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9581 SST R5
Return Path Analyzer
Operation Manual
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Trilithic Company Profile
Trilithic is a privately held manufacturer founded in 1986 as an engineering and assembly
company that built and designed customer-directed products for telecommunications, military, and
industrial customers. From its modest beginnings as a two-man engineering team, Trilithic grew
over the years and broadened its offerings of RF and microwave components by adding
broadband solutions to its product line. This was accomplished with the acquisition of
components manufacturer Cir-Q-Tel and instruments manufacturer Texscan.
Today, Trilithic is an industry leader providing telecommunications solutions for major broadband,
RF, and microwave markets around the world. As an ISO 9000:2001 certified company with over
40 years of collective expertise in engineering and custom assembly, Trilithic is dedicated to
providing quality products, services, and communications solutions that exceed customer
expectations.
Trilithic is comprised of five major divisions:
Broadband Instruments and Systems
Offers test, analysis, and quality management solutions for the major cable television
systems worldwide.
Telecom Solutions
Offers affordable, easy-to-use instruments for testing and measurement of Telecom
networks.
RF Microwave Components
Provides components and custom subsystems for companies specializing in cellular,
military, and other wireless applications.
Emergency Alert Systems
Leading supplier of government-mandated emergency alert systems used by broadcast
TV, cable TV, IPTV, DBS, and radio stations.
XFTP
Offers a specialty line of field technical products for cable operators and technicians, as
well as a line of products for installing electronics in the home of the future.
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Table of Contents
1. General Information .............................................................................................................. 5
Helpful Website ..................................................................................................................... 5
Where to Get Technical Support ............................................................................................. 5
How this Manual is Organized ................................................................................................ 6
Conventions Used in this Manual ........................................................................................... 7
Precautions ...........................................................................................................................8
2. Introduction........................................................................................................................... 9
System Overview ...................................................................................................................9
Application ............................................................................................................................ 9
Balancing the Return Path .............................................................................................. 10
Measuring Ingress and Noise .........................................................................................10
Return Path Maintenance ..................................................................................................... 11
9581 SST Headend Analyzer ...............................................................................................12
Included Equipment .............................................................................................................12
Optional Equipment .............................................................................................................12
A Guided Tour of Your 9581 SST R5 .................................................................................... 13
Front View ......................................................................................................................13
Back View ...................................................................................................................... 14
3. Optimizing the Return Path ...............................................................................................15
Introduction .......................................................................................................................... 15
Return Path Perfomance Parameters ...................................................................................15
Signal-to-Noise Ratio .....................................................................................................16
Signal-to-Ingress Ratio ...................................................................................................16
A Balanced System ........................................................................................................16
4. Installation ........................................................................................................................... 19
Overview ............................................................................................................................. 19
Pre-Installation Considerations ............................................................................................ 19
Reverse Test Carriers..................................................................................................... 19
Forward Data Carrier .....................................................................................................20
Installing the 9581 SST R5 ...................................................................................................21
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Display Screen Overview ..................................................................................................... 23
Instrument Information .....................................................................................................23
Instrument Time, Date, & Internal Temperature ........................................................... 23
Firmware & Software Version Numbers .................................................................... 23
Setup Menu Navigation ..................................................................................................24
Viewing the Network Settings .................................................................................... 24
Viewing the RX Frequency Settings .......................................................................... 25
Viewing the RX Level Settings .................................................................................. 25
Viewing the Link Frequency Settings ......................................................................... 26
Viewing the Remote Detection Type Settings ............................................................ 26
Adjusting the Speaker Settings .................................................................................27
Adjusting the Display Screen Contrast Settings .........................................................28
5. Operation............................................................................................................................. 29
Overview ............................................................................................................................. 29
Setting up the 9581 SST R5 ................................................................................................ 29
Remote Operation ............................................................................................................... 30
Return Path Alignment .......................................................................................................... 30
Adjusting the Fiber Link ....................................................................................................... 31
Adjusting Amplifiers ............................................................................................................. 32
Ingress ................................................................................................................................. 34
Extending the Measurement Range ..................................................................................... 36
Reconfigure the 9581 SST R5 for Greater Range ........................................................... 36
Increase Sensitivity and Range .......................................................................................36
Effect of the Offset on the 860 DSP and 860 DSPi ......................................................... 36
6. Appendix .............................................................................................................................37
Specifications ...................................................................................................................... 37
Warranty Information ............................................................................................................ 38
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Chapter 1
1. General Information
Helpful Website
The following website contains general information which may be of interest to you:
http://www.trilithic.com
Trilithics website contains product specifications and information, tips, release information,
marketing information, Frequently Asked Questions (FAQs), bulletins and other technical
information. You can also check this website for product updates.
Where to Get Technical Support
Trilithic technical support is available Monday through Friday from 8:00 AM to 5:00 PM EST.
Callers in North America can dial 317-895-3600 or 800-344-2412 (toll free). International callers
should dial 317-895-3600 or fax questions to 317-895-3613. You can also email technical
support at techsupport@trilithic.com.
For quicker support response when calling or sending e-mail, please provide the following
information:
Your name and your company name.
The technical point of contact (name, phone number, e-mail).
Product name, model number, and serial number.
