TK-7108
29
Control Circuit
The CPU carries out the following tasks:
1) Controls the WIDE, NARROW, TX/RX outputs.
2) Adjusts the AF signal level of the AF filter (IC251) and
turns the filter select compounder on or off.
3) Controls the display unit.
4) Controls the PLL (IC401).
5) Controls the D/A converter (IC161) and adjusts the vol-
ume, modulation and transmission power.
■
Memory Circuit
The transceiver has a 64k-bit EEPROM (IC66). The
EEPROM contains adjustment data. The CPU (IC101) con-
trols the EEPROM through three serial data lines.
IC161
D/A
converter
IC401
PLL
IC101
CPU
LD
DT
CK
PLLE
EEPCK
IC101
CPU
IC66
EEPROM
EEPDT
EEPWP
■
Display Circuit
The shift register controls the display LEDs through the CL
and DI lines from the CPU (IC101).
When the transceiver is busy, LED G line becomes high
impedance, turning on Q4 and the green LED (D11) lights, in
transmit mode, the LED R line becomes low impedance, and
the red LED (D12) lights.
Backlit LEDs (D1~D4) are provided and will only goes off
when MBL line becomes low impedance.
When a function key (MON, PF, C1, C2, C3 or C4) is se-
lected, its respective line becomes low impedance (LED
MON, LED PF, LED C1, LED C2, LED C3 or LED C4), the
amber LED lights.
Q4
SW
Q10
SW
Q9
SW
IC101
CPU
D1~D4
IC1
Shift
register
CL
LED MON
LED PF
LED C1
LED C2
LED C3
LED C4
LED R
LED G
MICBL
DI
D6
D5
D7
D8
D9
D10
D12
D11
!
`mr
!"#$
NF
!"!#$
=L
!"
OF
^c
=Ef`ORNF=
^c
!"#$%&'()*
!"#
PF
!"#$
QF
!"#$
=Ef`QMNF
RF
L
!
=Ef`NSNF=
!"#$ %&'()*+
!"#
!"#$
SQâJÄáí=bbmolj=Ef`SSF
bbmolj
`mr=Ef`NMNF=
!"#$%&
bbmolj
!"#
!"#$
`mr=Ef`NMNF=
!"
`i
af
!"
iba
!"#$%
iba=d
!"#$%&
nQ
iba
EaNNF=
!"#$
iba=o
!"#$%&
iba=EaNOF=
j_i
!"#$%&'()
iba=EaN
aQF=
!
!
=Ejlk
mc
`N
`O
`P
`QF=
!"#$%&'
!"#$%
=Eiba=jlk
iba=mc
iba=`N
iba=`O
iba
`P
iba=`QF
!"
iba
Fig. 10
Control circuit /
NM
!
Fig. 11
Memory circuit /
NN
!"
Fig. 12
Display circuit /
NO
!
CIRCUIT DESCRIPTION /
!
