PORTABLE TERMINAL, ON-VEHICLE DEVICE AND VEHICLE APPROACH ANNOUNCING SYSTEM

摘要

PROBLEM TO BE SOLVED: To achieve a communication method to easily identify the type (for example: an on-vehicle device, a portable terminal, etc.) of a partner station while using the same channel between different types of stations. SOLUTION: A transmission processing part 120 of the portable terminal 100 is equipped with an on/off-modulation processing means with which a transmitted on-signal is frequency-modulated. A frequency discriminator 513 of the on-vehicle device 500 is provided as a means for demodulating frequency modulation of a carrier sent out from the transmission processing part 120 of the portable terminal 100. A determination part 514 outputs a reception signal (r) to a signal analysis part 531 when its frequency variation range▵f is above a predetermined threshold value. The determination part 514 ignores the reception signal (r) when the frequency variation range▵f is below the predetermined threshold value. The signal analysis part 531 in the post stage analyzes the input reception signal (r) as a normal signal transmitted from the portable terminal 100. COPYRIGHT: (C)2007,JPO&INPIT