Motorola SG 2000 Level Control, Options and Accessories, Model Description Function, Adu

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O v e r v i e w

Level Control

The gain of hybrid IC amplifiers varies with temperature. In addition, changes in system channel loading and/or splices in the fiber link can change the level of the received signal.

The standard TCU board compensates for anticipated hybrid gain changes by sensing housing temperature and signaling needed changes to the RF attenuator.

The ADU board, an optional plug-in module, monitors the amplitude of a selected pilot frequency. The pilot frequency is an available analog television channel not scrambled by the sync suppression method. Any changes in amplitude are fed back to the RF attenuator that makes appropriate corrections.

The input to the ADU contains a JXP-* pad. The factory-installed value of this pad is 6 dB (JXP-6) for bridger level outputs and 0 dB (JXP-ZX) for trunk level outputs. Under normal conditions, it should not be changed.

Options and Accessories

Table 2-3 provides a list of options and accessories for the SG 2000:

Table 2-3

Options and accessories

Model	Description	Function
ADU-*	Automatic drive	This option automatically adjusts gain by monitoring changes
	unit	in the level of the selected pilot carrier. Either an ADU or TCU
		must be installed.
TCU	Thermal control	The TCU controls amplifier gain for changes in hybrid gain at
	unit	the sensed temperature.
JXP-*A	Fixed	Attenuator pads are used to adjust amplifier levels and are
	attenuator	available in 1 dB steps from 1 through 24 dB. The appropriate
		value must be installed.
JXP-ZX	0 dB attenuator	This attenuator is used in place of JXP-*A pads when no
		attenuation is needed.
FTEC	Crowbar	The FTEC is an electronic crowbar/surge protector that can be
	overvoltage	used to replace the existing 230-volt gas discharge surge
	protection	protector.
LL-SG2	LIFELINE	This module enables the system operator to monitor the SG2
	module	from a remote location. See Section 5, “Operation” for
		parameters monitored. Several frequencies are available. See
		the product catalog for additional information.
GFAL	Test probe	This probe is used to evaluate node performance.
F/JXP	Injection probe	This probe is used to inject a signal for test purposes.