A detailed description of the problem you are having, including any error or information
messages.
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How this Manual is Organized
This manual is divided into the following chapters:
Chapter 1, General Information provides Trilithic contact information and describes how
this operation manual is structured.
Chapter 2, Introduction explains what the 9581 SST R5 does and provides an overview of
the physical features of the device.
Chapter 3, Optimizing the Return Path provides an overview of how to provide a reliable
return path in order to optimize the systems performance.
Chapter 4, Installation provides installation instructions for the 9581 SST R5 and explains
the use of the front display screen.
Chapter 5, Operation provides instructions on how to use the 9581 SST R5 to balance
the return path in order to optimize the systems performance.
Chapter 6, Appendix provides detailed technical specifications and warranty information.
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Conventions Used in this Manual
This manual has several standard conventions for presenting information.
Connections, menus, menu options, and user-entered text and commands appear in bold.
Section names, web and e-mail addresses appear in italics.
A WARNING alerts you to any condition that could cause
personal injury.
A CAUTION alerts you to any condition that could cause a
mechanical failure or potential loss of data.
A NOTE is information that will be of assistance to you related
to the current step or procedure.
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Precautions
A strong electromagnetic field may affect the accuracy of the
9581 SST measurements.
Exposure of data cables to a field with high-voltage and fast
transient signals may cause measurement errors in the
9581 SST.
A shielded CAT-5 cable is recommended for Ethernet
connection.
Do not use the 9581 SST in any manner not recommended by
the manufacturer.
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Chapter 2
2. Introduction
This chapter:
Describes the purpose of the 9581 SST R5
Lists the features of the 9581 SST R5
System Overview
The 9581 SST R5 Return Path Maintenance System is a single test system that enables
management of all aspects of return path upkeep; including both ingress control and system
balancing. At the core of the system is the 9581 SST R5 Return Path Analyzer, a 4.125 to 85.5
MHz digitizing spectrum analyzer which is installed at the headend of the cable system.
The 9581 SST R5 monitors all signals arriving at the headend, including reverse signal traffic,
noise, ingress and test carriers from the 860 DSP or 860 DSPi field analyzer(s).
A single 9581 SST R5 can monitor up to sixteen separate headend test points simultaneously,
allowing analysis of the condition of each test point. The 9581 SST R5 analyzes test signals and
the return spectra separately and packages measurement results into a data stream that it
transmits to the 860 DSP or 860 DSPi.
Each 860 DSP or 860 DSPi are addressed individually (A - F) which allows six field analyzers to
be in operation at any one time. Each field analyzer transmits up to eight test carriers at usersettable frequencies. The 9581 SST R5 measures these test carriers to compute the gain and tilt
of the return path. The 860 DSP and 860 DSPi can store up to 24 sweep displays which can be
reviewed at a later time or uploaded to a PC.
During system testing, the 9581 SST R5 sorts out the test carrier measurements for each field
analyzer and tags the data with the individual addresses (A F) so that each field analyzer
displays the appropriate information. When the field analyzer receives its data, it displays the
response of the return path as either a line graph or as numeric values for gain and tilt. Ingress
and noise data are presented as a spectrum analyzer display. For more information, refer to the
860 DSP and 860 DSPi Operation Manual.
Application
The 9581 SST Return Path Maintenance System can be used to:
Balance the return path
Measure the return paths ingress and noise
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Balancing the Return Path
In the basic test architecture, test signals are injected upstream by the 860 DSP or 860 DSPi
field analyzer. The 9581 SST R5 measures these signals automatically at the headend. The
measurement data is transmitted back to the field analyzer for display.
To balance the return path of the system, several alignment objectives must be considered.
The fiber return path link must be set to the systems design specifications. Additionally, each
line amplifier must be set so that it will compensate for the gain and tilt of the cable and
passives to the next amplifier.
The 860 DSP and 860 DSPi have two types of displays which will accommodate amplifier
adjustment differences:
Eight-carrier line graph for amplifiers that require screwdriver adjustments
Calculated gain and tilt values for amplifiers that use pads and equalizers
Measuring Ingress and Noise
In the basic test architecture, the spectrum analyzer of the 9581 SST R5 return path analyzer
measures the incoming ingress and noise. It then transmits this measurement data to the 860
DSP or 860 DSPi field analyzers. The field analyzers display the ingress data as a spectrum
pattern.
While analyzing the return path, it must be determined if the return frequencies carrying the
traffic have an adequate signal-to-noise ratio. To calculate the signal-to-noise ratio, the
effective ingress power must be calculated first. For narrow band ingress, such as CB or
shortwave, measure the ingress power directly. For broadband ingress, such as interference
from machinery, treat the ingress as noise and correct for video or data bandwidth. In the
formulas below, measured power (MP) equals the reading from the 9581 SST R5 and IP
equals the effective ingress power.
Compute the effective noise in a 4 MHz video bandwidth; take the reading from the
9581 SST R5 and add 10.3 dB. IP = MP + 10.3 dB
Compute the effective noise for data bandwidth, take the reading from the 9581 SST
R5 and add 10 times the log (data BW divided by .375 MHz). IP = MP + 10 x log (data
BW/.375 MHz)
Maintain good picture quality, video signals require narrow band ingress to be between
-40 and +60 dBc, depending on the offset from the video carrier and broadband
ingress to be at least -40 dBc
Quadrature phase shift keying (QPSK) should have an effective ingress power of -20 dBc for
either type of ingress for a bit error rate (BER) of approximately 1 x 10E-6.
