Constellation - Televes H30+ Manual

H30+ H30D+ - CATV & DOCSIS 3.1 Meter /Analyzer
Selected channel
User can change it using
Change using
List of
measurements
with pass/fail
indicators
5.2. Setup
Press to change Spectrum options.
- Ter. Plan: Selects the channel plan
- Aim antenna: Emits a modular audible signal
with frequency directly proportional to signal level
in the spectrum trace relative to reference level. It is
recommended to set the reference level manually,
as well as to select the span to include a frequency
range wide enough.
The audible signal becomes continuous when the
signal leves is close to the reference level.
Then it is necessary to increase the reference level
to get a more accurate adjustment.
Span
(+)
or (-)
Reference level
(Auto)
This is a useful feature to point antennas without
having to look at the display.
- Span: 2.5MHz, 6.25MHz, 12.5MHz, 25MHz,
62.5MHz, 125MHz, 250MHz, 500MHz, Full.
Set the span of the spectrum. To easily change the
span, use the OK Button to decrease the span and
the Back Button to increase the span.
- Ref. Level: Select the reference level of the
spectrum graph
- Tuning: Channel, Frequency
- A/D: Auto, Analog, Digital.
- dB/div: 5 dB/div, 10 dB/div
- C/N: ON, OFF. Shows/Hides the C/N measure.
- Hold mode: ON, OFF. Shows/Hides the maximum
graph.
- Save datalog: Saves
measurements. You can see the datalogs using
the remote control application.

6. 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).
Ideally, each of the symbols in a constellation
diagram should display a clean dot indicating a
perfect QAM signal.
The H30+/D+/D+Adv's 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
6.1. Main window
Below is a capture of a Constellation window with
a brief explanation of its features:
the current scan
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