Operation Manual Part 3

Digital Liquid Cooled UHF
TV Equipment
Description / Test points / Location of units
9946 V1
45321648.01 104 A E
preliminary
103 / 131
Numéro / Number Doc. Rev. Lan
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u.
16/06/2006
Pa
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Information contained is this document is confidential, is THOMSON property and cannot be disclosed in whatever form without prior written authorization of THOMSON.
• the sensors,
• the hydraulic cabinet.
The multiplex card is connected to the Central Processing Unit by a multiplexed bus; seven users
can be connected in parallel across this bus (the group of sensors + 5 PS/amplifiers +1 hydraulic
ports).
♦ transmission of AGC voltages from the power amplifiers to the exciter cards,
All AGC voltages from the amplifiers are applied to an "OR" logic gate. This "OR" gate on the
multiplex card extracts the largest of these AGC voltages. This voltage is used to control the power
delivered by the power amplifiers,
On transmitter with “separate channel” amplification, it excites an AGC vision separate loop and an
AGC sound loop.
♦ transmission of black/white voltage from video treatment card + Fl, from exciter plugged on the
antenna to the power amplifiers.
♦ detection and presence signals for the power supplies to the power amplifiers,
♦ switching on and switching off the amplifier power supplies in addition to switching on and off the
cooling system through a loop protection system,
♦ selection of equipment starting steps order: dependent on cooling (air or liquid),
♦ in case of several multiplex boards (2 or 3): the +5V_DC power supply redundancy is made by the
converter of one of the additional multiplex boards.
Switching on-air and switching off-air
The switching on and off of the amplifier power supplies and of the cooling system is controlled by the
position of the by-stable relay K1. The starting steps order depend on cooling.
♦ Air cooling:
• The closing of this contact by activating the "ON" command enables the transmission of the
+5 V voltage supply to the loop protection system and if this is closed the amplifier power
supplies are switched on. This ON condition is detected by an analogue "OR" circuit on the
multiplex card which triggers the start-up of the cooling system.