User’s Guide
Agilent Technologies
ESA-E Series Spectrum Analyzers
Option 227
Cable TV Measurement Personality
This manual applies to Cable TV Measurement Personality version A.02.00.
This manual provides documentation for the following instruments:
ESA-E Series
E4401B (9 kHz - 1.5 GHz)
E4402B (9 kHz - 3.0 GHz)
E4404B (9 kHz - 6.7 GHz)
E4405B (9 kHz - 13.2 GHz)
E4407B (9 kHz - 26.5 GHz)
Manufacturing Part Number: E4401-90228
Printed in USA
July 2000
© Copyright 2000 Agilent Technologies
Notice
The information contained in this document is subject to change without notice.
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including but not limited to, the implied warranties of merchantability and fitness
for a particular purpose. Agilent Technologies shall not be liable for errors
contained herein or for inc idental or con sequentia l damages in conn ection with the
furnishing, performance, or use of this material.
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software on equipment that is not furnished by
Agilent Technologies.
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FAR 52.227-19 for other agencies.
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ii
Warranty Information
IMPORTANT Certification
Agilent Technologies certifies that this product met its published specifications at
the time of shipment from the factory. Agilent Technologies further certifies that
its calibration mea surements are tracea ble to the United St ates Nati onal Instit ute of
Standards and Technology (NIST, formerly NBS), to the extent allowed by the
Institute’s calibration facility, and to the calibration facil it ie s of other International
Standards Organization members.
NOTE The actual warran ty on your instrument dep ends on the date it was ordered as well
as whether or not any warranty options were purchased at that time. To determine
the exact warranty on your instrument, contact the nearest Agilent Technologies
sales or service office with the model and serial number of your instrument. See
the list of sales and service offices in this document.
This Agilent Technologies instrument produc t is warranted against de fects in
material and workmanship for the warranty period. During the warranty period,
Agilent Technologies will, at its option, either repair or replace products which
prove to be defective.
If the warranty covers repair or service to be performed at the Buyer’s facility, then
the service or repair will be performed at the Buyer’s facility at no charge within
Agilent Technologies service travel areas. Outside Agilent Technologies service
travel areas, warranty service will be performed at Buyer’s facility only upon
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round-trip trave l expenses. In al l other areas , products must be r eturned to a ser vice
facility designated by Agilent Technologies.
If the product is to be retu rned t o Agilent Technologies for service or repa ir , it must
be returned to a service facility designated by Agilent Technologies. Buyer shall
prepay shipping charges to Agilent Technologies and Agilent Technologies shall
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from another country.
Agilent Technologies warrants that its software and firmware designated by
Agilent Technologies for use with an instrument will execute its programming
instructions when p roperl y ins tall ed on t hat instr ument. Agi lent Technologies does
not warrant that the operation of the instrument, or software, or firmware will be
uninterrupted or error-free.
iii
Limitation of Warranty . The fore going warra nty shall not apply to defects r esulti ng
from improper or inadequate maintenance by Buyer, Buyer-supplied software or
interfacing, unauthorized modification or misuse, operation outside of the
environmental specifications for the product, or improper site preparation or
maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. AGILENT
TECHNOLOGIES SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND
EXCLUSIVE REMEDIES. AGILENT TECHNOLOGIES SHALL NOT BE
LIABLE FOR ANY DIRECT, INDIRECT, SPECIA L, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT,
OR ANY OTHER LEGAL THEORY.