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When the 9581 SST R5 is setup according to this manual, it reserves about 15 dB of
amplitude measurement range to prevent the digitizer from being overloaded by powerful
ingress transients. Experience has indicated that 15 dB is much more margin than is needed
in all but the dirtiest systems. Up to 10 dB of the guard band can be reassigned to extend
the measurement dynamic range of the 9581 SST R5. For more information, see Chapter 5:
Operation, Extending the Measurement Range.
Return Path Maintenance
Cable television operators who maintain a two-way cable television distribution system knows that
many factors can affect the performance of the system. Cumulative noise, signal ingress,
incorrect gain, or bad flatness all conspire to harm the return path which can lead to loss of service
and customer complaints.
The 9581 SST R5 is component of the next generation of the 9581 Return Path Maintenance
System. The 9581 SST R5 monitors all of the troublesome parameters in a single, simple to use
system. The 9581 SST R5 is a component of Trilithics Guardian II Return Alignment System which
includes the 9581 SST R5 and 860 DSP or 860 DSPi with SSR or RSVP option. For additional
information on each of the components in the Guardian II Return Alignment System, refer to the
operation manual for each of the components.
The 9581 SST R5 differs from the 9581 SST R4 in several ways:
The telemetry signal resides on a single transmitter which can be placed anywhere
between 50 MHz and 1 GHz
The bandwidth has been increased to 85.5 MHz
There is no live display on the 9581 SST R5
The 9581 SST R5 Return Path Maintenance System is more than just a return alignment system.
It also monitors the total performance of the return path by evaluating ingress and return noise. In
any operation mode of the 9581 SST R5, transient events can be captured. In the Fast mode of
the 9581 SST R5, the scan rate is tripled so smaller-duration transients can be captured. The
Peak Hold mode enables the 9581 SST R5 to display the highest ingress points in Norm or Fast
modes. This makes the 9581 SST R5 a powerful tool for capturing transient ingress. The
Averaging feature is included and can be used to reduce the noise floor displayed when
measuring CW or common path. The digitizer for the 9581 SST R5 handles 85.5 MHz in two
bands.
The 9581 SST R5 is also equipped with TraffiControl. This feature enables the 9581 SST R5 to
measure and plot the ingress spectra of bands occupied by return traffic. TraffiControl
automatically filters all the desired signals from scanned return spectra so that only the ingress
spectrum remains.
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9581 SST Headend Analyzer
The 9581 SST R5 headend analyzer is compact; occupying only 3.5" (2U) of rack space, and is
easily set up and operated. A single 9581 SST R5 headend analyzer can support up to six
860 DSP or 860 DSPi field analyzers at a time with no loss of operating speed.
The 9581 SST analyzes sweep and ingress signals on sixteen separate test points individually. It
sends the appropriate ingress spectrum and sweep data to each 860 DSP or 860 DSPi field
analyzer to which it is connected.
Even when the 9581 SST R5 is not supporting the 860 DSP or 860 DSPi field analzyers, the
9581 SST R5 can function as a monitor for return path quality. Unattended locations can be
monitored since the 9581 SST R5 can send ingress and sweep measurement data to a PC
located in a central office (refer to the Viewer II Operation Manual for more information).
Included Equipment
The 9581 SST R5 Return Path Analyzer includes the following items:
9581 SST R5 Return Path Analyzer
Power Cable
SST Configure Software on CD
Operation Manual on CD
Optional Equipment
The following optional items are also available:
Additional 9581 SST R5 headend analyzers
860 DSP or DSPi field analyzer
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A Guided Tour of Your 9581 SST R5
Front View
Power Button
Press this button to enable or disable
operation of the instrument. To turn off the
instrument, remove the power cable.
Select Button
Press this button to select a menu or edit
a configuration parameter.
Down Arrow Button
Press this button to scroll down through
the configuration menus and to perform
downward adjustments of configuration
parameters.
Up Arrow Button
Press this button to scroll up through the
configuration menus and to perform
upward adjustments of configuration
parameters.
Info button
?
Press this button to view the hardware and
software version numbers of the instrument.
Test
Test button
Press this button to view the internal
temperature, date, and time of the instrument.
Setup Button
This button is not used.
Node Button
This button is not used.
Display Screen
The display screen is used to display
configuration and setup parameters.
Internal Speaker
The internal speaker will sound a beep
each time a button is pressed.
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Back View
A
A. FORWARD OUTPUT - This is the output connection that the 9581 SST R5 transmits
measurement results back to the 860 DSPi on a downstream telemetry signal.
B. TEST POINT INPUTS - These are the test point input connections that the 9581 SST
R5 uses to analyze data from a test point in the headend or field.
