User's Manual

PTRL-LCD & RXRL-LCD
ELETTRONICA
29 / 36
User Manual
Rev. 2.3 - 26/06/19
• 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
7.6.2 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.
7.6.3 PLL/VCO stage
This stage of the card generates the modulated radiofrequency signal. It is based
on a PLL scheme which uses an integrated PLL model MB15E06.
7.6.4 Sezione Driver stage
Before going through the final stage (power amplifier), the RF signal is preamplified
in this stage by the BFR540 transistor. When the exciter is in stand-by, the driver
is inhibited.
7.7 Power Amplifier
The power stage is mounted on a heatsink which enables the dissipation of the
generated heat which is contained in a totally shielded metallic box fixed in the
central part of the bottom back of the unit.
The RF signal coming from the VCO at a level of around 10mW reaches the pilot
stage (BFG35) and is amplified from the final stage (MRFE6S9060NR1) up to
20W.
The signal goes through a low-pass filter which provides the elimination of the
armonic emissions.
A directional coupler enables the reading of the direct and forward power of the load,
such signals are then sent to the monitoring card for the necessary controls.
The reading of the direct power is also indicated on the panel card in order to
enable the display of the data on the LCD screen situated on the front panel.