| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce the number of drive circuits as much as possible in signal transmission using a plurality of antennas. <P>SOLUTION: If an antenna A is activated, a CPU 101 allows an LF drive circuit 102 to output a drive current, and a switch SW1 is turned on. On the other hand, switches SW2 and SW3 are turned off. A connector terminal 131-2 and GND are connected through the switch SW1, so that a closed circuit which includes the LF drive circuit 102 and the antenna A is structured. Thereby, the antenna A is activated, and it outputs LF-wave signals. A closed circuit which includes the LF drive circuit 102 and an antenna B is not structured through the switches SW2 and SW3. In addition, a closed circuit included with an antenna C is not also structured. Therefore, both of the antennas B and C are not activated. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
