NXR-710
17
5. Display unit
The Display unit (X54-3580-20) is the same circuit as
X54-3580-20, used in TKR-750/850/751/851.
The Display unit (X54-3580-20) consists of the following
circuits:
(1) LED circuit
(2) Key switch circuit
5-1. LED circuit
The display circuit consists of various types of LEDs:
7-segment type D506 and D507 (red), D503 (red: transmis-
sion), D504 (green: busy), D505 (green: power on).
IC502 to IC505 are shift registers that convert MCU se-
rial data to parallel data and turn on LEDs.
5-2. Key switch circuit
There are PF key 1 to PF key 6 on Display unit. Using
these key switches, mode settings are available.
The logic signals pushing these key switches are entered
directly into the MCU (IC20).
Fig. 16 Modulation circuit (Analog/Digital signal processing)
INT_SP
EXT_SP
SPO
SPI
SPO
RD
RD
RA
TD
TA
MOD
MOD
IF
signal
MIC
DAC
IC412
DAC
IC412
DAC
IC412
Audio_AMP
SW
IC402
AMP_SW
AMP_B
MICADC0
MICADC1
MODDAC
SPDAC
PWM1
IFR
ADC1
LPF
IC501
IC405
(C/4)
IC404
(B/2)
IC404(A/2)
CR-LPF
LPF
LPF
DET
LPF
MCU
IC20
Squelch DAC
IC14
DSP
IC6
CIRCUIT DESCRIPTION