Atec JDSU-DSM-6300 - Manual (Page 3)

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DSAM-6300 DigitAl Service AnAlySiS Meter
A constellation graph shows impairments on the
network with patterns in the display. By identifying
the pattern, technicians can figure out the probable
cause of the impairment.
DQI displays intermittent, short-duration impair-
ments that MER and BER miss as well as steady-state
issues that MER and BER typically capture.
The optional Field View capability greatly improves
the success rate and efficiency in locating return-path
ingress. Field technicians can view the return spec-
trum that the JDSU PathTrak Return Path Monitoring
System receives. Both the remote spectrum and the
local spectrum view can be compared on the meter.
Constellation Mode
Various elements in a network can compromise video quality. The DSAM-6300 con-
stellation mode displays patterns of data points on a graph for easy interpretation,
letting technicians detect and quickly diagnose sources of digital video problems.
Digital Quality Index (DQI) Mode
DQI is an indicator of the overall health of a QAM stream. This JDSU exclusive
measurement is extremely effective in tracking intermittent problems. QAM signal
health is represented by an easy to understand index rating from “0” to “10” with
10 being the highest quality. DQI also catches errors sometimes missed by BER and
errored seconds measurements. To help troubleshoot intermittent issues, the index
is plotted on a 180-second graphical history display.
QAM Ingress Mode
Traditionally, detecting the presence of ingress within downstream digital signal
spectrum is nearly impossible without turning off the service. The tightly spaced
QAM carriers hide any visual presence of ingress or intermodulation distortions. An
MER test will indicate that an issue exists, but with the DSAM-6300 and the patented
QAM Ingress mode, technicians can inspect what is actually going on beneath the
digital “haystack” without interrupting service.
Field View™ Option
Field View provides the communication between JDSU PathTrak™ return-path
monitoring systems and field meters such as the DSAM-6300. A JDSU HSM-1000
sends spectrum measurements from PathTrak to the field meter, where the results
are displayed on the DSAM screen. By comparing local spectrum measurements
to those from PathTrak, field technicians can quickly resolve return-path ingress
problems.
The QAM Ingress test lets technicians see spectrum
underneath a live digital carrier which is usually not
viewable due to the presence of the “haystack.”