C. ETHERNET - This connection is used for web based setup and upgrades.
D. 100-240 V - AC power input connection
E. PORT-1 & PORT-2 - (For Future Use)
B
C D E
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Chapter 3
3. Optimizing the Return Path
Introduction
To provide complex interactive services on cable, operators must ensure that they provide a
reliable return path or customers will not have access to pay services. The high power
transmissions from citizens band (CB), ham radio, and shortwave operators in the 5 to 30 MHz
range, as well as other RF noise generating devices, present a threat to the return path as they
can enter the cable system and interfere with upstream traffic. Additionally, signals from AM
broadcast can enter the cable system and increase the power loading on the return laser to
problematic levels.
As the return paths converge on their way to the headend or node, they act as interference
concentrators. The various sources of ingress tend to add together and these independent
sources of noise can merge to form a single strong ingress where the branches converge.
Since return path problems are amplified as the branches converge, the best location within the
system to measure return path performance is at the headend, just before the upstream data is
recovered. Return path performance monitored at the headend needs to be available to the
technician in the field for alignment and troubleshooting. The 9581 SST R5 Return Path
Maintainance system simplifies this process as follows:
The 9581 SST R5 Return Path Analyzer measures the system ingress as well as the test signals
from the 860 DSP and 860 DSPi field analyzer(s) and then transmits the results as data back to
the 860 DSP or 860 DSPi field anayzer(s), thus enabling the field technician to align the system
and troubleshoot ingress problems from anywhere in the system.
Return Path Perfomance Parameters
Reliable upstream performance depends upon:
Proper gain and tilt banance
Adequate signal-to-ingress ratio
It is important to balance gain and tilt in order to optimize the systems performance. Refer to A
Balanced System later in this chapter for instruction in balancing gain and tilt.
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Signal-to-Noise Ratio
Gain in a particular branch, if set either too high or too low, can adversely affect the signal-tonoise ratio in a segment of the return path, or in the entire return path.
If set too low, signals on this branch could be swamped by the noise of other branches.
If set too high, noise on this branch might be amplified enough to interfere with signals on other
branches.
To minimize noise-induced communication errors, upstream data systems use robust
modulation schemes like quadrature phase shift keying (QPSK), which typically operates at a
data rate of 1.544 Mbps. Even when using QPSK as the modulation format, the return system
must provide a signal-tonoise ratio of at least 10 dB, as measured in a 1 MHz bandwidth
around the data carrier center frequency to provide a marginally adequate bit error rate (BER)
of 10E-5. Incorrect gain settings, in some or all of the return paths, degrade the signal-to-noise
ratio and increase the BER of the return path system.
Signal-to-Ingress Ratio
When using QPSK, the sum of all ingressing signals lying within the data signal bandwidth
(approximately 1 MHz for the data signal as discussed in SIGNAL TO NOISE RATIO above)
should be at least 20 dB below the level of the data signal. As the sum of ingressing signals
exceeds this level, the BER performance of the return path system is degraded. If ingress
levels approach 10 dBc, communication may be seriously degraded.
A Balanced System
When the system is balanced, a signal on one branch is degraded equally by noise on all
branches to the same node.
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If the gain of one path is set higher than the other paths, its noise could disrupt traffic on all
other paths.
If the gain of one path is set lower than the others, its signals are disrupted by the noise of all
other paths.
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Chapter 4
4. Installation
Overview
Before the 9581 SST R5 can be installed, the carrier frequencies, device security, and IP
connectivity must be set up. The information in this chapter will assist in making pre-installation
determinations and provide instruction in installing the 9581 SST R5 Return Path Analyzer. For
additional information regarding the operation of the referenced 860 DSP or 860 DSPi Field
Analyzer, refer to the 860 DSP and 860 DSPi Operation Manual.
Pre-Installation Considerations
Several decisions must be made concerning the location of the 9581 SST R5 as well as the
placement and levels of the reverse test carrier and forward data carrier before installing the
9581 SST R5 Return Path Analyzer.
The 9581 SST R5 is designed to be rack-mounted so that it will provide easy access to the power
cord. Consideration should be given to ensure that the location provides a reliable protective
earth connection, proper ventilation, and a stable environment.
Do not use the 9581 SST R5 in any manner not recommended
by the manufacturer.
The levels vary from one cable system to another depending on the characteristics of the signals
already present on the cable system. Several of the following decisions REQUIRE information
concerning the cable systems design.
Reverse Test Carriers
As many as eight reverse test carrier frequencies may be selected. Before selecting the
reverse test carriers, the following should be considered:
Return band edges - Typically the highest and lowest frequency test carriers will be near
the return band edges (i.e. at 6 MHz and at 85 MHz).
Problem frequencies - A test carrier may be placed at a frequency in the return pass
band where problems may occur due to the particular models of passives (taps, power
inserters, etc.), which are being used in the system. For instance, some 750 and 1000
MHz passives have significant roll-off below 10 MHz. In this case, it is suggested that
test carriers be placed around 5 and 10 MHz to average the compensation for low-end
roll-off.
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Selected frequencies - Occupied frequency bands such as those carrying data or video
must be avoided. If multiple 860 DSP or 860 DSPi field analyzers are in use, the
following clear bandwidth ABOVE the frequency of each test signal must be provided.
Clear frequency BW = (number of field analyzers - 1) x 100 kHz
The desired return signal output level is determined by the headend design. This
desired return output level MUST be established to set up the 9581 SST R5 Return
Path Analyzer successfully. Consult the design documentation for the headend or
calculate it based on the modem level requirements and the headend architecture to
determine the correct figure.
