Atec 2715 User Manual

Digital and Analog Testing for Hybrid
Networks

The 2715 Cable TV Spectrum
Analyzer now includes auto­mated tests for both analog
and digitally-modulated
channels. When you are
ready to begin installing
digital transmission of video,
data or voice, the 2715 is
ready to help. After setting
up the 2715 with the new,
companion Cable TV RF
Measurement Software for
Windows, the analyzer auto­matically determines the cor­rect measurements for each
channel type – analog, digi­tal, FM or pilot.

Dependable, In-service Analog
Carrier Measurements at an
Affordable Price

Now you can make more
proof of performance and
other cable system measure­ments without disruption of
service to subscribers. And
you can minimize the incon­venience of making measure­ments at the output of set-top

converters. The 2715 pro­vides accurate and automated
measurement of carrier-to­noise, in-channel response,
and coherent distortion sig­nals as well as carrier levels,
frequencies, and more…with­out removal of video carriers
or modulation. In-service
measurement of CTB requires
an unoccupied channel adja­cent to the test channel.

Characterize your Digital Channels

Channel averaged power,
noise and distortions on digi­tally modulated channels can
all be measured by the 2715.
It’s important to understand
the performance of each of
the digital channels in your
system as well as their inter­action with your analog
channels. Both broadband
random noise-like distor­tions, and coherent distor­tions – plus noise – can be
measured. They all can
degrade the bit-error-rate
behavior of your digital
signals. The 2715 includes

Copyright © 1999 Tektronix, Inc. All rights reserved.

2715
Cable TV Spectrum Analyzer

The 2715 is a complete cable TV RF testing solution.

IN-SERVICE RF TESTING FROM
TEKTRONIX

In-service Measurements Minimize
Program Interruption, Reduce Cost
of Acquiring Performance Data
– Compatible with NTSC and PAL
Systems

Digital Channel Measurements Are
Ready When You Are – Characterize
Averaged Power; Check Noise and
Distortions that Can Worsen BER
– Applicable to QAM, QPSK, QPR,
VSB, and OFDM Signals

Addresses All FCC Proof of
Performance Measurements

Cable TV Measurements Enhance
Measurement Repeatability and
Reduce Technician Training Time

Carrier Level, Carrier Frequency,
Carrier-to-noise, Hum/LFD, and
Other Key Measurements Execute
Automatically from Easy-to-use,
On-screen Menu

Unattended and Remote
Measurement Modes Reduce
Personnel Requirements in the Field

75 Ω Input with Quick-change F and
BNC Connectors Reduce Repair
Costs and Minimize Down Time

Enhanced Troubleshooting Power
with Built-in Preamplifier, Audio and
Video Demodulation – All Standard

Frequency Coverage to 2.15 GHz,
with Options 50 and 75, Can View
Downconverted Satellite Signals
(L-Band)

Includes Windows

™

-compatible PC
Software for Programmed
Measurement Configuration, Data
Collection, Measurement Results
Printouts, Limits Checking,
Alarming and Control of a Locally or
Remotely-located 2715

High Portability, On-board Non­volatile Memory, Four Digital
Displays for Spectral Display
Storage and Comparison, Plus True
Analog, Continuous Gray Scale
Display for Detecting Low Level
Beats and Spurs Amidst Noise and
Active Video

page 2

digital channel averaged
power, desired-to-undesired
signal power ratio (D/U) and
CTB/CSO measurement. You
also can verify the spectral
occupancy of your digital
modulators with an adjacent
channel leakage (ACL) mea­surement. The distortion and
noise measurements require a
brief removal of the digital
signal. You get all this capa­bility in a 23.5 lb., compact,
easy-to-carry package … at an
attractive price. All of the
common cable system spec­tral measurements are built
in and menu-selectable
including those needed to
address field FCC proof of
performance requirements.
An accompanying Microsoft
Windows™-compatible PC
software package adds mea­surement configuration, data
collection, measurement
results printouts, limits
checking, alarming and more.

What used to be complicated
measurement procedures,
even for engineering, are now
push-button simple. Techni­cians can easily perform
extensive cable system analy­sis and data collection in the
field, all automatically.

Measurements and data col­lection can also be done
remotely under computer
control. Or the 2715 can be
left unattended to run auto­matic measurements and data
collection initiated by the
built-in real-time clock. Data
collected in the field can be
transferred from the 2715’s
memory via an RS-232 or
GPIB interface to a PC. The
2715’s accompanying Win­dows PC software package
includes easy transfer of data
to your choice of Windows­compatible spreadsheet or
database programs for cus­tomizing analysis or reports.

Quick, Repeatable, Automated
Measurements

The 2715 contains the follow­ing measurements and capa­bilities in its cable TV
(CATV/APPL) application
menu:

Analog Channels:

• Direct channel tuning and
automatic positioning of
visual and aural carriers

• Visual and aural carrier
level and frequency
measurement

• Survey of system visual
and aural carrier levels and
frequencies

• Depth of modulation adjust­ment and measurement

• Aural carrier FM deviation
adjustment and
measurement

• Visual carrier-to-noise
measurement

• In-channel response
measurement

• Hum/low-frequency distur­bance measurement

• System frequency response

• View baseband modulation
(field and line) and view
picture

• Aural carrier demodulation
(listen mode)

• Intermodulation distortion
measurement (CTB and
CSO)

• Cross modulation
measurement

Digital Channel
Measurements:

(applicable to QAM, QPSK,
QPR, 8VSB and OFDM sig­nals)

• Averaged power

• Desired-to-undesired signal
power ratio (D/U)

• Adjacent channel leakage
(ACL)

• CSO and CTB

• Direct channel tuning and
automatic positioning of
digital signal

• Survey of system digital
channel levels

• System frequency response

Measurements selected from
the menu are automatically
executed, and the results are
displayed on the CRT screen.
Not only are complex mea­surements reduced to push­button simplicity for less­experienced spectrum ana­lyzer users, but measurement
repeatability is high.

