TRANSMITTER, KEYLESS ENTRY SYSTEM, PNEUMATIC PRESSURE MONITORING SYSTEM OF TIRE

摘要

A transmitter comprising a transmission antenna section, an output section for obtaining an output current from the joint node of first and second switches connected in series between two different potentials to the transmission antenna section, an output drive section performing switching control on the first and second switches, and a duty ratio setting means for variably setting the duty ratios of the first and second switches by the output drive section. Radio wave arriving range of the transmission antenna section can be regulated easily without requiring a complex work.