4 - 4
The PLL IC contains a prescaler, programmable counter,
programmable divider and phase detector, etc. The entered
signal is divided at the prescaler and programmable counter
section by the N-data ratio from the CPU. The divided signal
is detected on phase at the phase detector using the refer-
ence frequency.
If the oscillated signal drifts, its phase changes from that of
the reference frequency, causing a lock voltage change to
compensate for the drift in the oscillated frequency.
4-3-2 VCO CIRCUIT (MAIN UNIT)
The VCO circuit contains a separate RX VCO (Q17, D9) and
TX VCO (Q16, D10, D13). The oscillated signal is amplified
at the buffer amplifiers (Q15, Q29) and is then applied to the
T/R switch (D16, D17). Then the receive 1st LO (Rx) signal
is applied to the 1st mixer (Q6) and the transmit (Tx) signal
to the YGR amplifier circuit (PA unit; Q704).
A portion of the signal from the buffer amplifier (Q15) is feed
back to the PLL IC (IC21, pin 6) via the buffer amplifier (Q14)
as the comparison signal.
LINE
VCC
+5V
S5V
R5V
T5V
DESCRIPTION
The voltage from the connected battery pack.
Common 5 V converted from the VCC line at the
+5 regulator circuit (IC7). The output voltage is
supplied to buffer amplifiers (Q21), PLL IC
(IC21),etc.
Common 5 V converted from the VCC line at the
S5 regulator circuit (Q26–Q28). The output volt-
age is supplied to the ripple filter (Q20), etc.
Receive 5 V converted from the S5V line at the
R5 regulator circuit (Q25). The output voltage is
supplied to the tripler (Q22), FM IF IC (IC9), IF
amplifier (Q7), 1st mixer (Q6), RF amplifier (Q5),
etc.
Transmit 5 V converted from the S5V line at the
T5 regulator circuit (Q24). The output voltage is
supplied to the APC amplifier (IC16), PA unit etc.
Shift register
Prescaler
Phase
detector
Loop
filter
Programmable
counter
Programmable
divider
X2
15.3 MHz
10
Buffer
Q15
Buffer
Q21
Buffer
Q29
Buffer
Q14
14
15
16
SCK
SO
PLST
to transmitter circuit
to 1st mixer circuit
D16
D17
4
6
Q16, D13
TX VCO
Q17, D11
RX VCO
IC21 LMX2352
3
45.9 MHz 2nd LO
signal to the FM IF IC
(IC9, pin 2)
Tripler
Q22
"LVIN" signal to the CPU
(IC22, pin 49)
LPF
• PLL CIRCUIT
4-4 POWER SUPPLY CIRCUIT
4-4-1 MAIN UNIT VOLTAGE LINE
