| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce an influence of an external circuit as much as possible without characteristic deterioration of a specific path without causing increase of chip size and chip costs. <P>SOLUTION: First to tenth switches 1 to 10 of an antenna switching circuit chip 25 are constituted so that their on/off are controlled by a switching control signal from an antenna switching decoder circuit chip 22, for example, the first switch 10 is turned on and a transmitting part connection terminal 30 and a transmitting/receiving part antenna connection terminal 32 are defined as through paths, the sixth and the eighth switches 6, 8 of a receiving part connection terminal 33 are turned on, thus, they are grounded via a capacitor 11 like high frequency and the influence of the external circuit on the side of the receiving part connection terminal 33 is suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
