User's Manual

Innovator CU5-1800BTD/BRD ATSC Transmitter/ Board Descriptions
Regenerative Translator
Instruction Manual, Rev. 0 56
sensing resistors and a differential input IC that supplies a voltage output that is
proportional to the current for metering purposes. The +42VDC from the (A8) power
supply connects to TB2 and TB4 on the board. The +42VDC from the (A9) power supply
connects to TB8 and TB10 on the board. The +42VDC input at the TB2 input senses the
current to the (A1) 878 output amplifier pallet through TB1 on the board. The +42VDC
input at the TB4 input senses the current to the (A2) 878 output amplifier pallet through
TB3 on the board. The +42VDC input at the TB8 input senses the current to the (A3)
878 output amplifier pallet through TB7 on the board. The +42VDC input at the TB10
input senses the current to the (A4) 878 output amplifier pallet through TB9 on the
board.
The four sensing circuits are identical only one will be described. For the (A1) 878
amplifier pallet, the +42VDC from the (A8) switching power supply connects to TB2. R1
and R2 are the parallel .01Ω current sensing resistors which supplies the voltage values
to the U1 current sense amplifier IC. R11 is a gain adjust, which is adjusted to eliminate
any rSense Error and to place the OpAmp output at 2.61V for 40Amps sense as
measured at TP3. The current sense output at J1-1 connects to the (A7) control board
for metering purposes.
(A5) 4 Way Splitter Board (1308933)
The 4 way splitter board takes the RF Input at J1 (≈11Watts ATSC) on the board and
splits it into four equal outputs (≈4.75Watts ATSC) that connect to the inputs of the four
878 amplifier pallets at J1.
(A1-A4) 878 Amplifier Pallets (1310138)
There are four 878 Amplifier Pallets mounted on the 500 Watt Amplifier Heatsink
Assembly. Each of the 878 pallets has approximately +16dB of gain for the UHF
frequency range of 470 to 860 MHz. The pallets operate Class AB and generate 150
Watts ATSC with an input of 4.75 Watts ATSC.
(A6) 4 Way Combiner Board (1312368)
The 4 way combiner board takes the four RF Inputs at J4, J5, J6 & J7 (≈150Watts ATSC)
on the board and combines them to a single output (≈500Watts) at J1 that connects to
J2 the 7/16” (1.1cm) Din RF output jack of the tray.
(A8 & A9) 250 Watt and 500 Watt Amplifier Tray Power Supplies
The 230VAC, needed to operate the tray, connects through the AC power cord at J3, the
power entry module located on the rear panel of the tray. In the 500W amplifier tray,
there are two On/Off 20A/250VAC circuit breakers that are mounted on the back panel
of the tray on either side of J3 the AC input jack. The AC lines are connected to a
terminal block TB1. With the circuit breakers switched On, the AC is distributed to the
two (A8 and A9) DC power supplies. TB1 has three varistors (VR1-VR3) connected
across the AC input lines for surge and over voltage protection. The AC input from TB1
also connects to through 2 amp fuses to the two fans (A11 & A12) mounted in the tray.
Both fans will run immediately when AC is applied to the tray.
The +5VDC for the operation of the amplifier control board in the tray is generated by
the (A8 & A9) power supplies at J1-9 on each power supply. The +5VDC from the (A8)
power supply connects to J4-8 and the +5VDC from the (A9) power supply connects to