SG 2000
Telecommunications Optical Node
Installation and Operation Manual
4
2
6
IN
7
Caution
Caution
CautionCaution
These servicing instructions are for use by qualified personnel only. To reduce the risk of electrical shock, do not perform any servicing other than that
contained in the Installation and Troubles hoot ing I ns t ruct ions unless you a r e qua lified t o do s o. Refer all servicing to qualified service personnel.
Special Symbols that Might Appear on the Equipment
Special Symbols that Might Appear on the Equipment
Special Symbols that Might Appear on the EquipmentSpecial Symbols that Might Appear on the Equipment
This is a class 1 product that contains a class IIIb laser and is intended for operation in a closed environment with fiber
attached. Do not look into the optical connector of the transmitter with power applied. Laser output is invisible, and eye
damage result. Do not defeat safety features that prevent looking into optical connector.
This product contains a class IIIb laser and is intended for operation in a closed environment with fiber attached. Do not look
into the optical connector of the transmitter with power applied. Laser output is invisible, and eye damage can result. Do not
defeat safety features that prevent looking into optical connector.
This symbol indicates that dangerous voltage levels are present within the equipment. These volt a ges ar e not insula t ed a nd
may be of sufficient strength to cause serious bodily injury when touched. The symbol may also appear on schematics.
The exclamation point, within an equilateral triangle, is intended to alert the user to the presence of important installation,
servicing, and operating instructions in t he document s a c co mpa nying t he equip ment .
For continued protection against fire, replace all fuses only with fuses having the same electrical ratings marked at the
location of the fuse.
transformation or adaptation) without written permission from Motorola, Inc.
Motorola, Inc. reserves the right to revise this publication and to make changes in content from time to time without obligation on the part Motorola, Inc.
to provide notification of such revision or change. Motorola Inc. provides this guide without warranty of any kind, either implied or expressed, including,
but not limited, to the implied warranties of merchantability and fitness for a particular purpose. Motorola, Inc. may make improvements or changes in
the product(s) described in this manual at any time.
________________________________________________________________________________________________________________________________
MOTOROLA, the stylized M logo, and STARLINE are registered trademarks, and LIFELINE is a trademark of Motorola, Inc.
All other product or service names are the property of their respective owners.
Contents
Section 1
Introduction
Using this Manual ..........................................................................................................................................1-3
Related Documentation ..................................................................................................................................1-3
If You Need Help...........................................................................................................................................1-4
Calling for Repairs .........................................................................................................................................1-5
Port Locations................................................................................................................. .......................2-2
Power Supply................................................................................................................................................2-4
Analog Return Path ..................................................................................................................................... 2-10
Analog Return Transmitt ers ..................................................................................................................2-10
Digital Return Path ......................................................................................................................................2-12
Options and Accessories.............................................................................................................................. 2-14
Gain Selection...................................................................................................................................... 2-16
Powering the Node ........................................................................................................................................3-3
Power Supply Settings.......................................................................................................... .........................3-5
Single Power Supply o r Commonly Po wered Redunda nt Supplie s.............................................................3-7
Launch Amplifier Outpu t Stage Paddi ng........................................................................................................3-14
Link Performance ........................................................................................................................................ 3-15
Installing the DS-SG2-DRRB Bo ard Option ...................................................................................................3-1 8
Installing the Status Monito r Option .............................................................................................................. 3-2 2
SG2-FPT Optical Trans mitter.......................................................................................................................5-15
SG2-DFBT Optical Transmitt er .....................................................................................................................5-16
SG 2000 Instal lation and Opera tion Manual
Contents iii
SG2-DFBT/3 Optical Trans mitter..................................................................................................................5-18
DS-SG2-DRT/A Digital Return T ransmitter....................................................................................................5-20
DS-SG2-DRT-2X/A Digi tal Return T ransmitter............................................................................................... 5-22
SG2-PS Power Supply..........................................................................................................................5-25
Status Monitoring ........................................................................................................................................ 5-26
Manual Control Board..................................................................................................................................5-27
Table A-12 Optical output power vs. wavelength for DS-SG2-DRT*/A transmitters .............. A-6
SG 2000 Instal lation and Opera tion Manual
vi Contents
Table A-13 Current requirements ......................................................................................A-7
Table A-14 SG2-75 performance, with 77 channels............................................................ A-8
Table A-15 SG2-87 performance, with 94 channels............................................................ A-8
Table A-16 SG2-87 performance, with 110 channels.......................................................... A-8
SG 2000 Instal lation and Opera tion Manual
Section 1
Introduction
Motorola’s SG 2000 telecommunications optical node performs light wave-to-RF and RF-to-light
wave signal conversions in an optical transmission link. This product is designed to support a wide
variety of advanced hybrid-fiber/coaxial network topologies.
As broadband communication systems continue to evolve, the demand increases for optical links that
carry the signal further into the transport system. These systems require additional features and
functionality such as digital compression and alternate access at significantly lower costs. Fully
configured, the SG 2000 supports these next-generation telecommunication networks. It also
supports a variety of single and two-way broadband network applications such as broadcast video,
interactive video, telephony, and data.
