Kenwood TM-631A Service Manual page 17
144/220mhz fm dual bander
Hide thumbs
Also See for TM-631A:
- Instruction manual (37 pages) ,
- Instruction manual (36 pages) ,
- Instruction manual (36 pages)
Advertisement
T
16
M-631A
CIRCUIT DESCRIPTION
*
Tone
Output
Signals
from pins
P40
to
P43
and
P50
to
P53
of
the
microprocessor
are fed to
a
ladder resistor network
(IC104)
which
performs
D-A conversion
and provides 38
signals rang-
ing from
67.0
to
250.3.
Fig. 24
shows
the internal structure of
IC104.
P43
P42
P4\
P40
Tone output
Ps3
P52
PSI
P50
Fig. 24
Ladder
Network:
Internal
Structure of
KRR-C001
(Control Unit 1C104)
©
S
meter and
RF
meter input
The S
meter and
RF meter voltages
are
coupled separately
for
the main band and subband and are provided as the
M1
and
M2 inputs
to the PTHOO and
PTH01
pins of the
microprocessor.
The
input
voltage
is
converted internally
to
a
4-bit digital value
(16 levels)
and sent to the
display.
¢
Busy
Input
BUSY
signals
are
supplied separately
to the
microprocessor
for the main band and
subband.
If
squelch
is
on, the
microprocessor receives
a
Low
input
when the received sig-
nal is
present, and lights
the
BUSY
indicator.
*
Input and
Output for
CTCSS
Unit (Option)
The microprocessor provides
data for the
CTCSS
unit from pins
P70, P71,
and
P73. This
data
specifies
the
CTCSS
tone fre-
quency and
CTCSS
unit
on/off information.
When
a
tone
is
detected
from the
CTCSS
unit, the
microproces-
sor
receives
a
High input at P121 and opens the squelch gate.
from
IC3
6
pin
CTCSS
MAIN/SUB select
when
"'L''
level: MAIN
2OK
os
=<
20K
0
=e
20K
20K
os
20K
2OK
12
AAA
AAA
3
AAA
2OK
4
2OK
4
20K
20K
5
6
20K
20K
from
SUB
RD
(RDS)
to
AIM
15
0
a
from MAIN RD
(RDM)
6
5
3
2
¢
Input and Output for
Remote Control Unit
(RC-10,
Option}
When
the remote control unit
is
connected,
the
microproces-
sor receives
a
High input at
P123
and
switches
the
following
pin
functions:
P03
>SI
:
Serial data input
pin
P02
»SO
:
Serial data output
pin
P01
»SCK
:
Serial
clock
input/output
pin
Data transfer between the microprocessor
in
the set and the
microprocessor
in
the remote control unit
takes place over these
lines.
T
16
M-631A
CIRCUIT DESCRIPTION
*
Tone
Output
Signals
from pins
P40
to
P43
and
P50
to
P53
of
the
microprocessor
are fed to
a
ladder resistor network
(IC104)
which
performs
D-A conversion
and provides 38
signals rang-
ing from
67.0
to
250.3.
Fig. 24
shows
the internal structure of
IC104.
P43
P42
P4\
P40
Tone output
Ps3
P52
PSI
P50
Fig. 24
Ladder
Network:
Internal
Structure of
KRR-C001
(Control Unit 1C104)
©
S
meter and
RF
meter input
The S
meter and
RF meter voltages
are
coupled separately
for
the main band and subband and are provided as the
M1
and
M2 inputs
to the PTHOO and
PTH01
pins of the
microprocessor.
The
input
voltage
is
converted internally
to
a
4-bit digital value
(16 levels)
and sent to the
display.
¢
Busy
Input
BUSY
signals
are
supplied separately
to the
microprocessor
for the main band and
subband.
If
squelch
is
on, the
microprocessor receives
a
Low
input
when the received sig-
nal is
present, and lights
the
BUSY
indicator.
*
Input and
Output for
CTCSS
Unit (Option)
The microprocessor provides
data for the
CTCSS
unit from pins
P70, P71,
and
P73. This
data
specifies
the
CTCSS
tone fre-
quency and
CTCSS
unit
on/off information.
When
a
tone
is
detected
from the
CTCSS
unit, the
microproces-
sor
receives
a
High input at P121 and opens the squelch gate.
from
IC3
6
pin
CTCSS
MAIN/SUB select
when
"'L''
level: MAIN
2OK
os
=<
20K
0
=e
20K
20K
os
20K
2OK
12
AAA
AAA
3
AAA
2OK
4
2OK
4
20K
20K
5
6
20K
20K
from
SUB
RD
(RDS)
to
AIM
15
0
a
from MAIN RD
(RDM)
6
5
3
2
¢
Input and Output for
Remote Control Unit
(RC-10,
Option}
When
the remote control unit
is
connected,
the
microproces-
sor receives
a
High input at
P123
and
switches
the
following
pin
functions:
P03
>SI
:
Serial data input
pin
P02
»SO
:
Serial data output
pin
P01
»SCK
:
Serial
clock
input/output
pin
Data transfer between the microprocessor
in
the set and the
microprocessor
in
the remote control unit
takes place over these
lines.
Advertisement
