8-VSB Singulus Lite Cricket Quick Start Tutorial

8-VSB Singulus Lite Cricket
Quick Start Tutorial
Contents
Contents............................................................................................................................................................................. ii
1
Technical Support Information..............................................................................................................................3
1.1
Address and Telephone Numbers...................................................................................................................3
1.2
Internet Addresses.............................................................................................................................................3
2
Introduction ...............................................................................................................................................................4
3
What is 8-VSB? ..........................................................................................................................................................4
4
Monitoring Terrestrial Broadcast with 8-VSB Cricket ......................................................................................5
5
Configuring an 8-VSB Cricket ...............................................................................................................................5
6.
Understanding an 8-VSB Cricket Measurements...............................................................................................7
7.
Configuring a Synchronized Capture...................................................................................................................9
8.
Conclusions..............................................................................................................................................................10
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1
Technical Support Information
Updated documentation, software and information for this and other products are available on the IneoQuest
web site.
1.1 Address and Telephone Numbers
Address, USA:
IneoQuest Technologies Inc.
170 Forbes Blvd.
Mansfield, MA
02048
Telephone, USA:
+1 508 339 2497
FAX Telephone Number, USA
+1 508 339 4727
Toll-Free Technical Support Telephone, USA:
+1 866 464 4636
1.2 Internet Addresses
E-Mail:
[email protected]
URL:
http://www.ineoquest.com
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2 Introduction
The Singulus 8-VSB Cricket is a video quality and service assurance troubleshooting tool for 8-VSB broadcasters
needing to verify and debug their digital terrestrial service. This tutorial briefly describes the technology and
how the 8-VSB Cricket is configured.
3 What is 8-VSB?
8 Band Vestigial Sideband modulation, or 8-VSB is a physical layer, RF Modulation method. It is utilized
mostly within the United State and Canada by the DTV (ATSC) digital television standard to transmit digital
television over the airwaves to the home consumer. The FCC has mandated that all analog terrestrial
transmission will be turned off by February 2009. A typical 8-VSB network is shown in Figure 1.
Figure 1 Typical 8-VSB Environment
The RF modulated 8-VBS interface carries a 19.39 Mbit/sec MPEG-II transport stream encoded on a 6MHz
frequency band. The modulated signals are carried over the Terrestrial frequency bands, known as NTSC, RS
170 and include the VHF, FM Radio and UHF frequency ranges which include the frequency range 50 and 807
MHz.
One subtle difference over a traditional IP MPEG-2 transport stream is that prior to RF modulation, part of the
188 byte MPEG-2 transport stream is modified. The leading sync byte is discarded and replaced with the ATSC
segment sync and the Reed Solomon encoding algorithm adds an additional 20 bytes onto the tail end of the
original packet. Reed Solomon is a Forward error correction algorithm used to attempt to correct bit errors that
occur during transmission. Atmospheric noise, signal fades, and transmitter non-linearities may all create
received bit errors. Forward error correction can detect and correct these errors, up to a reasonable limit. The
additional 20 bytes are removed prior at the receiver by the Reed Solomon decoder.
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4 Monitoring Terrestrial Broadcast with 8-VSB Cricket
An 8-VSB Cricket contains a single RF Tuner which can be configured to continuously scan a sequence of RF
channels or tune to a specific frequency to monitor and alarm for customer effecting problems; such as loss
events, outage, bit-rate variation, PCR clock variation, ETR 101 290 errors. Physical layer problems such as ReedSolomon corrected and uncorrected errors can additionally be monitored. By default, it will scan the North
American standard terrestrial frequency range of frequency 53 MHz – 857MHz. Custom frequency maps are also
supported.
A unique and important feature of the 8-VSB Cricket is the ability to report physical layer characteristics such
Reed-Solomon errors while simultaneously reporting MPEG-2 layer errors. This allows the customer to more
easily isolate transmission problems from encoder or multiplexer problems. 8-VSB Crickets can be deployed at
the transmission site and at the corresponding receiver sites to perform end-to-end monitoring.
In addition, synchronized triggered captures across multiple targets can be performed when specific userconfigured alarm conditions occur. When a loss or other event occurs on a receiver probe, a synchronized trigger
can be performed on the probe at the original transmission location (also further back in the network) and at the
receiver location. This allows the user to the ability show correlation of events at the various points in the
network to isolate problems more easily.
5 Configuring an 8-VSB Cricket
The following initial configurations need to be verified prior to using the 8-VSB Cricket.
1.
Configure management port settings. The Cricket can be managed via direct connection to a PC via a
USB port or remotely via a Fast Ethernet connection to the primary port. The default IP address of the
USB port is 10.0.0.2 and the default IP address of the primary port is 198.100.100.100.
2.
Configure the RF Tuner for 8-VSB operation with the standard RF channel map. Since the 8-VSB Cricket
can monitor either 8-VSB or QAM inputs, it must be specifically configured for 8-VSB. The default mode
for the 8-VSB Cricket has the 8-VSB option enabled. To change the mode, open a web browser and select
the ‘RF Tuner Parameters’ page. A ‘Save and Reset’ operation should be performed after a configuration
change to ensure the settings are valid after a power cycle.
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Figure 2 RF Tuner Parameters Configuration Template
3.
Perform an automatic Learn operation to detect the valid 8-VSB channels, by opening a web browser
and select the ‘RF Tuner Config’ page. Press the ‘learn’ button to initiate a complete scan of the entire
frequency spectrum, as shown in Figure 3. A list of the default standard frequencies can be obtained by
selecting the ‘RF Tuner Channels’ in the Help section of the Tuner Configuration page.