The actual return signal level arriving at the INPUT port(s) of the 9581 SST R5 must be
equal to, or greater than, -10 dBmV for accurate measurements over the full dynamic
range of the 9581 SST R5. Include coupling losses and any inline pads in your
calculation.
Levels before adjustment will differ due to the varying length of fiber to the node. One of
the objectives for using the 9581 SST R5 is to balance receivers to the same output
level; either through built-in adjustments or by inserting external padding, depending on
the receivers design.
For signal-to-noise considerations, it is necessary that all fiber
receivers sharing the same headend data modem have the
same output level. For this reason, the 9581 SST R5 expects to
see the same return level at each return test point.
Forward Data Carrier
The characteristics of the forward data carrier must be defined. Select a forward data carrier
frequency.
The selected frequency must be clear of other traffic for 400 kHz above and below the
data carrier.
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Installing the 9581 SST R5
The following section explains the procedure used to physically install the 9581 SST R5. In order
to properly setup the 9581 SST R5 the following steps must be completed in this order. Do not
skip any steps.
DO NOT plug in the 9581 SST R5s power cord until instructed below.
1. Mount the 9581 SST R5 in a standard rack using four retaining screws.
Make sure the fan intake holes on the left of the 9581 SST R5 and the
fan exhaust holes on the right of the 9581 SST R5 remain unblocked.
Fan Intake Holes Fan Exhaust Holes
2. Plug the 9581 SST R5s power cord into the 100-240 VAC Power Connection and then
into an AC power source. When power is supplied to 9581 SST R5, the screen on the front
of the 9581 SST R5 is illuminated.
If the display screen is not illuminated upon connecting power
to the 9581 SST R5, call Trilithic Application Support at 1-800344-2412 for assistance.
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3. Now that the system levels and frequencies have been determined, the 9581 SST headend
analyzer can now be installed in the headend. Refer to Chapter 2: Introduction, A
Guided Tour of Your 9581 SST R5, Back View for more information on the connections
located on the rear panel of the 9581 SST R5.
Forward Connections
For forward connections, a forward signal injection point must be provided. If
necessary, install a 6 dB to 20 dB coupler before the forward test point. Ensure that the
coupler is installed in the proper orientiation.
The injection point must be before the headends forward
output test point.
Reverse Connections
For reverse connections, test point couplers must be installed (in the range of 6 to 20
dB) at the outputs of the reverse paths fiber receiver outputs.
Take note of the coupler loss value, this data will be entered in
the 9581 SST R5 during the setup procedure.
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Display Screen Overview
The front panel display screen on the 9581 SST R5 provides a view of the setup information of the
analyzer.
When the 9581 SST R5 is powered on, the splash
screen shown to the right will appear momentarily.
Instrument Information
Instrument Time, Date, & Internal Temperature
From any menu, press the
the current time, date, & internal temperature of
the instrument.
The time and date of the unit are set at the
factory and are not adjustable at this time. The
time is set to Greenwich Mean Time (GMT).
In this example the internal temperature is
designated as XX, the date is designated as
MM/DD/YYYY, and the time is displayed in a 24 hour format as HHMM.
To exit this screen and return to the previous menu, press the Select button.
Test
button to display
Firmware & Software Version Numbers
From any menu, press the ? button to display
the current firmware & software version numbers
and Trilithic contact information.
To exit this screen and return to the the previous
menu, press the Select button.
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Setup Menu Navigation
After the splash screen disappears, the SETUP
MENU will appear as shown to the right.
Use the or buttons to highlight the desired
setup parameter and then press the Select button
to view/edit the selected parameter.
The Speaker and Contrast settings can be adjusted from the
Setup Menu, all other settings are for reference only and can be
adjusted using the included SST Configure Software.
Viewing the Network Settings
To view the Network settings, perform the following steps:
1. From the SETUP MENU, highlight NETWORK and then press the Select button to
display the NETWORK menu.
2. The MAC address and current network settings will be displayed.
3. Use the Select button to return to the SETUP MENU.
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Viewing the RX Frequency Settings
To view the RX Frequency settings, perform the following steps:
1. From the SETUP MENU, highlight RX FREQ and then press the Select button to
display the RX FREQ menu.
2. The available RX Frequencies will be displayed. The active RX Frequencies are
indicated by an asterisk (*) to the left of the frequency.
3. Use the Select button to return to the SETUP MENU.
Viewing the RX Level Settings
To view the RX Level settings, perform the following steps:
1. From the SETUP MENU, highlight RX LEVEL and then press the Select button to
display the RX LEVEL menu.
2. The current RX Input Level and Tap Value will be displayed.
3. Use the Select button to return to the SETUP MENU.
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Viewing the Link Frequency Settings
To view the Link Frequency settings, perform the following steps:
1. From the SETUP MENU, highlight LINK FREQ and then press the Select button to
display the LINK FREQUENCY menu.
2. The current Link Frequency and TX Attenuator Level will be displayed.
3. Use the Select button to return to the SETUP MENU.
Viewing the Remote Detection Type Settings
To view the Remote Detection Type settings, perform the following steps:
1. From the SETUP MENU, highlight REMOTE DET and then press the Select button
to display the REMOTE DET menu.
