System Description Chapter 2

10-kW UHF Transmitter with Chapter 2, System Description
Feedforward Driver
840A, Rev. 0 2-9
METER FUNCTION
Reads power in terms of a percent of the calibrated power value (a
full-scale reading will be 100%)
With Switch S4 in
Position
Display
Switch (S4), Power Meter
Selects the desired visual output
power, aural output
power and the reflected
output power readings
Visual Output
Reads the visual output power of the
10-kW amplifier (100%)
Aural Output
Reads the aural output power of the
10-kW amplifier (100%)
Power Meter
(M3)
Reflected
Reads the reflected visual output
power from the 10-kW amplifier
(<10%)
Table 2-11. 10-kW Amplifier Assembly Switches
SWITCH FUNCTION
Meter Polarity (S3)
Changes the polarity of the measured
current applied to the meter. To properly
read the plate I and screen I, the meter
polarity switch must be in the Up (+)
position to give an upscale reading. To read
the control grid I properly, the switch must
be in the Down (-) position. The normal
setting of the meter reverse switch is the
Up position.
Transmitter (S5)
The momentary switch (S5) applies a
ground to K3, a latching Operate/Standby
relay on (A7) the transmitter control board.
K3 switches either to Operate or to Standby
depending on which direction S5 is pushed.
When S5 is switched to Operate, a low
Operate (Enable) command is applied to
(A1) the control logic board to start the
automatic turn-on procedure for the 10-kW
transmitter. The opposite occurs when S5 is
switched to Standby.
Mode Select (S6)
The momentary switch (S6) applies a
ground to K1, a latching Auto/Manual relay
on (A7) the transmitter control board. K1
switches the transmitter to Automatic or
Manual depending on which direction S6 is
pushed. In Automatic, a video fault
command from the upconverter tray
controls the transmitter. The transmitter
switches to Standby if the video input is lost
and will switch to Operate when the video is
reapplied. In Manual, the transmitter is
controlled through the normal automatic