iv
Getting Started
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Checking the Shipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Supported Spectrum Analyzer Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Licensing the Cable TV Measurement Personality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Installing the Cable TV Measurement Personality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Uninstalling the Cable TV Measurement Personality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Measurements
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Making Channel Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Step 1. Configure the test system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Configuration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
User Defined Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Measurement Bandwidth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
External Preamplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
External Pad Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Step 2. Connect the signal to the analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Step 3. Make the measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Optimizing the Dynamic Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Optimizing the Total Power at the Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Access the TV Picture Mode (Optional). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Modifying the Channel Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
If You Have a Problem
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
If the Test Results Are Not What You Expected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
How to Contact Agilent Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Channel Measurements Menu Map
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Channel Measurements Menu Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
SCPI Commands
SCPI Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Test Descriptions
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Visual Carrier Level and Visual-to-Aural Level and Frequency Difference Test Description. . . . . . . . . . 6-3
Carrier-to-Noise Ratio Test Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Composite Second Order (CSO) Test Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Composite Triple Beat (CTB) Test Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Hum Test Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Depth of Modulation Test Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
v
Specifications and Test Aids
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-2
Cable TV Measurement Specifications and Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
C/N, CSO, and CTB Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-6
Channel Identification Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8
Safety and Regulatory Information
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Cleaning Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Shipping Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Before Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
Warnings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4
Instrument Markings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5
Safety, Earth, Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-5
Agilent Technologies Sales and Service Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-6
vi
1 Getting Started
Getting Started
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter provi des step-by- step procedur es for setti ng up a spectru m analyzer t o
perform cable TV measurements. This chapter contains the following sections:
• Introduction
• Checking the Shipment
• Supported Spectrum Analyzer Requirements
• Licensing the Cable TV Measurement Personality
• Installing the Cable TV Measurement Personality
• Uninstalling the Cable TV Measurement Personality
1-2 Cable TV Measurement Personality User’s Guide
Getting Started
Introduction
Introduction
With the Agilent Technologies ESA E-Series with Option 227 your spectrum
analyzer is both a full-featured spectrum analyzer and a cable TV service and
installation analyzer.
The cable TV mode is used to perform channel-by-channel measurements. This
allows execution of a single measurement on a single channel.
Cable TV Measurement Personality User’s Guide 1-3
Getting Started
Checking the Shipment
Checking the Shipment
Verify that the following items are in this shipment. Contact your nearest Agilent
Technologies sales or service office. (Refer to the Agilent Technologies Sales and
Service Offices” on page 8-6) if any items are missing or damaged.
Table 1-1 ESA Option 227 Materials Supplied
Description Agilent Technologies
Part Number
ESA Option 227
Cable TV Measurement Personality User’s
Guide
Personality (Version A.02.00)
(provided on 3.5-inch floppy disks)
E4401-90228 1
E4401-10006 1
Quantity
1-4 Cable TV Measurement Personality User’s Guide
Getting Started
Supported Spectrum Analyzer Requirements
Supported Spectrum Analyzer Requirements
The ESA Option 227 is designed to operate with 75 Ω and 50 Ω ESA-E Series
spectrum analyzers.
Cable TV Measurement Personality User’s Guide 1-5
Getting Started
Licensing the Cable TV Measurement Personality
Licensing the Cab le TV Measureme nt Personality
In order to start using the features of the Cable TV Measurement Personality, it
must be licensed. To license your Cable TV Measurement Personality:
NOTE If you ordered the Cable TV Measurement Personality with a new spectrum
analyzer proceed to st ep 5 of the Installing the Cable TV Measurement
Personality” on page 1-7, and verify that the program is already installed.
1. Turn the spectrum analyzer on. After the analyzer has completed its power on
sequence. Press
System, Licensing.
2. Press
Option and use the alpha editor keys to enter the name of the option . For
the Cable TV Measurement Personality the option name is 227.
3. Press
Return to go back to the licensing menu and select License Key . Use
the numeric keypad and the alpha editor keys to enter the appropr ia te licensing
key for your spectrum analyzer.
4. Press
Return to return to the licen sing menu and p ress Activate to license your
installed personality.
1-6 Cable TV Measurement Personality User’s Guide
Getting Started
Installing the Cable TV Measurement Personality
Installing the Cable TV Measurement Personality
The Cable TV Measurement Personality is supplied on a floppy di sk. To install the
program into your spectrum analyzer:
1. Press
System, Personalities.
The screen will list the personalities currently installed in your analyzer.
2. Insert the Cable TV Measurement Personality floppy disk into the analyzer
disk drive and press
now or verify the disk. Press
3. After the installation has been completed press
Install. The installer utility will ask if you wish to install
Install Now to install the personality.
