User's Manual

Innovator CU0TD-1/CU0RD-1 – CU4TD/CU4RD Board Descriptions
ATSC Transmitter/Regenerative Translator
Instruction Manual, Rev. 1 65
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 external ATSC Amplifier Drawers
(A7) Amplifier Control Board (1315011 or 1312260)
Amplifier Control Board
The Amplifier Control Board is mounted in the top front facing the rear of the Amplifier
Drawer as shown above.
The Amplifier Control Board uses a Programmable logic device, U12, to control the
amplifier drawer. It takes an enable signal from an external driver drawer, and turns
the power supplies on whenever the driver has told it to turn on, unless it detects faults
internal to the drawer. 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
drawer 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 drawer, through J4, so the information can be displayed on
that drawer'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
drawer to see what fault has occurred.
A CUB transmitter System can have up to 4 external amplifier drawers and since they
are all the same, without differences in the wiring harness, there needs to be a way to
identify which amplifier drawer is which. The rotary switch SW1 is used to specify the
amplifier ID number which generates a unique serial address so that the individual
amplifier drawers will respond when polled for information.
The +5 VDC inputs to this board are routed through J4-8 and J5-8. 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 single pallet amplifier drawer, there
are two sensing circuits which are used. In the multiple pallet amplifier drawer, there
are four sensing circuits which are used. Each circuit has two parallel .01Ω series
current 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
SW1