3.3.3.2.2.4.3.- QPSK
(only the satellite band)
This function measures the BER of a digital signal with QPSK modulation. The information
window is exactly the same as the window for the QAM and COFDM modulations. The
submenu is the following:
Figure 85.-
QPSK measurements
If you do not dispose of the MER option, onscreen you will see the MER text "Option”.
3.3.3.2.2.4.3.1.- Parameters
The parameters that can be selected for a QPSK signal are the following: Symbol Rate (
27500
,
24500
,
22000
,
15000
,
OTHER
), Code (
Auto
,
2/3
,
3/4
,
5/6
,
7/8
,
1/2
), and Spectrum Inversion
(
ON
,
OFF
,
AUTO
). The parameters are selected in the same way as with the previous functions.
3.3.3.2.2.4.3.2.- Error packets
The window that opens when this function is selected and the information that is displayed is
exactly the same as with the COFDM modulation.
This function is very useful when identifying problems in an installation, which a certain
measurement at a specific time has not been able to detect.
3.3.3.2.2.4.3.3.- BER
When this function is selected, the error packet window closes and the BER measurement
window appears again.
It is very important to take into account that the CBER parameter determines quite clearly
the quality of the installation. This is why we have simplified the interpretation of this
parameter with these colours. The VBER is a parameter that has practically only got two
states, either very good or very bad, which makes it difficult to use to appropriately
evaluate the installation. This is why we recommend using the CBER status to assess the
quality of the installation (it should be a small as possible).
3.3.3.2.2.4.3.4.- MPEG
With this option, the MPEG mode of a QPSK channel is enabled. The functions in the same way
as in QAM and COFDM.
3.3.3.2.2.4.3.1
3.3.3.2.2.4.3.2
3.3.3.2.2.4.3.3
3.3.3.2.2.4.3.4
Multimetter FSM 500
Ref. 5903
72
