D/A Converter Ic - Icom IC-2720H Service Manual

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