Figure 1-1 illustrates a closed SG 2000 telecommunications optical node:
Figure 1-1
SG 2000 — closed
6
78
3
2
1
4
5
SG 2000 Instal lation and Opera tion Manual
1-2 Introduction
A
A
Figure 1-2 illustrates an open SG 2000 telecommunications optical node:
Figure 1-2
SG 2000 — open
H
L
JXP 2
JXP 4
L
H
SSEMBLED IN MEXICO
-20dB
-20dB
CAUTION:
CONTAINS PARTS
ND ASSEM B LI E S
SUSCEPTIBLE TO
DAMAGE BY
ELECTROSTATIC
DISCHARGE (ESD)
-20dB
-20dB
REFER TO
MANUA L F OR
FUSE VALUES
-20dB
H
L
JXP 1
L
H
PORT 1PORT 2
FTEC
PORT 3
JXP 1
FWD EQ
ON
-20dB
+24 V DC
IS
IS
JXP 3
JXP 3
-20dB
FWD EQ
MDR
VARILOSSE R
RCVR
INPUT
ADU
ON
OFF
MAN
SG2-
FRB
STATUS MO NI TOR
RPM/*
SG 2000
Optical Node
FWD EQ
JXP 2
TCU
JXPADU
IS
IS
ADU
ADU
FWD EQ
-20dB
JXP 4
PORT 4
Base
Lid
Features include:
! 52 through 870 MHz forward passband, 5 through 40 MHz return standard (other splits are
available, see Appendix A, “Specifications”)
! Optical receivers - up to three
! Optical transmitters - up to two
! Four independent RF outputs
! Ingress switching capability through manual or headend control
! Redundant powering capability
! 15 A power passing
SG 2000 Instal lation and Opera tion Manual
Introduction 1-3
! Optional LIFELINE
! User-friendly fiber management
! 60/90 volt powering
! Digital return redundancy capability
! Modular plug-in diplex filters and equalizers
! Custom configuration for unique system requirements
™
status monitoring
Using this Manual
The following sections provide information and instructions to install, configure, and operate the
SG 2000:
Section 1 Introduction provides a brief description of the product, identifies the information
Section 2 Overv iew describes the SG 2000 node and includes details regarding your options
Section 3 Bench Setup provides full configuration, set-up of options, and bench testing
Section 4 Installation provides instructions for installing the SG 2000 in a distribution
contained in this manual, and gives the help line telephone number and repair
return information.
and their functions.
procedures that are recommended before installation.
system.
Section 5 Operation provides information governing the use of various options and
applications required by your system.
Appendix A Specifications provides technical specifications for the SG 2000 node and major
options.
Appendix B Torque Specifications provides the appropriate torque specifications for the
screws, clamps, connectors, and bolts used in the SG 2000.
Abbreviations
and Acronyms
The Abbreviations and Acronyms list contains the full spelling of the short forms
used in this manual.
Related Documentation
Although these documents provide information that may be of interest to you, they are not required
to install or operate the SG 2000.
# LL-CU LIFELINE Control Unit Installation and Operation Manual
# LIFELINE for Windows Site Preparation Guide
# LIFELINE for Windows Software Operations Manual
# Return Path Level Selection, Setup, and Alignment Procedure Reference Guide
SG 2000 Instal lation and Opera tion Manual
1-4 Introduction
Document Conventions
Before you begin to use the SG 2000, familiarize yourself with the stylistic conventions used in this
manual:
Bold type
SMALL CAPS
*
(Asterisk)
Italic type
Indicates text that you must type exactly as it appears or indicates a default value
Denotes silk screening on the equipment, typically representing front and rear-
panel controls, I/O connections and indicators (LEDs).
Indicates that there are several versions of the same model number and the
information applies to all models. When the information applies to a specific model,
the complete model number is given.
Denotes a displayed variable, a variable that you must type, or is used for
emphasis
If You Need Help
If you need assistance while working with the SG 2000, contact the Motorola Technical Response
Center (TRC):
# Inside the U.S.: 1-888-944-HELP (1-888-944-4357 )
# Outside the U.S.: 215-323-0044
# Online: http://www.motorola.com/broadband
Support, then click Web Support.
The TRC is open from 8:00 a.m. to 7:00 p.m. Eastern Time, Monday through Friday and 10 AM to
6 PM Eastern Time, Saturday. When the TRC is closed, emergency service only is available on a
call-back basis. Web Support offers a searchable solutions database, technical documentation, and
low priority issue creation/tracking 24 hours per day, 7 days per week.
, click HTML/Modem Version, click Customer
SG 2000 Instal lation and Opera tion Manual
Introduction 1-5
Calling for Repairs
If repair is necessary, call the Motorola Repair Facility at 1-800-642-0442 for a Return for Service
Authorization (RSA) number before sending the unit. The RSA number must be prominently
displayed on all equipment cartons. The Repair Facility is open from 7 AM to 4 PM Pacific Time,
Monday through Friday.
