BTN2 Broadband Telecommunications Node

Transcription

STARLINE®
BTN2
Broadband
Telecommunications Node
Installation and Operation Manual
Caution
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 Troubleshooting Instructions unless you are qualified to do so. Refer all servicing to qualified service personnel.
Special Symbols That Might Appear on the Equipment
DANGER
INVISIBLE LASER RADIATION
AVOID DIRECT EXPOSURE TO BEAM
PEAK POWER 5.0mW
WAVELENGTH 1300nm
CLASS IIIb LASER PRODUCT
THIS PRODUCT COMPLIES WITH 21CFR
CHAPTER 1 SUBCHAPTER J
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 can 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 voltages are not
insulated and 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 the documents accompanying the equipment.
For continued protection against fire, replace all fuses only with fuses having the same electrical ratings marked at
the location of the fuse.
Copyright © 2001 by Motorola, Inc.
All rights reserved. No part of this publication may be reproduced in any form or by any means or used to make any derivative work (such as translation,
transformation or adaptation) without written permission from Motorola, Inc.
Motorola reserves the right to revise this publication and to make changes in content from time to time without obligation on the part of Motorola to
provide notification of such revision or change. Motorola 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 may make improvements or changes in the product(s)
described in this manual at any time.
Motorola, the stylized M logo, Cableoptics, LIFELINE, and STARLINE are registered trademarks and OmniStar is a trademark of Motorola, Inc. All other
product or service marks are the property of their respective owners.
Contents
Section 1
Introduction
Using This Manual ........................................................................................................................... 1-2
Document Conventions ..................................................................................................................... 1-2
If You Need Help .............................................................................................................................. 1-2
Calling for Repairs ........................................................................................................................... 1-3
Section 2
Overview
Housing .......................................................................................................................................... 2-1
Mounting Holes ............................................................................................................................... 2-2
Port Locations ................................................................................................................................. 2-3
Gaskets .......................................................................................................................................... 2-4
The Cableoptics ® Link ...................................................................................................................... 2-5
Node Overview ................................................................................................................................. 2-5
Forward Path ................................................................................................................................... 2-5
Return Path ..................................................................................................................................... 2-7
Powering ......................................................................................................................................... 2-7
Additional Optical Configurations ...................................................................................................... 2-8
Configuration................................................................................................................................ 2-11
Optical Receiver Module ................................................................................................................. 2-13
Return Path Data Transmitter .......................................................................................................... 2-14
Return Path Video Transmitter ......................................................................................................... 2-15
Return Path Video and Data Transmitter ........................................................................................... 2-17
Section 3
Pre-installation Bench Testing
BTN2 Setup and Bench Testing .......................................................................................................... 3-1
Setting for 90 Vac System Power ....................................................................................................... 3-3
Receiver Output Levels ..................................................................................................................... 3-4
Installing Pads ................................................................................................................................ 3-5
Gain Control Options ........................................................................................................................ 3-7
Manual Thermal Control ............................................................................................................. 3-8
Automatic Level Control ............................................................................................................. 3-8
Installing Gain Control Options ......................................................................................................... 3-8
Installing Forward Path Options......................................................................................................... 3-8
Redundant Forward Option................................................................................................................ 3-9
BTN2 Installation and Operation Manual
ii
Contents
Installing Return Path Options ......................................................................................................... 3-12
Single Return Transmitter ............................................................................................................... 3-12
Redundant Return Transmitters ....................................................................................................... 3-13
Split Return Option ........................................................................................................................ 3-14
Coax Return Option ........................................................................................................................ 3-17
Installing the Status Monitor Option ................................................................................................ 3-17
Surge Protection ............................................................................................................................ 3-18
Sweep Response and Gain Testing on the Bench ................................................................................. 3-18
Sweep
Sweep
Sweep
Sweep
Sweep
Testing
Testing
Testing
Testing
Testing
the
the
the
the
the
AM-RM9/* Receiver ............................................................................................ 3-18
RF Amplifier Module ............................................................................................ 3-19
Return Path ........................................................................................................ 3-20
Return Amplifier ................................................................................................. 3-20
Return Transmitter .............................................................................................. 3-21
Section 4
Installation
Splicing Fiber ..................................................................................................................................4-1
Installing the BTN2...........................................................................................................................4-2
Powering the Node in the Field ...........................................................................................................4-3
Receiver/Link Performance Checks and Adjustments............................................................................4-5
Amplifier Output Level ......................................................................................................................4-6
Manual Gain Control ........................................................................................................................ 4-6
Manual Thermal Control, Model BTN-S-TCU ........................................................................................ 4-6
Automatic Level Control, Model ADU.................................................................................................. 4-7
Return System Checks ......................................................................................................................4-7
Closing the Housing..........................................................................................................................4-8
Appendix A
Specifications
Abbreviations and Acronyms
Contents
iii
Figures
Figure 1-1 BTN2 node ...................................................................................................................... 1-1
Figure 2-1 BTN2 housing dimensions - front and side view .................................................................... 2-1
Figure 2-2 Rear view of housing, strand clamps, and pedestal mounting holes ........................................ 2-2
Figure 2-3 Port locations ................................................................................................................. 2-3
Figure 2-4 Housing gaskets .............................................................................................................. 2-4
Figure 2-5 Fiber-to-the-feeder link .................................................................................................... 2-5
Figure 2-6 BTN2 block diagram ......................................................................................................... 2-6
Figure 2-7 Single-forward optical configuration .................................................................................. 2-8
Figure 2-8 Single-forward, single RF return configuration .................................................................... 2-8
Figure 2-9 Dual-forward, single-return optical configuration ................................................................ 2-9
Figure 2-10 Single-forward, single-return optical configuration ............................................................ 2-9
Figure 2-11 Single-forward, split-return optical configuration ............................................................ 2-10
Figure 2-12 Configuration notation ................................................................................................. 2-11
Figure 2-13 Block diagram of AM-RM9/* receiver ............................................................................. 2-13
Figure 2-14 Block diagram of AM-MB-RPTDB/* transmitter................................................................ 2-14
Figure 2-15 Block diagram of AM-TC-DFBT/* transmitter ................................................................... 2-16
Figure 2-16 Block diagram of AM-TC-RPT/* transmitter ..................................................................... 2-17
Figure 3-1 Location of major BTN2 components................................................................................... 3-2
Figure 3-2 RF amplifier module cover................................................................................................. 3-3
Figure 3-3 dc supply settings for 60 Vac and 90 Vac powering ............................................................... 3-4
Figure 3-4 AM-RM9/* minimum output versus optical input power ........................................................ 3-5
Figure 3-5 Drive unit selector ........................................................................................................... 3-7
Figure 3-6 BTN-S-TCU board ............................................................................................................. 3-8
Figure 3-7 BTN2 housing lid (fully loaded)........................................................................................ 3-10
Figure 3-8 Redundant receiver A/B select switch .............................................................................. 3-11
Figure 3-9 Split return option cable harness..................................................................................... 3-16
Figure 3-10 Setup for sweep testing the AM-RM9/* .......................................................................... 3-18
Figure 3-11 Setup for testing the amplifier module ........................................................................... 3-19
Figure 3-12 BDR-8BTN/11 controls ................................................................................................. 3-20
Figure 3-13 Test setup for the return transmitter .............................................................................. 3-21
Figure 4-1 Service cable connection and compression fitting................................................................ 4-1
Figure 4-2 Center conductor length ................................................................................................... 4-2
Figure 4-3 Module cover showing location of fuses .............................................................................. 4-4
Figure 4-4 Fusing diagram................................................................................................................ 4-4
Figure 4-5 Optical input power versus test point voltage ...................................................................... 4-5
Figure 4-6 Housing bolt torquing sequence ........................................................................................ 4-8
iv
Contents
Tables
Table 3-1 BTN2 pad chart .................................................................................................................3-6
Table 4-1 Fuses ............................................................................................................... ................4-3
Table A-1 BTN2 optical characteristics ...............................................................................................A-1
Table A-2 Station RF characteristics ..................................................................................................A-1
Table A-3 BTN2 general characteristics ..............................................................................................A-2
Table A-4 Typical power requirements ................................................................................................A-2
Table A-5 BTN2 performance with 77 channels ....................................................................................A-3
Table A-6 BTN2 performance with 110 channels ..................................................................................A-3
Table A-7 AM-MB-RPTDB/* RF specifications ..................................................................................... A-3
Table A-8 AM-TC-RPT/* RF specifications ...........................................................................................A-4
Table A-9 AM-TC-DFBT/* RF specifications .........................................................................................A-4
Table A-10 AM-TC-DFBT3/* RF specifications .....................................................................................A-4
Section 1
Introduction
Motorola’s Broadband Telecommunications Node, BTN2, performs lightwave to RF and RF to
lightwave conversions in a Community Antenna Television (CATV) optical transmission link.
The BTN2 also supports a wide variety of advanced hybrid fiber/coaxial network architectures.
As broadband communications systems continue to evolve, the demand increases for optical links
that carry the signal further into the transport system. The BTN2 improves distortion
performance, extends transmission distances, increases system reliability, and reduces system
maintenance by incorporating the latest advances in RF, optical receiver and laser transmitter
technologies. The BTN2 supports two-way operation and provides a scalable solution for
deployment in broadband systems.
BTN2 features include:
§
750 MHz or 870 MHz forward bandwidth option
§
Up to four RF outputs
§
15 A power passing
§
User friendly fiber management
§
Custom configuration for unique system requirements
§
60/90 V powering
§
Optional:
§
Optical return transmitter or RF amplifier output
§
Ingress switching
§
Lifeline status monitoring
®
Figure 1-1 illustrates a closed BTN2 node:
Figure 1-1
BTN2 node
1-2
Introduction
Using This Manual
This manual provides instructions for the installation, setup, and operation of the BTN2.
Section 1
Introduction provides a brief introduction to the product, identifies the information contained in this manual,
gives the helpline telephone number, and lists instructions for returning units for repair.
Section 2
Overview describes the BTN2 node and includes details regarding your options and their functions.
Section 3
Pre-installation Bench Testing provides full configuration, set-up of options, and bench testing procedures that
are recommended before installing the BTN2.
Section 4
Installation provides instructions for installing the node and for performing field adjustments and checks.
Appendix A
Specifications provides technical specifications for the BTN2 and major options.
Abbreviations
and Acronyms
The Abbreviations and Acronyms list contains the full spelling of the short forms used in this manual.
Document Conventions
Before you begin using the BTN2, familiarize yourself with the stylistic conventions used in this
manual:
Bold type
Indicates text that you must type exactly as it appears or indicates a default value.
SMALL CAPS
Denotes silk screening on the equipment, typically representing front- and rear-panel controls
and input/output (I/O) connections, and LEDs.
* (asterisk)
Indicates that several versions of the same model number exist and the information applies to
all models; when the information applies to a specific model, the complete model number is
given.
If You Need Help
If you need assistance while working with the BTN2 node, call the Motorola Technical Response
Center (TRC) at 1-888-944-HELP (1-888-944-4357). The TRC is open from 8:00 AM to 7:00 PM
Eastern Time, Monday through Friday. When the TRC is closed, emergency service only is
available on a callback basis.
