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User Manual
Rev. 1.0 - 22/08/14
TEX1002LCD
7. Working Principles
7.1 Panel card
The panel board accommodates the microcontroller that runs equipment firmware
and all user interface elements (display, LEDs, keys, …).
This board is interfaced with other equipment modules via flat cables and provides
for power supply, control signals and measurement distribution.
7.2 Main Board
The main board performs the following tasks:
• Audio and SCA input treatment;
• Generation of carrier frequency;
• Modulation ;
• R.F. amplification (Driver).
The board also features a stereophonic coder.
7.2.1 Audio input section
The audio input section accommodates the circuitry that performs the following
tasks:
• Input impedance selection
• 15 kHz filtering for R and L channels
• Stereophonic coding
• Preemphasis
• Mono, MPX and SCA channel mixing
• Clipper (limits modulating signal level so that frequency deviation never exceeds
75kHz)
• Modulating signal measurement.
7.2.2 PLL/VCO section
This section of the board generates the modulated radiofrequency signal. It is
based on a PLL architecture that includes an MB15E06 integrated circuit.
