Promax PROLINK-4/4C Premium Manual De Instrucciones página 191

USER'S MANUAL. PROLINK-4/4C
In the following figures several Constellation Diagrams are shown as an example
corresponding to differents common deteriorations in the digital transmission.
QAM
64 QAM
6875 kSymb
400.00 Mhz
MER= 23.5
BER= 4.4E-4
Figure 25.- Constellation Diagram of a
signal with noise.
QAM
64 QAM
6875 kSymb
400.00 Mhz
MER= 19.5
BER= 1.0E-2
Figure 27.- Signal with noise and levels IQ
nonbalanced.
Such effects can induce to errors in the detection process and cause erroneous
bits on recovered digital signal.
The PROLINK-4/4C
extend the presentation to only a quadrant between four available ones. Press the key
repeatedly to change of quadrant and to switch on or off the zoom function. It
allows so, a more detailed analysis of the observable effects and facilitates therefore
the accurate diagnosis about causes or agents responsible for the digital signal
deterioration (see figure 29).
REMARK: In the equipments with colour screen (PROLINK-4C Premium) one
visualizes qualitatively, by means of a colour gradation, the density of
symbols that are concentrated in a certain area. This scale of colours
goes from black (absence of symbols) to the red one (maximum density),
runing through blue and yellow (in ascending order).
06/2005
Premium
QAM
64 QAM
6875 kSyimb
400.00 Mhz
MER= 23.5
BER= 4.4E-4
Figure 26.- Signal showing nonbalanced
QAM
64 QAM
6875 kSymb
400.00 Mhz
MER= 19.5
BER= 1.0E-2
Figure 28.- Signal with phase error.
Premium incorporates in addition, the ZOOM function to
IQ levels.
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