When calling from outside the United States, use the appropriate international access code and then
call 526-314-1000, extension 3194, to contact the Repair Facility.
When shipping equipment for repair, follow these steps:
1 Pack the unit securely.
2 Enclose a note describing the exact problem.
3 Enclose a copy of the invoice that verifies the warranty status.
4 Ship the unit PREPAID to the following add ress:
Motorola BCS
c/o Exel
Attn: RSA #___________
6908 East Century Park Dr.
Tucson, AZ 85706
SG 2000 Instal lation and Opera tion Manual
Section 2
Overview
Designed to be flexible, you can configure the SG 2000 with up to three optical receivers, four
independent high-level RF outputs, and two return-path optical transmitters. Multiple receiver and
transmitter combinations are available to satisfy split-band or redundancy requirements. The forward
passband is extended to 870 MHz to increase channel capacity and support advanced interactive
services and global applications.
Housing
The aluminum housing protects the electronics from weather damage and dissipates internally
generated heat. Figure 2-1 illustrates the housing dimensions of the SG 2000 optical node:
Figure 2-1
SG 2000 housing di mensions - front and s ide view
12.25
6
78
3
2
1
21.6010.99
4
5
34 OUT
For strand mounting, the optional bracket must be used. If the node is configured for strand
mounting, the bracket is installed on the node at the factory. The bracket provides two clamps,
located 16-7/8 inches apart, that secure the strand with 5/16 × 20 stainless steel bolts.
Coaxial cable connections to the housing are made using conventional 5/8 inch × 24 threads per inch,
stinger-type connectors.
Mounting Holes
Two threaded holes are located on the horizontal centerline on the back of the housing. These
5/16 × 18 × ¾ holes are separated by 11 inches center-to-center and can be used for pedestal or
surface mounting.
SG 2000 Instal lation and Opera tion Manual
2-2 Overview
Port Locations
The five housing ports, shown in Figure 2-2, provide connection for coaxial cables. Note that the
housing ports are not labeled the same as the ports on the RF chassis. Side-by-side connector fittings
are limited to .750 inches at ports 1 and 2 and/or ports 3 and 4. These ports are protected by factory
inserted threaded plugs or plastic cap plugs which are discarded when the cable connectors are
installed. Port 2 is used only for connection to an external 60 Vac or 90 Vac power supply. Port 4 is
unused.
Figure 2-2 illustrates a front and end view of the housing and port locations:
Figure 2-2
Port locatio ns
6
78
3
2
1
4
5
Port 1Port 2
AC portUnused
Port 3Port 4
12IN
Lid
34 OUT
SG 2000 Instal lation and Opera tion Manual
Overview 2-3
A
A
Gaskets
Each housing is equipped with a woven-wire gasket and a silicone-rubber weather gasket between
the housing base and lid as shown in Figure 2-3:
Figure 2-3
Housing ga skets
Weather ga ske t
(silicone rubber)
H
L
JXP 2
JXP 4
L
H
SSEMBLED IN MEXICO
-20dB
-20dB
CAUTION:
CONTAINS PARTS
ND ASSEMBLIES
SUSCEPTIBLE TO
DAMAGE B Y
ELECTROSTATIC
DISCHAR GE (E SD)
-20dB
-20dB
REFER TO
MANUAL FO R
FUSE VALUES
-20dB
H
L
JXP 1
L
H
PORT 1PORT 2
FTEC
PORT 3
JXP 1
FWD EQ
ON
-20dB
+24 V DC
IS
IS
JXP 3
JXP 3
-20dB
FWD EQ
MDR
VARILOSSE R
RCVR
INPUT
ADU
ON
OFF
MAN
SG2-
FRB
STATUS MO NI TOR
RPM/*
SG 2000
Optical Node
FWD EQ
JXP 2
TCU
JXPADU
IS
IS
ADU
ADU
FWD EQ
-20dB
JXP 4
PORT 4
RF gasket
(woven wire)
The gaskets provide efficient ground continuity, RF shielding and weather protection. Both gaskets
must be in place and in good condition to ensure proper operation and protection of the node. The
silicone rubber gasket should be lightly covered with silicone grease each time the node is opened.
Replace the gasket if it is damaged or deformed.
SG 2000 Instal lation and Opera tion Manual
2-4 Overview
Power Supply
The SG 2000 power supply (SG2-PS2) is located in the housing lid to optimize heat transfer and to
balance the thermal load between the base and the lid . F or high rel iab il ity or redun dancy
applications, two power supplies can be used. An umbilical cord connects the SG2-PS2 to the lid
motherboard (LIDB).
A flexible power-distribution design enables you to power the node from any of the four RF ports.
Using fuses and shunts you can configure the node to distribute power to the remaining active ports.
You can also power the node locally through the ac only port (port 2) while a second cable-plant
power supply loops through the other two main RF ports.
The power supply includes a heavy-duty, gas discharge tube surge protector located on the amplifier
module. You can replace this surge protector with the optional FTEC surge protector. The FTEC
triggers at approximately 230 V and presents a short circuit to the line during periods of over
voltage. After the ac input voltage returns to normal, the FTEC returns to its open-circuit state. This
provides the node with a level of protection against surge currents on the ac line. The same protector
is used for both supplies unless the split ac-feed option is implemented; then, the secondary or
redundant power supply is protected by a conventional heavy-duty gas discharge tube.
The 20-ampere fuses are installed at the factory to provide power passing to additional amplifiers.
Section 3, “Bench Setup,” discusses fusing options that are also diagrammed in Figure 3-1.
Figure 3-2 illustrates the location of the fuses.
The SG 2000 optical node can be powered from either 60 Vac or 90 Vac system power supplies. The
unit is shipped from the factory set for 60 Vac powering. For systems equipped with 90 Vac
powering, the suitcase jumper on the dc power supply can be repositioned to optimize the supply
start-up voltage for the higher input range. Section 3, “Bench Setup” provides a description of this
procedure.
Figure 2-4 illustrates the SG2-PS2 power supply:
Figure 2-4
SG2-PS2 power supply
SG2-PS2
NO USER SERVICEABLE PARTS INSIDE
CAUTION
VOLTAGES IN EXCESS OF
300 VOLTS ARE PRESENT
UNDER COVER AND MAY
BE PRESENT AFTER POW ER
IS REMOVED
SEE INSTALLAT ION MANUAL FOR SERVICE
LO HI
ASSEMBLED IN MEXICO
24V5V
ADJ
TEST
POINT
TEST
POINT
The optional SG2-PS power supply is required to support DS-SG2-DRT-2X/A transmitters in a
redundant configuration. The SG2-PS2 and SG2-PS power supplies are interchangeable.
SG 2000 Instal lation and Opera tion Manual
Overview 2-5
Network Monitoring
The optional LIFELINE Status Monitoring System (LL-SG2) enables you to monitor the SG 2000
from a headend or a remote location. The transponder consists of a plug-in module mounted on the
main RF board. If you do not employ status monitoring and use redundant receivers and/or
transmitters, a manual control board (MCB) occupies the same position on the main RF board.
The entire LIFELINE system includes:
LL-CU control units
Are connected to the system at the headend and interrogate each
SG 2000 field transponder with FM outbound and inbound
transmissions. A variety of outbound and inbound frequencies can be
selected depending on the configuration of the system. The control unit
reports this information to the status monitor computer.
Status Monitor
Computer and
Software
LL-SG2-* Field
Installed
Transponders
Includes an IBM
unit (CU) through an RS-232 link. LIFELINE software enables the
operator to view measurements taken by the transponders.
Installed in individual field components, this unit interfaces with the CU at
the headend. It reports such parameters as: forward amplifier dc current
draw, ac and dc voltage, temperature, automatic drive unit (ADU-*) drive
-compatible computer that is connected to the control
voltage, management and control of RF ingress switching, and tamper
status.
Configuration
To accommodate unique system criteria, the SG 2000 is shipped as a configured product. Hundreds
of variations are available with configurations designed to address numerous system requirements
that include:
! Varying RF output configurations
! Forward bandwidth to 750 MHz or 870 MHz
! Forward slope options L, M, H, and U
! Band splits S, J, A, K, E, and M
! Silicon or GaAs technology
! Forward and return path redundancy
# High and low gain options
# Network monitoring
# RF output level control - thermal or automatic
# Multiple return options
Optional hardware features include:
! Analog and digital return transmitter options
! Service cable
# Surge protection
# Chromate or epoxy housing finish
# SC/APC or FC/APC optical connectors
# Ingress switching
SG 2000 Instal lation and Opera tion Manual
2-6 Overview
You can order the SG 2000 in a number of configurations to suit system requirements. The shipped
configuration is noted in a label on the lower portion of the RF chassis cover.
