Service Manual

PLL Synthesizer
The PLL synthesizer circuit is common to both the transmitter and receiver,
The synthesizer comprises:
Data
RF Out
12.8 MHZ TCXO
X1 is VCTCXO, which provide stable oscillator of 12.8 MHZ to PLL IC.
Frequency adjustment is provided by VR1.
.Voltage controlled oscillator module(VCO)
The module produces carrier frequencies during transmit and local oscillator frequencies
During receive.
The module cont
ains one VCO and three outputs. One for producing carrier frequencies during
Transmit and one for producing the local oscillator frequency during receive and the other
Output is for PLL IC(IC1) Fin.
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TCXO
DC
Regulator
Charge Pump
Loop Filter
IC1
PLL
TX OR RX
VCO