A battery pack option makes
2715 measurements and data
collection possible even where
AC power isn’t available.

More Troubleshooting Help...

In addition to automated
measurements, the 2715 also
provides analog channel
video and aural carrier
demodulation. Aural carrier
demodulation allows you to
listen to the program audio
on the selected channel. Sim­ilarly, the demodulated video
feature allows you to view
the video on the currently
selected channel (or from a
down-converted satellite sig­nal). Also, full-field or indi­vidual horizontal line wave­forms can be viewed.

All of these features aid posi­tive channel or program iden­tification in the field. They
also aid recognition of many
system problems.

...And Maintenance Help

Built-in adjustment modes
for audio carrier deviation
and video depth of modula­tion assist in day-to-day
maintenance of your system.
These adjustment modes are
conveniently accessible from
within the automated FM
deviation and depth of modu­lation measurement routines.

Check filters, line amplifiers, cables

The 2715’s 75 Ω External
Tracking Generator (Option

05) provides a convenient
means of measuring fre­quency response on key sys­tem components. You can
also sweep most two-port
devices.

The 2715 capitalizes on PC power

The Microsoft Windows-com­patible software package that
accompanies the 2715 runs
automated cable TV measure­ments via an RS-232 or GPIB
interface and collects mea­surement history for tracking
system performance.

The software package
provides the following
capabilities:

page 3

Channel table generator –

You can create your own
channel tuning tables in
addition to the standard
tables provided. Creating

your own custom channel
tuning tables is a simple mat­ter of editing one of the stan­dard tables or creating a com­pletely new table by filling in
a predefined, on-screen chan­nel-setup form. Your custom
tables can then be transferred
to the 2715 to be used with
its built-in measurement fea­tures. Result: data will be
consistently taken on all of
your system carriers includ­ing scrambled channels, aero­nautical offsets, and non­standard frequencies.

High-level test sequences –

You can configure automatic
test sequences from the
2715’s built-in measure­ments. Creating a test
sequence is a simple matter
of indicating the desired tests
in an on-screen setup matrix

Your test sequences can then
be transferred to the 2715 for
later execution via front­panel selections, or run from
a PC situated at another loca­tion. This capability allows
less experienced technicians
to easily execute high-level
test sequences that have been
defined and loaded into the
2715 by a cable TV system
engineer or senior technician.

Additionally, a time of day
can be specified for auto­matic execution of any test
sequence. You can also spec­ify the number of times that a
test is to be repeated and the
interval of time between test

repetitions. This allows you
to leave the 2715 unattended
while it automatically per­forms its time initiated test
procedures and stores results.
For example, you can leave
the 2715 at a node site
overnight or over the week­end for unattended monitor­ing and data collection.

Labor-saving ancillary
features – Detailed or

summary current or historical
measurement results can be
printed directly from the
2715 PC Software or can be
copied into another Microsoft
Windows-compatible
program for report
customization.

You can execute tests from a
remotely-located 2715 by
using the CATV RF Measure­ments PC Software in con­junction with the Terminal
Program that is a standard
accessory of the Windows
operating system software.
You can place the 2715 at a
node of another remote site
while measurements and data
collection are controlled from
a centrally located PC. This
configuration can signifi­cantly reduce the number of
field trips necessary to moni­tor and diagnose system trou­ble spots. The RF Measure­ment Software also includes
limits checking, alarming and
271X display transfer
functions.

The demodulated video display aids channel or program identifica­tion. It also aids trouble-shooting by showing gross picture anoma­lies, such as the hum bars displayed here.

Measurement conditions and results are clearly displayed on­screen. Text can even be added, to describe measurement location
for example.

2715
Characteristics

The following specifications and features
apply after a 15 minute warmup period and
after all normalizations, including reference
normalizations, have been performed. CATV
characteristics represent typical perfor­mance and are dependent on general spec­trum analyzer specifications. CATV charac­teristics need not be verified independently
providing that all spectrum analyzer specifi­cations are verified.

CABLE TV MEASUREMENTS

Channel Selection –

Visual and aural carriers displayed when
channel number is entered or front-panel
selected.
Tune Configuration: STD, HRC, IRC, and
custom; configured using 2715 PC
software.
Channel Range: 0 to 999; configured using
2715 PC software.
Frequency Range: 1 MHz to 2.15 GHz;
dependent on selected Channel Table.

Visual Carrier Frequency –

Measured with internal counter to 1 Hz

resolution with accuracy of 5x10–7x Carrier
Frequency ±10 Hz ±1 Least Significant
Digit.

Visual-to-Aural Carrier Frequency –

Aural carrier measured with internal counter
relative to visual carrier.
Difference Range: 1 MHz to 10 MHz
(depending on selected channel table) for
an amplitude difference of <30 dB and aural
carrier to noise >15 dB (300 kHz RBW).
Resolution: 1 Hz.
Accuracy: ±15 Hz for visual-to-aural carrier
difference <8 MHz.

Visual Carrier Peak Level –

Absolute peak amplitude measured with
preamp off.
Amplitude Range: –18 dBmV to
+58.8 dBmV for visual carrier to noise
>30 dB (300 kHz RBW) and total input
power <+70 dBmV.
Frequency Range: 15 MHz to 1015 MHz.
Resolution: 0.1 dB.