| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a radio clock having high stability synchronized with a reference clock without increasing a circuit scale in an extended radio device. <P>SOLUTION: A mobile communication system includes a radio base station 1 which generates the reference clock S1 based on host apparatus data, generates a clock for converting the data into a base band signal based on this reference clock, converts the base band signal into a light signal and guides the signal to an optical cable 3. The extended radio device 2 converts the optical signal inputted from the optical cable 3 into a base band signal, extracts the clock from this signal, controls to oscillate a VCXO 25 by this clock, and generates a radio clock. The radio base station 1 detects the level decrease of the optical signal, and controls to stop the radio signal by means of the extended radio device 2. Thus, a cause of a clock abnormal position in the extended radio device 2 can be easily searched. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
