Televes H30 CRYSTAL, Instruction Manual

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H30 CRYSTAL
18
Ideally, each of the symbols in a constellation
diagram should display a clean dot indicating a
perfect signal.
The
H30Crystal
real time constellation, allows the
installer to assess the size and shape of the build
up of dots indicative of problems which contribute
to bit errors leading to service disruption
9.1. Main window
Below is a capture of a Constellation window with
a brief explanation of its features:
Modulation
List of measurements
with pass/fail indicators
Constellation
diagram
Selected channel
Change using
9.2. Setup
Press to change Constellation options.
The measurements made for analog channels are
video carrier level and V/A. For digital channels the
measurements are power and C/N.
The analog channels will have an extra, smaller
white bar indicating the level of the audio carrier.
8.1. Main window
Below is a capture of a Learning Plan window with
a brief explanation of its features:
List of measurements
with pass/fail indicators
Bar graph representing
found channels
Color according to
checkmarks
Indicates that the
scan is finished.
Press to save
the plan
Selected channel
Change using
9. Constellation
Digital video often does not show signal
impairment until it is too late due to the small
margin between acceptable quality and failure.
Constellation diagrams are an indispensable tool
to help detect the presence of noise, phase jitter,
interference, and gain compression, all of which
impact overall signal quality and thus reduce
Modulation Error Ratio (MER).