R.V.R. Electronica PTRL, Руководство пользователя

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PTRL & RXRL LCD
39 / 44 User Manual Rev. 1.2 - 31/01/05
power supply interface, which is used automatically in order to collide with possible
AC supply absences.
10.3 Panel card
The panel 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.
10.4 IF Card
The IF card realizes the following functions:
• Processing of the audio and SCA outputs
•
Generation of the 10.7MHz signal
• Demodulation
This circuit receives the 70MHz signal, which is filtered, amplified and then passed
into a mixer which presents a signal coming from a 59.3MHz chrystal oscillator to the
other input. The signal (10.7MHz) obtained from the difference between these two
signals is filtered and amplified an once it is processed it is sent to the front-end.
This card also processes the different audio MONO, MPX, SCA and RDS signals,
and sends them, together with the muting signal, to the Front-end card.
10.4.1 Audio input stage (mono version)
The audio input stage contains the circuits which realize the following functions:
• 15KHz filtering of the mono channel
• De-emphasis of the mono channel
•
Separation of the mono, MPX and SCA channels.
• Measurement of the demodulating signal
10.4.2 Audio input stage (stereo version)
There are two 15KHz filters for the filtering of both L and R channels, and an integrated
stereo. The other functions are the same as in the mono version.
10.5 Front End
Tis card receives the RF signal, filters it, amplifies it and mix it in the mixer section
with the signal coming from the VCO/PLL