| 摘要 |
PURPOSE:To prevent a receiver from being affected by the generation of noise due to the switching of an antenna, by performing the switching of a signal at a preamble signal part where is not the information signal part of a time divisionally multiplexed signal. CONSTITUTION:The preamble part 210 and the information part 220 of a reception modulation wave signal are multiplexed time divisionally. Level measurement is performed in the receiving period of the part 210. Therefore, when the part 210 is detected in a frame separation circuit 121, a control circuit 160 is started up by a signal 161. The circuit 160, when receiving the signal 161, outputs a contorl signal 103 to a switching circuit 110, and switches the switch for the antennae 101 and 102 timedivisionally. Corresponding to the above, a level measuring circuit 150 measures the levels received at the antenna 101 and 102, and signals 162 representing results to the circuit 180 respectively. The circuit 160 compares two level measured results, and outputs the signal 163 so as to select the antenna representing a higher level.
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