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User Manual
Rev. 1.0 - 22/08/14
TEX1002LCD
•
Control of the power level in output, depending on the setting
•
Reduction of the power supplied when in presence of high-level reflected
power
•
Measures of the current absorbed by the power amplifier
•
Measures of the temperature
This board also features an RF sampling of approximately -46dB RF (for
TEX1002LCD
model) with respect to the output, which is available on a BNC
connector below the transmitter output connector. This sample is useful for
verifying the characteristics of the carrier, but not for verifying those of the upper
harmonics.
7.6 Bias card
The main function of this board is to check and correct the MOSFET polarization
voltage of the RF amplifier section.
It also provides the measurement of the absorbed current and contains a circuit
for signaling power supply unit faults.
If no alarms are present, the voltage is adjusted only depending on the set output
power, with a feedback mechanism based on the reading of the power really
delivered (AGC).
The voltage is also affected by other factors, such as:
•
Excess of reflected power.
•
External AGC signals (Ext. AGC FWD, Ext. AGC RFL).
•
Excess of temperature.
•
Excess of absorbed current from the RF module.
7.7 Low pass filter card
This card provide the low-pass filtering of the RF signal in output and measure the
reflected and forward power output.
7. Driver card
Before passing to the final power amplifier, the RF signal is preamplified in this
section by an BFG35 and an MRFE6S9060NR1 transistor. When the transmitter
is placed on stand-by, the driver is by-passed.
