5-22 Operation
SG 2000 Installation and Operation Manual
DS-SG2-DRT-2X/A Digital Return Transmitter
The DS-SG2-DRT-2X/A is an SG2 return transmitter that digitizes two independent analog
5 MHz-42 MHz return-path signals to produce two 1.25 Gbps data streams. These two data streams
are then multiplexed to create a 2.5 Gbps data stream. This data stream is then routed to a digital
laser for transmission to a corresponding digital return receiver.
The transmitter can be configured with a digital laser wavelength that is applicable to the required
link length. An APC system regulates the optical output power from the laser. Two user-accessible
input level-control adjustments enable you to independently adjust the transmitter input levels +2 to
−13 dB from an input level of 15 dBmV. All transmitter status-monitor information is available at
the digital return receiver.
To facilitate easy upgrades, the DS-SG2-DRT-2X/A fits the same footprint and has the same set-up
levels as the analog return transmitters.
Figure 5-23 illustrates a block diagram of the DS-SG2-DRT-2X/A:
Figure 5-23
DS-SG2-DRT-2X/A
Serializer
Transmit
signal
processing
logic
A/D
converter
RF
XFMR
XO
XO
Anti-
aliasing
LPF
Return
band RF
5-42 MHz
CATV
gain block
A/D
converter
RF
XFMR
Anti-
aliasing
LPF
Return
band RF
5-42 MHz
CATV
gain block
Digital
lightwave to
SG2 output
Optical transmitter module
Serial bit
stream
@2.5 Gbps
Figure 5-24 illustrates the DS-SG2-DRT-2X/A and attached cable:
Figure 5-24
DS-SG2-DRT-2X/A
INPUT
A
INPUT
B
STATUS DS-SG2-DRT-2X/A
1310 DFB
RF
INPUT
B
SG2000
Digital Transmitter
DANGER
Test
Point
Test
Point
B
You can gain access to test point A through the transmitter test cable MCX-F (DS-SG2-DRT-TC,
P/N 476803-001).
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