2. The current remote detection type will be displayed.
3. Use the Select button to return to the SETUP MENU.
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Adjusting the Speaker Settings
To edit the Speaker settings, perform the following steps:
1. From the SETUP MENU, highlight
SPEAKER and then press the Select
button to display the SPEAKER MENU
menu.
2. Use the or buttons to highlight
the desired speaker setting and then
press the Select button to edit the
selected parameter.
3. Use the or buttons to highlight
ON or OFF and then press the Select
button to accept the changes.
4. Once you have adjusted the desired
speaker settings, Use the or
buttons to highlight EXIT and then press
the Select button to return to the
SETUP MENU.
KEY PRESS
THRESHOLD ALARM
LOW ALARM
SHUTDOWN
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Adjusting the Display Screen Contrast Settings
To edit the Display Screen Contrast settings, perform the following steps:
1. From the SETUP MENU, highlight
CNTRST ADJ and then press the Select
button to display the CONTRAST
ADJUST menu.
2. Use the button to make the screen
darker and the button to make the
screen lighter.
3. Use the Select button to return to the
SETUP MENU.
After pressing the Setup button, if the display screen is not
visible because the screen contrast is at the default setting,
press the Select button then the Up or Down arrow buttons as
appropriate until the screen is visible.
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Chapter 5
5. Operation
Overview
The first step in developing a successful alignment and maintenance strategy for the return path
depends on understanding what constitutes a properly operating system. Refer to Chapter 4:
Optimizing the Return Path and Chapter 5: Setting up the 9581 SST for instruction in
collecitng the following system parameters:
Proper levels at the headend
Proper injection points for the node and each type of amplifier in the system
Proper injection level for each device in the return system including coupling and test probe
losses
Setting up the 9581 SST R5
Now that the 9581 SST R5 Return Path Analyzer is powered on, the following parameters must be
entered into the non-volatile memory:
Return Sweep Frequencies
Desired Return Level at the Headend
Test Point Coupling Value
Data Link Frequencies and Attenuator Value
Data Link Levels
Security Information
IP Connectivity Information
To configure the 9581 SST R5, you must use the included SST Configure software. The only
method for changing device settings on the 9581 SST is via remote administration, using the SST
Configure program.
Initial configuration of the 9581 SST R5 must be completed using a serial connection between the
9581 SST R5 and the host computer on which the SST Configure software is installed.
For more information about the initial setup proceedure of the 9581 SST R5 using the SST
Configure software, see the SST Configure Operation Manual.
Now that the 9581 SST R5 Return Path Analyzer has been installed and set up as instructed in the
SST Configure software Operation Manual and the 860 DSP or DSPi Field Analyzers are set up,
the 9581 SST R5 is ready to be deployed.
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Remote Operation
The 9581 SST R5 Return Path Analyzer can be accessed and controlled via a PC and the Viewer
II program. When used in the Remote mode, the 9581 SST R5 becomes a status monitoring tool
when used with the Viewer II program. The 9581 SST R5 will continue to operate normally when it
is under the control of a remote operating program.
Return Path Alignment
The alignment procedure for the reverse path should be initiated at the headend. The 9581 SST
R5 Return Path Analyzer will be used to monitor the ingress for each return path that will be
aligned.
For the 9581 SST R5 to achieve sweep accuracies greater than ±1 dB (and for the return data
system to function properly), ingress must be at least 20 dB below the expected return levels. If
the SST 9581 R5 is properly configured, the ingress level will be 30 dB below full-scale on the
ingress display. Carefully inspect the spectrum around each test carrier frequency; if ingress is
excessive, perform one of the following procedures to reduce the ingress:
If several return paths have been combined, try disconnecting some return paths to reduce
total ingress
If the system has no active carriers, turn down the gain or remove the pads in the reverse
amplifiers
Temporarily pick a higher operating level for the 9581 SST R5 and 860 DSP or 860 DSPi
Locate and repair major ingress problems. The 9581 SST R5 can be used to troubleshoot
ingress from in the field
If ingress exceeds -20 dB relative to the desired return level, the 860 DSP or 860 DSPi sweep
display will display an X rather than the usual frequency marker (bar). The X display is an
indication that there is an ingress problem, which must be located and repaired.
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Adjusting the Fiber Link
Adjustment of the fiber link will require two technicians since the fiber receiver output must be
adjusted with the 860 DSP or 860 DSPi connected to the node as shown in the following figure.
This could be achieved with one technician but it would involve
a lot of back and forth runs to the headend and the node.
To adjust the fiber path properly, consult the manufacturers datasheets to determine how to set
gain in the fiber receiver. It is suggested that the optical power at the receiver input be measured
to ensure that it meets the recommended levels prior to starting alignment. Inject the 9581 SST
R5 test signals at the system design level into the node test point.
If the fiber receiver uses pads to set the gain, use the Gain/Tilt display on the 860 DSP or 860
DSPi Field Analyzer to determine the correct pad to use in the fiber receiver. The 860 DSP or
860 DSPi will show a maximum gain error of ±9.9 dB. If the initial gain is off by more than ±9.9
dB, it may be necessary to zero in on the correct pad by changing the pad value until the reading
falls within the scale. A pad can then be selected accordingly in order to set the gain as close as
possible to 0.0 dB. When finished, switch to the Sweep display to observe the sweep response.
