Patent ID: 8717227
Filing Date: 2014-05-06
Classification: G01S

Abstract:
1. A communication processing apparatus that processes and transmits a command to an RFID tag by modulating a carrier wave, receives and processes a reflected wave from the RFID tag in response to an unmodulated carrier wave while transmitting the unmodulated carrier wave, and decodes and processes a response signal of the RFID tag from the received reflected wave, the apparatus comprising: a phase detector that detects a phase of the reflected wave received in the reception processing; a phase changer that changes a phase of the unmodulated carrier wave in response to a start of reception of the reflected wave in the reception processing; and a distance measurer that measures a time from when the phase of the unmodulated carrier wave is changed to a time when a corresponding change occurs in the phase of the reflected wave detected by the phase detector, and that uses the measured time to measure a distance to the RFID tag that returned the reflected wave.