R.V.R. Electronica PTRL, User Manual

Page: 39 / 48

PTRL & RXRL LCD
35 / 44 User Manual Rev. 1.2 - 31/01/05
9.3 Pannel card
The pannel card contains the microprocessor (PIC16F877Q) which implements the
monitoring software of the unit, the display and the other elements which are necessary
for the interface with the user.
This card is the interface with the other modules of the unit, both for the distribution of
the supply units and monitoring and for the measurements.
9.4 Monitoring card
The monitoring card provides for the management of the readings and the regulation
of the parameters referring to the direct and forward power, monitors the gain and
the "FOLDBACK" input and it surveys the internal temperature of the unit.
The card works as an interface between the panel card and the final stage for the
power regulation, the protection, the readings and the remote monitorings.
9.5 Main card
The main card has the following functions:
• Processing of the audio and SCA inputs
• Generation of the carrier
• Modulation
• R.F. Amplifier (Driver)
The difference between the Mono and Stereo versions of this card is the audio stage,
since the stereo version contains a stereophonic coder.
9.5.1 Audio input stage (mono version)
The audio input stage contains the circuits which realize the following functions:
• Selection of the input impedance
• 15 kHz filtering of the mono channel
• Preenfasis of the mono channel
•
Mixing of the mono, MPX and SCA channels
• Clipper (limits the level of the modulating signal so that the frequency deviation
does not exceed the 75 kHz level)
• Measurement of the modulating signal
9.5.2 Audio input stage (stereo version)
Two 15Khz filters are present in this card for the filtering of both Left and Right channels,
and an integrated stereophonical generator. The other functions are the same in the
mono version.