Atec Acterna-JDSU-SDA-5000 - Manual (Page 5)

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Time domain view of ingress in the Zero Span
mode captures elusive ingress
PathTrak Field View option compares headend
node spectrum with field testpoint spectrum
Graphical reverse testpoint compensation
Level measurement
The SDA instruments have a compre-
hensive single-channel level display
with tuned channel, video frequency
and level, audio frequency and level,
and the difference between video and
audio carrier levels.
Making accurate digital average power
measurements is addressed with the
digiCheck measurement function. The
digiCheck feature is compatible with
most non-bursty digital modulations in
use today (that is, 16, 32, 64, 128, and
256 QAM, QPR, QPSK, VSB, and CAP16 ).
Analog and digital signal limits
Analog signal threshold limits have
always been a technician’s favorite
feature of Acterna instruments.
Automatic limit checks provide a quick
GO/NO-GO status for audio and video
levels. The SDA Series extends this
capability with a dedicated digital limit
set that can be applied exclusively to
the forward digital carriers defined in
a channel plan. By assigning separate
analog and digital limits, test time is
reduced, since no calculation is neces-
sary to determine if analog and digital
level relationships are within system
specifications. Analog and digital limit
capability is available in both the Scan
and Autotest modes.
Carrier-to-noise measurement:
in-service
Carrier-to-noise measurements (on a
non-scrambled channel) is just as easy
with the SDA Series and there is no
need to remove modulation from the
video carrier. No tunable preselector
filter is needed.
Hum measurement: in-service
Measuring hum on a channel (non-
scrambled) is as simple as pressing the
“HUM” key with the versatile Acterna
SDA Series. Since the instrument is
battery powered, the measurement is
independent of ground loops and is,
therefore, isolated from the line
(mains). Hum is revealed as either
single (60 Hz) or double (120 Hz)
horizontal bars across the video screen.
Modulation measurement
SDA Series modulation measurements
include NTSC, PAL, and SECAM formats.
Demodulation of the audio is done for
both AM and FM. FM is used to hear
audio distortion on the FM radio chan-
nels or the sound of the TV program.
AM is used to recognize short-wave
interference signals in the reverse band.
Tilt measurement
Tilt is the easiest and most efficient
tool for balancing amplifiers. For cable
plants requiring multiple tilt measure-
ments, such as comparing today’s tilt
measurement with a historical record
and then making an additional meas-
urement for a new wider channel plan,
the technician simply uses markers to
indicate the tilt channels that define
the new limits with the SDA Series.
Intermodulation distortion
Intermodulation distortion (CSO/CTB)
can be automatically measured using
the CTB/CSO mode from the spectrum
analyzer. CTB/CSO distortions produced
by intermodulation of analog TV carriers
can degrade the signal quality of QAM
modulated signals used by digital
video and cable modems.
Scan measurement
The SDA Series Scan mode provides
a quick graphical view of the entire
channel plan with bars representing
the video level for each channel. Both
video and audio may be displayed.