TEX30LCD/S
ELETTRONICA
31
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User Manual
Rev. 2.0 - 02/09/18
7.3 Telemetry board
This board is designed to inform the user of the equipment operation state. All
input and output signals are available on the DB15 connector.
The same board also features the “INTERLOCK” BNC connector for disabling the
device. By grounding the central pin, the output power is reduced to zero until the
connection is removed.
When an R.V.R. amplifier is used, this connector is linked to the power amplifier
REMOTE or INTERLOCK by means of a BNC-BNC connection. In case of amplifier
faults, the central conductor is grounded thus forcing the machine to enter in
stand-by mode.
7.4 Power Supply
The
TEX30LCD/S
power supply unit is a switching-type unit whose +28 V main
output powers the machineÌs RF amplifier. The power supply also features
stabilizers for generating cont5 V and +18 V voltages for supplying the
other equipment circuits. Note that the power supply is a “direct from mains”
type, or rather it is without a transformer, and it can be connected to any voltage
between 90 and 260 V without any adjustments or manual settings. The power
supply unit is also connected to 24 V auxiliary continuous voltage inputs used to
automatically buffer the mains power cutoff.
7.5 Power Amplifier
The final power stage is enclosed in a totally shielded metal container fastened
in the centre of the device.
The RF signal coming from the “main” card reaches the pilot, is amplified and is
then sent to the final stage that sees to its final amplifications up to 30W.
In addition to the actual RF amplification, this circuit carries out the following
functions:
•
Measures of the forward and reflected power by means of directional
couplers
•
Low-pass filtering of the RF signal in output
This board also features an RF sampling of approximately -30dB RF with respect
to the output, which is available on a BNC connector below the transmitter output
connector. This sample is is useful for verifying the characteristics of the carrier,
but not for verifying those of the upper harmonics.
