User's Manual

Innovator CU0TD-1/CU0RD-1 – CU4TD/CU4RD System Description
ATSC Transmitter/Regenerative Translator
Instruction Manual, Rev. 2 17
The CU1TD/RD-3, 750 Watt ATSC system is made up of a CX driver drawer and a 750
Watt amplifier drawer. The output of the driver drawer connects to the amplifier drawer
and supplies the needed drive level to produce the 750 Watts output of the system. The
control and operating parameters of the amplifier drawer are displayed on the LCD
Screen on the driver drawer. In the amplifier drawer the input RF signal at J1, located
on the rear panel of the drawer, is fed to J1 on the 4 Way Splitter Board, which supplies
four outputs, one to each 888A amplifier pallet. Each amplifier pallet has approximately
15 dB gain. The amplified outputs of the pallets are combined in the 4 Way combiner
board whose output is at J1.
The RF is connected to J2 the 7/16” (1.1cm) Din RF output jack located on the rear
panel of the drawer. The 4 way combiner board supplies a forward and a reflected
power sample to the amplifier control board for metering and monitoring purposes. The
typical sample value at J6, a 50Ω BNC jack located on the front panel of the drawer, is
approximately 65dB down from the output power level of the drawer.
In higher power systems, multiple amplifier drawers are used along with splitters and
combiners to produce the desired output. A System Metering Board (1312666) provides
forward, reflected, over-temperature and other parameters to the exciter/driver drawer
from the external power amplifier chain.
The CU2TD/RD is made up of a driver drawer, a two way splitter, two amplifier drawers
and a two way combiner with a reject load. The reject load provides isolation protection
of the operating power amplifier if the other amplifier fails. One–half the power of the
operating amplifier drawer connected to the combiner will be dissipated by the reject
load with the other half of the power going to the output filters and the antenna.
The CU3TD/RD is made up of a driver drawer, a three way splitter, three amplifier
drawers and a three way combiner with reject load.
The CU4TD/RD is made up of a driver drawer, a four way splitter, four amplifier drawers
and a four way combiner with reject load. The reject loads in the multi-amplifier
systems have thermal switches connected to them which monitor the temperature of the
load and provide the over-temperature fault, if it occurs, through the system metering
board to the exciter/driver drawer.
The On Channel RF output of the amplifier drawer either connects directly to the digital
mask filter and low pass filter and then to the antenna in single amplifier systems or to a
combiner, the digital mask filter, low pass filter, output coupler and finally to the
antenna in multiple amplifier systems. The output coupler provides a forward and a
reflected power sample to the system metering board which detects the samples and
supplies the forward and reflected power levels to the exciter/driver drawer for use in
the metering circuits.