Operation
Terminate TWTA RF input and output. Connect external Interface as desired. Apply prime power.
Caution: The TWTA must never be placed in Operate without proper RF termination. This can lead
to TWT oscillations which can permanently damage the TWT.
Power TWTA On:
Press t e manual WARM UP button to power t e TWTA. T e manual WARM UP button will
illuminate. Front panel display will s ow “Warm up” and t e remaining warm-up time in t e status
area.
At initial power-up, eater voltage will be less t an nominal to limit excessive current drawn by a cold
filament. As t e filament warms it will draw less current and t e filament voltage will increase until
nominal voltage is reac ed. Negative Bias voltage is applied to t e Grid. Body and Collector supplies
are off. T e standard warm-up period is 5 minutes.
Standby from Warm-up:
After t e warm-up period as elapsed t e TWTA is placed in STANDBY by t e main microprocessor.
Hig voltage supplies and Grid voltage remain unc anged from t e WARM UP state. T e manual
STANDBY button is illuminated and t e WARM UP/OFF button is extinguis ed. T e front panel
display will indicate “Standby” on t e status area. T e TWTA can be now placed in OPERATE.
Operate:
Press t e OPERATE button to place t e TWTA in OPERATE state or send t e OPERATE command
from t e remote computer. T e OPERATE button is illuminated and t e STANDBY button is
extinguis ed. T e front panel display will indicate “Operate” on t e status bar and t e background
color will c ange to green.
T e Main microprocessor engages t e Collector voltage soon after t e OPERATE command is received
and t e Body voltage 500 ms after t e Collector voltage stabilizes. T en it waits up to 3 seconds for t e
Collector voltage to stabilize before going to OPERATE. Bot STANDBY and OPERATE buttons are
illuminated during t e Hig Voltage on sequence. T e amplifier goes to RESET if t e voltages don’t
reac t e nominal values wit in allowed time. 8 s after t e ig voltages ave reac ed t eir nominal
values, pulses are passed unaltered to t e Floating Deck w ere t ey are subject to PRF (Pulse
Frequency) and PW (Pulse Widt ) limiting. T e TWT beam current will be present wit in up to 13.5 s
after t e TWTA OPERATE command is sent.
If RF and video pulses (pulsed units) are supplied, t e TWTA will produce an amplified RF output.
Standby from Operate:
W en placed in STANDBY by user command, t e main processor sequentially interrupts video pulses
to t e Floating Deck, disengages t e Body and Collector supplies and returns t e TWTA to STANDBY.
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