The transmission method and radio station narrowband communications system

摘要

PPROBLEM TO BE SOLVED: To provide a dedicated short range communications (DSRC) in which an on-vehicle apparatus needs to be adaptable to the ASK modulation system and the π/4 shift QPSK modulation system and when a transmission circuit block such as a power amplifier is shared between both modulation systems, transmission output powers can be set to optimum values in the respective modulation systems. PSOLUTION: A wireless station in the dedicated short range communications is provided with a switching means so that gain of the power amplifier or an attenuation of an attenuator between both modulation systems can be switched. As the switching means, a digital potentiometer whose resistance can be varied by an electric control signal or an analog switch or the like which is switched by an electric control signal is used. PCOPYRIGHT: (C)2008,JPO&INPIT