When contacting the TRC from outside the United States, call the main switchboard number,
1-215-323-1000, and ask for extension 4200.
Introduction
1-3
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 7:00 AM to
4:00 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 address:
Motorola Inc.
c/o William F. Joffroy, Inc.
Attn: RSA #___________
1480 North Industrial Park Dr.
Nogales, AZ 85621
Section 2
Over view
This section presents an overview of the major components of the BTN2 node and also provides
node configuration data. The major components include:
§
Optical receiver module
§
Return path data transmitter
§
Return path video transmitter
§
Return path video and data transmitter
Housing
The BTN2 node is furnished in an aluminum housing that protects the electronics from weather
and dissipates internally generated heat.
Figure 2-1 illustrates the housing dimensions of the BTN2:
Figure 2-1
BTN2 housing dimensions - front and side view
21.600
8.256
10.639
Coaxial cable connections to the housing are made with conventional 5/8 inch × 24-thread,
stinger-type connectors. For strand mounting, two clamps (illustrated in Figure 2-2) are located
at the top of the housing and are secured with 5/16-18 stainless steel bolts.
2-2
Overview
Mounting Holes
Two threaded holes, separated by 11.0 inches center-to-center, are located in the back of the
housing on the horizontal centerline as illustrated in Figure 2-2. You can use these holes and the
bolts from the strand clamps for pedestal mounting. These holes are threaded to a depth of 0.55
inches.
Figure 2-2
Rear view of housing, strand clamps, and pedestal mounting holes
Strand clamps
11.000 in
Overview
2-3
Port Locations
The housing provides six cable connections (five RF ports and one optical-fiber port). You can use
the port labeled IN for the RF return option. Port 2 is used as the power input port. All ports are
protected by factory-inserted threaded plugs or plastic cap plugs. Discard these plugs when you
install the cable connectors.
Figure 2-3 illustrates a front and end view of the closed housing with port locations:
Figure 2-3
Port locations
RF return
input port
Fiber
input
Base
Base
AC power
port input
RF output
RF output
Lid
RF output
RF output
2-4
Overview
Gaskets
Each housing is equipped with a woven-wire RF gasket and a silicone-rubber weather gasket to
provide a seal between the housing base and lid. These 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 station. The weather gasket should be
lightly coated with silicone grease each time the node is opened. Replace this gasket if it becomes
damaged or deformed.
Figure 2-4 illustrates the housing gaskets:
Figure 2-4
Housing gaskets
Weather gasket
(silicone rubber)
TO
RTN TX
L
RF RTN
OPTION
FROM
FW D
RX
BTN 2-20 dB
-20 dB
OUT
H
H
BTN S
2F
L
JXP IN
AU TO
JXP OUT
M AN
-20 dB
JXP
M AN
RE FE R TO
M ANU AL FO R
FU SE VAL UE S
AD U
TDU
JXP A DU
POWER
ICS
CON TROL STATU S
M ONITOR
+24 VD C
PORT 2
-20 dB
RTN EQ
POWER ON
JXP 1
JXP THERM
CHE CK V O LTA GE
S E LE CTO R
RE FE R TO M ANUAL
-20 dB
AD U
PORT 4
I
C
S
JXP
JXP
PORT 1
L
H
STATU S
M ONITOR
INPUT
JXP 4
H
L
-20 dB
STATU S
M ONITOR
OUTPUT
I
C
S
FTEC/B TA
ICS
-20 dB
JXP 1
PORT 3
JXP 4
JXP 3
-20 dB
H
L
JXP 3
CAUTION:
CONTAINS PARTS
AND ASSEMBLIES
SUSCEPTIBLE TO
DAMAGE BY
ELECTROSTATIC
DISCHARGE (ESD)
RF gasket
(woven wire)
-20 dB
ASSEMBLED IN MEXICO
Overview
2-5
The Cableoptics® Link
An 870 MHz Cableoptics fiber-to-the-feeder (FTF) link consists of a Cableoptics transmitter
and a BTN2 node, as illustrated in Figure 2-5. The input to the Cableoptics transmitter is
typically the combined headend RF output, consisting of up to 110 analog television channels,
plus digital channels between 750 MHz and 870 MHz.
Figure 2-5
Fiber-to-the-feeder link
Modulator
Headend
Fiber link
Processor
Modulator
Cableoptics
transmitter
BTN2-87SS/
DSTN-SAHN-SNNN-NX
Bridger
outputs
Processor
Node Overview
The BTN2 provides a forward band of 52 MHz to 870 MHz or 52 MHz to 750 MHz and a return
bandpass of 5 MHz to 40 MHz. This frequency band arrangement is for a 40-52 split, but other
splits are available through plug-in accessories. RF and dc power supply circuitry are integrated
in a single electronics package.
The six-fiber service cable enters the housing cover through a compression sleeve that seals the
penetration and keeps water out of the housing. The fibers, which are terminated with SC/APC
or FC/APC connectors, are then routed to the bulkhead fittings. Two fibers are available for
AM-RM9/* optical receivers, two are available for AM-MB-RPTDB/* data or AM-TC-RPT/* video
or AM-TC-DFBT/DFBT3 data and video optical transmitters, and two are spares.
The RF output of the AM-RM9/* optical receiver is applied to the RF module at the input
equalizer location through the BTN-S-2F plug-in and RF jumper cables.
Forward Path
The BTN2 node can be purchased, or field-modified, for operation in a redundant receiver
configuration. In the redundant configuration, input to the RF amplifier is switched from the
primary to the standby receiver if the primary receiver loses optical input. Restoration of the
primary path results in the node automatically switching back to that path. Automatic path
switchover is accomplished through either the optional status monitor or redundancy switch
driver modules.
2-6
Overview
Figure 2-6 depicts a functional block diagram of the BTN2 node with all available options. The
dotted lines represent alternate signal paths for the various configuration options.
Figure 2-6
BTN2 block diagram
To Status
Monitor input
-20dB
RF Main Board
TP -20dB
Forward EQ
location
**
JXP
**
TP -20dB
**
Forward
RF from
optical RX
Port IN
Verilosser
**
**
JXP
BTNS2F
RF return
option
**
BDR
**
JXP
**
ADU
Diplex
filter
**
HI
**
JXP
**
**
FEQ
LO
**
JXP
**
**
JXP
TP -20dB
**
HI
**
JXP
**
TP -20dB
HI
**
HI
Return RF
to optical
TX
**
BTN2R*
RF/ Port 3
RF AC
AC
LO
Input diplex
filter location
**
From Status
Split return
Monitor output
accessory
-20 dB
board
**
Combined
return
ICS
option
TP -20dB
TP -20dB
**
HI
TP -20dB
RF/ Port 1
RF AC
AC
LO
**
JXP
TP -20dB
**
REQ
**
THERM
**
JXP
**
**
JXP
**
**
JXP
**
ICS
**
JXP
**
ICS
**
JXP
ICS
TP -20dB
ICS
drive
TP -20dB
To Status
Monitor
Status
Monitor
Connector
Power
supply
Split
return
option
Forward Redundancy Control
from Status Monitor
BTN2 Lid Electronics
AM-RM9
RX main
Single RX option
AM-RM9
RX redundant
Jumper
**
Redundant RX option
Fiber
to/from
headend
**
Single TX option
Jumper
TC-RPT
TX main
TC-RPT
TX redundant
**
Redundant TX option
**
Split return TX option
**
** Indicates plug-in module
Indicates optional path
**
TP -20dB
Lid board
Output
port
RF/ Port 4
RF AC
AC
LO
LO
Optical
return
option
RF/
RF AC
AC
F F F
u u u
s s s
e e e
F
u
s
e
Overview
2-7
The RF amplifier electronics subassembly is an 870 MHz amplifier which provides 35 dB of
operational gain from a single input to each of four outputs. High distribution levels are made
possible by a dedicated, power-doubling hybrid at each output.
An interstage varilosser is provided in the RF amplifier module to compensate for gain changes
caused by temperature variations. The varilosser may be controlled manually or thermally
(through the standard BTN-S-TCU drive unit), or automatically (through the optional ADU-*
drive unit). The BDR-8BTN/11 response correction board, in combination with optional plug-in
FEQ-* mid stage equalizers, provides a full range of linear tilt options: L for 10 dB, S for 12.5 dB,
H for 14 dB, and U for 16 dB. The varilosser, thermal compensation unit, and three-stage design
enable the BTN2 to maintain its distortion performance despite temperature fluctuations.
Return Path
Consistent with the dual optical receivers, the dual return-path optical transmitters also provide
redundant functionality. Figure 2-6 illustrates the return redundancy configuration. Note that
both return lasers are always active, transmitting the combined RF return signals. In the event
of path failure, return path redundancy is accomplished at the headend or receive site by
switching to the alternative fiber.
Powering
The integrated dc power supply incorporates power-factor correction, which reduces the ac
current drawn by the BTN2 and improves the efficiency of the system power supply. The dc
power supply is capable of delivering 3.5 A at +24 V. The dc supply fuse is rated at 5 A.
Power passing is limited to 15 A at the RF ports; the ac input port (port 2) has a current carrying
capacity of 15 A. The BTN2 is shipped with automotive-style fuses installed in all port fuse
locations. Power passing fuses are rated at 20 A. These fuses may be replaced with optional
BCB-5 thermal circuit breakers, or with autofuse jumpers.
The BTN2 is equipped with a removable 230 V surge protector. Improved protection is available
by installing the fast trigger electronic crowbar (FTEC-BTA) option.
2-8
Overview
Additional Optical Configurations
Figures 2-7 through 2-11 provide simplified illustrations of the various available options:
Figure 2-7
Single-forward optical configuration
BTNS2F
Forward EQ
location
Forward/return motherboard
RM9
RCVR
A
Figure 2-8
Single-forward, single RF return configuration
BTNS2F
Forward EQ
location
H
L
Combined RF return
Input
diplex
filter
RM9
RCVR
A
Overview
2-9
Figure 2-9
Dual-forward, single-return optical configuration
Figure 2-10
Single-forward, single-return optical configuration
BTNS2F
Forward EQ
location
BTN2-R*
Input diplex filter
location
RM9
RCVR
A
RPT*
TRANS
A
2-10
Overview
Figure 2-11
Single-forward, split-return optical configuration
Forward equalizer
location
BTN2 RF chassis (housing)
BTN2SF
Input diplex filter Return path Return path
location
equalizer
hybrid
BTN2-R*
Combined return from
Port 1 and Port 3
=
BTN2 SRB
accessory
board
Combined return from
Port OUT and Port 4
BTN2 optics (lid)
Return path hybrid
in lid board
RPT*
XMTR
A
RPT*
XMTR
B
RM-9
RCVR
A
Overview
2-11
Configuration
The BTN2 node can be ordered and shipped in a number of configurations. The shipped
configuration is noted on a label placed on the cover of the RF module.
