Alcad 905-TO Series, Руководство пользователя, Страница: 36 / 67

9. ADJUSTMENT OF LEVELS
9.1 Verifying the TO modules
Check that the IN digital channel hook-up indicator (21), the 'correct MPEG
transmodulation' indicator (28) and the 'correct HF output channel'
indicator (29) on the transmodulators are activated.
9.2 Levels of the TO 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 TO module furthest from the amplifier and verify
that the output level of the TO module is at -0 dB. Tune each of the
remaining TO and adjust the output level of each TO module until reaching
the same level as that in the TO module, which is furthest from the amplifier.
Fig. 10 - Adjusting the levels of the modules
We recommend programming the lowest output frequencies in the TO
modules furthest from the amplifier, and successively programme higher
output frequencies. This achieves the best width-frequency response for the
TO 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.
ENG - 35 Serie 905-TO
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