Figure 2-5 illustrates a sample model using the configuration notation:
Figure 2-5
Configuration notation
Return Path Configurations (Analog Return)Key
No Transmitter
SG2-DFBT/*
Dual SG2-DFBT/* w/split return
Dual SG2-DFBT/* w/redundancy
E
F
N
D
Return Path Configurations (Digital Return) ***
DS-SG2-DRT/A-1310-DFB/SC w/redundancy
DS-SG2-DRT/A-1550-DFB/SC w/redundancy
DS-SG2-DRT/A-1510c-DFB/SC w/redundancy
DS-SG2-DRT/A-1530c-DFB/SC w/redundancy
23242526272829
Key
SG2-DFBT3/* (2mw)
I
DS-SG2-DRT/A-1550c-DFB/SC w/redundancy
SG2-FPT/*
Dual SG2-FPT/* w/split return
Dual SG2-FPT/* w/redundancy
SG2-EIFPT/*
Dual SG2-EIFP T/* w/split return
Dual SG2-DFBT3/* w/split return
Dual SG2-DFBT3/* w/redundancy
J
K
M
O
DS-SG2-DRT/A-1570c-DFB/SC w/redundancy
DS-SG2-DR T-2x /A-1470c-DF B/SC w/ s pl it return
DS-SG2-DR T-2x /A-1490c-DF B/SC w/ s pl it return
DS-SG2-DRT-2x/A-1590c-DFB/SC w/split return
30
31323334353637383940414243
Dual SG2-EIFPT/* w/redundancy
T
R
S
P
DS-SG2-DRT-2x/A-1610c-DFB/SC w/split return
DS-SG2-DRT/A-1470c-DFB/SC
DS-SG2-DRT/A-1490c-DFB/SC
DS-SG2-DRT/A-1590c-DFB/SC
DS-SG2-DRT/A-1610c-DFB/SC
Finish
Key
DS-SG2-DRT-2x/A-1470 c -DF B/ SC w/r e dun dancy split return
Mounting
None
Chromate
Pedestal
Strand
N
C
X
Y
Key
Ingress switch
None
Ingress switches
N
S
Key
Status Monitoring
None
AMC/Frequency agile
TollG/Frequency agile
J
N
H
NLT
SC/APC
S
MNMCB w/SIC
Power Supply
Single
Dual
Redundant w/SIC
SDR*
Key
Service Cable
6 FiberSer Cable
None
C
N
Key
FC/APC
Surge Protection
F
Surge Arre sto r
FTEC BTA Crowbar
F
N
Key
Forward Receivers
Freq
Vendor
DS-SG2-DRT-2x/A-1490 c -DF B/ SC w/r e dun dancy split return
DS-SG2-DRT-2x/A-1590 c -DF B/ SC w/r e dun dancy split return
DS-SG2-DRT-2x/A-1610 c -DF B/ SC w/r e dun dancy split return
Refer to the current Motorola catalog for option and feature availability.
Forward Path
The multiple receiver functionality of the platform accommodates split-band and/or redundancy
applications. A typical split-band configuration has analog signals in the 52 MHz through 550 MHz
band feeding one receiver (C location in Figure 2-6). Digital transmissions or narrowcast signals are
carried between 450/550 MHz and 870 MHz on another fiber and processed by the second receiver
(A location). You can use the optional third receiver (B location) as a back up in the event that the
narrowcast receiver loses optical signal input. Automatic path switchover occurs through either the
optional status monitoring or manual control-board modules.
Figure 2-6 provides a diagram of the signal flow-path through the SG 2000:
Figure 2-6
Signal flow diagram
SG2 lid
Receiver C
Receiver B
Receiver A
Power supply
Power supply
Optical transmitter
Optical transmitter
JXP
JXP
JXP
Data lines
TP
TP
SG2-ABJ/P
forward
A/B
jumper
TP
TP
TP
-1.0
JXP
*
JXP
**
-1.5
Switch
JXP
JXP
+24 VDC
+5 VDC
ACV
Status monitor
SG2-FBS
forward
band
split
HP
filter
+15 Lo
+21.5 Hi
SG2-FJB/P
forward
jumper
board
-3.5-3.5
SG2-RPLPF
SG2 RF chassis
SG2-RPM/C
-2.0
LP filter
SG2-RPM/S
LP filter
LP filter
SG2-RPLPF
-2.0-1.5
AttenuatorSG2-FRB
-2.0
@ Min atten
Ingress control
-3.5+8.5
-3.5
-2.0
All forward and return path test points (TP) are -20dB
5dB
*
With second transmitter pad = 5dB; withou t second transmitter pad = 15dB
**
POT
DUJXP
MDR
+ 18.5
mplifier
Splitter
-0.5
-8.0
Splitter
Splitter
-1.0
EQ
JXP
Ingress
-2.0
EQ
JXP
Ingress
EQ
JXP
Ingress
JXP EQ
Ingress
mplifier
+18.5
JXP
mplifier
JXP
mplifier
JXP
mplifier
JXP
-0.5
TP
TP
TP
TP
-1.0
-1.0
Diplex
filter
H
L
-0.5
Diplex
filter
H
L
Diplex
filter
H
L
Diplex
filter
H
L
TP
-0.5
TP
TP
TP
SG 2000 Instal lation and Opera tion Manual
2-8 Overview
To assess fiber link status, the optical-power monitor circuit is active at all times (even when the
receiver is disabled). An integrated optical bulkhead connector and module link status indicators
enhance fiber management and reduce troubleshooting time. The receiver module is fully compatible
with the status monitor transponder for remote monitoring of key module and link performance
parameters.
Several plug-in boards are available to configure the SG 2000 lid board for single, redundant, or
narrowcast receiver arrangements. A low-noise pre-amplifier hybrid amplifies the signal to a level
suitable for connection to the RF chassis.