If the fiber receiver has a screwdriver adjustment, use the Sweep display and adjust the receivers
gain so that the sweep response is positioned on the center graticule of the Sweep display.
Some fiber nodes have a gain adjustment in the node, which
must be set first (i.e. Texscans FLAMETHROWER). Consult
the manufacturer for the proper procedure for making this
adjustment prior to setting the fiber receivers gain.
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If a sweep response cannot be displayed on the scales range, attempt the following procedures:
Ensure that the injection test point is pointing the correct direction (toward the headend)
Ensure that the fiber transmitter and receiver are functioning properly and that the proper
light level is reaching the headend
Increase or decrease the 860 DSP or 860 DSPi field analyzers TX level in 5 dB
increments until the sweep response is displayed on the screen
Note the difference that is necessary for the output setting and adjust the gain accordingly. The
860 DSP or 860 DSPi can now be returned to the proper output level and the gain setting can be
fine-tuned.
Adjusting Amplifiers
When an amplifier is balanced properly, its gain and tilt will virtually cancel the loss and tilt of
everything in the upstream path between the amplifier and the next amplifier upstream as shown in
the following figure.
With the node adjusted properly, proceed to the first amplifier from the node. Set the TX level of
the 860 DSP or 860 DSPi to the proper injection level for the amplifier. Connect it to the
amplifiers input test point(s).
When setting the injection level, allow for test point or coupling
losses.
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For amplifiers with fixed pads and equalizers, use the Gain/Tilt display. The 9581 SST R5 will
display a maximum gain error of ±9.9 dB. If the initial gain is off by more than ±9.9 dB, it may be
necessary to zero in on the correct pad by changing the pad value until the reading falls within the
scale. The equalizer can then be installed to compensate for tilt. Once the tilt is corrected, fine
tune the pad value to give an overall gain of 0.0 dB. Now the Sweep display can be used to
observe the sweep response.
If the amplifier has screwdriver gain and tilt adjustments, use the Sweep display and adjust the
amplifiers gain so that the sweep response falls within the display. Adjust the amplifiers tilt for a
flat response, then fine-tune the gain adjustment to position the sweep response on the center
graticule of the display. Switch to the Gain/Tilt display to confirm the settings numerically.
If a sweep response cannot be displayed on the scales range, attempt the following procedures:
Ensure that the 860 DSP or 860 DSPi is receiving the data carrier as evidenced by the
cursor pointing to Car Det (carrier detect) on the display of the 860 DSP or 860 DSPi
Ensure that the injection test point is pointing the correct direction (toward the headend)
Increase or decrease the TX level of the 860 DSP or 860 DSPi in 5 dB increments until the
sweep response is displayed on the screen
Note the difference that is necessary for the output setting and adjust the gain accordingly. The
860 DSP or 860 DSPi can now be returned to the proper output level and the gain setting can be
fine-tuned.
Proceed to the next amplifier and repeat the process until all of the amplifiers have been aligned.
Ensure that the TX level of each 860 DSP or 860 DSPi has been adjusted, if necessary, when
changing amplifier types.
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Ingress
Ingress along the return path can cause serious disruptions to a subscribers cable service. This
makes regular monitoring of ingress an essential part of a sound return maintenance strategy.
The 9581 SST R5 was designed to provide a simple solution for reverse monitoring.
When using the 9581 SST R5 to monitor ingress, there are configuration trade-offs that must be
considered. The most important of these concerns are the number of return paths connected to a
single input on the 9581 SST R5. Combining multiple returns may economize on hardware but it
complicate localizing the source of system ingress.
If ingress control is a necessity for system maintenance, as it is in the case of telephony or
commercial data transfer, consider using more than one 9581 SST R5 so that each return can be
monitored separately.
Ingress monitoring can be automated by using the Ingress ManageR and Viewer II (the 9581
SSTs remote monitoring software), with a PC. When ingress problems do occur, the software
allows the following operations:
The return path which is experiencing ingress can be determined and isolated. Disconnect
the combined return paths one at a time until the path affected by ingress is isolated.
Read and record ingress levels at several frequencies.
Go to the node (first amplifier in an all-coaxial system) and read the ingress at the nodes
return input using an SLM.
Ensure that a downstream-looking test point is selected; not
one that is looking toward the headend.
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Compare the ingress measured at the node to the levels measured at the headend. If the levels
are still about the same, divide the number of amplifiers in each leg in half and test at that point.
Continue to divide the amplifier spans in half until the amplifier farthest from the node that still has
the ingress problem is located.
Once the ingress has been localized, the hardware and the drops of the target amplifier can be
troubleshot. When the ingress source has been pinpointed, connect the 860 DSP or 860 DSPi
field analzyer to the system and verify that the ingress problem has been remedied by observing
the ingress pattern.
Many ingress problems are transient in nature. For example, ingress from a CB radio will only be
present when the radio is keyed on and the vehicle in which the radio is installed is nearby the
ingress point within the cable plant. Transient events will be on the order of 1 or 2 seconds.
