Improved Radio-Over-Fiber Transponder With Multistage Automatic Gain Control

In this paper, improved transponders with multistage automatic gain control (AGC) for radio-over-fiber-based distributed antenna systems are presented. Error vector magnitude performance measurements for both uplink and downlink paths are carried out to verify the feasibility of applying this system for IEEE 802.11g signal transmission. The developed conventional radio-over-fiber system shows its capability of supporting the wireless local area network signal transmission for an input dynamic range of approximately 14 dB. The improved radio-over-fiber systems with a single- and two-stage AGC are also demonstrated to have a better input dynamic range of 27 dB and more than 37 dB, respectively. The error vector magnitude for the case with a two-stage AGC is much better than that with a single-stage AGC.