Adjustment Of Levels - Alcad 912-TP Série Manuel D'installation Et Programmation

38 - ENG
9.

ADJUSTMENT OF LEVELS

9.1 Verifying the TP modules
Check that the INPUT satellite transponder hook-up indicator (22), the
'correct MPEG transmodulation' indicator (28) and the 'correct HF output
channel' indicator (29) on the transmodulators are activated.
9.2 Levels of the TP modules
Connect a field measurer to the TEST connector of the PA amplifier, and
verify that the output of said amplifier is charged using a distribution cable
or with a 75 Ω charge, of the RS-275 (cod. 9120011) type. Tune the output
channel measurer of the TP module furthest from the amplifier and verify that
the output level of the TP module is at -0 dB. Tune each of the remaining TP
and adjust the output level of each TP module until reaching the same level
as that in the TP module, which is furthest from the amplifier.
We recommend programming the lowest output frequencies in the
modules furthest from the amplifier, and successively programme higher
output frequencies. This achieves the best width-frequency response for the
TP module.
9.3 Level of the PA amplifier
Connect the field measurer to the TEST connector of the amplifier and verify
that the output of said amplifier is charged using a distribution cable or with
a 75 Ω charge, of the RS-275 (cod. 9120011) type. Tune the measurer to
the highest output channel and adjust the RF output signal level using the
regulator of the PA amplifier, taking into account that the TEST tap is at -30
dB.
Installation and programming manual
Fig. 13 - Adjusting the levels of the modules
OUT
TEST
EXT
TP