| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system which is superior in noise characteristics and distortion characteristics in a ROF(radio-on-fiber) system and relaxes the demand of a wide band to an optical transmitter. SOLUTION: In the communication system wherein a control station 1 and an antenna station 3 are connected by an optical fiber 3, the control station 1 after converting an IF signal and a local signal for frequency conversion into light signals by an optical transmitter 11 for IF signal and an optical transmitter 13 for local signal couples them by an optical coupler 14 and sends the resulting signal out to an optical fiber 3, and the antenna station 2 converts the light signal transmitted by the optical fiber 3 into an electric signal by a photoelectric converter 20. Filters 21-1 and 21-2 extracts, the IF signal and local signal for frequency conversion from the output of the photoelectric converter 20, and convert the IF signal by a frequency converter 22 into a desirable radio frequency signal, which is passed through a power amplifier 25 and then radiated from an antenna 4. |
