User's Manual

PINEAPPLE TECHNOLOGY, INC.
UTX2.5K ULTRA Operating and Service Manual
V -- THEORY OF OPERATION
(CONTINUED) (Page 4 of 5)
F. MA5000 MODULATO
R
The heart of any TV Transmitter is the MODULATOR. This equipment receives the video and audio
signals was well as any control signals needed. The base band signals are converted to RF with
an output on the desired operating channel.
Detail operation of the Modulator with schematics and parts list are provided by the equipment
manufacturer and included in the UTX2.5K ULTRA package shipped with the transmitter.
REFER TO INSTRUCTION MANUAL PROVIDED WITH THIS PACKAGE.
G. UDR100AC 100 WATT DRIVER AMPLIFIER
The RF output from the MA1000 modulator is accepted by the UDR100AC DRIVER AMPLIFIER.
This amplifier increases the drive level to that required for each of the PAK1 power amplifiers
to make rated power. The UDR100AC is powered by 110 VAC.
H. US200-3 3-WAY SPLITTER
The US200-3 3-Way Splitter receives the output from the UDR100AC Driver Amplifier
and splits it into 3 parts with phase and power levels equal. This unit is an isolated
in-phase splitter and will provide some isolation in the event one PA fails.
SEE SECTION VI.F FOR PARTS LIS
T
I. MFA2PA POWER AMPLIFIER HOUSING
The MFA2PA is the main RF Power Amplifier housing which accommodates two (2) PA1K
A
mplifiers. The housing includes the following:
2 each 330 CFM cooling fans
2 each
A
ir filter assemblies
2 each Front panel status PC boards
1 each
Main chassis
2 each Mechanical slide assemblies
1 each
A
C Filtered inlet for cooling fans
SEE SECTION Vl.D FOR SCHEMATICS AND PARTS LIS
T
I-1. PA1K POWER AMPLIFIER
The PA1K is the main RF Power Amplifier Assembly used in the UTX2.5K ULTRA.
Each amplifier assembly is made up of one (1) U250LD power pallet and two (2) U500LDA power
pallets. These amplifiers are operated in Class A/AB or sometimes referred to as "HARD AB". This
refers to the bias levels to achieve best linerarity.
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