Exit Installer to go back to the
analyzer mode and cycle the power to the analyzer.
4. To verify that the Cable TV Measurement Personality has been properly
installed, press
MEASURE and ch eck that the last key is lab eled CATV.
Cable TV Measurement Personality User’s Guide 1-7
Getting Started
Uninstalling the Cable TV Measurement Personality
Uninstalling the Cable TV Measur ement Personality
To uninstall the Cable TV Measurement Personality from the spectrum analyzer
follow these steps:
1. Press
2. Press
System, Personalities.
Uninstall and using the up
Meas. Pers
3. Press
Uninstall Now. The analyzer will ask you to confirm the command by
pressing
Uninstall Now again. After t he confir mation the Ca ble TV per sonality
will be uninstalled.
.” field.
and down ⇓ arrows select the “
⇑
Cable TV
1-8 Cable TV Measurement Personality User’s Guide
2 Measurements
Measurements
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter contain s informatio n describing how to make cable TV measurements
and how to modify channel plans.
The tests are listed on the following pages along with the keys that activate them.
2-2 Cable TV Measurement Personality User’s Guide
Measurements
Making Channel Measurements
Making Channel Measurements
This section explains the steps that are necessary to make channel measurements.
The steps are as follows:
1. Configure the test system
2. Connect the signal to the analyzer
3. Make the measurements
NOTE Early versions (before personality version A.01) required that each measurement
must be turned off prior to changing the channel. Press
measurement.
To speed up the testing process the newer personality version allows changing the
channels after the measurement has produced a result.
Meas Off to turn off the
Table 2-1 Channel Measurements
To activate Press
Carrier Level and Frequency
Carrier to Noise C/N Ratio
Composite Second Order/Composite Triple Beat CSO/CTB
Hum Hum
Depth of Modulation Depth Mod
Carrier Lvl
Cable TV Measurement Personality User’s Guide 2-3
Measurements
Making Channel Measurements
Step 1. Configure the test system
Use MEASURE, CATV, Setup, TVSTD to set up TV standard, channel tu ning, a
user defined channel, and an external preamplifier.
NOTE An additional way to set the TV standa rd i s prov ide d if TV Trigger (Option B7B)
is installed. This method is by pressing keys
two methods of setting the TV standard work independently of each other.
However, wh en a CATV measurement is started, wha tever standard i s set under t he
Trig menu is changed to match the standard that was set under MEASURE.
Therefore , it is important that
MEASURE, CATV, Setup, TVSTD is used to set the
TV standard before starting CATV measurements.
NOTE The information is stored in nonvolatile analyzer memory. This means that the
analyzer retains the information, even when the power is turned off, until you
access the setup menu again and change it.
Configuration Procedures
Trig, TV Trig Setup, Standard. The
1. Press
NOTE The default TV standard is set to NTSC-M.
2. Press
MEASURE, CATV, Setup.
TVSTD and choose the appropriate TV standard: NTSC-M, NTSC-J,
PAL-M, PAL-B/G, PAL-D/K, or PAL-I (the default TV standard is set to
NTSC-M).
3. Press
NOTE The channel plan that i s shown in th e menu will de pend on which TV standard wa s
Plan and the appropriate channel plan key.
enabled in step 2. For example, if the TV standard NTSC-M was enabl ed i n st ep 2
then the channel plan menu would display the following selections: STD, AIR,
IRC, HRC, and T, but would not show the CBL, VHF, or other channel plans.
The default configuration menu allows you to select one of the following
channel formats:
• NTSC-M and PAL-M channel plans
— STD Standard Cable
— AIR Broadcast Channels
— HRC HRC Cable
— IRC IRC Cable
— T Upstream Channels
2-4 Cable TV Measurement Personality User’s Guide
Making Channel Measurements
• NTSC-J
— CBL Japan Standard Cable
— AIR Japan Broadcast channels
•PAL-B/G
— HRC HRC Cable
— VHF VHF Channels
— UHF UHF Channels
— S S Channels PAL-B/G Standard
— S-Cable S Channels PAL-B/G Cable
— CENELEC CENELEC Channels
•PAL-D/K
— DS China Broadcast Channels
Measurements
— Z China Standard Cable
•PAL-I
— HRC HRC Cable
— VHF VHF Channels
— UHF UHV Channels
Cable TV Measurement Personality User’s Guide 2-5
Measurements
Making Channel Measurements
User Defined Channel
The following keys in the set up menu allow you to de fine the cente r frequenc y and
span for a user def ine d chan nel. This channe l is t hen ac cesse d b y sel ectin g c hannel
0 (zero). Refer to Figure 2-1.
Chan 0 Freq Channel 0 center frequency
•
Chan 0 Span Channel 0 span
•
One convenient use for Channel 0 is for testing at 44 MHz IF.
Figure 2-1 Channel Tuning Menu
Measurement Bandwidth
Measuremen t Bandwidth carrier to noise, bandwidth default is
4 MHz for NTSC-M, NTSC-J and PAL-M.
NOTE Bandwidth default for PAL-I, PAL-B/G and PAL-D/K is 5 MHz.
2-6 Cable TV Measurement Personality User’s Guide
Measurements
Making Channel Measurements
External Preamplifier
1. Using an external preamplifier, for analyzers without an internal preamplifier:
An external p reamplifier ma y be required for the carrier-to-noise test. Se e
Chapter 6, “Test Descriptions,” which contains more i nformat ion abou t when a
preamplifier is required for the carrier-to-noise test. The carrier-to-noise test
calculates the noise contribution of the external preamplifier, and reports the
correction on the
More Info screen of the carrier-to-noise test. If an external
preamplifier is used, enter the preamplifier gain and noise figure using
Ext Amp Gain and Ext Amp NZ Fig in the Setup menu.
NOTE Inaccurate values used for Ext Amp Gain and Ext Amp NZ Fig can result in
significant measurement errors. Use Agilent 85905A preamplifier with measured
data for accurate results.
NOTE If an external preamplifier is not used, Ext Amp Gain and Ext Amp NZ Fig values
must be set to zero or carrier-to-noise ratio calculation errors may occur.
2. Connect the cable TV signal as described in “Step 2. Connect the signal to the
analyzer” on page 2-8.
External Pad Compensation
EXT P AD Yes No key can be used to compensate for the amplitude loss caused
1.
by using a 50 Ω to 75 Ω external matching pad. (A 50 Ω to 75 Ω external
matching pad is used to match the signal from a 75Ω impedance system to a
spectrum analyzer with a 50 Ω impedance input.) The external pad function
compensates for the 5.8 dB amplitude loss of the external pad by setting the
spectrum analyzer's reference level offset to 5.8 dB.
2. If you are using a spectrum analyzer with 50 Ω input impedance but are not
using an external matching pad, the cable TV analyzer mode will compensate
for most of the impedance mis mat ch, but ampl itude measure ments ca n have up
to ±0.2 dB error caused by the uncompensated mismatch over the frequency
range.
This function is set to
No when the ESA Option 227 personality is loaded into
analyzer memory.
The setting of the external pad function is stored in nonvolatile spectrum
analyzer memory. Storing the setting in nonvolatile memory means that once
the external pad function is set to
Yes, it will remain set to Yes until you
change the setting or delete the ESA Option 227 personality program from
analyzer memory.
MEASURE, CATV, Setup to access Ext Pad Yes No.
Press
Cable TV Measurement Personality User’s Guide 2-7
Measurements
Making Channel Measurements
Step 2. Connect the signal to the analyzer
CAUTION To prevent the analyzer input circuits from being damaged, the total power at the
analyzer input must be less than +75 dBmV.
To optimize the analyzer input mixer for the best measurement range without
being overloaded, the tota l power at the analyzer input mixe r must be l ess t han +47
dBmV for C/N and less than +37 dBm for CSO/CTB. Total power greater than
these will add anal yzer atte nuation. The se values a re 10dB great er tha n the Agilen t
8591C Spectrum Analyzer, resulting in more measurement dynamic range using
the Agilent ESA analyzer. Compare the accuracy and characteristics graphs of
Figure 7-1 on page 7-7 with those of the Agilent 8591C analyzer.
For systems with unequal carrier levels (system tilt), the total power must be
calculated by summing the individual carriers. The
accounts for system tilt.
Total Power key function
You can measure the input power by pressing
Power
. The total power is displayed at the bottom of the screen.
MEASURE, CATV, Setup, Total
Total power at the input mixer can be reduced by increasing input attenuation.
Amplitude, Attenuation and make the adjustment. The analyzer retains a
Press
manually selected attenuation until you either select a new value, or reset the
analyzer power-on default conditions. For all tests provided by the cable TV
measurement personality, the analyzer automatically selects the attenuator setting
to meet the above requirements.
2-8 Cable TV Measurement Personality User’s Guide
Measurements
Making Channel Measurements
Step 3. Make the measurements
Most measurements updat e the result at the end of a sweep or at the en d of multiple
sweeps. Refer to each measurement type.
NOTE
Carrier Level and
Frequency Test
1. If you accidentally use the wrong key sequence, re-enter the channel. Press
MEASURE, CATV, Channel, enter the channel number, and press Enter.
2. If you want to set the analyzer to the power-on default conditions after using
the cable TV functions, you can either cycle the power or press
1. Select a channel and press
MEASURE, CATV, Carrier Lvl. The peak visual
Preset.
carrier level and visual-to-aural carrier difference appear on the screen. See
Figure 2-2.
Frequencies and power ratios for both sound carriers are displayed when the
following TV standards (and associated sound carriers) are used:
• PAL-I with NICAM
•PAL-B/G
• PAL-B/G with NICAM
See Figure 2-3 on page 2-10 and Figure 2-4 on page 2-11.
2. If it is available, press
Nicam On Off (On). A true RMS power measurement is
made across the NICAM band and the visual-to-sound power ratios are
displayed.
NOTE The Nicam key is availabl e onl y whe n PAL-I or PAL-B/G has been selected in the
TVSTD menu. It is not an indication that a NICAM carrier is present in the
channel.
3. Press
Cable TV Measurement Personality User’s Guide 2-9
MEASURE, CATV, Meas Off to exit th e test.
Meas Control to control single sweep, pause, and restart.
Press
Measurements
Making Channel Measurements
Figure 2-2 Carrier Level Measurement (NTSC-M)
Figure 2-3 Carrier Level Measurement (PAL-B/G with Nicam Off)
2-10 Cable TV Measurement Personality User’s Guide
Making Channel Measurements
Figure 2-4 Carrier Level Measurement (PAL-B/G with Nicam On)
Measurements
NOTE For best results, the carrier-to-noise ratio (in 4 MHz BW or 5 MHz BW) of the
system should be 40 dB or greater, and the measured signal level should be 30 dB
or greater above the displayed noise during the test.
For sync suppressed scrambled signals the results will be inconsistent. To stabilize
the result press
the max hold function then
View/Trace, Max Hold. To exit the test, press Clear Write to exit
MEASURE, CATV, Measure Off. To speed level
measurements on a number of channels, a new channel can be tuned during the
measurement. Press
Channel, enter the channel number, and press Enter or use the
up arrow ⇑ or down arrow ⇓ to move to adjacent channels.
Carrier-to-Noise
Test
1. Select a channel, then press
2. Perform th e following steps:
MEASURE, CATV, C/N Ratio.
a. The marker defaults to the minimum system noise near the lower channel
boundary. Wait for the analyzer to return an answer.
b. Remove the carrier and modulation to perform the carrier-to-noise test.
c. Press
Marker, then using the knob, move the marker to the desired position
in the indic ated “FCC MEASUREMENT RANGE.” Refer to Figure 2-5 on
page 2-12.
Cable TV Measurement Personality User’s Guide 2-11
Measurements
Making Channel Measurements
NOTE “FCC Measurement Range” is onl y applied fo r NTSC-M, NTSC-J and PAL-M TV
standards . The messag e “Measurement Range” will be di sp layed for the other TV
standards. See Figure 2-6 on page 2-13.
