Atec Acterna-JDSU-SDA-5000 - Manual (Page 4)

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QAM View ensures quality forward
path digital services
For measurement and analysis of
digital TV and forward modem signals,
the new digital QAM View option
provides a full complement of digital
quality measurements. Included is a
64/256 QAM constellation display
with zoom, average digital power
level, bit error rate (BER), 21 to 35-dB
modulation error ratio (MER), and a
noise margin “cliff effect” parameter.
An equalizer display shows equalizer
stress and distance to fault.
In addition, an exclusive Noise mode
enables technicians to see ingress/
noise under an active digital carrier.
This tool is invaluable for detecting
forward path ingress otherwise hidden
by conventional spectrum views.
One button, in-service C/N measurements on
TDMA return path cable modem signals (DOCSIS,
EuroDOCSIS, EuroModem)
Zero span/time domain expert mode, showing the
TDMA bursty return path cable modem power ramp
of 3.5 ms
In-service cable modem analyzer
For bursty digital signals such as TDMA
technologies used on cable modems
for reverse services, the SDA-5000
offers two measurement choices.
The first, a one-button cable modem
analyzer test, shows carrier-to-noise
measurements quickly. The second,
an advanced zero span feature, uses
a time domain display to allow power
measurements while the modem is in
service. Both modes are compatible
with DOCSIS/EuroDOCSIS, CBR/
switched circuit telephony, and
proprietary cable modem standards.
Detecting ingress in the field
When detecting ingress in the field,
first the operator looks at the ingress
present at the field testpoint using
the spectrum display on any of the
receivers and then switches to reverse
ingress/noise to see the ingress at the
headend for comparison. This time-
saving procedure helps in locating
sources of ingress. An adjustable dwell
time ensures that even intermittent
ingress is detected. The preamp and
lowpass filter also assures that even
low-level ingress is seen. The preamp
and lowpass filter on the SDA-5000
assures that ingress can be measured
on devices with bidirectional testpoints
or testpoint values of 30 dB or more.
PathTrak Field View option
When a network is equipped with the
Acterna PathTrak Performance Moni-
toring System, system technicians can
benefit from the ultimate tool to com-
bat ingress – the PathTrak Field View
option for the SDA-5000. With Field
View, the SDA-5000 receives a return
path headend spectrum broadcast
from the PathTrak unit and compares it
with a return path spectrum at any field
testpoint. The side-by-side spectrum
comparison instantly reveals to the
technician whether the ingress source
is originating at the technician’s cur-
rent testpoint or at a different location.
The comparative spectrum technique
reduces noise/ingress troubleshooting
time dramatically, since the technician
can immediately verify whether correc-
tive action performed in the field (local
trace) results in improvement in the
headend spectrum (remote trace).
Comprehensive testing
The SDA Series provides an extensive
set of signal analysis features designed
for proving and improving network
quality. Its key capabilities include
level measurement, analog and
digital signal limits, tilt measurement,
scan measurement, in-service
carrier-to-noise measurement, hum
measurement, modulation measure-
ment, and local amplifier alignment
with loopback tests.
In-service ingress spectrum showing CTB/CSO-
intermodulation problems due to analog-TV
channels