PURPOSE: To immediately start the transmission of data and to prevent the useless time of communication from being generated by using a preamble signal for synchronization, which is transmitted from a fixed side communication equipment to a mobile object side communication equipment before a data signal, as an activation signal.
CONSTITUTION: A signal processing circuit 16 of an inquiry device 1 sends out the preamble signal as the activation signal to a transmission circuit 11. When a response device 2 fitted to a mobile object receives the rise of the preamble signal, a signal processing circuit 26 starts operation and a transmission circuit 28 modulates a non-modulation wave, which arrives at a transmission/reception antenna 29, by a response signal and returns the wave to the inquiry device 1. The inquiry device 1 fetches the response signal through a transmission/reception circuit 14 to the signal processing circuit 16 and immediately outputs the data signal to the transmission circuit 11. The data signal is inputted to a modulation circuit 12 and transmitted as the electromagnetic wave of a frequency f1 from a transmission antenna 13.
KOZUKA KAZUHIRO
TOMIOKA HIDEHIRO
YAMAMOTO ARATA
OTA NORIKAZU
HARADA YOSHIHISA
ISHIKAWA SOICHI
OKUDA TAKEHIKO
TOYOTA MOTOR CORP