System Description Chapter 2

10-kW UHF Transmitter with Chapter 2, System Description
Feedforward Driver
840A, Rev. 0 2-4
output metering. It also contains (A2) a
visual/aural metering board (1161-1103
or 1161-1115) for aural output and visual
output power levels and reflected power
levels for VSWR protection.
2.2 Control and Status
Information on the control and status of
this system is provided by control,
status, and LED indicators and meters on
the front panel of the trays. The functions
of these control and status indicators are
described in the following tables.
2.2.1 Exciter/Driver Cabinet
2.2.1.1 UHF Exciter Tray
Table 2-2. UHF Exciter Tray Meters
METER FUNCTION
Reads power in terms of a percentage of the calibrated output
power level on the upper scale. The voltage level or frequency
level is read on one of the two bottom scales. A full-scale
reading on the top scale is 120%; 100% is equivalent to the
full-rated 350 watts peak of sync visual. This meter also reads
% Aural Power, % Exciter Power, audio levels, video levels, and
ALC levels.
With Switch S3 in
Position
Display
Switch (S3), Meter
Selects the desired ALC voltage
reading, % Exciter Power, % Visual
Power, % Aural Power, video levels, or
audio levels.
Audio
Reads the audio level, ±25 kHz
balanced or ±75 kHz composite, on
the 0 to10 (0 to100 kHz) scale.
Indicates baseband audio if it is
connected to the transmitter and even
with the video + 4.5 MHz SCA input
selected.
ALC
(0 to 10 V)
Reads the ALC voltage level, .85
VDC, on the 0 to10 scale
% Exciter
(0 to 120)
Reads the % Exciter Output Power
level needed to attain 100% output of
the transmitter on the top scale
% Aural Power
(0 to 120)
Reads the % Aural Output Power of
the exciter/driver assembly
(100%=45 watts at 10 dB A/V ratio)
on the top scale
% Visual Power
(0-120)
Reads the % Output Power of the
exciter/driver assembly (100%=450
watts peak sync) on the top scale
Meter (A4-A18)
Video
(0-1V)
Reads the video level, 1V at white, on
the 0-10 scale