Figure 2-12 illustrates the configuration notation:
Figure 2-12
Configuration notation
Key
Forward Receivers
Key
Return Path Configurations
A
1 AM-RM9* Single Thru Receiver
X
No Transmitter
B
2 AM-RM9* Dual Receivers with optical redundancy
A
RF Return Only (RA-KIT/4-***)
X
None
B
AM-MB-RPTDB/* 1310 Data
C
Dual AM-MB-RPTDB/* 1310 Data w/ Redundancy
D
AM-TC-RPT/* 1310 Video or Data
Key
RF Configurations
B
2 Bridger
E
Dual AM-TC-RPT/* 1310 Video or Data w/ Redundancy
C
3 Bridger
F
AM-TC-DFBT/* (1mW)
D
4 Bridger
G
Dual AM-TC-DFBT/* w/ Redundancy
E
F
1 Trunk; 2 Bridger
2 Trunk; 2 Bridger
Connectorization*
SC/APC
H
AM-TC-DFBT3/* (2mW)
Dual AM-TC-DFBT3/* w/ Redundancy
G
2 Trunk; 1 Bridger
F
FC/APC
K
Dual AM-MB-RPTDB/* 1310 Data w/ Split Return
H
2 Trunk; 1 Bridger/Al
X
None
L
Dual AM-TC-RPT/* 1310 Video or Data w/ Split Return
M
Dual AM-TC-DFBT/* w/ Split Return
N
Dual AM-TC-DFBT3/* w/ Split Return
Key
Key
S
J
Tilt
Key
Control
L
10 dB
S
12.5 dB
T
TCU
H
14 dB
A
ADU 499.25/S
U
16 dB
B
ADU 439.25/S
C
ADU 549.00/S
Key
Key
Vendor
Housing & Finish
C
Chromate
Key
Bandpass
D
ADU 403.25/S
X
None
X
Standard
75
750 MHz
E
ADU 445.25/S
A
AMC
P
Epoxy
87
870 MHz
F
ADU 325.25/S
T
Tollgrade
E
E-pack only
BTN2
87
S
S
D
S
T
N
S
A
H
X
S
X
X
X
X
X
Key
Reserved
X
Reserved
X
X
Key
Bandpass Split
Key
Surge Protection
Key
Ingress switch
S
J
5-40 MHz/52-870 MHz
5-55 MHz/70-870 MHz
N
F
Surge Arrestor
FTEC BTA Crowbar
S
X
Ingress switch per port
A
5-65 MHz/85-870 MHz
K
5-42 MHz/54-870 MHz
E
5-30 MHz/47-870 MHz
Key
M
5-80 MHz/108-870 MHz
S
Technology
Silicon
N
None
Key
Service Cable
Key
Key
Ergonomics
C
AM-6 Fiber Ser/Cable
X
None
E
Ergonomic
X
None
A
LL-BTA2-52/5.5
N
Standard
B
LL-BTA2-89/21
C
LL-BTA2-51/6.5
Key
Power Supply
S
Single (only choice)
Status Monitoring
2-12
Overview
Using the node configuration shown in Figure 2-5 as an example, a
BTN2-87SS-DSTN-SAHX-SXXX-XXXX-N is a node with:
n
A forward passband of 52 MHz to 870 MHz with standard 12.5 dB slope and a return
passband of 5 MHz to 40 MHz
n
Four bridger outputs
n
Silicon hybrid
n
Automatic Thermal Control Unit
n
Surge protection
n
SC/APC optical connectors
n
One AM-RM9/* receiver
n
One AM-TC-DFBT3/* transmitter
n
Single power supply
You can order the BTN2 in any configuration and modify it as system requirements dictate. The
following optional items are available to configure the node appropriately for its application:
Forward System
JXP-*A attenuation pad
SG2-FEQ-3/870 forward equalizer for 12.5dB linear tilt
SG2-FEQ-4/870 forward equalizer for 14dB linear tilt
SG2-FEQ-6/870 forward equalizer for 16dB linear tilt
ADU-* automatic slope control
BDR-8BTN/11
AM-RM9/* optical receiver
AM-FAB motherboard: The AM-FAB is used where the BTN2 node is configured with
dual receivers for redundancy. This board incorporates a switch that switches the
input of the RF amplifier module from the primary receiver to the secondary
receiver if the primary receiver loses optical signal. This option must be used with a
status monitor or the AM-RSD redundancy switch driver.
AM-RSD redundancy switch driver: This option provides for automatic switching
between dual receivers in nodes when the status monitoring option is not installed.
AM-FST daughterboard. Used for single forward receiver configuration only
Powering Options
BCB-5 circuit breaker
FTEC/BTA crowbar surge protector
Autofuse jumper
Overview
Return System
2-13
AM-TC-RPTDB/*, AM-TC-RPT/*, AM-TC-DFBT/*, or AM-TC-DFBT3/* transmitter
RA-Kit/40H return amplifier kit
BTN2-R* return path interface board
JXP-*A attenuation pad
AM-RRD-KIT: The AM-RRD-KIT is used where the BTN2 is configured for redundant
return optical transmitters, both actively transmitting on independent fibers. The
RRD board equally splits the common RF return signals between the two
transmitters. The kit includes an RRD board and a return coaxial cable jumper.
AM-RST: The AM-RST is used for single return path transmitter configurations. This
kit includes an RST board, a return hybrid, and a BTN2-R* interface board.
AM-SRB-KIT: The SRB-KIT is used to implement the split return option. It provides a
means to route two of the four return paths to return transmitter A and the other
two to return transmitter B. The kit includes the SRB split-return plug-in accessory
board, the AM-RSP plug-in accessory board, a return hybrid amplifier, a cable to
make the appropriate interconnection, and hardware to secure the accessories.
AM-RSP: The AM-RSP is a plug-in accessory board intended for use with the
SRB-KIT split-return option. This board is installed on the electronics lid board and
provides a means for connecting a return-path hybrid amplifier to amplify the
combined Port Out and Port 4 return-path signals. This amplified, combined signal
is then routed to optical transmitter A. The AM-RSP also contains a test point for
monitoring the combined return path signals.
Status Monitor System
LL-BTA2-*/* status monitor module. Various frequency combinations are available.
Optical Receiver Module
The AM-RM9/* receiver module consists of a positive intrinsic-negative (PIN) diode
photodetector and a hybrid preamplifier. The input to the module is through a short length of
fiber that connects to the bulkhead fitting mounted within the housing. Figure 2-13 illustrates a
functional block diagram.
Figure 2-13
Block diagram of AM-RM9/* receiver
Photodetector
Fiber
input
RF
amplifier
RF
output
dc
amplifier
T.P.
2-14
Overview
The RF output signal from the photodetector is applied to a hybrid preamplifier. This amplifier
is optimized for low noise to maximize carrier-to-noise (c/n) performance. A circuit is included to
monitor the received optical power. The calibrated voltage is available at a test point that is
accessible through the cover of the receiver module. The test point voltage is scaled, and 2 V
represents 1 mW of receiver optical power. The same voltage is made available to the optional
status monitor module through the power connector.
Return Path Data Transmitter
The AM-MB-RPTDB/* is a low-power laser diode transmitter capable of sending up to 10 data
channels to the headend or hub. Data channels are defined here as ±150 kHz frequency shift
keying (FSK) channels; your return signal format may differ.
The transmitter consists of an RF amplifier and a laser diode with a typical optical output power
of 400 µW. The output of the laser diode is monitored by an optical detector and the resultant
signal is used to adjust the laser bias through a dc amplifier. The amplifier output also provides
voltage that represents laser output power. The output of the dc amplifier is accessible at a test
point and is scaled to indicate 10 V dc per mW. The same voltage is made available to the
optional status monitor module through the power connector.
The transmitter is designed to operate with an RF input level from +25 dBmV to +35 dBmV per
FSK channel. Up to ten data channels can be carried with a recommended total input level for
full data loading of +40 dBmV. The optimum input level is +35 dBmV per channel. Higher levels
may cause distortion due to clipping, while very low levels may cause data errors due to
insufficient c/n ratio.
Figure 2-14 illustrates a functional transmitter block diagram:
Figure 2-14
Block diagram of AM-MB-RPTDB/* transmitter
Laser diode
RF
input
RF
amplifier
T.P.
Fiber
output
dc
amplifier
Laser bias
Overview
2-15
Return Path Video Transmitter
The AM-TC-DFBT/* module uses a high-performance 1310 nm distributed feedback (DFB) laser
diode with an output power of 1mW. The primary advantage of a distributed feedback laser is its
lower noise floor (also called relative intensity noise-RIN) as compared to the Fabry-Perot (FP)
laser diode. The DFB laser enables an increase in dynamic range and a suitable c/n ratio at
lower carrier levels. An integrated optical-isolator reduces spurious noise and ensures consistent
and reliable performance. Packaged with the laser diode in a hermetically-sealed module, a PIN
photodiode monitors the optical power emanating from the diode. Superior RF linearity ensures
optimal c/n and distortion performance.
This module transmits up to two National Television Standards Committee (NTSC) video
channels or 35 MHz of digital data on a dedicated fiber to a companion optical receiver in the
headend. The recommended total composite input power level of +45 dBmV provides an optimal
c/n ratio. Higher levels can cause distortion due to clipping, while very low levels can cause data
errors due to an insufficient c/n ratio.
This new optical transmitter uses temperature compensation that ensures consistent system
performance. Although the laser operating point varies with temperature fluctuations there is
minimum change in the optical modulation index (OMI). As a result, the change in received RF
signal level caused by thermal slope efficiency is minimized.
An automatic power control (APC) system regulates the optical output power from the laser. The
APC system uses a PIN photodiode to sense the optical power emitted by the laser. Adjustment
to the laser bias current maintains a constant monitor photodiode current. This feature
compensates for changes in the laser threshold current and slope efficiency caused by
temperature and aging.
The optical-power test point, driven by the APC system, verifies the optical output power in the
field. The test point indicates the output of the dc amplifier using a scale of 10 V dc per milliwatt
of optical power. The same voltage is made available to the optional status monitor module
through the power connector.
2-16
Overview
Two connector styles, SC or FC angled physical connectors (APC), terminate the
transmitter-module output fiber pigtail. Use model AM-TC-DFBT/SC or AM-TC-DFBT/FC for
system flexibility and precision performance.
Figure 2-15 illustrates the basic design of the AM-TC-DFBT/* transmitter:
Figure 2-15
Block diagram of AM-TC-DFBT/* transmitter
Laser diode
RF
input
Optical
output
Matching
network
T.P.
dc
amplifier
Laser bias
Overview
2-17
Return Path Video and Data Transmitter
The AM-TC-RPT/* is designed to carry one NTSC video channel plus two data channels back to
the headend.
This module includes a high performance Fabry-Perot laser with a typical output power of
400 µW. The output fiber pigtail is terminated by an SC/APC connector. This module is designed
to carry video plus data in the bandpass from 5 MHz to 200 MHz on a dedicated fiber to a
companion receiver in the headend. While the module can operate effectively over this bandpass,
it is limited by the diplex filters in the fiber node.
The required RF input level for the NTSC video channel ranges from +35 dBmV to +45 dBmV.
The recommended module input level of +45 dBmV provides optimum carrier-to-noise ratio. The
two data channels that can be carried simultaneously are normally suppressed by 10 dB below
the video carrier level.
