ANTENNA CHANGEOVER DIVERSITY DEVICE

PURPOSE:To select an antenna with excellent communication quality even with a long packet length by detecting a change in a reception level at a head of a packet and a changing direction and selecting an antenna according to the result of detection. CONSTITUTION:The device has antennas 30,32 and an antenna changeover device 34 selects one of them. A reception signal is fed to a transmission reception section 36, in which transmission reception processing is implemented. A signal from the changeover device 34 is inputted to a reception level detector 38, which detects a signal level and outputs a signal with a relevant level. An output of the detector 38 is converted by an A/D converter 40 and the result is inputted to an average arithmetic section 42. The arithmetic section 42 outputs a mean value of received data. A mean value storage section 44 is connected to the arithmetic section 42 and stores the calculated mean value. The stored data is inputted a mean value comparator 46, which compares received data and outputs a signal of H or L level. A signal from the comparator 46 or the like is inputted to an antenna changeover signal generator 60, which activates the changeover device 34 to select any of the antennas 30,32.