User's Manual

User Handbook L-RU Revision C
CONFIDENTIAL
PROPRIETARY
Reg. No.: User Handbook 1100182-C.DOC Page 13 of 29
Figure 6: Block schematic of the Remote Unit
A detailed block schematic of the RU is shown in Figure 4 indicating the optical transceiver
part in red, the monitoring electronic in blue, the PSU in yellow and the RF amplifier block
in grey.
In downlink, an optical receiver ORx converts the optical input signals from the Optical
Master Unit to RF signals. The BP/LP separates RF communications signals from the
monitoring pilot tone. A cascade of amplifiers provides sufficient RF gain imbedded in an
ALC which keeps the output power level constant compensating optical losses of the opti-
cal link. The duplexer separates downlink output signals from uplink input signals.
In uplink, the RF amplifier is embedded in an ALC, which compensates varying input
power levels. The output power into the laser OTx is limited protecting the laser against
damages. The BP/LP module combines the RF signals with the pilot tone in UL.