The laser output is monitored by an optical detector and the resultant signal is used to adjust
the laser bias through a dc amplifier. The output of the dc amplifier is accessible at the
front-panel test point and is scaled to indicate 10 V dc per mW of optical power. The typical
voltage at the test point is 4 V dc. The same voltage is made available to the optional status
monitor module through the power connector. A functional block diagram of this module is
shown in Figure 2-16:
Figure 2-16
Block diagram of AM-TC-RPT/* transmitter
Laser diode
RF
input
T.P.
Optical
output
Matching
network
dc
amplifier
Laser bias
Section 3
P r e-i n s t a l l a t i on B en c h Tes t i n g
Before you install the BTN2, it must be equipped with the accessory and optional items required
for the node location. Bench testing the node before you install it ensures proper alignment of all
components and simplifies the field installation and balancing procedure significantly.
BTN2 Setup and Bench Testing
The following subsections describe standard bench-testing procedures, as well as, how to
configure the node using the various options. Setup and bench testing of the BTN2 should be
performed by an experienced technician.
DANGER!
To avoid the possibility of damage due to static charges, wear a wrist strap grounded to the housing
when performing service on the receiver or node.
CAUTION!
Handle the fiber cable carefully. Especially avoid shock, excessive bending, and strain.
3-2
Figure 3-1 illustrates an open BTN2 and the location of major components:
Figure 3-1
Location of major BTN2 components
BTN2-R* plug-in
input diplex filter
Port IN - Input
(used for RF
return option)
BTN-S2F plug-in
forward EQ
BTN2 Node
amplifier module
TO
RTN TX
L
RF RTN
OPTION
-20dB
L
AUTO
JXP OUT
MAN
JXP ADU
PORT 4
Port 4 Output
PORT 3
Port 3 Output
POWER
ICS
CONTROL STATUS
MONITOR
+24 VDC
PORT 2
-20dB
RTN EQ
POWER ON
JXP 1
JXP THERM
CHECK VOLTAGE
SELECTOR
REFE R TO M ANUAL
Port 1 Output
ADU
TDU
-20dB
ADU
JXP
JXP
PORT 1
L
-20dB
H
L
-20dB
STATUS
MONITOR
OUTPUT
I
C
S
H
STATUS
MONITOR
INPUT
JXP 4
I
C
S
JXP 4
FTEC/BTA
ICS
JXP 3
JXP 1
-20dB
Port OUT Output
-20dB
JXP
MAN
REFE R TO
MANUAL FOR
FUSE VALUES
Port 2 ac power
OUT
H
IN
H
L
JXP 3
C AU TIO N :
C ON TAI NS PA RTS
A ND A SSE M BLI ES
SU SC EP TIB LE TO
D AM A G E BY
ELE CTR O STATI C
D ISC H AR G E ( ES D)
-20dB
A SSE M BLE D IN M E XIC O
Optics lid board
or AM-FAB (used
with forward
redundancy)
AM-FST forward
daughter board
AM-RST,
AM-RRD, or
AM-RSP return
daughter board
Fiber FC/APC or SC/APC
connector bracket
Receiver A
Transmitter A
Cable
bracket
(F-81C
adapter)
Receiver B
Transmitter B
Location for status
monitor module OR
redundant switch
driver (RSD) board
3-3
Figure 3-2 illustrates the RF amplifier cover and the location of optional items within the RF
amplifier module:
Figure 3-2
RF amplifier module cover
TO
RTN TX
L
RF RTN
OPTION
FROM
FWD
RX
BTN2-20dB
-20dB
H
OUT
H
BTNS
2F
JXP IN
L
AUTO
JXP OUT
MAN
-20dB
JXP
MAN
REFER TO
MANUAL FOR
FUSE VALUES
ADU
TDU
JXP ADU
POWER
ICS
CONTROL STATUS
MONITOR
+24 VDC
PORT 2
-20dB
RTN EQ
POWER ON
JXP 1
JXP THERM
CHECK VOLTAGE
SELECTOR
REFER TO MANUAL
-20dB
L
PORT 4
I
C
S
H
L
-20dB
STATUS
MONITOR
OUTPUT
H
STATUS
MONITOR
INPUT
JXP 4
JXP
JXP
PORT 1
ADU
I
C
S
FTEC/BTA
ICS
PORT 3
JXP 4
JXP 3
-20dB
H
L
JXP 3
CAUTION:
CONTAINS PARTS
AND ASSEMBLIES
SUSCEPTIBLE TO
DAMAGE BY
ELECTROSTATIC
DISCHARGE (ESD)
-20dB
JXP 1
-20dB
ASSEMBLED IN MEXICO
Setting for 90 Vac System Power
The BTN2 node can be powered from either 60 Vac or 90 Vac system power supplies. The unit is
shipped set for powering with 60 Vac. If your system uses 90 Vac powering, you should
reposition the suitcase plug on the dc power supply board to optimize the supply turn-on voltage
for the higher input range.
No damage will result if the jumper is not changed; in a 90 Vac system, changing the jumper
ensures that the dc supply does not turn on until the proper input voltage level is reached. This
prevents excessive loading of the system power supply during turn-on after a power-off situation.
To set for 90 Vac power:
1
Open the housing and disconnect all cabling to the RF amplifier module.
2
Loosen the bolts holding the RF module in the housing and remove the module from the
housing.
3
Turn the module over and remove the dc supply cover.
4
The BTN2 is shipped with a suitcase plug connecting J2 and J4 on the dc supply circuit
board, as shown in Figure 3-3. This positioning of the plug is correct for 60 Vac powering.
3-4
To set the node for 90 Vac powering, reposition the plug so that it connects J2 and J3, as
indicated in Figure 3-3.
Figure 3-3
dc supply settings for 60 Vac and 90 Vac powering
Power supply
circuit board
60 or 90 Vac
selector
(shown in 90 V position)
J2
J3
J4
Surface coated with
thermal compound
5
Fasten the dc supply cover on the RF module, and return the module to the housing,
fastening it with the captive mounting bolts.
6
Reconnect any cabling disconnected in Step 1.
Receiver Output Levels
The expected output from the AM-RM9/* receiver is a function of the optical input power and the
depth of modulation of the laser transmitter. Levels are assumed to consist of analog video
between 52 MHz and 750 MHz plus digital video between 750 MHz and the upper limit of the
system (870 MHz). For 77 analog channel systems, the digital video is assumed to operate not
more than 10 dB below the level at 550 MHz. This difference between analog and digital levels
can result in misleading measurements; exercise care to avoid erroneous adjustments. The
AM-RM9/* receiver output is flat. All channels between 50 MHz and 550 MHz should be
essentially flat, followed by a reduced signal level for the digital video channels. This step-down
in level is created at the headend by appropriate combining. A sweep signal inserted at the
headend will appear flat.
3-5
The graph in Figure 3-4 shows the minimum AM-RM9/* optical input versus the minimum
signal output level. Average levels are about 2 dB above the minimum. It is assumed that
modulation consists of 77 analog channels plus digital channels. The output level can be used as
a secondary indication of optical input power to the receiver, provided 77 channels are present.
Figure 3-4
AM-RM9/* minimum output versus optical input power
Optical input level
dBm
mW
dc test
point
(Vdc)
3
2.00
4.00
2
1.60
3.20
1
1.25
2.50
0
1.00
2.00
-1
0.79
1.50
-2
0.63
1.25
-3
0.50
1.00
-4
0.39
0.80
-5
0.31
0.65
-6
0.25
0.50
-7
0.20
0.40
11
13
15
17
19
21
23
25
27
29
Receiver output (dBmV)
Installing Pads
You can install fixed plug-in attenuators in several locations in the forward path of the
amplifier. The JXP-*A between the mid-stage driver amplifier and the output stage (the
interstage pad) is selected to control internal levels to achieve optimum performance.
The output pads (PORT OUT, PORT 1, PORT 3, PORT 4) are selected to obtain output levels from all
ports within 2 dB of each other. If the levels are outside this range, pad the highest level output
to bring it within this range.
All pad locations are marked on the amplifier cover and are accessible without removing the
cover. Needle-nose pliers or an equivalent tool is helpful when installing or removing pads.
31
3-6
The pad values selected for use have a significant impact on the performance of the node. Table
3-1 lists typical pad values recommended for achieving optimum performance at various input
and output levels.
Table 3-1
BTN2 pad chart
O u tp u t (d B mV) a t 870 MHz (or a t 750 MHz for th a t op tion )
I n p u t (d B m )
Pa d Loc a tion s
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
+1.0
FWD IN
16
15
17
16
15
17
16
15
17
16
15
14
13
12
11
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
15
14
16
15
14
16
15
14
16
15
14
13
12
11
10
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
14
13
15
14
13
15
14
13
15
14
13
12
11
10
9
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
13
12
14
13
12
14
13
12
14
13
12
11
10
9
8
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
12
11
13
12
11
13
12
11
13
12
11
10
9
8
7
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
11
10
12
11
10
12
11
10
12
11
10
9
8
7
6
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
10
9
11
10
9
11
10
9
11
10
9
8
7
6
5
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
9
8
10
9
8
10
9
8
10
9
8
7
6
5
4
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
8
7
9
8
7
9
8
7
9
8
7
6
5
4
3
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
FWD IN
7
6
8
7
6
8
7
6
8
7
6
5
4
3
2
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
+0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–3.5
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
1, 3, 4
3-7
O u tp u t (d B mV) a t 870 MHz (or a t 750 MHz for th a t op tion )
I n p u t (d B m )
Pa d Loc a tion s
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
–4.0
FWD IN
6
5
7
6
5
7
6
5
7
6
5
4
3
2
1
Interstage
6
6
3
3
3
3
3
3
0
0
0
0
0
0
0
FWD OUT,
3
3
3
3
3
0
0
0
0
0
0
0
0
0
0
1, 3, 4
Gain Control Options
RF amplifier gain is ultimately controlled by a standard varilosser, such as Model MB-VA/750.
This board is an electronically-controlled attenuator.
The varilosser is intended to compensate for changes in fiber link attenuation and for
temperature-induced changes in hybrid gain. The varilosser must operate in the proper portion
of its dynamic range. To ensure proper operation, it is important to set the gain reserves.
The available gain control options include: Manual, Manual Thermal, and Automatic Level
Control.
Ma n u a l Con trol
There are no corrections in amplifier gain due to temperature or input level changes. The output
level is adjusted by the potentiometer identified as MAN on the module cover (Figure 3-2). The
drive unit selector must also be in the MAN position as identified on the cover (illustrated in
Figure 3-5).
Figure 3-5
Drive unit selector
Auto
Manual
3-8
Ma n u a l T h erm a l Con trol
The standard drive unit, model BTN-S-TCU, is installed as shown on the module cover (Motorola
model TDU drive unit cannot be used in this location). The drive unit selector must be set in the
AUTO position for the BTN-S-TCU to be effective. Gain reserve of 4 dB is set with the thermal
level control on the BTN-S-TCU as shown in Figure 3-6.
