Kenwood TM-D700A Manuale utente

TM-D700A/E

SENWOUD

SERVICE

MANUAL

©

1999-11

PRINTED

IN

JAPAN

B51-8504-00(S)

880

Microphone

assy

(T91-0396-05:E,M4)

(T91-0615-05:K)

Panel

(A62-0775-03)

Botton

knob

(K29-5400-11)

Knob

(SQL)

(K29-5223-03)

Knob

(ENC)

(K29-5381-03)

Knob

(VOL)

Cabinet

(UPPER)

0-03)

(K29-5222-

(A01-2122-13)

Photo

is

TM-D700A

(K

type)

CONTENTS

CIRCUIT

DESCRIPTION

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3

PC

BOARD

VIEWS

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53

SEMICONDUCTOR

DATA

.........scssseeeeees

17

SCHEMATIC

DIAGRAN

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65

DESCRIPTION

OF

COMPONENTSG..........

20

BLOCK

DIAGRAM

..........::::cescssseseeseesseess

77

TERMINAL

FUNCTION

............sccsscseseveoes

22

WIRING

DIAGRAM

...........ccccseseresesssessreoes

79

PARTS

LIST

.........:csesesecersssorssensesesersnncenens

23

LEVEL

DIAGRAM..............:s:sssessssseessesssees

80

EXPLODED

VIEW

.........:ccsscssessesserscenseeene

35

OPTION

(PG-4X)

......ccsececeseestesseresseseaesaens

8|

PACKING

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36

SPECIFICATIONS

...............-

BACK

COVER

ADJUSTMENT

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37

TM-D700A/E

CIRCUIT

DESCRIPTION

Outline

This

device

is

a

dual-band

144/430MHz

FM

car

transceiver

planned

and

designed

for

amateur

radio

communications

and

has

the

following

features.

1.

10.

11,

Has

a

built-in

TNC

which

conforms

to

the

AX.25

protocol.

With

a

portable

computer,

allows

you

to

enjoy

Packet

operation

quite

easily.

Includes

a

program

for

dealing

with

data

formats

supported

by

Automatic

Packet/

Position

Reporting

System

(APRS,).

Is

capable

of

receiving

packet

data

on

one

band

while

receiving

audio

on

another

band.

Enhanced

Programmable

Memory

(PM)

channels

store

virtually

entire

current

operating

environments

for

your

quick

recall.

Contains

a

total

of

200

memory

channels

to

program

frequencies

and

other

various

data.

Allows

each

memory

channel

to

be

named

using

up

to

8

alphanumeric

and

special

ASCII

characters.

“Visual

Scan”

graphically

and

simultaneously

shows

the

conditions

of

up

to

181

frequency

channels.

Continuous

Tone

Coded

Squeich

System

(CTCSS)

or

Digital

Code

Squelch

(DCS)

rejects

unwanted

calls

from

other

stations.

The

separate

front

panel

can

be

mounted

in

a

convenient

different

place

from

the

main

unit.

Equipped

with

an

easy-to-read

large

LCD

with

alphanumeric

display

capability.

Enhances

the

functions

of

an

optional

VC-H1

Interactive

Visual

Communicator

designed

for

plug-and-play

color

slow-scan

television

(SSTV).

Utilizes

Sky

Command

System

II

designed

to

control

a

KENWOOD

HF

transceiver

at

a

remote

location

(U.S.A//

Canada

only).

List

of

Destinations

Model

Guarantee

frequency

range

(MHz)

|Output

Power

(W)

144

430

144

430

TM-D700A|

K

144~148

438~450

50

35

M4

144~146

430~440

25

TM-D700E|

E

144~146

430~440

50

35

K:

U.S.A/Canada

M4:

Taiwan

E:

