DIVERSITY RECEIVER FOR PORTABLE RADIO EQUIPMENT

PURPOSE:To reduce the power consumption and to improve the speech quality by selecting an antenna changeover diversity or an after-detection synthetic diversity after detecting the phasing frequency. CONSTITUTION:The phasing frequency is measured by a phasing pitch detector and a controller 14. When the phasing frequency is low, a switch 11 is connected to a switch 10. Then the switch 10 functions as an antenna changeover switch for antenna switch diversity. The controller 14 delivers the commands shown by broken lines to mixers 2' and 4', an amplifier 6', a demodulator 7', a switch 13, etc. Then the parts turn off power supplies to reduce the current consumption. When the phasing frequency is high, the switch 10 is connected to an antenna 1 by a command of the controller 14. While the switch 11 connects an antenna 1' to the mixer 2'. Then the mixer 2' and others (4', 6', 7' and 13) are actuated as the after-detection changeover diversity receiver after the power supply is turned on. Thus the noise problem is solved.