high-frequency signal is a high-frequency signal of a predetermined frequency range based on an output of the binarization circuit, and thus judges through which of the first and second antennas the received high-frequency signal is input, and wherein the semiconductor integrated circuit is operative such that a state of operation is changed based on an output signal of the interface judgment circuit.