TEX2503TFT
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User Manual
Rev. 1.0 - 04/12/20
The amplification stage consists of two main blocks:
•
Amplification stage;
•
Low-pass filter, which also includes the power meter.
In this block there is an RF pickup at approximately -46dB (for the
TEX2503TFT
model) with respect to the output available on a BNC connector below the
transmitter output connector. This pickup is used to assess the characteristics of
the carrier, but not those of the upper harmonics.
7.6 Bias Board
The main functions of this board are:
•
Control of the output power level according to the setting
•
Reduction of the power delivered in the presence of high levels of reflected
power
•
Measurement of the current absorbed by the power amplifier
•
Temperature measurement
In the absence of alarm conditions, the voltage is regulated only according to the
set output power controlled by the automatic levelling control (ALC).
Voltage is also affected by other factors, i.e.:
•
Excess of reflected power.
•
External AGC signals (Ext. AGC FWD, Ext. AGC RFL).
•
Over-temperature.
•
Excess current drawn by the RF module.
7.7 Driver Board
Before passing to the final power amplifier, the RF signal is pre-amplified in this
section and when the transmitter is put on standby, the driver is also inhibited.
