Axcera DT325B, Инструкция по эксплуатации

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350-Watt Digital VHF LB Transmitter Chapter 4, Circuit Descriptions
DT325B, Rev. 0 4-11
output of U2D is connected to J5-1, DC
O/P 1.
The second RF sample input enters the
board at the RF I/P 2 SMA jack J2.
Resistors R22, R17 and R23 form a 50O
input impedance matching circuit. The
sample is connected to a detector circuit
made up of CR3, R24 C8, R42, and C9.
For digital operation the jumpers, W2 on
J6 and W5 on J9, are both between pins
1 & 2. The detected output is buffered
by the operational amplifier U1B and
then connected to RF I/P 2 power adjust
pot R26, which adjusts the gain of U2B.
The output of U2B is split and connected
to J5-2 and J5-3, DC O/P 2.
The third RF sample input enters the
board at the RF I/P 3 SMA jack J3.
Resistors R34, R29 and R35 form a 50O
input impedance matching circuit. The
sample is connected to a detector circuit
made up of CR5, R36, C11, R43, and
C13. For digital operation the jumpers,
W3 on J7 and W6 on J10, are both
between pins 1 & 2. The detected output
is buffered by the operational amplifier
U1C and then connected to RF I/P 3
power adjust pot R38, which adjusts the
gain of U2C. The output of U2C is split
and connected to J5-6 and J5-5, DC O/P
3.
The +12 VDC needed for the operation of
Op Amps U1 and U2 enters the board at J5-10. The voltage is connected through
a filter and isolation circuit consisting of
L2, C10, and C15 before it is distributed
to the rest of the board.
4.3.2 (K1) Isolation Relay Board
(1002-1108; Appendix A)
The Isolation Relay Board is located on
the inside right side panel of the cabinet.
The Isolation Relay Board when
energized supplies the enable to the VHF
amplifier tray.
The +12 VDC from the Driver/
Amplifier Chassis Assembly is connected
to the board at J1-1, one side of the
energizing coil. -12 VDC from the
Driver/Amplifier is connected to J2-1
which is the NC contacts of the relay. J2-
4 which is the other contact of the NC
connection is not used in this
configuration.
When the Driver/Amplifier Chassis
Assembly is switched to Operate, an
Enable, ground, is applied to J1-2, which
energizes the relay. The contacts of the
relay close which connects J2-2 to J2-1
that applies the -12 VDC, Enable, to the
VHF Amplifier Tray. The opposite occurs
when the On Air Driver/Amplifier Chassis
Assembly is switched to Standby.
This completes the circuit description of
the boards that make up the DT325B.