Patent ID: 6275552
Filing Date: 2001-08-14
Classification: G07B,G08G,H04J,H04W

Abstract:
A communication system comprising:on-board communication equipment mounted in a vehicle and used to execute a communication processing according to communication signals received when passing a specified communication area;wherein the on-board communication equipment includes:a receiver configured to (i) detect at least two synchronizing signals when receiving the communication signals and (ii) execute a subsequent communication by setting a communication timing according to the detected synchronizing signals; andwherein each synchronizing signal includes a predetermined bit pattern and a predetermined data length defined by a number of bits in the bit pattern, the data length of one of the synchronizing signals being longer than the data length of the other synchronizing signal, and a portion of the bit pattern of the one synchronizing signal having the longer data length matching an entirety of the bit pattern of the other synchronizing signal;a first detecting circuit in which the bit pattern of a comparator is set so as to detect the synchronizing signal having the shorter data length from among the synchronizing signals; anda second detecting circuit configured for comparing another portion of the bit pattern of the synchronizing signal having the longer data length than that of the detected synchronizing signal, the other portion being undetected by the first detecting circuit, comparing in order to detect the synchronizing signal having the longer data length.