Icom IC-2720, Service Manual

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4 - 11
Outputs shift signal to the 430 MHz
bandpass filter for left side display.
High:While receiving 310–450 MHz
on left side display.
Outputs the 430 MHz receiver circuit
select signal for right side display.
Low: While receiving 360–549.990
MHz on right side display.
Outputs the 144 MHz receiver circuit
select signal for right side display.
Low: While receiving 118–174 MHz
on right side display.
Outputs the RX RF power supply con-
trol signal for right side display.
High:While receiving on left side dis-
play.
Outputs the VCO select signal for left
side display.
High:While transmitting 400–479
MHz on left side display.
Outputs 430 MHz bandpass filter shift
signal for right side display.
High:While receiving 360–450 MHz
on right side display.
Output VCO select signal for right side
display.
High:While receiving 118–174 MHz
on right side display.
Outputs PLL loop select signal for right
side display.
Outputs PLL loop select signal for left
side display.
Input port for the PLL unlock signal for
right side display (IC1008, pin 7).
Low: The PLL lock voltage is
unlocked for right side display.
Outputs packet band select signal.
Input ports for Initial matrix.
Outputs serial signal to the PLL IC
(IC1008, pins 9, 10 and VCO unit; IC1,
pins 9, 10).
Outputs Initial matrix signal.
75
76
77
78
79
80
81
82
83
84
85
86–89
90
91
93
94
95
96
L_400SHIFT
R_RX400
R_RX140
LR_R5CTRL
L_VCO_SHIFT
R400_SHIFT
R_VVCO_SEL
L_PLLSW
R_PLLSW
R_UNLOCK
P_L/R_SEL
MATRIX_IN1–
MATRIX_IN4
PLLDATA
PLLCK
MATRIX_OUT1
MATRIX_OUT2
MATRIX_OUT3
MATRIX_OUT4
Pin Port
Description
number name
Output tracking signals to the band-
pass filter for right side display.
Output tracking signals to the band-
pass filter for left side display.
Outputs the attenuator circuit control
signal for left side display.
Outputs the attenuator circuit control
signal for right side display.
Outputs control signal for RF output
power.
Output tracking signals to the band-
pass filter for right side display.
2, 3
4–7
8
9
12
18, 19
R_BPF3
R_BPF4
L_BPF1,
L_BPF2,
L_BPF3,
L_BPF4
L-ATT
R-ATT
PWRCON
R-BPF1,
R-BPF2
Pin Port
Description
number name
CPU-Continued 4-5-2 D/A CONVERTER IC (CONTROL UNIT; IC4)