SDA-4040D STEALTH DIGITAL ANALYZER
3
In-service cable modem analyzer
For bursty digital signals such as TDMA technologies used on cable modems for
reverse services, the SDA-4040D offers two choices. The first is a one-button cable
modem analyzer and the second uses advanced zero span capabilities to make the
measurement. The one-button cable modem analyzer quickly shows carrier-to-
noise measurements, while the zero span option utilizes a time domain display to
enable power measurements while the modem is in service. Both methods are
compatible with global cable modem standards.
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, and 256 QAM,
QPR, QPSK, VSB, and CAP16).
Analog and digital signal limits
Reverse digital modem signal
PathTrak Field View option compares headend node
spectrum with field testpoint spectrum
Analog signal threshold limits have always been a technician’s favorite feature of
JDSU 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 necessary to determine if analog and digital level
relationships are within system specifications. Analog and digital limit capabilities
are available in both the Scan and Autotest modes.
Tilt measurement
Tilt is the easiest and most efficient tool for balancing amplifiers. For cable plants
requiring multiple tilt measurements, such as comparing today’s tilt measurement
with a historical record, and then making an additional measurement for a new
wider channel plan, the technician simply uses markers to indicate the tilt chan-
nels that define the new limits.
Intermodulation distortion
Sweepless Sweep display
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
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.
Carrier-to-noise measurement: in-service
Carrier-to-noise measurement (on non-scrambled channels) is just as easy, and
there is no need to remove modulation from the video carrier. No tunable
preselector filter is needed.
Graphical reverse testpoint compensation
JDSU [ JDS UNIPHASE CORPORATION ]
