5.5 Power Amplifier (PA)
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5.5.5 TX FIL board (05P0736)
The TX FIL board, consisting of L.P.Fs, eliminates and suppresses the higher harmonics
included in the signal from PA board. The insertion loss is -0.5 dB or less.
T1 and T2, placed in the input and output circuits of the L.P.F, are VSWR detectors. At
self-test, the CPU decides that TX FIL board is normal if detectors detect the forward
signal. The signal detected by T2 is also used to generate Automatic Level Control
(ALC) signal. The ALC signal is sent to “POWER CONT“ circuit on TX/RX board.
The T-CPU does not use ALC signal received. R76 adjusts output power.
Fig.5.5.7 Block diagram of TX FIL board
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