CATV Measurements
5–6
2715 User Manual
Channel tables are the central data that controls the actions of the measurements.
The 2715 uses channel tables to tune to different channels in any one CATV
system. Thus, the resident firmware provides three commonly used (factory-
loaded) channel tables: STD, HRC, and IRC.
In addition, you can create your own customized channel table(s) using the
Cable TV RF Measurements Software for Windows and an IBM-compatible PC
or you may choose to modify any of the channel tables directly from the 2715
front panel. These two features; creating and editing customized channel tables,
allows the technician to accommodate all nonstandard channel frequencies and
operating conditions in a unique system.
2
The following defaults are common to all channels in the factory-loaded channel
tables:
Color System
NTSC
Channel Allocation Width
6 MHz
Aural Carrier Offset
4.5 MHz
Channel Edge
(Visual Carrier –1.25 MHz)
Signal Type
TV
Video Polarity
Negative
Sync Polarity
Positive
Skip Status
False
Scrambling Status
False
VITS
None
Channels 907 through 913 in the STD factory-loaded channel table (Table 5–4)
represent channels T–7 through T–13.
There are a number of different television standards worldwide that differ in
video modulation polarity. In negative video modulation, maximum carrier
power occurs during the sync tips. In positive video modulation, maximum
carrier power occurs during white program material. All defined systems use
negative modulation except for the A, C, E, and L systems, which use positive
modulation. When modifying or creating a channel table, be sure to select the
correct video polarity for your system. (The sync polarity will always be the
opposite of the video polarity.)
In defined systems, if the video polarity is positive, the aural modulation type is
AM instead of FM. The 2715 automatically selects AM aural modulation for any
channel that uses positive video polarity.
2
Frequencies above 1.8 GHz are not supported by the Cable TV RF Measurements Software.
The 2715 Spectrum Analyzer with either Option 50 or Option 75 installed is capable of frequencies up to
2.15 GHz. For frequencies above 1.8 GHz you are limited to the 2715 front panel to create and edit the
channel tables.
Channel Tables
Содержание 2715
Страница 4: ......
Страница 12: ...Table of Contents viii 2715 User Manual ...
Страница 18: ...Preface xiv 2715 User Manual ...
Страница 19: ...Introduction ...
Страница 20: ......
Страница 24: ...Introduction 1 4 2715 User Manual ...
Страница 25: ...Getting Started ...
Страница 26: ......
Страница 46: ...Getting Started 2 20 2715 User Manual ...
Страница 47: ...Operating Basics ...
Страница 48: ......
Страница 70: ...Operating Basics 3 22 2715 User Manual ...
Страница 71: ...Dedicated Controls ...
Страница 72: ......
Страница 108: ...Dedicated Controls 4 36 2715 User Manual ...
Страница 109: ...CATV Measurements ...
Страница 110: ......
Страница 181: ...Spectrum Analyzer Menus ...
Страница 182: ......
Страница 274: ...Spectrum Analyzer Menus 6 92 2715 User Manual ...
Страница 275: ...Appendices ...
Страница 276: ......
Страница 302: ...Appendix B Broadcast AM FM and TV Signal Sources B 2 2715 User Manual ...
Страница 318: ...Appendix C System Messages C 16 2715 User Manual ...
Страница 334: ...Appendix E External Input and Output E 12 2715 User Manual ...
Страница 339: ...Glossary and Index ...
Страница 340: ......
Страница 359: ......
Страница 360: ......