| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a higher signal detection sensitivity without dependence on the polarizing condition or the temperature environment. <P>SOLUTION: A host controller 13 transmits a laser beam to a base station 12 via an optical fiber communication network 14. After modulating the leaser beam, based on an electrical signal fm from a portable communication apparatus 11, it is transmitted to the host controller 13. For detecting it, the generated laser beam is modulated according to a modulating signal on a frequency fm2 and transmitted to the base station 12, the laser beam transmitted from the base station 12 is photoelectrically converted to generate an electric signal from which an interference signal ¾fm2-fm¾ is detected for the detection, and the laser beam is controlled generated according to a component of the frequency fm2 detected from the electric signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
