| 摘要 |
PROBLEM TO BE SOLVED: To obtain a narrow area communication DSRC(dedicated short-range communication) on-vehicle device that can quickly process data of a received signal independently of a difference in a transmission frequency from an on-road device. SOLUTION: The on-vehicle device 2A is provided with a reception circuit 5 that receives a signal A from a reception antenna 3 a local oscillator 9 which changes oscillated local frequency given to a reception mixer 4, a controller 10A that controls the frequency and conducts reception data processing, a detection diode 11 that demodulates the received signal, an electric field strength discrimination circuit 12 that produces an electric field strength discrimination signal D when the electric field strength of the received signal is prescribed strength or over, and an AND circuit 13 that generates an AND signal E between an output signal A5 of the reception circuit and the electric field strength discrimination signal. The controller initially selects a 1st frequency, monitors the AND signal in response to the electric field strength discrimination signal, fixes the frequency to the 1st frequency when the AND signal is at a high level but selects a 2nd frequency when the AND signal is at a low level. |