An SG2-FRB flatness board, at the input to the RF chassis, compensates for hybrid and accessory
response signatures. A variable attenuator circuit enables fine adjustment of the output level, and is
driven either by the standard thermal control unit (TCU) or optional ADU pilot automatic gain
control (AGC) module to compensate for tempera tur e and input lev el var ia tion s.
The MDR-*/* circuit board provides a fixed linear equalizer for either 750 MHz or 870 MHz. This
equalizer comes in numerous values to support various levels of output tilt. The MDR board also
compensates for the low frequency roll-off inherent in plug-in diplexers.
A driver-hybrid amplifies the signal to a sufficiently high level to feed up to four power-doubling
output stages. These output hybrids can be either conventional silicon or premium gallium arsenide
types for even higher station output at low distortion. Plug-in facilities are available ahead of each
output stage for individual equalizer boards. These can be installed to customize the tilt for the
various ports. At one output, a minus 16 dB directional coupler provides signal to the optional ADU
and status-monitor modules. This signal is used only when either or both of these options is installed.
It is not necessary to terminate the coupler output when neither option is present.
Minus 20 dB directional test points are available at various points in the signal paths of the node.
Because these test points are 75-ohm source impedance, special test probes are not required.
Model JXP-* attenuator pads are used for adjusting signal levels within the signal path. The unit is
shipped with JXP-ZX versions installed.
SG 2000 Instal lation and Opera tion Manual
Overview 2-9
SG2-LR Receiver
The receiver module (SG2-LR) is designed specifically for high performance in the SG 2000. The
SG2-LR receiver uses an integrated optical-hybrid photo-detector for improved RF performance over
the entire 40 MHz through 870 MHz passband. It is enabled and disabled in response to a signal
from the status monitor transponder or manual control board (MCB). This provides excellent
isolation, improved reliability, and reduced power consumption when the receiver is used in
redundant applications.
Figure 2-7 illustrates a functional block diagram of the SG2-LR receiver:
Figure 2-7
SG2-LR receiver function al diagram
Module
enabled
Threshold
comparators
Module
enable
Optical
input
+24V
Module enable
logic
Optical receiver hybrid
Hybrid current
monitor
Optical power
monitor
Threshold
comparators
Module
fault
Matching
network
Hybrid current
sense signal
(10V/A)
Hybrid current
test point
(1.0 V/A)
RF
output
Optical power
test point
(1 V/mW)
Optical power
sense signal
(1 V/mW)
Low
Normal
High
SG 2000 Instal lation and Opera tion Manual
2-10 Overview
Analog Return Path
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:
Table 2-1
Analog return transmitters
Model Description
SG2-IFPT/*
SG2-FPT/*
SG2-DFBT/*
SG2-DFBT/3
SG2-EIFPT/*
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.
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.
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.
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.
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.
SG 2000 Instal lation and Opera tion Manual
Overview 2-11
Figure 2-8 illustrates a functional block diagram of the SG2 transmitter:
Figure 2-8
SG2 transm itter block d iagram
Hybrid
current
test
RF
input
Thermal
compensation
Optical
power
test
JXP
factory calibration
only
Laser
bias
control
Laser
diode
module
Fiber
output
Laser
current
test
SG 2000 Instal lation and Opera tion Manual
2-12 Overview
Digital Return Path
The digital return transmitter series (DS-SG2-DRT*) converts a broadband analog RF return-path
signal into digital optical signals with 10-bit resolution.
The transmitters used for digital return applications are divided into two families: DS-SG2-DRT/A
and DS-SG2-DRT-2X/A.
Seven digital return transmitters per family are available to meet the needs of most digital return
applications.
Table 2-2 identifies the fourteen opti cal dig it al re turn transmitters:
Table 2-2
Digital return transmitters
DS-SG2-DRT/A DS-SG2-DRT-2X/A
DS-SG2-DRT/A-1310 FP DS-SG2-DRT-2X
DS-SG2-DRT/A-1310 DFB DS-SG2-DRT-2X/A-1310 D FB
DS-SG2-DRT/A-1470 DFB DS-SG2-DRT-2X/A-1470 D FB
(1)
/A-1310 FP
DS-SG2-DRT/A-1490 DFB DS-SG2-DRT-2X/A-1490 D FB
DS-SG2-DRT/A-1550 DFB DS-SG2-DRT-2X/A-1550 D FB
DS-SG2-DRT/A-1510c
DS-SG2-DRT/A-1530c DFB DS-SG2-DRT-2X/A-1530c DFB
DS-SG2-DRT/A-1550c DFB DS-SG2-DRT-2X/A-1550c DFB
DS-SG2-DRT/A-1570c DFB DS-SG2-DRT-2X/A-1570c DFB
DS-SG2-DRT/A-1590 DFB DS-SG2-DRT-2X/A-1590 D FB
DS-SG2-DRT/A-1610 DFB DS-SG2-DRT-2X/A-1610 D FB
(1) 2X in the model number denotes time division multiplexing (TDM)
(2) c in the model number denotes coarse wave division multiplexing (CWDM)
(2)
DFB DS-SG2-DRT-2X/A-1510c DFB
To prepare for an anticipated increa se in retu rn tra ff ic, provisi oning fo r CWDM is buil t into the
transmitters. The CWD M optio n con sis ts of las ers at predef ined wavelengths. This option is
available to support multiplexing in the optical domain, using eight-wavelength wave division
multiplexing (WDM) in the DS-SG2-DRT/A-15XX DFB and DS-SG2-DRT-2X/A-15XX DFB
windows.