Europe

Accessories

Name

Parts

number

Remarks

Destination

K

|

E

iM4

Modular

cable

E30-3391-05

|

3m

1/1|1

Panel

bracket

J29-0663-03

1{4i4

J29-0664-13

1/1/14

Bracket

J29-0628-23

1/1/14

Microphone

T91-0396-05

111

T91-0615-05

|

DTMF

BACK

LIT

|

4

DC

cord

E30-2111-15

1/1/44

Fuse

F51-0017-05

115A

1)1/1

Mic

Hook

J19-1526-04

1

B62-1228-00

|

English

1/141

B62-1232-00

|

French

1/1

B62-1231-00

|

Spanish

1/1

instruction

manual

B62-1230-00

|

German

1

B62-1233-00

|

Dutch

1

B62-1273-00

|

English

APRS

t}4141

B62-1234-00

|

Chinese

1

B62-1229-00

|

Italian

1

Warranty

card

B46-0469-10

1

B46-0337-03

1

Cable

E30-3400-05

|

@2.5mm

GPS

jack

|

1

|

1

|

1

Screw

set

N99-0331-05

|

For

the

body

1/4

Screw

set

N99-0382-05

|

For

the

body

and

MIC

1

Screw

set

N99-2014-05

|

For

the

panel

bracket!

1/1

|

1

Foot

J02-0488-04

|

For

protect

from

alala4

scratch

on

a

desk

Pamphlet

B59-1684-00

1

Units

for

Each

Model

and

Destination

Model

TX-AX

UNIT

LCD

ASSY

K

X57-5860-11

B38-0820-05

TM-D700A

fig

X57-5860-21

TM-D700E|

E

X57-5862-71

TM-D700A/E

CIRCUIT

DESCRIPTION

1.Frequency

configuration

The

TM-D700

has

an

individual

VCO

and

PLL

unit

for

both

VHF

and

UHF

bands.

Using

these

separate

VCO

and

PLL

circuit,

it

can

receive

2

separate

bands

at

the

same

time.

Also,

you

can

perform

the

full-duplex

operation.

The

UHF

VCO

is

used

for

the

following

functions:

(i)

UHF

transmission

(ii)

The

first

local

oscillator

for

the

main

band(UHF)

reception.

(ii)The

first

local

oscillator

for

the

sub

band(VHF)

reception(halved).

The

VHF

VCO

is

used

for

the

following

functions:

(i)

VHF

transmission

(ii)

The

first

local

oscillator

for

the

main

band(VHF)

reception.

(iii)

The

first

local

oscillator

for

the

sub

band(UHF)

The

PLL

reference

frequency

is

generated

by

a

12.8MHz

crystal

oscillator

connected

to

the

VHF

and

UHF

PLL

ICs.

This

reference

frequency

is

used

for

both

PLL

circuits.

The

second

local

oscillator

for

the

VHF

band

uses

the

tripled

reception(doubled).

12.8MHz

reference

oscillator

frequency.

The

45.05MHz

second

local

oscillator

for

the

UHF

band

is

generated

by

the

IF

IC

crystal

oscillator

circuit.

ANT

MIC

H

A

y—

MIC

AMP

[5

PLL

1

VCO

1

|

,

UHF

TX

ly

1/2

G

ltst

iF

TNC

AF

|

45.0SMHz

MAIN

B

UHF

RX

[|

I

osc

;

—L

T

c

SUB

Cc

Crystal

VHF

AX

[774

TT

12.8MHz

45.505MHz

Crystal

|

12.8MHz

128MHz

k

D

AQKY

ose

PLL

2

vco

2

I

VHF

TX

|

J

2nd

IF

xe

SP

v7

450kHz

list

iF

AF

|

|38.85MHz

MAIN

AF

AMP

T]

DET

IF2

|

t

E

VHF

RX

[774

|

es Ge

L

Lt

xs

38.4MHz

FE

susp

|_|

UHF

RX

A}

K

|

438.000~449.995MHz

D|

K

|

144.000~147.995MHz

{Gj

K

|

392.950~404.945MHz

K

|

182.850~186.85

MHz

E

|

430.000~439.995MHz

E

|

144.000~145.995MHz

E

|

384.950~394.945MHz

E

|

182.850~184.815

MHz

M4

|

430.000~439.995MHz

M4

|

144.000~145.995MHz

M4

|

384.950~394.945MHz

M4

|

182.850~184.815

MHz

B|

K

|

438.000~439.995MHz

E!