Figure 3-6
BTN-S-TCU board
Thermal
level
Au toma tic Level Con trol
Automatic level control is available by installing the optional automatic drive unit (ADU) in
place of the BTN-S-TCU. The ADU monitors a pilot carrier and controls the varilosser in the
amplifier according to the amplitude of the carrier. Changes in signal level are then assumed to
be caused by changes in laser modulation level and the effects of temperature changes on the
hybrids. The appropriate control is the potentiometer identified as ADU on the module cover.
Installing Gain Control Options
To install the ADU you must remove the amplifier module cover.
To install these options:
1
Locate the area for the ADU or BTN-S-TCU on the circuit board. The ADU plugs in and
makes use of all pin connectors on the amplifier circuit board, while the smaller BTN-S-TCU
uses only three of the pins.
2
Set the drive unit selector to the AUTO position (see Figure 3-5).
If you use the ADU option the level control is adjacent and to the right of the ADU.
3
Re-install the module cover after installation of the option is complete.
Installing Forward Path Options
You can upgrade a basic single receiver BTN2 to a redundant RX configuration. In the
redundant configuration, the RF amplifier is switched from the primary to the secondary
receiver if the primary receiver loses optical input. Restoration of the primary path results in the
node switching back to that path automatically. This installation should be done by technicians
skilled in both RF and fiber-optic practices. Care must be taken to avoid pinching fibers and
coaxial cables. Fiber connections must be kept clean and protected at all times.
3-9
Redundant Forward Option
The forward path redundancy option can be installed at the factory or in the field. Before you
install return-path options please refer to Section 2 “Overview,” Configuration, Forward System
for a list of the kits and components that are required for the various return-path options.
3-10
Automatic path switching requires either an AM-RSD redundancy switch driver or a status
monitor module. If the node is not equipped with a status monitor and you want to install one at
this time, proceed to Installing the Status Monitor Option. Refer to Figure 3-7 to locate the
redundant option accessories:
Figure 3-7
BTN2 housing lid (fully loaded)
BTN-S2F
cable assembly
Status monitor
input and
output cables
Spiral-wrapped
status monitor
control cables
BTN2-R*
Spiral-wrapped
RF cables
Forward-return
motherboard
Return
daughterboard
Transmitter A
Forward
daughterboard
Receiver A
AM-RM9/*
Transmitter B
Receiver A
Receiver B
Optical
bulkhead
adapter
F-81C adapter
Transmitter B
AM-MB-RPTDB/* or
AM-TC-RPT/*
AM-TC-DFBT/*
AM-TC-DFBT3/*
Transmitter A
AM-MB-RPTDB/* or
AM-TC-RPT/*
AM-TC-DFBT/*
AM-TC-DFBT3/*
LL-BTN2-*/*
status monitor module
or
AM-RSD switch driver
Receiver B
AM-RM9/*
3-11
To install a redundant AM-RM9/* receiver:
1
Mount the AM-RSD board in the location shown in Figure 3-7 using the hardware provided.
2
Attach the connector of the power interconnect cable to the AM-RSD.
3
Disconnect all coax cables from the forward-return motherboard.
4
Disconnect the power connector from the forward-return motherboard.
5
Carefully remove the fiber cable from the fiber tray.
6
Loosen the two fiber tray hold-down screws and remove the fiber tray.
7
Remove all four screws at the corners of the sheet metal cover over the forward-return
motherboard.
8
Remove the six nuts securing the sheet metal cover to the F-connectors on the motherboard
and remove the shield.
9
Remove the four PC-board mounting screws that secure the motherboard to the housing lid
and remove the motherboard.
10 Install the new AM-FAB forward-return motherboard (included in kit) using the same
screws removed in Step 9 (do not re-install the sheet metal shield).
11 Re-connect all coax cable connections and the power connector disconnected in steps 3 and 4.
12 Re-install the fiber tray.
13 If the original motherboard (removed in step 9) contained a plug-in daughterboard for the
return path, install this plug-in into the new AM-FAB motherboard.
14 Carefully dress the fiber back into the fiber tray.
15 Install the redundant AM-RM9/* in the open receiver location and push down gently to
engage the connector on the back plane. Tighten the two captive mounting bolts.
16 Connect the coaxial lead from the M-RM9/* to an empty F-81C adapter on the bracket in the
housing lid. Connect the RD-179 coax cable (supplied) from the adapter to the receiver B
connector on the AM-FAB motherboard.
17 Connect the fiber pigtail lead from the newly installed AM-RM9/* to an empty connector on
the optical bulkhead adapter (illustrated in Figure 3-7) then carefully dress the fiber into the
fiber spool tray in the lid of the housing.
If you are finished installing forward-path options, you may close the housing following
instructions in Section 4 “Installation,” Closing the Housing.
You can operate the A/B switch in manual or automatic modes. In manual mode you can select
receiver A or receiver B by positioning the suitcase jumper located in the top left corner on the
AM-FAB motherboard as shown in Figure 3-8. Positioning the suitcase jumper in the AUTO
position, as shown, enables automatic switching of the receivers.
Figure 3-8
Redundant receiver A/B select switch
AUTO
A
B
3-12
Installing Return Path Options
Return path configurations in the BTN2 may be either factory or field installed. In addition to
the basic single transmitter and optional redundancy transmitter configurations, the BTN2 can
also be configured with a coaxial return. Return transmitters (1310 nm) are available both in low
density data (AM-MB-RPTDB/*) and single analog video/high density data (AM-TC-RPT and
AM-TC-DFBT) versions.
CAUTION!
To avoid damage to the node, remove power before installing powered options.
CAUTION!
DO NOT look into the optical connector of the transmitter with power applied. EYE DAMAGE MAY
RESULT. (Refer to the installation manual provided with the transmitter for other safety guidelines).
Return amplifier input signal levels can be measured at the four –20dB return path input
locations marked on the chassis cover. You can insert a sweep signal into the return path by
using an F/JXP adapter on any of the JXP facilities marked in red on the top of the cover (JXP,
JXP1, JXP3, and JXP4).
Note that the return path is interrupted while the F/JXP is installed. After you have completed
measurement or testing, replace the JXP -*A pad or jumper.
You can measure the return amplifier output signal level at the return output -20dB test point
location marked on the chassis cover.
If using an optical transmitter option, you can also measure the return amplifier output signal at
the coax bulkhead fitting in the cover of the housing. This is a direct measurement and no test
point correction needs to be added to the indication.
Before you install return-path options please refer to Section 2 “Overview,” Configuration,
Return System for a list of the kits and components that are required for the various return-path
options.
Single Return Transmitter
The AM-RST-KIT is required.
To install a single return transmitter:
1
Open the housing and remove the RF amplifier cover.
2
Install the return amplifier hybrid on the RF amplifier board and then install the hold-down
screws.
Exercise special care when installing the return hybrid to ensure that all pins enter the
appropriate sockets on the circuit board. Misaligned pins could be damaged if handled
carelessly.
3-13
3
Install the appropriate return equalizer into the sockets on the main RF board. Typically, a
zero-type return equalizer is installed.
4
Install a JXP-ZX jumper or the desired JXP -*A attenuator in the return amplifier output
pad position.
5
Pass the end of the BTN2-R* cable terminated with the circuit board through the opening in
the module cover and plug the circuit board into its sockets on the main RF board.
6
Re-install the cover on the RF amplifier module.
7
Connect the end of the BTN2-R* cable assembly to the return path input port of the
forward-return motherboard.
8
Position the transmitter module in the transmitter A location and push down gently to
9
Connect the coaxial input lead from the transmitter to the F-81C adapter in the housing lid
that is already connected to one of the return output ports on the forward-return
motherboard.
10 Connect the fiber pigtail from the transmitter to a spare optical bulkhead adapter, then
dress the fiber into the fiber spool tray in the lid of the housing.
11 Plug the AM-RST daughterboard into the return section of the forward-return motherboard.
12 Apply spiral wrap as shown in Figure 3-7.
13 Re-check all connections and proper dress of interconnecting cables. Make adjustments as
necessary.
14 Close the housing carefully while observing the cables to ensure that they are not pinched.
Redundant Return Transmitters
A second AM-MB-RPTDB/*, AM-TC-RPT/*, AM-TC-DFBT/*, or AM-TC-DFBT3/* transmitter
and the AM-RRD-KIT are required.
To install dual transmitters:
1
If a single return transmitter is already installed, skip steps 2 through 11 and go directly to
step 12.
2
3
Install the return amplifier hybrid on the RF amplifier board, and install the hold-down
screws.
carelessly.
4
Install the appropriate return equalizer into the sockets on the main RF board. Typically, a
zero type return equalizer is installed.
5
Install a JXP-ZX jumper or the desired JXP -*A attenuator in the return amplifier output
pad position.
6
Pass the end of the BTN2-R* cable terminated with the circuit board through the opening in
the module cover and plug the circuit board into its sockets on the main RF board (at the
diplex filter port-in position).
3-14
7
Re-install the cover on the RF amplifier module.
8
Connect the end of the BTN2-R* cable assembly to the return path input port of the
9
Position the first transmitter module in the transmitter A location and push down gently to
10 Connect the coaxial input lead from the transmitter to the F-81C adapter in the housing lid
that is already connected to one of the return output ports on the forward-return
motherboard.
11 Connect the fiber pigtail from the transmitter to a spare optical bulkhead adapter, then
dress the fiber into the fiber spool tray in the lid of the housing.
12 Plug the AM-RRD daughterboard into the return section of the forward-return motherboard,
replacing any daughterboard previously present.
13 Position the second transmitter module in the open B location as shown in Figure 3-7, and
push down gently to engage the connector on the back plane. Tighten the two captive
mounting bolts.
14 Connect the coaxial input lead from the second transmitter to an empty F-81C adapter in the
housing lid. Connect the RG-179 coax (supplied) from this adapter to the second return
output port on the forward-return motherboard.
15 Connect the fiber pigtail from the second transmitter to a spare optical bulkhead adapter
connection, then dress the fiber into the fiber spool tray in the lid of the housing.
16 Apply spiral wrap as shown in Figure 3-7.
17 Re-check all connections and proper dress of interconnecting cables. Make adjustments as
necessary.
18 Close the housing carefully while observing the cables to ensure that they are not pinched.
Split Return Option
The AM-SRB-KIT is required.
This procedure assumes that two return path laser transmitters are already installed in the
BTN2 node. If not, follow the applicable procedures in this manual to install two (redundant)
return path transmitters.
To install the split return option:
1
Open the housing. Disconnect the cable clamps from the coax cable interface harness and the
status monitor cable harness, unplug the status monitor connector, and remove the RF
amplifier chassis cover.
2
Remove the coax cable interface harness assembly from the BTN2 as follows:
(a) Noting the location of the connections beforehand, disconnect the FWD IN and the RET IN
coax F-type connectors on the cable harness from the forward-return motherboard in the
housing lid. You may need needle-nose pliers to loosen the F-type connectors.
(b) Disconnect the harness from the cable clamp attached to the AM-RM-9/* receiver
illustrated in Figure 3-7.
3-15
(c) Remove the two plug-in boards (BTN-S2F and BTN-R*) from the main RF board at the
other end of the cable harness. Lay the coax cable harness aside temporarily.
