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2.3 CMN-2330 RECEIVER
2.3.1 Composition
The CMN-2330 Receiver is composed of following section:
1) Power supply section
2) Receiver section
3) Input/Output section
2.3.2 Specification of input and output
1)
Power supply section
Input voltage
Output voltage
2)
Receiver section
Input frequency
Input impedance
Output frequency
2.3.3 Description of operation
1) Power supply section
The power supplied through the terminal board (TB1-11,12) passes the fuses (F1,F2),
the switching regulator of 5V (IC2) and contact point of the relay (K2), then enters
to 9V regulator (IC9).
The power supply is turned ON by pressing the POWER key on the control panel which
sets the D-Flip Flop (IC8) over 2 second and turns the power supply relay (K2) ON.
And as the power supply is ON, the power supply is turned OFF by pressing the
POWER key over 2 second, which resets the D-Flip Flop (IC8).
When the polarity of the power supply is wrong, current flows through CD8 and F1,
then blows the fuse F1.
All the digital circuit in the equipment function on 5V and analog circuit on 9V.
2) Receiver section
For 518kHz signal input, there are 3 ports namely HIGH-Z terminal to connect with
the wire antenna etc., input terminal for 50Ω antenna and terminal for the dedicated
Navtex Receiver Antenna unit (NAW-330).
Received input signal passes the protection circuit composed of diodes (CD17,18,
CD13-16) and is supplied to the tuning circuit(T1,C70).
Then after passing further 2 stage of the tuning circuit, the signal is amplified by the
FET AMP (TR1).
Then its bandwidth is limited to 518kHz ± 250Hz by the Mechanical filter (FL1) and
the signal is amplified and mixed with BFO signal by IC1 and becomes signal of
1,700Hz ± 85Hz then appears to the FS OUT (ST1-1) as output.
The signal input from "FS IN"(ST1-2) is sent to the Main Processor.
The BFO consisted of crystal oscillator (X1) and transistor (TR6), oscillates the
4130.4kHz.
: DC 10.8V∼35V
: +5V
+9V
: 518kHz
: 50Ω
High-impedance
: 1,700Hz ± 85Hz
0dBm (600Ω, UNBAL.)
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