The FCC measurement range ba ndwi dth is defined as 4 MHz. Mea sur ement r ange
bandwidths other than the FCC measurement range bandwidth are defined as 5
MHz.
Change the measurement bandwidth by pressing
Meas BW, and enter the desired bandwidth.
d. Use averaging to stabilize the result. Press
MEASURE, CATV, Setup,
BW/Avg, Averaging On. Check
that the average type is set to video.
The carrier-to-noise test compares the system noise level at the analyzer input
to that of the analyzer itself. If these levels are within 3 dB of each other, the
analyzer will display the message “
See More Info
” (under
the measurement result. If the difference is less than 2.2 dB, the message is in
inverse video. Refer to Chapter 6, “Test Descriptions,” for more detailed
information about the carrier-to-noise measurement.
3. Press
More Info to display the carrier-to-noise calculation. See Figure 2-7 on
page 2-13. To exit the test, press
MEASURE, CATV, Meas Off.
Figure 2-5 Carrier-to-Noise — FCC Measurement Range (NTSC-M)
Meas Setup) next to
2-12 Cable TV Measurement Personality User’s Guide
Figure 2-6 Carrier-to-Noise (PAL-B/G)
Measurements
Making Channel Measurements
Figure 2-7 Carrier-to-Noise, More Information (NTSC-M)
Cable TV Measurement Personality User’s Guide 2-13
Measurements
Making Channel Measurements
Carrier to Noise
with an External
Preamplifier
Preamplifier noise is calculated and corrected when an external preamplifier is
used. External preamplifier gain and noise figure are used for this calculation.
External preamplifier keys
Ext Amp Gain and Ext Amp NZ Fig are used only for
this purpose. Refer to the notes under “External Preamplifier” on page 2-7 for
proper usage.
1. When using a tunable bandpass filter, first peak the filter using the
Carrier Lvl key. Press Meas Off, C/N Ratio. Place the marker to measure the
carrier- to-noise clos e enough to the car rier to minimi ze any roll-of f ef fect of the
bandpass filter.
2. Carrier-to-noise measurement accuracy is degraded as the cable TV system
noise approaches the analyzer noise. This is reflected in the magnitude of the
analyzer noise correction value.
3. Note the analyzer noise correction value by pressing
More Info.
• if less than 0.5 dB, then C/N accuracy is ±1 dB
• if equal to 0.5 dB, then C/N accuracy is ±1.25 dB
• if equal to 3 dB, then C/N accuracy is ±2 dB
• if equal to 7 dB, then C/N accuracy is ±3.5 dB
• if greater than 7 dB, C/N is out of measurement range
4. The analyzer input a ttenuator se ts the noise f loor of th e analyzer. The attenuator
is set to not overload the first mixer. For carrier to no ise, the attenu ator switch
point from 0 to 5 dB is at +47 dBmV to tal power at the input. (This r ange is 10
dB more than the Agilent 8591C spectrum analyzer.)
Optimizing the Dynamic Range
Limiting the number of carriers input to the analyzer allows the measurement
routine to select a lower attenuator value, providing the analyzer a lower noise
floor . This ca n be done with individ ual channel filters, a high pass filt er , a low pass
filter or an adjustable bandpass filter.
When the attenuator switches to the next higher value, the noise floor raises 5 dB
which degrades the signal to noise ratio by 5 dB. For C/N, the attenuator switches
from 0 dB to 5 dB at +47 dBmV. Keeping the total power just below that will
obtain the best signal to noise ratio.
A 1 dB (or smalle r than 5 dB) step attenuator used in conjuncti on with a filter will
provide the best coverage of signal range for optimizing the total power at the
input.
Optimizing the Total Power at the Input
If the analyzer correc tion value dict ates that it is nece ssary to optimize the analyzer
noise floor for a particular configuration, press
Power
.
