An RF electronic identification system 10 is disclosed and claimed. The system includes a reader 12 and a plurality of transponders 14.1 to 14.n. When energized by an interrogation signal from the reader, each transponder automatically responds by repeatedly retransmitting a signal burst including identification...http://www.google.com.hk/patents/US6154136?utm_source=gb-gplus-share專利 US6154136 - Free running RF identification system with increasing average inter transmission intervals
