NEC DTU-70, Инструкция по эксплуатации

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GWP-G22996
2 - 1
SECTION. 2 GENERAL INFORMATION
2-1 Scope
This instruction manual contains information on the operation and maintenance of the
DTU-70D series UHF DIGITAL TV transmitter, including information on the separately
installed equipments of the Water pump for cooling.
Information for each units used in this transmitter should be referred to the each of unit
instruction manuals.
2-2 General
The DTU-70D series UHF DIGITAL TV Transmitter is the latest UHF DIGITAL TV
transmitter used for TV broadcasting.
The major features are as follows.
(1) Doherty-Technology Amplifier
The amplifiers of this transmitter, consisted of main amplifier and peak amplifier called
Doherty amplifier, only are applicable to the single channel. Thus, this technology
contributes to more than 18% efficiency improvement from conventional model. In
case of frequency change, implement with replacement of a few parts helps operators
to reduce time needed to frequency change.
(2) Voltage control in the amplifier to improve power efficiency
In case of wide band configuration voltage control to the power transistors in the
amplifiers via TX control allows transmitter efficiency to be optimized in wide band
operation. This voltage control significantly improves efficiency, especially when a
transmitter is operated at reduced output power.
(3) High-Efficiency and easily handling Cooling System
The liquid cooling system features a jet liquid cooling system which provides an
extremely high-efficiency liquid flow, and employs a hybrid closed circuit that takes
advantage of both open and closed circuits. Compared with the conventional closed
circuit, our circuit has the following advantages: