Analog Return Path; Analog Return Transmitters; Table 2-1 Analog Return Transmitters - Motorola Starline SG 2000 Installation And Operation Manual

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A n a l o g R e t u r n P a t h
Similar to the multiple optical receivers, the dual return-path optical transmitters also have
split-return or redundant functionality. In split-return applications two of the four RF return signals
are fed to one optical transmitter while the remaining two return signals are fed to the second
transmitter.
Signal levels are adjusted in each return path using model JXP-* attenuator pads. Units are shipped
with a JXP-5 (5 dB) attenuator pad at the input position of each installed transmitter. If only one
transmitter is in the unit, there will be a 15 dB pad at the second transmitter input position to serve as
a termination. Ingress switching is also an available option. If ingress switches are not used, JXP-2
pads are installed.
When configured for redundancy, both return lasers are active and transmit the combined RF return
signals simultaneously. Or, they can be activated independently using the status monitor transponder
or the MCB. In the event of path failure, return path redundancy is accomplished at the headend or
the receive site by switching to the alternate or active return fiber.

Analog Return Transmitters

Five optical analog return transmitters are available to meet the needs of most return applications.
Table 2-1 identifies and describes the five analog return transmitters:
T able 2- 1
An a log ret u r n t r an sm it t e r s
Model Description
SG2-IFPT/* Uses an isolated, uncooled, Fabry-Perot laser operating at 400 µW. It carries a
full 35 MHz of digital data or up to two video channels.
SG2-FPT/* Uses a non-isolated, uncooled, Fabry-Perot laser operating at 400 µW. It carries a
full 35 MHz of digital data or up to two video channels.
SG2-DFBT/*
Uses an uncooled, isolated DFB laser operating at 1 mW for improved link
performance. It carries a full 35 MHz of digital data or up to two video channels.
SG2-DFBT/3
Uses an uncooled, isolated DFB laser operating at 2 mW for improved link
performance. It carries a full 35 MHz of digital data or up to two video channels.
SG2-EIFPT/*
Uses an uncooled, enhanced, and isolated Fabry-Perot laser operating at 1 mW
for improved link performance. It carries a full 35 MHz of digital data or up to two
video channels.
The transmitters include thermal compensation circuitry to minimize the change in received optical
and RF signal level at the headend as the node temperature varies. To reduce power consumption and
enhance reliability, the transmitters can be enabled and disabled in response to a signal from the
status monitor transponder or the MCB. An integrated optical bulkhead connector and module status
indicators enhance fiber management and reduce troubleshooting time. For remote monitoring of key
module performance parameters, the return modules are fully compatible with the status-monitor
transponder.
S G 2 0 0 0 I n s t a l l a t i o n a n d O p e r a t i o n M a n u a l