3
Carefully remove the fiber cable from the fiber tray. If necessary, disconnect the fiber
FC/APC (or SC/APC) connectors from the optical bulkhead. Attempt to keep the fiber cables
loosely coiled so that they are not overly stressed. You may use a small piece of cellophane
tape to secure the cables as a single coil bundle to ensure they do not interfere with the
following steps.
4
Loosen the two fiber tray hold-down screws and remove the fiber tray. To prevent damage to
the cables exercise care when loosening the screw near the coax and power cables.
5
In the BTN2 housing lid, disconnect and remove the RG-179 coax jumper labeled RET B from
the return B connector on the forward-return motherboard and the F-81C bulkhead
connector adapter bracket. This cable will not be re-used.
6
Remove the plug-in AM-RST or the AM-RRD return daughterboard (Figure 3-1 or 3-7), if
redundant return transmitters are already installed, from the return section of the
7
Install the AM-RSP plug-in daughterboard into the same sockets in the return path section
of the forward-return motherboard.
8
Install the return amplifier hybrid, provided in the SRB-KIT, in the sockets provided on the
AM-RSP daughterboard. Secure the hybrid using the mounting screws provided.
Exercise special care when installing the hybrid gain block to ensure that all pins enter the
appropriate sockets on the circuit board. Misaligned pins could damage the hybrid.
9
Replace the fiber tray and secure with the two hold-down screws.
When replacing the tray, ensure that the coax and power cables are properly routed through
the opening provided in one corner on the underside of the tray.
10 Carefully rewind the fiber cable onto the fiber tray. If necessary, disconnect the fiber
FC/APC (or SC/APC) connectors from the optical bulkhead adapter to properly dress the
fiber cable. Ensure that the connectors are cleaned before reconnecting them to the bulkhead
adapter.
11 On the port 4 forward-path power-doubler hybrid, remove the hybrid hold-down screw that
is located closest to the ADU plug-in accessory.
12 Remove the two blue JXP-ZX jumpers located in the Port Out and Port 4 ICS sockets (located
directly below the ADU module).
13 Install the SRB plug-in accessory board into the Port Out and the Port 4 ICS sockets.
14 Retrieve the coax cable interface harness removed in Step 2. Beginning with the end of the
coax cable harness terminated with the F-type connectors, remove approximately 16.7 inches
of the spiral wrap.
15 Add the split return coax cable, provided in the SRB-KIT, to the cable harness keeping all
three F-type connectors on the cable harness even with each other.
16 Begin rewrapping the spiral wrap. After rewrapping approximately 8.2 inches, separate the
RG-179 coax cable, identified with the RET IN label, from the remaining coax cables. The
other end of this cable is terminated with the MCX connector that connects to the BTN2-R*
plug-in accessory. Continue rewrapping the spiral wrap. When completed, the new cable
assembly should look similar to the harness represented in Figure 3-9
3-16
Figure 3-9
Split return option cable harness
F-type connector
(to RET IN)
SMB connector
(to SRB board)
F-type connector
(to lid board)
MCX connector
(to BTN2-R*)
F-type connector
(to lid board)
FWD IN
BTN-S2F
board
8.50
16.70
11.50
17 Install the BTN-S2F plug-in board, in its sockets on the main RF board (input EQ position).
18 Install the BTN2-R* plug-in board, in its socket on the main RF board (input diplex filter
location).
19 Pass the end of the third cable within the harness (shaded cable in Figure 3-9) through the
large opening labeled CONTROL STATUS MONITOR in the chassis cover. Connect the SMB
connector to the SRB plug-in accessory board installed in Step 13.
20 Re-install the chassis cover on the RF amplifier module. Reconnect the status monitor
connector in its socket on the main RF board. Re-attach the coax cable interface harness and
the status monitor cable harness to the cable clamps on the cover.
21 Route the RG-179 coax cable that is marked with the label RET IN to the F-81C cable bracket
adapter and attach it to the transmitter B F-type connector (J603).
22 Route the remaining two coax cables to the forward-return motherboard and attach the
black coax cable labeled FWD IN to the appropriate connector on the board.
23 Connect the remaining RG-179 coax cable coming from the SRB plug-in accessory board, to
the RET IN connector on the forward-return motherboard. This connection was formerly
occupied by the cable labeled RET IN which is now connected to transmitter B through J603
on the F-81C bulkhead cable bracket adapter.
24 Re-attach the cable harness to the clamp located on the AM-RM9/* receiver module.
25 Visually inspect all connections, cables, clamps, and chassis cover screws for proper location,
fit, and tightness. Close the housing carefully, ensuring that the cables are not pinched.
26 Tighten the housing hold-down bolts to the proper torque specifications and in the sequence
illustrated in Figure 4-6.
3-17
Coax Return Option
The return amplifier kit (RA-KIT/40H) is required.
To install the coax return option:
1
2
Install the return hybrid from the RA-Kit/40H on the RF amplifier board.
carelessly.
3
Install and tighten the hybrid hold-down screws.
4
Install the appropriate return equalizer into the sockets on the main board. Typically a zero
type return equalizer is installed.
5
Install the appropriate diplex filter (depending on the band split in use) into the sockets on
the main circuit board.
6
Install a JXP-ZX jumper or desired JXP-*A attenuator in the return amplifier JXP output
pad position. Re-install the cover on the RF amplifier module.
Installing the Status Monitor Option
The model LL-BTN2-*/* status monitor transponder is available as part of Motorola’s
®
LIFELINE status monitoring system. The transponder reports back critical node operating
parameters, through the return system, to the status monitor control computer.
To install the transponder:
1
Remove the clamp holding the status monitor control cable in the housing lid.
2
Install the transponder in its location on the housing lid (Figure 3-1) and secure it with the
captive mounting bolts.
3
Connect the control cable to the CONTROL connector on the transponder.
4
Loosen the screws on the RF amplifier module cover and lift the cover to gain access to the
amplifier circuit board.
5
Passing the coaxial cable through the appropriate opening in the amplifier module cover,
connect the FORWARD (INPUT) cable from the transponder to the STATUS MONITOR INPUT
connector on the amplifier board, and connect the RETURN (OUTPUT) cable from the
transponder to the STATUS MONITOR OUTPUT connector on the amplifier board.
6
Re-install the module cover mounting screws.
7
Bundle the transponder control and coaxial cables and spiral wrap them to help prevent
pinching when the housing lid is closed (see Figure 3-7).
Further information on the LL-BTN2-*/* status monitor transponder is available in the
Installation Sheet provided with the unit.
3-18
Surge Protection
A heavy-duty 230 V gas discharge surge arrestor is furnished with the node. It is centrally
located near the status monitor control male-connector. You can replace the surge protector with
a crowbar surge protector, Model FTEC/BTA.
Sweep Response and Gain Testing on the Bench
The recommended test method is to sweep the unit on the bench. To perform the tests you will
need:
§
A model AM-750ATH or OmniStar Cableoptic transmitter equipped with the chosen laser
module to test the AM-RM9/* receiver
§
Approximately 10 dB of fiber
§
A Wavetek model 1081 with a model 1076 comparator, or equal
™
After the optical receiver has been checked, the RF amplifier can be aligned and tested.
Sweep Testing the AM-RM9/* Receiver
The optical loss between the transmitter and AM-RM9/* optical receiver should approximate the
loss of the fiber link in the field. This is typically 10 to 14 dB. Connect the transmitter laser
output through the appropriate optical loss to the AM-RM9/* optical receiver before applying
power to the transmitter. This test verifies flatness of the fiber system.
Connect the equipment as shown in Figure 3-10.
Figure 3-10
Setup for sweep testing the AM-RM9/*
Sweep
transmitter
(output at
+15 dBmV)
Optical
transmitter
with
laser module
Fiber
BTN-2
AM-RM9/*
receiver
60 Vac power
Sweep
receiver
Sweep
display
After all connections are made:
1
Apply power to the transmitter.
2
Switch the transmitter into the MANUAL depth-of-modulation mode to avoid changing
signal levels generated by intermittent sweep signals.
If you are using the OmniStar transmitter, simply select the MANUAL mode.
3
Apply a flat sweep signal at approximately +15 dBmV to the input of the transmitter.
The output of the receiver should be the recovered sweep signal at an amplitude of
approximately 25 dBmV and may be used to make flatness measurements. Typical flatness
is expected to be less than 1.5 dB peak-to-valley.
4
3-19
Operate the sweep test equipment following the recommendations of the manufacturer. If
the test equipment permits, store the sweep trace for later comparison.
The response correction network in the BTN2 RF amplifier can be used to optimize the overall
system response. This adjustment, if necessary, should be made after the amplifier is aligned
and the system is fully installed and operational.
Sweep Testing the RF Amplifier Module
Connect the equipment for testing the amplifier as shown in Figure 3-11. The Wavetek 1076
comparator includes a slope function. It produces a “down tilt” (lesser amplitude at the higher
end of the bandpass). This slope can be selected by a switch on the front panel, and it should be
adjusted to the appropriate tilt between 52 MHz and 870 MHz. The tilt produced by the test
equipment will result in a flat trace when sweeping the amplifier.
Figure 3-11
Setup for testing the amplifier module
Wavetek 1901
Wavetek 1061
Wavetek 1076
Input
60 Vac input
Output
Receiver
interface
RF module
under test
Output port
Terminate other
output ports
BTN2
To test the amplifier module:
1
Calibrate the sweep equipment by following the manufacturer’s recommendations. Select
SLOPE on the comparator and adjust the comparator for the appropriate slope between
52 MHz and 870 MHz.
2
Connect the BTN2 to the test equipment and apply power. Note that the input to the RF
amplifier module is made at the forward equalizer input location, not at the housing port, as
is the convention in other applications.
(a) To connect the input signal to the RF amplifier module, disconnect receiver A from the
forward-return motherboard and connect the sweep signal input at this location.
3-20
3
Select manual gain operation, if necessary, by installing the gain select jumper in the
MANUAL location. Turn the GAIN control to maximum gain, then reduce the gain by 4 dB.
At this point, the sweep response of the amplifier should be flat. You can correct response
flatness through adjustments available on the BDR-8BTN/11 board (located on the main RF
board) and SG2-FE3* for 12.5dB of tilt. Use the SG2-FE4* if the system tilt is 14 dB. Other
SG2-FEQ* plug-ins are available for other tilt options. Figure 3-12 illustrates the location of
the controls for the BDR-8BTN/11 board:
Figure 3-12
BDR-8BTN/11 controls
R2
C7
R3
R4
C2
C3
R5
C6
C1
C4
Trimmers C3, C2, and C7, together with potentiometers R2, R3, and R4, are used to
compensate for diplex filter low-end roll off. Trimmer C4 and potentiometer R5 are for
high-end roll off. C1 and C6 are for mid-band.
After the required flatness has been obtained, the operational gain of the amplifier can be
measured. The gain should be as stated in Appendix A, “Specifications.” (The gain specification
only applies to the amplifiers with JXP -*A pads installed in the factory). The amplifier’s gain is
the measured gain plus 12.5 dB, which is the slope of the test equipment, plus any miscellaneous
losses that may exist in the test setup.
