Atec Acterna-DSAM-6000 - Manual (Page 2)

Signal Level Meter (SLM)
Traditional SLM test functions for analog video and audio levels as well as JDSU’s
extremely accurate digiCheck™ digital power level measurements are supported
by the DSAM-6000. Furthermore, the ability to measure carrier-to-noise (C/N)
on analog carriers comes standard. The DSAM-6000 can measure downstream
carriers to a full 1GHz and analyze 64, 128 and 256 QAM, including deep
interleave (i=128, j=4) modulation. Also included are MER and pre- and post-
FEC BER on both digital video and DOCSIS carriers, allowing technicians to
validate that digital services are received and they meet adequate margin and
quality specifications.
Miniscan and Full Scan Modes
When measuring analog and digital as well as DOCSIS signals, technicians can see
high- and low-frequency channels and verify how much level headroom remains
when limits are activated. In miniscan mode, the DSAM monitors up to 12 chan-
nels at a time and in full scan mode it monitors the entire channel plan, up to 999
channels. The results of both scans are displayed either as an easy-to-see bar graph
or in an informative table.
Tilt Mode
Tilt mode is used while sweeping to check the forward tilt of the channel levels at
the low and high ends of the frequency spectrum. The variances of the levels,
which are displayed at the bottom of the DSAM-6000 screen, indicate distortion
of the frequency spectrum. Based on these results, technicians know which
equalizer pad to select that will provide optimum flatness at the end of the line.
Hum Analysis Mode
A hum measurement may be performed on a nonscrambled analog channel. Since
the instrument is battery powered, the measurement is independent of ground
loops and therefore is isolated from the line (mains). Severe hum is revealed on a
TV as either single (60/50 Hz) or double (120/100 Hz) horizontal bars across the
video screen. The DSAM-6000 hum display indicates the composit level of all
frequency components below 1000 Hz as well as the fundamental hum frequency.
The lower levels of adjacent frequencies as well as the fundamental are displayed
across a frequency graph. This is valuable in determining the source of hum
generation by displaying a telltale signature of the source (patent pending).
Constellation Mode
There are various elements in a network that compromise video quality. The
DSAM-6000 constellation mode displays patterns of data points on a graph,
which are easily interpreted, enabling technicians to detect and quickly diagnose
the source of digital video problems.
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DSAM-6000 DIGITAL SERVICE ANALYSIS METER
Features
Undesired electrical interference can appear on a
video channel as one or two horizontal bars. A Hum
measurement reveals if any electrical interference is
present on tested channel.
A Constellation graph shows impairments on the
network with patterns in the display. By identifying
the pattern technicians can figure out what is the
probable cause of the impairment.
Level mode on an analog channel displays video
and audio signal levels and their delta value.
Carrier-to-Noise (C/N) ratio is also displayed.
Miniscan measures signal strength of up to 12
channels simultaneously.