Kenwood TK-80 Service Manual page 21

TK-80
5-12. Final unit control signal
The transmission LPF section signal and KAT-2 control sig-
nal to the final unit are output as serial data (Fig. 15).
5-13. AT unit control signal
Concerning the preset AT, based on the KAT-2 installation
signal (ATI), variable condenser position data (POD1, POD2)
and preset position data, the CPU controls the variable con-
denser drive motor rotation direction and rotation speed, us-
ing feedback control to ensure it stops at preset positions.
The tap signal from the tuning circuit is synthesized from the
transmit LPF selection signal from the final unit.
The KAT-2 does not tune below 2.0MHz, forcibly entering
the AT-through mode (Fig. 16).
5V
IC7
I/O port
40
APRE
41
ATA
39
PR11
38
PR12
37
PR21
36
PR22
9
SPED
57
ATI
69
Vref
70
AVss
72
POD1
73
POD2
IC5
CPU
Fig. 16 KAT-2 control circuit
20
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CIRCUIT DESCRIPTION
IC7
I/O port
7
FEN4
34
UCK
35
UDA
IC5
CPU
CONTROL UNIT
Fig. 15 Final unit control signal
DGND
14V
DGND
14S
ATI
SPED
APRE
ATA
PR11
PR12
PR21
PR22
ATG
VREF
POD2
POD1
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The MAT-100 control signal is bi-directional and conducts
tuning while handshaking with the MAT-100 (Fig. 17).
5-14. Selective call unit control signal
Based on the KPE-1 installation signal, DTMF decode
data, FSK decode data and other data, the CPU transmits call
codes, turns AF muting on and off, etc.
28AT
24AT
21AT
LPF3
LPF4
CN3 CN3 5V
3
FEN4
4
UCK
UDA 5
FINAL UNIT
CN6
1
2
5A
3
4
5
IC7
6
I/O port
7
8
9
TSO
10
11
12
13
IC5
14
CPU
15
16
Fig. 17 MAT-100 conrol circuit
IC4
Band data decoder
11 10
LPF1
Q5 Q4
LPF2
Q6 Q3
LPF5
Q7 Q2
LPF6
Q8 Q1
18AT
Q9 Q0
FEN4
Q10 LCK
UCK
Q11 CLK
UDA
SO DATA
OE NC
Vdd Vss
20 1
Q5
22
TTO
21
Q3
5V
56
TTI
55
Q6
TSI
Q4
CONTROL UNIT
LPF4 select
LPF3 select
21AT select
24AT select
28AT select
LPF1 select
LPF2 select
LPF5 select
LPF6 select
18AT select
CN3
TT
1
TS
2