Sweep Testing the Return Path
The recommended procedure for sweeping the return path is to check the return amplifier and
the return transmitter separately. The return path should be tested again after installation.
Sweep Testing the Return Amplifier
To sweep test the return amplifier:
1
Apply a sweep signal at a convenient level to any of the active forward amplifier output
ports. These are the inputs for the return signal. You have two options for making
connections to the return amplifier: (1) you can make connections to the return amplifier
output at the F-81C bulkhead adapter, which is the signal input to the return transmitter, or
(2) if the amplifier is configured with the RF return option, you can make the connection to
the return amplifier output at the forward Port In location.
2
Adjust the sweep generator to cover the bandpass of interest; approximately 5 MHz to
40 MHz in a subsplit system.
3
3-21
Check the flatness and gain using standard test procedures. The return amplifier gain
should be approximately 20 dB.
Sweep Testing the Return Transmitter
CAUTION!
DO NOT look into the optical connector of the transmitter with power applied. EYE DAMAGE MAY
RESULT. (Refer to the installation manual provided with the transmitter for other safety guidelines).
To sweep test the return transmitter:
1
Connect the equipment as shown in Figure 3-13. The setup requires approximately 10 dB to
14 dB of fiber, plus a model AM-RPR receiver installed in a model AM-RPRH4 return-path
receiver housing.
Figure 3-13
Test setup for the return transmitter
+ 35 dBmV
Sweep
generator
2
Fiber
loss
AM-RPT*
transmitter
AM-RPR
receiver
Sweep
receiver
Sweep
display
Apply a sweep level of approximately +35 dBmV to the input of the AM-TC-RPTDB/*
transmitter, or +45 dBmV to the input of the AM-TC-DFBT/* transmitters. This can be done
by connecting the sweep signal to the coax input connector of the return path transmitter.
The sweep response through the entire return system, when measured from transmitter
input to optical receiver output, should be flat within 2 dB peak-to-valley.
This completes the testing of the return path system. Remove any test equipment connections,
fasten the coax bracket into the cover of the housing, and verify that all connections have been
re-established.
Section 4
Installation
Installation consists of splicing the six-fiber service cable to the transportation fiber, installing
the housing and electronics on the messenger strand, and then applying power.
Splicing Fiber
You can splice the six-fiber service cable to the transportation cable at any time during the node
installation. Splicing does not need to coincide with the installation of the housing.
Fusion splicing is recommended since it has low insertion loss and is the most reliable method.
The splicing should be done by a technician experienced in splicing fiber. The procedure is as
follows:
2
Obtain the 50-foot, six-fiber service cable with the compression fitting from the node
package. See Figure 4-1.
Figure 4-1
Service cable connection and compression fitting
Water Compression
seal nut
nut
Main
body
Service
cable
Heat
shrink
SC/APC
connectors
2
Splice each fiber according to procedures recommended by the manufacturer of the splicing
equipment being used. Cleanliness in the work area is essential.
2
A blue-coded fiber is suggested for the forward signal distribution, and a brown-coded fiber is
recommended for the return path. Assemble the splice enclosure by following the
instructions furnished with the enclosure.
CAUTION!
It is important that the connections at the headend be duplicated. If they are different from the
above recommendations, follow the scheme used for the headend connections.
4-2
4
Installation
After splicing has been completed and the splice enclosure has been installed, the extra cable
may be suspended from the messenger using locally accepted methods. Commonly used
methods include suspending it from the messenger along its entire length and/or fashioning
a figure eight coil and suspending it from the messenger.
If you are installing the housing at a later time, you must protect the end of the service cable
with the compression fitting and the fiber connectors from dirt and moisture.
Installing the BTN2
There are no surge protectors over the center seizure screws, and none should be installed.
Adding surge arrestors will degrade the match of the housing port.
Connections to the housing are made using standard housing port entry connectors. Pin-type
connectors with a nominal center conductor diameter of 0.067 inches are required. Center
conductor pin length is 1.50 inches minimum, 1.65 inches maximum. See Figure 4-2.
Figure 4-2
Center conductor length
1.65" Max.
1.50" Min.
To install the configured node:
1
Hang the housing and install all of the aluminum cable connections. Contact the
manufacturer for instructions on installing the aluminum cable connector.
2
Open the BTN2 housing, remove the port plug located at the side of the housing lid, and
carefully pass the connector ends of the fiber service cable through this port.
It will be necessary to insert one connector at a time. Be careful not to bend the fiber any
more than is necessary.
3
Thread the compression fitting into the port.
The compression nut and rubber grommet must be sufficiently loose to allow the fitting to be
turned without turning the fiber cable at the same time. The main body of the fitting should
be torqued to 60 to 70 in. lbs.
4
Carefully dress the fiber into the fiber spool tray taking care that it is routed under the
retaining flanges.
5
Connect each fiber by removing the protective boot from the fiber connector, cleaning the
connector with pure isopropyl alcohol (99% by volume) and a lint-free wipe, then drying it
with filtered compressed air.
6
After cleaning the fiber, insert it into the appropriate bulkhead fitting in the mounting
bracket to connect it to the receiver.
Installation
7
4-3
Position the fiber service cable in the compression fitting to provide some slack in the fibers
inside the housing, then tighten the compression nut.
The compression nut should be tightened until it bottoms out.
8
Finally, tighten the water seal nut. This nut should be tightened until there is no gap
between it and the compression nut.
Powering the Node in the Field
The BTN2 node can be conveniently powered by applying 60 Vac or 90 Vac to port number 2.
This port is not used for RF purposes and is designed to carry 15 amps of current. The BTN2 can
also be powered from any of the other ports that are rated at 15 amps of continuous current and
are fused with common, blade-type 20 amp automotive fuses. The 5 amp fuse protects the dc
power pack and can also be used to disconnect power from the amplifier.
A 5 ampere thermal circuit breaker (model BCB-5) is available for systems where thermal circuit
breakers are preferred. The breaker is installed in place of the fuses that are furnished with the
amplifier.
In addition to providing overcurrent protection, the fusing also determines paths for ac bypass
through the housing. Table 4-1, Figure 4-3, and Figure 4-4 will assist you in setting bypass
configurations.
Table 4-1
Fuses
Fuse
Function
Ra ting
F1
Passes ac to or from IN port.
20 A
F2
For dc power supply (always required).
5A
F3
Passes ac to or from port 1.
20 A
F4
20 A
F5
20 A
F6
Passes ac to or from OUT port.
20 A
F7
Always required, except when power from ac
input (port 2) is to be blocked at this location.
20 A
A few examples may be helpful:
(1) ac powering is from the IN port and must be passed to the OUT port and to port 4, but
blocked from the other ports. In this situation you need to install fuses at locations F1, F2,
F5, F6, and F7, and remove fuses from locations F3 and F4.
(2) Power is provided from the ac port (port 2) and must be blocked from all other ports. In
this situation you need to install a fuse at location F2 and remove the fuse from F7.
You can perform the same ac routing using the optional Autofuse Jumpers. These jumpers fit in
the fuse receptacles, but they do not provide overload protection.
4-4
Installation
Figure 4-3
Module cover showing location of fuses
TO
RTN TX
RF RTN
OPTION
-20dB
H
L
JXP IN
AUTO
JXP OUT
MAN
-20dB
JXP
MAN
REFER TO
MANUAL FOR
FUSE VALUES
F7
F2
OUT
H
BTNS
2F
F1
F1
ADU
TDU
JXP ADU
+24 VDC
-20dB
RTN EQ
POWER ON
CHECK VOLTAGE
SELECTOR
REFER TO MANUAL
JXP 1
JXP THERM
F3
F3
ICS
CONTROL STATUS
MONITOR
-20dB
ADU
PORT 4
JXP
L
I
C
S
H
L
-20dB
STATUS
MONITOR
OUTPUT
I
C
S
H
STATUS
MONITOR
INPUT
JXP 4
JXP
PORT 1
PORT 3
JXP 4
FTEC/BTA
ICS
JXP 3
F5
-20dB
F4
F2
F7
POWER
PORT 2
F6
F6
BTN2-20dB
F5
FROM
FWD
RX
L
H
L
JXP 3
CAUTION:
CONTAINS PARTS
AND ASSEMBLIES
SUSCEPTIBLE TO
DAMAGE BY
ELECTROSTATIC
DISCHARGE (ESD)
-20dB
JXP 1
-20dB
ASSEMBLED IN MEXICO
Figure 4-4
Fusing diagram
In
F1
Port 2
F7
F2
F6
Out
F5
Port 4
F4
Port 3
dc
power
supply
Port 1
F3
F4
Installation
4-5
Receiver/Link Performance Checks and Adjustments
In the following procedure it is assumed that:
§
Optical connectors are clean and the optical receiver is properly spliced into the
transportation fibers as previously described.
§
The fiber transmitter is installed in the headend.
§
The transmitter is fully operational.
The following checks and adjustments should be performed:
1
Measure and record the voltage at the AM-RM9/* receiver test point with a voltmeter.
The voltage at this test point is scaled and represents the optical input power to the receiver.
2
Use Figure 4-5 to find the corresponding optical input power for the voltage recorded in
Step 1.
The received optical power value obtained from Figure 4-5 should be within 1 dB of the
calculated value. If it is not, the actual received power can be measured with an optical
power meter to confirm the test point measurement.
Figure 4-5
Optical input power versus test point voltage
4.5
2.0
1.75
3.5
1.5
3
1.25
2.5
2
1
.75
1.5
.5
1
.25
0.5
0
Optical power (mW)
Test point voltage (Vdc)
4
-8
-6
-4
-2
0
2
Optical power (dBm)
The receiver optical input power is normally between −7 dBm and +3 dBm. A signal level greater
than +3 dBm must be attenuated to maintain distortion performance while less than −7 dBm
may result in an unacceptable c/n. Optimum performance is achieved at optical input levels
between −4 dBm and +2 dBm.
4-6
Installation
Amplifier Output Level
Once the proper operation of the AM-RM9/* optical receiver is ensured, you must adjust the
BTN2 for proper operation.
Manual Gain Control
Adjusting the manual gain is necessary even when you operate the unit with the BTN-S-TCU or
the ADU option. This adjustment becomes reference for either of the two alternate modes of
operation and therefore should be adjusted with care.
To adjust the manual gain control:
1
Connect a signal level meter to the OUT test point and tune it to a channel near 870 MHz, or
near 750 MHz for the 750 MHz option.
2
Position the drive unit selector to the MAN position (see Figure 3-5).
3
Turn the MAN control to maximum (fully clockwise) and then reduce the output by 4 dB (the
gain reserve).
At this point, the output level of the high-end channel should be within 1 dB of the preferred
output signal level. Minor adjustments can be made using the MAN control.
4
If the output level is greater than required after performing step 3, change the input pad to
obtain the required level. Subtract the desired level from the measured level; the result is
the required pad value.
5
Remove the existing input pad or jumper and replace it with the proper value. Now repeat
steps 3 and 4.
6
Tune the signal level meter to channel 2. The level measured should be below the level
measured in step 3 by the slope of the system.