K

|

144.000~147.995MHz

H

|

K_

j

378.100~386.090MHz

K

|

199.575~205.572

5MHz

E

|

430,000~439.995MHz

E

|

144.000~145.995MHz

E_

{|

378.100~382.090MHz

E

|

195.575~200.512

SMHz

M4

|

430.000~439.995MHz

M4

|

144.000~145.995MHz

M4

|

378.100~382.090MHz

M4

|

195.575~200.572

5MHz

C

|

K

|

144.000~147.995MHz

F

|

K

|

438.000~449.995MHz

||

K_|

4189.050~193.045MHz

K_

|

399.150~411.1450MHz

E

|

144.000~145.995MHz

E

|

430.000~439.995MHz

E

|

189.050~191.045MHz

E

|

391.150~401.115

MHz

M4}

144.000~145.995MHz

M4

|

430.000~439.995MHz

M4

|

189.050~191.045MHz

M4

|

391.150~401.145

MHz

Fig.1

Frequency

configuration

TM-D700A/E

CIRCUIT

DESCRIPTION

2.

Receiver

system

2-1.Main

VHF

Receiver

The

incoming

signal

from

the

antenna

passes

through

a

filter

circuit

and

goes

to

the

RF

amplifier

(Q205).

The

amplified

signal

enters

the

helical

resonator

(L209,

L207,

L204).

The

helical

resonator

is

tuned

to

the

desired

frequency

according

to

the

BPF

voltage

output

from

the

CPU

with

the

varicap

(D206,

D205,

D202).

After

the

signal

passes

through

a

filter,

it

is

amplified

by

another

RF

amplifier

(Q202)

and

goes

to

the

single

balanced

mixer

(Q200,

Q201).

The

frequency

of

the

ANT

Y

LPF

AF

AMP

BPF

RF

AMP

he

Q205

mt

—

3SK239A

aS

L209,L207,L204

D206

D205

D202

TUNE

BY

VOLTAGE

CPU

signal

is

converted

by

the

first

local

oscillator

(Upper

heterodyne)

to

generate

a

38.85MH

first

IF

signal.

The

signal

passes

through

the

MCF

(XF100),

is

amplified

by

the

IF

amplifier

(Q112)

and

enters

the

IF

IC

(IC100).

Then

the

signal

is

converted

to

the

450kHz

second

IF

signal

by

the

second

iocal

oscillator,

which

is

tripled

12.8MHz

(Lower

heterodyne).

Then

it

is

detected

to

generate

an

audio

signal.

SINGLE

BALANCED

MIXER

IF

AMP

>

AF

Q102

2804649)

x3

(N.P)

12.8BMHz

Fig.2

Main

VHF

Receiver

circuit

2-2.Main

UHF

Receiver

The

incoming

signal

from

the

antenna

passes

through

a

filter

circuit

and

enters

the

RF

amplifier

(Q508).

The

amplified

signal

passes

through

the

SAW

filter

(L517),

is

amplified

by

another

RF

amplifier

(Q505).

Then

it

passes

through

the

LC

filter

(L508)

and

enters

the

single

balanced

mixer

(Q501,

Q502).

The

frequency

of

the

signal

is

converted

by

the

first

LC

BPF

local

oscillator

(Lower

heterodyne)

to

generate

a

45.05MHz

first

IF

signal.

The

signal

passes

through

the

MCF

(XF400),

is

amplified

by

the

IF

amplifier

(Q406)

and

enters

the

IF

IC

(IC400).

The

signal

is

converted

to

the

455kHz

second

IF

signal

by

the

second

local

oscillator

(Upper

heterodyne).

Then

itis

detected

to

generate

an

audio

signal.

SINGLE

BALANCED

IXER

ANT

HPF

LPF

REAMP

saweitteR

REAMP

|

—~

~h

Q508

oo

eS

PT

3SK239A

=

b>

AF

45.505MHz

[7]

7

Fig.3

Main

UHF

Receiver

circuit

TM-D700A/E

CIRCUIT

DESCRIPTION

2-3.Sub

VHF

Receiver

The

signat

distributed

from

the

RF

amplifier

(Q205)

at

the

main

VHF

receiver

circuit

passes

through

a

filter

circuit.

