System Description Chapter 2

10-kW UHF Transmitter with Chapter 2, System Description
Feedforward Driver
840A, Rev. 0 2-6
Table 2-5. UHF Exciter Tray Samples
SAMPLE DESCRIPTION
f(IF)
A sample of the visual IF that is taken from
the sample jack on the IF carrier oven
oscillator board
f(IC)
A sample of the intercarrier signal that is
taken from the sample jack on the aural IF
synthesizer board
f(s)
A sample of the channel oscillator output
that is taken from the sample jack of the
channel oscillator assembly
Exciter O/P
An output power sample of the exciter that
is taken from the UHF upconverter board
2.2.2 3-Watt Amplifier Tray
Table 2-6. 3-Watt Amplifier Tray Meter
METER
FUNCTION
Selects whether the % Reflected Power, % Input Power, %
Forward Power, power supply voltage, or AGC voltage is to be
viewed on the meter
With Switch S1 in position Display
% Refl (Reflected)
Reads the % Reflected Output
Power (<10%)
% Input
Reads the % Input Power to
the tray (10%)
% Forward Power
Reads the % Forward Power
(100%=3 watts CW)
P.S. Voltage
Reads the power supply
voltage (+24 VDC)
Power Meter, Switch
(S1)
AGC Voltage
Reads the AGC voltage
(2 VDC)
Table 2-7. 3-Watt Amplifier Tray Fault Indicators
FAULT INDICATOR FUNCTION
Overtemp (DS1)
Indicates that the temperature of the
heatsink, where the Q1 and Q2 current-
pass transistors for the +24 VDC power
supply are mounted, is above 175° F as
sensed by the thermal switch (S2) mounted
to the heatsink. When this fault occurs, the
Enable to the isolation relay is removed
immediately.
AGC Override (DS2)
Indicates that the level out of the 3-watt
amplifier board has requested the AGC
circuit to exceed the AGC limits. The fault is
generated on the AGC board in the 3-watt
amplifier tray.