Manual Thermal Control, Model BTN-S-TCU
To adjust the manual thermal control unit:
1
Temporarily position the drive unit selector to the MAN position (see Figure 3-5). Perform
steps 1 through 6 listed under Manual Gain Control.
2
Connect a signal level meter to the OUT test point and tune it to a channel near 870 MHz, or
near 750 MHz for the 750 MHz option. Record the RF level.
3
Position the drive unit selector to the AUTO position (see Figure 3-5).
4
Turn the level control on the BTN-S-TCU to the same output level as recorded in Step 2.
5
You can now set the BTN2 final output power level using the manually inserted JXP-*A
attenuator pads as described in Section 3 “Pre-installation Bench Testing-Installing Pads.”
Installation
4-7
Automatic Level Control, Model ADU
To adjust the automatic level control unit:
1
Temporarily position the drive unit selector to the MAN position. Perform steps 1 through 6
listed under Manual Gain Control.
2
Connect a signal level meter to the out test point and tune it to a channel near 870 MHz, or
near 750 MHz for the 750 MHz option. Record the RF level.
3
Position the drive unit selector to the AUTO position.
4
Turn the ADU level control to the same output level as recorded in Step 2. You can now set
the BTN2 final RF output level using manually inserted JXP-*A pads.
If adjustment of the ADU level control does not achieve the desired output level before the
mechanical limit of the control is reached, adjustment of the plug-in JXP*A attenuator at the
ADU input may be necessary. The location of this JXP*A is marked on the chassis cover. If
the output level is too low after adjusting the ADU level control, remove the chassis cover
and change the ADU JXP-*A attenuator to a larger value. Typically, a value of 2 dB more
than the existing value enables you to obtain the desired output level. Conversely, if the
output level is too high after adjusting the ADU level control, decrease the value of the ADU
JXP-*A by 2 dB. Best performance is obtained when the ADU JXP*A pad value is selected to
maintain the ADU level control near the mechanical center of its adjustment range.
Return System Checks
After the forward system (distribution) has been checked and found to be operating
satisfactorily, the return system can be checked and adjusted. It will be necessary to have a
return signal available for that purpose.
The return data signals applied to the return transmitter can be checked at the coax bracket in
the housing cover. To avoid clipping, the level should not exceed +35 dBmV for RPTD or
+45 dBmV for AM-TC-DFBT. Install an appropriate JXP*A pad at any return JXP pad location
(JXP, JXP1, JXP3, or JXP4 marked in red on the chassis cover) where the signal level is greater
than those stated above. Refer to Figure 3-2 in Section 3, “Pre-installation Bench Testing,” to
identify the JXP pads in question.
Install the cables disconnected earlier and recheck the input level of the return transmitter.
Check cover screws for tightness and all leads for proper dress.
Measure the test point voltage on the return transmitter. It should be approximately 4 Vdc and
indicates that the return optical power output is 400 µW. Record this reading for future
reference.
This completes the checks of the return path system.
4-8
Installation
Closing the Housing
To close the node housing:
1
Ensure that all accessories and options that are required at the node location are present.
2
Record all pertinent data for future reference.
3
Check amplifier cover screws, as well as module retaining screws, for proper tightness.
4
Close the housing with care to avoid pinching the cabling between components in the
housing lid and the RF amplifier module.
5
Tighten the housing closure bolts in the sequence shown in Figure 4-6 to a final torque of
between 10 and 12 ft. lbs.
Figure 4-6
Housing bolt torquing sequence
6
2
4
7
8
3
1
Torque housing bolts to 10-12 ft. lbs. in sequence shown.
5
Ap p en d i x A
Specifications
Specifications for the BTN2 and optional equipment are valid over the bandpass and operating
temperature range listed in this section. The current catalog may contain additional information
not provided below.
Table A-1 lists the optical characteristics for the BTN2 node:
Table A-1
BTN2 optical characteristics
Pa ra meter
Sp ecifica tion
Optical wavelength
1310 nm ± 20 nm through 1550 nm± 20 nm
Received optical power
minimum
maximum
–3 dBm
+3 dBm
Optical input return loss
45 dB minimum
Equivalent input noise current
8 pA/Hz½
Receiver minimum output level with
0 dBm input level, 110 channel load
23.5 dBmV/ch
Optical test point
2.0 V / mW ± 0.4
Table A-2 lists the station RF characteristics for the BTN2 node:
Table A-2
Station RF characteristics
Pa ra meter
Sp ecifica tion
Forward passband frequency
47 MHz through 870 MHz (dependent upon split)
Return passband, each port
5 MHz through 80 MHz (dependent upon split)
Splits
S
J
A
K
E
M
40/52 MHz
55/70 MHz
65/85 MHz
42/54 MHz
30/47 MHz
80/108 MHz
Return loss
16 dB
Launch amplifier operational gain
35 dB
Gain control range
±4 dB
Flatness over passband
±0.75 dB
Operational slope (linear)
Low slope - L
10.0 dB ±0.75 dB
Std. slope - S
12.5 dB ±0.75 dB
High slope - H
14.0 dB ±0.75 dB
Ultra high slope - U
16.0 dB ±0.75 dB
A-2
Specifications
Table A-3 lists the general characteristics for the BTN2 node:
Table A-3
BTN2 general characteristics
Pa ra meter
Sp ecifications
AC input voltage
38 Vac to 90 Vac quasi-squarewave
AC bypass current
15 A
Hum modulation
–64 dBc at 15 A bypass current (5 to 870 MHz)
Operating temperature range
–40° C to +60° C (–40° F to +140° F)
Housing dimensions
21.6”(L) × 10.6”(W) × 11.0”(D)
Weight
Minimum 27 lbs.
Table A-4 lists the general power requirements for the BTN2 node:
Table A-4
Typical power requirements
Option
AC pwr
90 V
60 V
52 V
44 V
38 V
BTN2
73.8 W
0.86 A
1.29 A
1.54 A
1.82 A
2.04 A
Additional receiver and
switch driver
9.0 W
0.11 A
0.16 A
0.19 A
0.22 A
0.25 A
Additional receiver and
status monitor
11.1 W
0.13 A
0.20 A
0.23 A
0.27 A
0.31 A
Addition of single return laser
8.2 W
0.10 A
0.15 A
0.17 A
0.20 A
0.23 A
Addition of redundant return laser
12.2 W
0.14 A
0.22 A
0.26 A
0.31 A
0.34 A
Addition of split-return laser
16.2 W
0.19 A
0.29 A
0.34 A
0.41 A
0.45 A
Addition of status monitor
3.0 W
0.04 A
0.06 A
0.07 A
0.08 A
0.09 A
Addition of ADU
2.1 W
0.03 A
0.04 A
0.04 A
0.05 A
0.06 A
Subtract for each forward output
eliminated
10 W
0.12 A
0.17 A
0.20 A
0.23 A
0.27 A
Specifications
A-3
Table A-5 lists distortion and c/n performance for the BTN2 with a load of 77 channels:
Table A-5
BTN2 performance with 77 channels
77 Ch a n n el s
T ru n k
F eed er
C/N
51
51
CTB
–70
–65
CSO
–65
–63
Link: AM-RM9 w/ALM11 77ch, 20 km
Loss budget 9.0 dB
12.5 dB tilt 750 MHz virtual level of 38.5 dBmV trunk, 47.5 dBmV feeder
200 MHz of compressed data 6 dB below analog channel level
Trunk output level (750/550/55 MHz), 32.5/35/26 dBmV
Feeder output level (750/550/55 MHz), 41.5/45/35 dBmV
Table A-6 lists distortion and c/n performance for the BTN2 with a load of 110 channels:
Table A-6
BTN2 performance with 110 channels
110 Ch a n n el s
T ru n k
F eed er
C/N
51
51
CTB
–67
–64
CSO
–63
–61
Link: AM-RM9 w/ALM11 77ch, 20 km
Loss budget 9.0 dB
12.5 dB tilt 870 MHz virtual level of 38.5 dBmV trunk, 47.5 dBmV feeder
120 MHz of compressed data 6 dB below analog channel level
Trunk output level (870/750/55 MHz), 32.5/36.5/26 dBmV
Feeder output level (870/750/55 MHz), 41.5/45.5/35 dBmV
Table A-7 lists the RF performance specifications for the AM-MB-RPTDB/* laser transmitter:
Table A-7
AM-MB-RPTDB/* RF specifications
Pa ra meter
Sp ecifica tion
Optical output power
0.4 mW
Laser type
Fabry-Perot
Optical wavelength
1310 nm
RF passband
5 MHz to 200 mHz
Flatness (peak to valley)
1.0 dB maximum
RF input return loss
18 dB minimum
Recommended total input power
+40 dBmV
Carrier to noise ratio 9 dB link, 35 MHz
BW
41 dB
A-4
Specifications
Table A-8 lists the RF performance specifications for the AM-TC-RPT/* laser transmitter:
Table A-8
AM-TC-RPT/* RF specifications
Pa ra meter
Sp ecifica tion
0.4 mW
Laser type
Fabry-Perot
Optical wavelength
1310 nm
RF passband
5 MHz to 65 mHz
1.0 dB maximum
18 dB minimum
+45 dBmV
Table A-9 lists the RF performance specifications for the AM-TC-DFBT/* laser transmitter:
Table A-9
AM-TC-DFBT/* RF specifications
Pa ra meter
Sp ecifica tion
1.0 mW
Laser type
Distributed feedback
Optical wavelength
1310 nm
RF passband
5 MHz to 200 mHz
1.0 dB maximum
18 dB minimum
+45 dBmV
BW
44 dB
Table A-10 lists the RF performance specifications for the AM-TC-DFBT3/* laser transmitter:
Table A-10
AM-TC-DFBT3/* RF specifications
Pa ra meter
Sp ecifica tion
2.0 mW
Laser type
Distributed feedback
Optical wavelength
1310 nm
RF passband
5 MHz to 200 MHz
1.0 dB maximum
18 dB minimum
Specifications
+45 dBmV
BW
44 dB
A-5
Abbreviations and Acronyms
The abbreviations and acronyms list contains the full spelling of the short forms used in this
manual.
A
ampere
ac
alternating current
ADU
automatic drive unit
APC
angled physical contact
APC
angled physical contact
CATV
Community Antenna Television
CIN
composite intermodulation noise
c/n
carrier-to-noise ratio
CSO
composite second order
CTB
composite triple beat
dB
decibel
dBm
decibels relative to 1 milliwatt
dBmV
decibels relative to 1 millivolt
dc
direct current
DFB
distributed feedback
FC
ferrule connector
FP
Fabry-Perot
FSK
frequency shift keying
FTEC
fast trigger electronic crowbar
kHz
kilohertz
km
kilometer
ma
milliampere
MHz
megahertz
µW
microwatt
mA
milliamp
mW
milliwatt
nm
nanoampere
NTSC
National Television Standards Committee
OMI
optical modulation index
PIN
positive intrinsic-negative
pA
picoampere
RF
radio frequency
RIN
relative intensity noise
Abbreviations and Acronyms-2
RSA
return for service authorization
SC
snap connector
TCU
thermal control unit
V
volt
480634-001-99
4/01

BTN2 Broadband Telecommunications Node

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