User's Manual

Innovator CU5-1800BTD/BRD ATSC Transmitter/ Board Descriptions
Regenerative Translator
Instruction Manual, Rev. 0 55
TP1 is equal to a 100% Forward Power reading on the meter. The SYS_FWD level
connects to J9 on the board that is cabled to J11 on the exciter/driver tray for use in the
control monitoring assembly. The RMT_FWD level connects to J10 on the board for use by
remote control and monitoring.
A sample of the reflected output power, from the external (A11) output coupler, enters
the board at the SMA jack J8. The signal is filtered and connected to resistors R26, R22
and R27 that form an input impedance-matching network to Pin 3 on U6. The reflected
power signal is detected by the RF detector IC U6. The detected output at pin 7 is
connected to the reflected calibration pot R25, which adjusts the level of the signal
connected to the amplifier IC U3B that is wired to the SYS_RFLD and RMT_RFLD Power
Metering Outputs. A reading of 2 VDC measured at TP2 is equal to a 25% Reflected
Power reading on the meter. The SYS_RFLD level connects to J9 on the board that is
cabled to J11 on the exciter/driver tray for use in the control monitoring assembly. The
RMT_RFLD level connects to J10 on the board for use by remote control and monitoring.
+12 VDC enters the board at J9-1, from the exciter/driver tray and is connected through a
filter and isolation circuit consisting of C31, C14 and L5 before it is connected to the
regulator IC U5. U5 supplies the +5 VDC needed for operation of the ICs on the board.
The +5 VDC is connected through a filter circuit consisting of C15, C19 and C21 before it
is connected to the rest of the board.
Circuit Descriptions of Boards in the CU250, 250 Watt and CU500, 500 Watt
ATSC Amplifier Trays
(A7) Amplifier Control Board (1312260)
The Amplifier Control Board uses a Programmable logic device to control the amplifier
tray. It takes an enable signal from an external driver tray, and turns the power
supplies on whenever the driver has told it to turn on, unless it detects faults internal to
the tray. The board monitors the forward and reflected power, the heatsink
temperature, the pallet currents, and the power supply voltage and will generate alarm
signals if any of those parameters exceed safe limits. The amplifier tray has no front
panel display other than a two LEDs, one for Status and one for Enable. The board
sends all its output information, including the forward and reflected levels, back to the
driver tray, through J4, so the information can be displayed on that tray's LCD Display.
The board will generate a Red Blinking Status LED if it detects an alarm, fault, prompting
the operator to look at the LCD display on the driver tray to see what fault has occurred.
The +5 VDC inputs to this board are routed through J4 and J5. The +5 VDC inputs are
diode Or connected so that either the +5VDC from the (A8) power supply or the +5VDC
from the (A9) power supply will operate the board. The +5VDC is split with one output
connected to U1 a voltage regulator IC, which provides +5V and +5V_ANALOG as
outputs. The +5 VDC is filtered before being connected to the rest of the board. The
other +5 VDC output is connected to the regulator IC U2 that supplies +3.3 V to the
microcontroller and programmable logic array.
(A10) Current Metering Board (1309130)
The current metering board measures the current into the RF output amplifier pallets
and supplies this value to the control board. In the CU500 amplifier tray, there are four
sensing circuits which are used. Each circuit has two parallel .01Ω series current