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User Manual
Rev. 1.0 - 29/11/05
PTRL NV/3 & RXRL NV/3
8. Operating principles
8.1 Description of transmitter componentry
The radio link transmitter comprises 7 internal modules shown in the "Assembly view
drawings" and in the "Main wiring diagram" included in the annex to this manual. The
following modules may vary depending on frequency range:
- Control and display CPU board
- BF and RF control mainboard
- Stereo coder board (option)
- Modulated oscillator board
- RF power amplifier
- Main power supply (mains power)
- Stabilised backup power supply and battery charger
For a detailed description of the modules discussed at the following pages, please
refer to the relevant wiring diagram in the relevant section of the manual.
8.1.1 Control and display CPU board
In spite of its complex tasks, the transmitter controller board is basically simple. It
houses the CPU, the keyboard and a few other circuits briefly described below.
The CPU has three 8-bit digital ports and one analogue port. The analogue port is
interfaced with the analogue signals that need to be measured in the transmitter.
A fast peak rectifier built around IC4 drives the first analogue line
AN0/ANA_MUX
.
All audio/BF modulation signals and some constant or slow-varying signals are
multiplexed to this input by IC3. This way, a single, accurate peak rectifier is sufficient
and a greater number of analogue channels are made available on the board.
An analogue channel carries the temperature reading of sensor T3.
The CPU queries the keyboard continually to determine whether any key has been
pressed. Serial/parallel converter IC5 drives the front panel LEDs and display
backlighting via TR2.
The alphanumerical LCD (Liquid Crystal Display) is a separate module connected
to the board through a small flat cable. 11 digital lines of the CPU drive this module.
Trimmer RT1 on the control board adjusts LCD contrast and may be used to improve
visibility under particular lighting conditions. The operating current for the backlighting
LEDs of the display is supplied by resistors R41 and R42; these resistors run hot
when the display is fully lit and their heat may somehow affect the internal temperature
sensed by TR3.
Summary of Contents for PTRL NV/3
Page 1: ...PTRL NV 3 RXRL NV 3 User Manual Volume 1 Manufactured by Italy...
Page 4: ...PTRL NV 3 RXRL NV 3 ii User Manual Rev 1 0 29 11 05 This page was intentionally left blank...
Page 8: ...4 52 User Manual Rev 1 0 29 11 05 PTRL NV 3 RXRL NV 3 This page was intentionally left blank...
Page 55: ...51 52 User Manual Rev 1 0 29 11 05 PTRL NV 3 RXRL NV 3 10 Ensemble View 10 1 PTRL NV 3...
Page 56: ...52 52 User Manual Rev 1 0 29 11 05 PTRL NV 3 RXRL NV 3 10 2 RXRL NV 3...