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4.3.7 CONSTELLATION measurement mode
This measurement mode is selected from MER/BER mode by pressing F2 key. This mode displays DVB-
T channel constellation diagram. See Figure 4.3.13:
On the screen you will see the following data:
1 – channel number
2 – quadrant marker
3 – channel name (when working with selected channel plan)
4 – demodulator status
5 – MER value in dB
6 – preBER value
7 – postBER value
8 – diagram zoom scale choosing key
When there is not sinchonization with the channel, constellation diagram is empty. After sinchronization
is being achieved quadrature modulation points is displayed on the diagram. For example, for QAM64
subcarrier modulation 64 points of data subcarriers and 4 points of pilot subcarriers will be displayed. View of
constellation diagram allows to determine distortion behavior in the channel.
MER, preBER and postBER measurement values are displayed in positions 5, 6 and 7.
With
,
, ◄ , and ► keys you can choose diagram quadrant for being zoomed. Choosed quadrant is
marked with the arrow (position 2). For activating zoomed view mode press F3 button. Press F3 button once
again to return to native view mode.
Press
key to return to MER/BER measurement mode (Section 4.3.6).
4.4
Data manager
4.4.1 General information
Data manager provides automation of measurement and result recording procedures. The Analyzer
offers two tools: Channel plan manager and Data log manager. The memory capacity allows you to save up
to 16 channel plans (up to 112 channels per plan), and up to 130 data log pages (with maximum number of
channels). The IT-14 allows you to view the saved data in stand-alone mode or by means of a computer.
4.4.2 Channel plan manager
The
icon in the data manager menu refers to this mode. The mode allows you to perform all the
operations with channel plans (viewing, editing, deleting, and creating channel plans). The screen view is
represented in the Figure 4.4.1.
On the screen you will see the following data:
Figure 4.3.13
Figure 4.4.1
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