| 摘要 |
Electric field intensity of a signal corresponding to a plurality of receivers and received through antennas are converted into direct currents. The converted durect currents thus converted are fed to electric field level detection circuit. The electric field level detection means detects the electric field level on the basis of the direct currents of respective receivers and feeds a detection signal to a control portion. The control portion compares the electric field level corresponding to the direct current value in said controller with a predetermined electric field level to make judgement that the received electric field is a strong electric field and stable. Then, a command is issued to keep one of the receivers, at which the higher electric field level is detected and to turn off other receiver. An electric power source control portion performs switching of the switch portions corresponding to respective of the receivers to supply only one of the receiver from a power source and to block power supply from the power source to other receivers. <IMAGE> |