If the desired frequencies have already been determined, an alias file containing those frequencies can be
downloaded into the target and the LEARN phase can be bypassed.
The LEARN phase will scan through the configured RF channels for valid 8-VSB signals and if found,
will further discover the programs within the channels. An alias will be automatically created for each
flow and program found. The Tuner Configuration page will show a current status of the programs as
they are detected, including the frequency, modulation type and number of programs detected (with and
without scrambling).
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Figure 3 RF Tuner Configuration Page
4.
Save RF channels and program aliases after the learn function to ensure that the aliases are saved after a
target power cycle.
5.
Configure Media Payload Alarm template to monitor PID bit-rates and outages.
6. Understanding 8-VSB Cricket Measurements
The 8-VSB Cricket supports the same measurements as the other members of the Cricket Family, with some
specific additions for the RF component, such as Reed-Solomon error detection and signal level
measurements. These measurements are described below.
It is important to note that although at any given time, the status of all the available flows are shown on the target, only
the flow that the target is currently tuned to will have live status. The active flow is highlighted in census mode by a
yellow indicator, or a ‘**’ in the real time view in the iVMS. All other channels will show the status as of the last time
that the flow was scanned. Although Reed Solomon errors are not specifically associated with an individual flow, they
are shown per flow so the media loss can be related to the Reed Solomon loss that was seen at the time. This can be an
important indicator when troubleshooting the location of detected problems.
The RF Tuner status can be viewed via the RF Tuner Status Browser page, shown below in Figure 4. The
Tuner status indicates the 1) current status of the RF Receiver; 2) frequency currently being monitoring, 3)
scan mode, 4) current signal to noise ratio and 5) the number of Reed Solomon Corrected and Uncorrected
Errors. This is for the duration of the scan period or until the counters are manually cleared. A yellow bar
across the channel table indicates that the highlighted frequency is currently being scanned. The RF
Channel status additionally shows the 1) detected modulation type, 2) number of programs detected (total
and number that are scrambled) and 3) the percent of total packets received with either Reed Solomon
Uncorrected or Corrected Errors. This is an important potential early indicator of problems on the physical
link.
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Figure 4 RF Tuner Status Page
The RF Flow Census page indicates the current alarm status of each 8-VSB RF Flow, the characteristics of the
detected flow, the amount of media loss (current loss rate, 15 minute loss and 24 hour loss) and other
miscellaneous information, as shown in Figure 5.
MDI:MLR : rate of loss, measured by number of MTPS/sec.
MDI:MLT15 and MLT24 : total media loss reported within the current 15 minute or 24 hour period (since
midnight)
RS-CO : rate of Reed Solomon errors seen in the current sample period.
RS-CO15 and RS-CO24 : number of Corrected Reed Solomon Errors seen in the current 15 minute or 24
hour period (since midnight)
RS-UC15 and RS-UC24 : number of UnCorrected Reed Solomon Errors seen in the current 15 minute or 24
hour period (since midnight)
PID Count : (T/M/F) : total number of PIDs detected on the flow/total number of PIDs currently being
monitored/total number of PIDs currently in an alarm state. The number of PIDs monitored may be less
than total number due to Media Payload Alarm Template and Program Alias settings.
ETR Alarms (M/F) : total number of PIDs currently being monitored for an ETR 101 290 condition / total
number of those currently in an alarmed state. The alarm conditions are set via the browser ETR 101 290
Template page.
Ghost PIDS : total number of PIDs currently detected on the flow that are referenced by either the PAT or a
PMT within the flow.
TSID : The transport stream ID of the flow, as detected in the PAT table.
Program Changes (+/-) : the total number of PAT / PMT program changes detected on the flow since it was
discovered.
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Figure 5 RF Flow Census Page
For further deep-dive analysis of the flows, IQMediaAnalyzerPro can also be used. A typical census view
from IQMediaAnalyzerPro is shown in Figure 6.
Figure 6 IQMediaAnalyzerPro Census View
7. Configuring a Synchronized Capture
Synchronized triggered captures across multiple targets can be performed when specific user-configured
alarm conditions occur. When a loss or other event occurs on a receiver probe, a synchronized trigger can
performed on the probe at the original transmission location (also further back in the network) and at the
receiver location. IQMediaAnalyzerPro can easily be configured to perform a synchronized recording across
multiple targets.
1.
Connect to the specific target IP Address using the IQMediaAnalyzerPro application that came with the
product.
2.
Double click on the specific flow in question in the Census view to enable the record mode.
3.
Configure the trigger conditions and enable ‘Sync Record’ on all probes in the capture chain. Enable the
capture on all by pressing the ‘Start’ button.
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Figure 7 Synchronized Trigger / Capture Example Configuration
1.
When a trigger condition occurs, as indicated by the status in the record window, upload the individual
captures to separate capture files. The file location is configured using the ‘Edit Preferences’ dialog box
which is accessible via the File menu.
8. Conclusions
The Singulus 8-VSB Cricket is a video quality and service assurance troubleshooting tool for 8-VSB
broadcasters needing to verify and debug their digital terrestrial service. It can be easily configured to either
automatically scan through a series of RF Channels or set to specifically monitor a single frequency for
reception quality. Reed Solomon errors can be used as an additional indicator of the location of the problem,
either pre- or post-RF conversion.
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Copyright © 2007
IneoQuest Technologies, Inc.
All Rights Reserved.
IneoQuest Technologies, Inc.
170 Forbes Boulevard
Mansfield, Massachusetts 02048
USA
www.ineoquest.com
November 26, 2007
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