| 摘要 |
<P>PROBLEM TO BE SOLVED: To excellently receive both first and second reception signals in reception means according to the electric field intensity of an installation site. <P>SOLUTION: A Yagi type antenna 2 is arranged in the arriving direction of first radio waves from a first transmission station transmitted by first transmission power, and a Yagi type antenna 4 is arranged in the arriving direction of second radio waves from a second transmission station transmitted by second transmission power smaller than the first transmission power. A radiator box 12 of the Yagi type antenna 2 includes: a variable attenuator 24 for adjusting first reception signals from the Yagi type antenna 2 to be attenuated or non-attenuated; an input terminal 14 to which second reception signals from the Yagi type antenna 4 are supplied; a mixer 20 for mixing the second reception signals from the input terminal 14 and the first reception signals from the variable attenuator 24; an output terminal 34 to which the output of the mixer 20 is supplied; and a DC on-off switch 38 between the output terminal 34 and the input terminal 14. <P>COPYRIGHT: (C)2012,JPO&INPIT |