DS-SG2-DRT/A
The DS-SG2-DRT/A digitizes a single analog 5-42 MHz return path signal to produce a 1.6 Gbps
data stream. This data stream is then routed to a digital laser for transmission to a corresponding
digital return receiver. The node can be configured with one or two DS-SG2-DRT/A transmitters,
with dual transmitters providing redundancy. In conjunction with these transmitters, the node must
also be configured with the SG2 Return Path Module/Combined (SG2-RPM/C). The return signals
from all four ports are combined and fed to the optical transmitters.
SG 2000 Instal lation and Opera tion Manual
Overview 2-13
When configured for redundancy , both return transm it t ers are normally active and transmit th e
combined RF return signal simultaneously. In the event of path failure, continuity of service is
accomplished at the headend or the receiver site by switching to the alternate or active return fiber.
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 installed, there will be a 15 dB pad at the second transmitter input position to serve as a
termination.
DS-SG2-DRT-2X/A
The DS-SG2-DRT-2X/A has two separate RF inputs. The transmitter digitizes these two independent
analog 5-42 MHz return-path signals to produce two 1.25 Gbps data streams. These two data streams
are then multiplexed to create a single 2.5 Gbps data stream that is then routed to a digital laser for
transmission to a corresponding digital return receiver. In conjunction with these transmitters, the
node must also be configured with the SG2 Return Path Module/Split (SG2-RPM/S). Return signals
from two of the four node ports are fed to one RF input of the transmitter while the remaining two
return signals are fed to the second RF input. The signal paths for both inputs are explained in more
detail in Section 5, “Operation”.
Signal levels are adjusted in each return path using Model JXP-* attenuator pads. The transmitter
gets one of its RF signals automatically when the unit is plugged into its appropriate slot. The second
RF signal comes through a special adapter from the adjacent connector, which is normally available
for installing a redundant transmitter. Therefore, the units are shipped with two JXP-5 attenuator
pads at the input positions.
Ingress control switching is an available option with any return transmitter configuration. If ingress
switches are not used, JXP-2 pads are installed in each ingress switch position on the main RF board.
The node can be configured with one or two DS-SG2-DRT-2X/A transmitters, with dual transmitters
providing redundancy. The redundancy configuration is explained in more detail in Section 5,
“Operation”.
Section 5, “Operation,” also provides detailed information and block diagrams for each series of
digital transmitters.
SG 2000 Instal lation and Opera tion Manual
2-14 Overview
Level Control
The gain of hybrid IC amplifiers varies with temperature. In addition, changes in system channel
loading and/or splices in the fiber link can change the level of the received signal.
The standard TCU board compensates for anticipated hybrid gain changes by sensing housing
temperature and signaling needed changes to the RF attenuator.
The ADU board, an optional plug-in module, monitors the amplitude of a selected pilot frequency.
The pilot frequency is an available analog television channel not scrambled by the sync suppression
method. Any changes in amplitude are fed back to the RF attenuator that makes appropriate
corrections.
The input to the ADU contains a JXP-* pad. The factory-installed value of this pad is 6 dB (JXP-6)
for bridger level outputs and 0 dB (JXP-ZX) for trunk level outputs. Under normal conditions, it
should not be changed.
Options and Accessories
Table 2-3 provides a list of options and accessories for the SG 2000:
Table 2-3
Options and accessories
Model DescriptionFunction
ADU-*
TCU
JXP-*A
JXP-ZX
FTEC
LL-SG2
Automatic drive
unit
Thermal control
unit
Fixed
attenuator
0 dB attenuator This attenuator is used in place of JXP-*A pads when no
Crowbar
overvoltage
protection
LIFELINE
module
This option automatically adjusts gain by monitoring changes
in the level of the selected pilot carrier. E ither an ADU or T CU
must be installed.
The TCU controls amplifier gain for changes in hybrid gain at
the sensed temperature.
Attenuator pads are used to adjust amplifier levels and are
available in 1 dB steps from 1 through 24 dB. The appropriate
value must be installed.
attenuation is needed.
The FTEC is an electronic crowbar/surge protector that can be
used to replace the existing 230-volt gas discharge surge
protector.
This module enables the system operator to monitor the SG2
from a remote location. See Section 5, “Operation” for
parameters monitored. Several frequencies are available. See
the product catalog for additional information.