Other events in the subscribers house, such as electrical transients from alternating-current
motors in electrical appliances, can be much shorter in duration. The 9581 SST R5 is sensitive
enough to capture these short-duration transient events by combining Fast mode and Peak Hold
mode. In Fast mode, the 9581 SST R5 analyzes each node at rates up to 120 Hz. This allows the
capture of transients in the millisecond range. In Peak Hold mode, these transients remain
displayed on the screen until the system has been reset.
The 9581 SST R5 does not support Sweep mode while
operating in Fast mode. All sweeping and gain balancing
functions will be halted until the 9581 SST R5 returns to Norm
mode.
An effective strategy for balancing a node is to use the 9581 SST R5 in Normal mode. After
obtaining a balance, allow the 9581 SST R5 to analyze the node in Fast mode for approximately
24 hours to verify that transient ingress is not a problem.
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Extending the Measurement Range
When the 9581 SST R5 is setup according to this manual, it reserves about 15 dB of its amplitude
measurement range to prevent the digitizer from being overloaded by powerful ingress transients.
Experience has indicated that 15 dB is much more margin than is needed in all but the dirtiest
systems. Up to 10 dB of the guard band can be reassigned to extend the measurement dynamic
range of the 9581 SST R5. You can reassign the offset via a simple variation of the normal 9581 SST
R5 set up procedure. You will also need to adjust the offset of the 860 DSP or 860 DSPi.
Reconfigure the 9581 SST R5 for Greater Range
The 9581 SST R5 evaluates system performance against a user-settable reference level.
This is the nominal RF amplitude expected from a return fiber receiver when a test signal of
the proper ampli-tude is injected into a return amplifier in the field.
Increase Sensitivity and Range
The 9581 SST R5 evaluates system performance against a user-settable reference level.
This is the nominal RF amplitude expected from a return fiber receiver when a test signal of
the proper amplitude is injected into a return amplifier in the field.
Effect of the Offset on the 860 DSP and 860 DSPi
The reference settings for the SWEEP and SPECTRUM Modes of the 9581 SST R5 are
linked. This means that offsetting the reference level of the SPECTRUM Mode will also offset
the reference for the SWEEP Mode by the same amount. To keep the 860 DSP or 860 DSPi
normal sweep output from being too large, you simply need to reduce the sweep output level
of the 860 DSP or 860 DSPi by the same offset amount.
Regardless of the offset amount, the SPECTRUM display will
read correctly.
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Chapter 6
6. Appendix
Specifications
Frequency Range 4.125 to 85.5 MHz
Input Level Range +25 to -10 dBmV for full 50 dB dynamic range in
Spectrum Mode
Return Inputs 16 standard
Field Units Supported Up to six (6) simultaneously
Sweep Mode 5 to 85 MHz with 0.25 dB resolution
Sweep Mode Resolution Bandwidth 25 kHz effective
Input Level Accuracy ±0.35 dB
Resolution Bandwidth 375 kHz
Sweep Rate 40 Hz per node in NORM, 120 Hz per node in FAST
Data Carrier TX Frequency 50 MHz to 1 GHz
Data Carrier TX Level 45 dBmV ± 6 dB in 0.5 dB steps
Data Carrier Spurious -60 dBc
Modulation FSK with 75 kbps data rate
Data Carrier Bandwidth 700 kHz at -60 dBc
Remote Access Via Ethernet for all displays
Display 64 x 128 pixel graphic LCD with backlight
Power Cord 3-Conductor rated at 1 A with IEC320 connector
Power Requirements 100 to 240 AC, 50 to 60 Hz, 1 A
Protective Conductor Terminal Label 16 standard
Operating Temperature 10 to 50 °C
Dimensions 3.5 x 17 x 12.3
Weight 10 lbs (4 kg)
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Warranty Information
Trilithic, Inc. warrants that each part of this product will be free from defects in materials and
workmanship, under normal use, operating conditions and service for a period of two (2) year
from date of delivery. Trilithic, Inc.s obligation under this Warranty shall be limited, at Trilithic, Inc.s
sole option, to replacing the product, or to replacing or repairing any defective part, F.O.B.
Indianapolis, Indiana; provided that the Buyer shall give Trilithic, Inc. written notice.
Batteries are not included or covered by this Warranty.
The remedy set forth herein shall be the only remedy available to the Buyer under this Warranty
and in no event shall Trilithic, Inc. be liable for incidental or consequential damages for any alleged
breach of this Warranty. This Warranty shall not apply to any part of the product which, without fault
of Trilithic, Inc., has been subject to alteration, failure caused by a part not supplied by Trilithic, Inc.,
accident, fire or other casualty, negligence or misuse, or to any cause whatsoever other than as a
result of a defect.
Except for the warranty and exclusions set forth above, and the warranties, if any, available to the
Buyer from those who supply Trilithic, Inc., there are no warranties, expressed or implied (including
without limitation, any implied warranties of merchantability of fitness), with respect to the
condition of the product or its suitability for any use intended for it by the Buyer or by the purchaser
from the Buyer.
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9710 Park Davis Drive
Indianapolis, IN 46235
(317) 895-3600
www.trilithic.com
P/N 0010331000 1/11 Made in U.S.A.
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