Atec Wavetek-JDSU-SDA-4040D - Manual (Page 2)

Measuring the Behavior of
DOCSIS/DAVIC Compatible Cable
Modem Signals in the Cable Plant. For
"bursty" digital signals, such as TDMA
technologies used on cable modems for
reverse services, the SDA-4040D uses the
advanced Zero Span capabilities to make
the measurement. Time domain displays of
TDMA signals allow power measurement,
D/U (desired/undesired measurements),
and detection of packet collisions, all while
the modem is in service. Technicians can
measure the level of interference in the
actual channel being used.
! Time domain view of ingress in the Zero Span
mode captures elusive ingress.
! Cable modem analysis using Zero Span mode
provides accurate, in-service, power and C/N
measurements.
Fast-Update Spectrum Display for
Detecting Ingress in the Field. The spec-
trum mode has the speed and versatility
to effectively troubleshoot difficult system
problems. A programmable dwell time
allows the meter to stay on each frequen-
cy longer to catch more ingress. Peak hold
mode captures and saves transient bursts
(like evasive return path electrical noise).
The SAM4040D detects signals as fast as
5µs, in both Zero Span and continuous
modes. The pre-amp and low-pass filter
on the SDA-4040D assures that ingress
can be measured on devices with bi-direc-
tional testpoints or testpoint values of
30dB or more.
! Reverse digital modem signal.
PathTrak Field View Option.
When your network is equipped
with the PathTrak Performance
Monitoring System, system technicians can
benefit from the ultimate ingress fighting
tool—the PathTrak Field View option for
the SDA-4040D. With Field View, the SDA-
4040D receives a return path headend
spectrum broadcast from the PathTrak unit,
and then 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 his current
testpoint or at a different location. The
comparative spectrum technique slashes
noise/ingress troubleshooting time, since
the technician can immediately verify
whether corrective action performed in the
field (local trace) results in improvement in
the headend spectrum (remote trace).
! PathTrak Field View option compares headend
node spectrum with field test-point spectrum.
Sweepless Sweep® Provides Non-
Intrusive Frequency Response. The trade-
marked Sweepless Sweep® passively pro-
vides frequency response information
about a network by measuring active carri-
ers. The SAM404D stores the levels of all
active carriers at one reference point in the
network, and then compares the relative
levels to another point within the network;
just like referenced sweep, but without the
need for a transmitter!