5
ORB 823/923 Series
Adjustments
English
2. 0
Forward
Channel
2.1
Forward path
amplifier
2.2
Optical
receiver
adjustment
The RF path of the optical receiver amplifies input signals received by
the optical circuit. The attenuator enables adjustment of the input RF level,
whilst the interstage equalizer enables pre
-
adjustment. Following this, the
signal travels to the outputs.
The ORB x23 optical receiver has been designed for use within FTTx
networks. It consists of the Optical input stage and the GaAs FET Power
-
Doubler output stage, which enables the amplifier to achieve high output
levels while maintaining low intermodulation distortions. Low
-noise input
stages feature a low noise factor and a high carrier to noise ratio (CNR).
The ORB x23 receiver can operate in one of the following two gain control
modes:
-
AGC OFF
–
The manual mode does not have the ability to maintain the out-
put power at a constant level during variations in the optical input power.
The gain control system attenuator is pre
-
set to provide a minimum attenua-
tion.
-
AGC ON
–
The automatic gain control mode holds the output level substan-
tially constant despite variations in the input power from
-
6 to 0dBm.
WARNING!
The automatic gain control system compensates for variations in the opti-
cal power across the range of
-
6…0dBm but it does not compensate for
variations in the modulation factor of the optical transmitter.
The magnitude of the optical input power is indicated by a multi
-
color
LED indicator:
Input Level range:
-10dBm…+1dBm
AGC range:
-
6dBm...0dBm
orange
P
IN
<
-
6
dBm
green
-
6 < P
IN
< 0
dBm
red
P
IN
> 0
dBm