MEASURE, CATV, Setup, Total
2-14 Cable TV Measurement Personality User’s Guide
Measurements
Making Channel Measurements
For carrier to nois e, th e attenuator switch point from 0 dB to 5 dB attenuatio n is at
+47 dBmV. The attenuator switch point from 5 dB to
10 dB is at +52 dBmV and increments proportionately with each 5 dB step in
attenuation.
Measuring C/N with modulation on is limited to a maximum range of 55 dB.
Measuring C/N with modulation off within 2 MHz of the carrier is limited to a
maximum range of 55 dB. For a higher maximum C/N range, measure noise
farther than 2 MHz from the carrier when th e carrier is on , o r turn the carrier off.
Refer to the g raphs shown in
Figure 7-1 on page 7-7.
Composite
Second
Order/Composite
Triple Beat
1. Select a channel, then press
2. Perform th e following steps:
a. The marker de faults to the lower beat.
MEASURE, CATV, CSO/CTB.
(CSO/CTB) Test
b. To perform the carrier-to-beats test remove the carrier and modulation by
turning the modulator off.
NOTE The carrier-to-b eats test for NTSC-M, NTSC-J, and PAL-M is done according to
FCC requirements.
c. Using the knob, move the marker to the desired beat. See
Figure 2-8 on page 2-17. Note that if the mar ker i s not a ct ive , yo u wi ll need
to press the
NOTE For NTSC-J, please refer to Figure 2-9 on page 2-17 and for PAL-B/G, PAL-D/K
Marker key. Alternatively, press Meas Setup, Next Beat.
and PAL-I refer to Figure 2-10 on page 2-18.
d. Turn averaging on by pressing
averaging type is video. Press
BW/Avg, Average On. Check that the
Return to get back to the cable measure
menu.
3. Move the marker to the nex t beat by pressing
Next Beat. Using the front-panel
knob will also allow measuring beats other than at the standard CSO/CTB
offsets.
The results of the measurement are displayed at the bottom of the analyzer
display.
4. Press
Meas Setup, and then Atten Down or Atten Up, to make the attenuator
check for analyzer gene rate d beats when no t usin g a bandpa ss fil ter. Switch the
attenuator up and down to check for changes in the beat level.
If the beat level does not change, then the beat is not generated in the analyzer.
If the beat level changes with attenuator changes, then raise the attenuator
setting until the bea t l ev el no longer changes. The di spl ayed noise may prevent
accurate measurement results.
Cable TV Measurement Personality User’s Guide 2-15
Measurements
Making Channel Measurements
NOTE The measurement automatically sets the attenuator to prevent analyzer generated
beats upon entering the test. The analyzer switches from 0 dB attenuation to 5 dB
attenuation at +37 dBmV of total power at the input.
5. Remove the carrier, or press
or below the carri er (i f an op en sp ace ex ists) . Eac h time
CTB Up or CTB Down to measure the CTB ab ove
CTB Up is pressed, the
marker is automatically positioned at the next CTB above the carrier (+6 MHz
increments). Each time
CTB Down is pressed, the marker is automatically
positioned at the next CTB below the carrier (−6 MHz increments).
NOTE ±6 MHz increments only are applied for NTSC-M, NTSC-J and PAL-M TV
standards. PAL-B/G, P AL-D/K and PAL-I will have ±7 MHz or ±8 MHz, ±8 MHz
and ±8 MHz increments respectively.
6. Press the
test, press
NOTE When using a tunable bandpass filter, first peak the filter using Carrier Lvl. Make
More Info key to display the carrier-to-beat calculation. To exit the
MEASURE, CATV, Meas Off.
sure the filter band width is suf fici ent that the beats are not rolled off. See Table 2-2
below .
Table 2-2 Boundary Beats
TV Standard Lowest
Beat (MHz)
Highest
Beat (MHz)
NTSC-M –1.25 +1.25
NTSC-J –1.25 +4.00
PA L-M –1.25 +1.25
PAL-B/G
(7 MHz span)
PAL-B/G
(8 MHz span)
PAL-D/K CTB +6.25
PAL-I CTB +6.25
CTB +5.25
CTB +6.25
2-16 Cable TV Measurement Personality User’s Guide
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