公开(公告)号：AU7182301A

公开(公告)日：2002-01-21

申请号：AU7182301

申请日：2001-07-05

Applicant: MICROCHIP TECH INC ,  CHECKPOINT SYSTEMS INC

Inventor： YOUBOK LEE PHD DR ,  FUREY LEE ,  GALLAGHER WILLIAM ,  SALESKY RONALD D ,  ALEXANDER SAMUEL E ,  SHINICHIRO INUI

IPC: H04L25/49

Abstract: A radio frequency identification (RFID) tag device having a pulse position modulation (PPM) decoder circuit which calculates a relative frequency relationship between an internal clock-oscillator of the RFID tag device and an external PPM source such as a RFID tag reader, and then synchronizes the RFID tag device PPM decoder circuit to the required precision for reliable PPM symbol decoding. The PPM decoder is synchronized by measuring the "counts per pulse" (CPP) from a calibration cycle having a plurality of pulses in a single symbol frame.