Portable radio device having antenna switching function

摘要

The present invention provides portable radio apparatus that keeps a good transmitting quality. In the invention, a receiving antenna is determined at reception from among transmitting/receiving antennas (12) and (14) on a per transmitting slot basis by way of the space diversity (16). Then, a determined result BRNC is output to a controller (18). The controller (18) outputs a control signal to a logic circuit (20) based on the determination result BRNC. The logic circuit (20) outputs switching signals (SUB 1) and (SUB 2) corresponding to the control signal to an antenna switching section (24), which selects a transmitting antenna. It is possible to select an antenna whose receiving quality is better at reception as a transmitting antenna in the next transmitting slot. This keeps the transmitting quality better. Switching between transmitting antennas is made on a per transmitting slot basis. This assures quick adaptive switchover to an antenna having a good transmitting quality.