GFAL
F/JXP
SG 2000 Instal lation and Opera tion Manual
Test probe This probe is used to evaluate node performance.
Injection probe This probe is used to inject a signal for test purposes.
Overview 2-15
Model Description Function
SG2-MCB
SG2-SB/*
SG2-PS
SG2-PS2
SG2-
SERCAB/*
SG2-FE-
*/750
SG2-FE*/870
SG2-IS
SG2-LR
DS-SG2-DRRB
Manual control
board
This board locally controls the ingress switch and
receiver/transmitter A/B redundant switching if the node is not
equipped with status monitoring.
Strand bracket Bracket for hanging a strand mounted node.
Power supply
Provides the +24 V and +5 V dc supply to the station. It has an
extended voltage range and is power-factor corrected.
Power supply
Provides the +24 V and +5 V dc supply to the station.
Service cable A 6-fiber service cable that is available with SC/APC or
FC/APC connectors.
Forward
equalizers
Used to increase output tilt at one or more ports in a 750 MHz
system. They are available in 1 dB increments from 2 dB
through 6 dB.
Forward
equalizers
Used to increase output tilt at one or more ports in an 870
MHz system. They are available in 1 dB increments from 2 dB
through 6 dB.
Ingress switch This switch enables the operator to troubleshoot without
shutting down the return path. It requires the use of either the
LL-SG2/* or the SG2-MCB.
Lightwave
receiver
Digital return
redundancy
board
This receiver converts the received optical signal to
broadband RF.
This board provides the redundant input to a
DS-SG2-DRT/A-2X digital return transmitter. One DRRB is
used for each -2X transmitter.
SG2-*
DS-SG2-DRT*
Analog return
transmitters
Digital return
transmitters
Table 2-1 identifies and describes the five optical analog
return-path transmitters.
Table 2-2 identifies all models of the optical digital return-path
information and block diagrams for each series of digital
transmitters.
SG 2000 Instal lation and Opera tion Manual
2-16 Overview
O
B
Gain Selection
Figures 2-9 through 2-13 illustrate SG 2000 gain and tilt selection charts based on frequency and
channel load options.
To use the gain option selection charts, Figures 2-9 and 2-10, first find the point on the left hand axis
that corresponds to the expected optical input power at the node. Move across this horizontal line to
the right until it intersects a vertical line corresponding to the desired RF output level.
If this intersection is above and to the left of the diagonal “lo gain limit” line for the channel loading
under consideration, the low-gain option will give optimum performance with minimum padding. If
the intersection lies between the “lo gain limit” and “hi gain limit” lines, then choose the high-gain
option. Operation at a combination of input and output levels below and to the right of the “hi gain
limit” line is not possible.
Figure 2-9 illustrates the gain option selection chart for 750 MHz:
Figure 2-9
Optical inp ut versus 750 MHz gain
2
1
0
m)
-1
-2
ptical input (d
-3
-4
-5
3840
Lo gain limit, 94 ch
Hi gain limit, 94 ch
Lo gain limit, 77 ch
Hi gain limit, 77 ch
750 MHz Gain Selection
42
Bridger output level (dBmV), 750 MHz equivalent
(Trunk output level is 10 dB lower)
4446485052
Figure 2-9 gives the output level at 750 MHz. For a system loaded with analog channels to
550 MHz, the actual level at 550 MHz is 3.5 dB lower with the standard overall tilt of 12.5 dB. For
the low tilt of 10 dB, the reduction at 550 MHz is 3.0 dB. For the high tilt of 14 dB, the 550 MHz
level is 4.0 dB lower than at 750 MHz.
SG 2000 Instal lation and Opera tion Manual
Overview 2-17
O
B
Figure 2-10 illustrates the gain option selection chart for 870 MHz:
Figure 2-10
Optical inp ut versus 870 MHz gain
2
1
0
m)
-1
-2
ptical input (d
-3
-4
-5
3840
Lo gain limit, 110 ch
Hi gain limit, 110 ch
Lo gain limit, 94 ch
Hi gain limit, 94 ch
870 MHz Gain Selection
42
Bridger output level (dBmV), 870 MHz equivalent
(Trunk output level is 10 dB lower)
4446485052
Figure 2-10 gives the output level at 870 MHz. For a system loaded with analog channels to
750 MHz, the actual level at 750 MHz is 1.7 dB lower with the standard overall tilt of 11.5 dB. For
the low tilt of 9.0 dB, the reduction at 750 MHz is 13 dB. For the high tilt of 14 dB, the 750 MHz
level is 2.1 dB lower than at 870 MHz.
For a system loaded with analog channels to 650 MHz, the actual level at 650 MHz is 3.1 dB lower
than the given 870 MHz level with the standard overall tilt of 11.5 dB. For the low tilt of 9.0 dB, the
reduction at 650 MHz is 2.4 dB. For the high tilt of 14 dB, the 650 MHz level is 3.8 dB lower than at
870 MHz.
SG 2000 Instal lation and Opera tion Manual
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