SG 2000 Installation and O peration Manual

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Contents A R L I N E Special Symbols that Might Appear on the Equipment Contents E r a t i o n InstallationTorque Specifications Abbreviations and Acronyms Specification sSG2-LR Tables N t e n t s SG 2000 closed SectionSG 2000 open Features includeRelated Documentation Using this ManualDocument Conventions If You Need HelpBold type Calling for Repairs Housing SG 2000 housing dimensions front and side viewMounting Holes Port locations Port LocationsGaskets Housing gasketsSG2-PS2 power supply Power SupplyNetwork Monitoring ConfigurationTo suit system requirements the RF chassis cover. notation Forward Path Signal flow diagramE r v i e w SG2-LR Receiver SG2-LR receiver functional diagramAnalog return transmitters Analog Return PathAnalog Return Transmitters Model DescriptionJXP SG2 transmitter block diagramDigital return transmitters Digital Return PathDS-SG2-DRT-2X/A Model Description Function Options and AccessoriesOptions and accessories Level ControlSG2-FE SG2-SBSG2-PS2 SG2Optical input versus 750 MHz gain Gain SelectionOptical input versus 870 MHz gain 10 illustrates the gain option selection chart for 870 MHzRelative level dB versus 750 MHz slope 77 channels Tilt SelectionRelative level dB versus 870 MHz slope 94 channels SG2 870 MHz Slope Chart Analog Channels, 220 MHz DigitalRelative level dB versus 870 MHz slope 110 channels SG2 870 MHz Slope Chart Analog Channels, 120 MHz DigitalN c h S e t u p G u r e 3 2 0 0 0 R F c h a s s i s W e r i n g t h e N o d e Fuse Functi o n Rati ng Ype W e r S u p p l y S e t t i n g s Illustrates the location of the LO-HIjumper Single Power Supply or Commonly Po wered Redundant Supplies I c k C h e c k s F u n c t i o n a l T e s t i n g N u a l G a i n C o n t r o l Analog Retu rn Path R w a r d P a t h P a d d i n g B l e 3 2 0 0 0 p a d c h a r t s t a n d a r d g a i n B l e 3 2 0 0 0 p a d c h a r t h i g h g a i n G u r e 3 N k P e r f o r m a n c e G u r e 3 1 N c h S e t u p Install i n g t h e D S S G 2 D R R B B o a r d O p t i o n G u r e 3 1 S G 2 D R R B b o a r d Install e d G u r e 3 1 C a t i o n o f J X P s o n E p a c k Digital Transmitter Install i n g t h e S t a t u s M o n i t o r O p t i o n 2 0 0 0 a c t i v a t i o n W o r k s h e e t DC powering Splicing Fiber Service cable connection and compression fittingInstallation Mounting bracket-front view Strand Wire MountingMounting bracket-rear and side views Coaxial Cables Fiber CablesCenter conductor length Housing lid and fiber spool tray Fiber spool tray Installation Single Receiver Mode Forward Path RF ConfigurationBroadband/narrowcast Redundant Receiver ModeBroadband/Narrowcast Mode Redundant receiverOverride AB Override FunctionalityStatus monitor/MCB operation Status Monitor/Manual Control OperationAnalog Return Path RF Configuration Redundant returnSplit return RF chassis and location of the SG2-RPM/C or SG2-RPM/S board DS-SG2-DRT/A redundant return Digital Return Path RF ConfigurationDS-SG2-DRT-2X/A redundant return DS-SG2-DRT-2X/A split returnInstalling SG 2000 Optical Modules SG 2000 Optical ModulesRemoving SG 2000 Optical Modules SG2 LR Optical Receiver Cleaning the Optical ConnectorFeature Description 0.3 Test-point voltage versus optical powerWavelength selection jumper Wavelength Selection JumperFeatureDescription SG2-IFPT featuresSG2 Ifpt Optical Transmitter Transmitter enable SG2-FPT featuresSG2 FPT Optical Transmitter SG2 Dfbt Optical Transmitter SG2-DFBT featuresSingle red LED that lights if the hybrid current is outside SG2 DFBT/3 Optical Transmitter SG2-DFBT/3 featuresSG2 Eifpt Optical Transmitter SG2-EIFPT featuresDS-SG2-DRT/A DS SG2 DRT/A Digital Return TransmitterDS-SG2-DRT/A features FeatureDS-SG2-DRT-2X/A DS SG2 DRT 2X/A Digital Return TransmitterDS-SG2-DRT-2X/A features DS-SG2-DRT-2X/A installed in SG DS-SG2-DRT-2X/A cable connectorSG2-PS Power Supply SG2-PS power supplyDS-SG2-DRT-2X/A second RF input cable connection Parameter Description Status MonitoringDescription Function Manual Control BoardThrough ICS4 Alarm test pointDB test point Potentiometers ICS1Ingress Control State DescriptionOff Appendix a Parameter SpecificationTable A-1 SG 2000 optical characteristics Table A-2 Station RF characteristicsParameterSpeci fic ation Table A-5 SG2-IFPT RF specifications Table A-6 SG2-FPT RF specificationsParameter Table A-8 SG2-DFBT/3 RF specifications Table A-7 SG2-DFBT RF specificationsTable A-10 SG2-DRT/A RF specifications Table A-9 SG2-EIFPT RF specificationsTable A-11 SG2-DRT-2X/A RF specifications Minimum Optical Model Output Power DBmOption Watts ac Amps Power @90V @60V @52V @44V Table A-16 SG2-87 performance, with 110 channels Channels Link Launch SystemTable A-14 SG2-75 performance, with 77 channels Table A-15 SG2-87 performance, with 94 channelsTorque Fastener Screw Size Wrench Size In-lbs Ft-lbs MHz DBcDBm DBmVOptical modulation index Return for service authorizationSnap connector National Television Standards CommitteeMgbi