| 摘要 |
PROBLEM TO BE SOLVED: To reduce costs by simplifying the structure of a wave transmitter/ receiver, by miniaturizing a cable, a transmission/reception switching part and an adder, and by reducing their scale. SOLUTION: A plurality of elements 110 of a wave transmitter/receiver 100 are divided into four groups consisting of a front beam group 101 at three circular regions with an equal area that are circumscribed one another and are inscribed to a circle for indicating the outer-enclosure line of a plurality of elements 110, a left rear beam group 102, a right rear beam group 103, and a three-beam outer group 104 at a region outside the three circular regions, thus outputting a reception signal by a plurality of elements in the units of four groups. As a result, the number of conductors of a cable 200 becomes four, the number of switching circuits of a transmission/reception-switching part 300 becomes four, and an adder has a single addition of four signals. Time difference detection parts 530a and 530b directly detect the time difference among a front beam signal FR, a left rear beam signal LB, and a right rear beam signal RB.
|
