JP2006020368A5 - - Google Patents

Claims (8)

In an optical transmission system for transmitting an optical signal analog-modulated by a radio frequency signal used for radio section communication of a mobile communication system via an optical transmission line,
An optical transmitter for generating the optical signal and sending it to the optical transmission line;
An optical receiver that receives the optical signal via the optical transmission line,
The optical receiver is
Monitoring means for detecting a light receiving level of an optical signal arriving via the optical transmission path;
Reproducing means for reproducing the radio frequency signal by optical / electrical conversion means for the incoming optical signal;
Level adjusting means for adjusting the level of the radio frequency signal reproduced by the reproducing means;
Control means for controlling the amount of adjustment of the level adjusting means based on the received light level detected by the monitoring means so that the level of the regenerated radio frequency signal is a specified value; system. The control unit includes a conversion table in which the adjustment amount is associated with the light reception level based on characteristics of the level adjustment unit, and controls the adjustment amount of the level adjustment unit based on the conversion table and the light reception level. The optical transmission system according to claim 1. 2. The control unit according to claim 1, wherein when the received light level is equal to or less than a predetermined threshold, the control unit controls an adjustment amount of the level adjusting unit so that the reproduced radio frequency signal is equivalent to a zero level. The optical transmission system described. 2. The optical transmission system according to claim 1, wherein the level adjusting means is a variable attenuator. 2. The optical transmission system according to claim 1, wherein the level adjusting means is a variable gain amplifier. Used in an optical transmission system for transmitting an optical signal analog-modulated by a radio frequency signal used in radio section communication of a mobile communication system via an optical transmission path, and receiving the optical signal via the optical transmission path In the optical receiver,
Monitoring means for detecting a light receiving level of an optical signal arriving via the optical transmission path;
Reproducing means for reproducing the radio frequency signal by optical / electrical conversion means for the incoming optical signal;
Level adjusting means for adjusting the level of the radio frequency signal reproduced by the reproducing means;
Control means for controlling an adjustment amount of the level adjusting means based on a received light level detected by the monitoring means so that the level of the regenerated radio frequency signal becomes a specified value; apparatus. In an optical transmission system for transmitting an optical signal analog-modulated by a radio frequency signal used for radio section communication of a mobile communication system via an optical transmission line,
An optical transmitter for generating the optical signal and sending it to the optical transmission line;
An optical receiver that receives the optical signal via the optical transmission line,
The optical receiver is
Monitoring means for detecting a light receiving level of an optical signal arriving via the optical transmission path;
Reproducing means for reproducing the radio frequency signal by optical / electrical conversion means for the incoming optical signal;
Level adjusting means for adjusting the level of the radio frequency signal reproduced by the reproducing means;
Control means for controlling the amount of adjustment of the level adjusting means based on the received light level detected by the monitoring means so that the level of the reproduced radio frequency signal is a specified value;
The control means includes
A conversion table in which the adjustment amount is associated with the light reception level based on the characteristics of the level adjustment unit, and the adjustment amount of the level adjustment unit is controlled based on the conversion table and the light reception level;
When the received light level is equal to or lower than a predetermined threshold value, the optical transmission system is characterized in that the adjustment amount of the level adjusting means is controlled so that the reproduced radio frequency signal is equivalent to zero level. In an optical transmission method used in an optical transmission system for transmitting an optical signal analog-modulated by a radio frequency signal used for radio section communication of a mobile communication system via an optical transmission path,
In the optical receiver that receives the optical signal via the optical transmission path, a monitoring step of detecting the light reception level of the optical signal that arrives via the optical transmission path;
A reproduction step of reproducing the radio frequency signal by optical / electrical conversion means for the incoming optical signal;
A level adjustment step of adjusting the level of the radio frequency signal reproduced in this reproduction step;
A control step of controlling the adjustment amount of the level adjusting means based on the received light level detected by the monitoring means so that the level of the reproduced radio frequency signal is a specified value;
This control process is
Controlling the adjustment amount in the level adjustment step based on the conversion table in which the adjustment amount is associated with the light reception level and the light reception level;
And a step of controlling an adjustment amount of the level adjustment step so that the reproduced radio frequency signal is equivalent to a zero level when the received light level is equal to or less than a predetermined threshold value.