Measuring Ber Of Qpsk Digital Channels Dvb-S (Qpsk) - Promax PROLINK-4/4C Premium Manual De Instrucciones

DVB-T channels tuning may require an adjusting process. It is recommended to follow
next procedure:
1.- From the spectrum analyser mode, tune the channel at its central
frequency.
2.- Switch to TV mode, BER measuring mode.
3.- If in the lower line of the screen does not appear MPEG-2 message (and
consequently BER is unacceptable), by turning the rotary selector deviate
the tuning frequency until MPEG-2 message appears. Finally tune channel
again to minimize the frequency deviation which optimizes the BER and
therefore minimize the BER.
If it is not possible to detect any MPEG-2 channel, make sure that digital signal
parameters are correctly defined and if signal level is too low, check that the 40 dB
attenuator is not activated (Attenuator 0 dB).

4.9.1.5.3 Measuring BER of QPSK Digital Channels DVB-S (QPSK)

Press the rotary selector to access the QPSK signals parameters that must be
defined by user and that are described below:
1) Symbol Rate
It is possible to choose between the following values : 30000, 27500, 22000,
20000, 19995, 6110, 6000, 5998, 5632, 5062, 4340, 4000 kbauds, or well to
define any other value (Other).
When selecting the Other option, a screen titled QPSK SYMBOL RATE will
appear. This screen shows present value, to modify it press key
the new value through the keyboard. The unit accepts any number with 5 figures
between 2000 and 35000 kbauds (fifth figure acts as validation). For example, to
select a symbol rate of 8200 kbauds it must be entered : 08200.
2) Code Rate
Also known as Viterbi ratio. It defines the ratio between the number of data bits
and actual transmission bits (the difference corresponds to the control bits for
error detection and correction).
It permits to choose between 1/2, 2/3, 3/4, 5/6, 7/8 and Auto. If Code Rate
parameter is not known it is possible to assign the Auto option.
3) Spectral Inv.
If necessary, activate the Spectral inversion. Reception will be bad if spectral
inversion has been incorrectly selected.
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USER'S MANUAL. PROLINK-4/4C
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