Then

it

enters

the

RF

amplifier

(Q507).

The

amplified

signal

goes

to

the

single

balanced

mixer

(Q501,

Q502).

The

frequency

of

the

signal

is

converted

by

the

first

local

oscillator

generated

by

half

of

the

UHF

VCO

oscillator

frequency,

using

the

prescaler

(1C303).

It

converts

to

the

upper

heterodyne

frequency

to

generate

a

45.05MHz

first

IF

signal.

The

signal

passes

through

the

MCF

(XF400).

Then

it

is

amplified

by

the

IF

amplifier

(Q406),

and

enters

the

IF

IC

(IC400).

The

signal

is

converted

to

the

455kHz

second

IF

signal,

using

the

second

local

oscillator

(Upper

heterodyne).

Then

the

signal

is

detected

to

generate

an

audio

signal.

SINGLE

BALANCED

ANT

Y

LPF

RF

AMP

LPF

HPF

RF

AMP

Q205

=

F'esxaa9a

oe

ma

MIXER

IF

AMP

MCF

IF

IC

Q406

2SC510B

IC400

He

AF

{Y)

1C303

tt

UPB

|

12

a

15086

45.505MHz

[1

LO

Fig.4

Sub

VHF

Receiver

circuit

2-4.Sub

UHF

Receiver

The

signal

distributed

from

the

RF

amplifier

(Q508)

at

the

main

UHF

receiver

circuit

passes

through

a

filter

circuit.

Then

it

enters

the

single

balanced

mixer

(Q200,

Q201).

The

signal

frequency

is

converted

by

the

first

local

oscillator,

generated

by

doubling

the

VHF

VCO

oscillator

frequency

(Lower

heterodyne)

by

Q7,

to

generate

a

38.85MHz

first

IF

signal.

The

signal

passes

through

the

MCF

(XF100).

Then

it

is

amplified

by

the

IF

amplifier

(Q112),

and

enters

the

IF

IC

(IC

100).

The

signal

is

converted

to

the

450kHz

second

IF

signal

by

the

second

local

oscillator

generated

by

tripling

the

12.8MHz

reference

oscillator

frequency

(Lower

heterodyne).

Then

the

signal

is

detected

to

generate

an

audio

signal.

ANT

SINGLE

BALANCED

Y

HPE

LPF

RF

AMP

HPF

MIXER

MCF

IF

AMP

Fic

ae

Q508

6200,201

=e

ps

=

3SK239A

Se

25K302

1C100

pe

A

(GR)

7

CF

a7

=

2505108

|

x2

—~e

(Y)

Qio2

2804649

}

x3

(N.P)

12.8MHz

Fig.5

Sub

UHF

Receiver

circuit

TM-D700A/E

CIRCUIT

DESCRIPTION

item

Rating

Item

Rating

Center

Frequency

38.85MHz

Center

Frequency

45.05MHz

Pass

band

width

+7.5kHz

or

more

at

3dB

Pass

band

width

+7.5kHz

or

more

at

3dB

Attenuation

band

width

+25kHz

or

less

at

40dB

Attenuation

band

width

+22kHz

or

less

at

25dB

Guaranteed

attenuation

80dB

or

more

within

fo

-910kHz

(Spurious:20dB

or

more

within

+1MHz)

Guaranteed

attenuation

80dB

or

more

within

fo

-910kHz

(Spurious:40dB

or

more

within

+1

MHz)

Rippie

1dB

or

less

Ripple

1dB

or

jess

Insertion

loss

3dB

or

less

Insertion

loss

4dB

or

less

Termination

impedance

5002

+5%,

6pF+0.5pF

Termination

impedance

8000

+10%,

2pF+10%

Table1

MCF(L71-0491-05)

(TX-RX

Unit

XF100)

Tabie4

MCF(L71-0409-15)

(TX-RX

Unit

XF400)

Item

Rating

Item

Rating

Norminal

center

450kH2

Norminal

center

455kHz

frequency

6dB

band

width

+7.5kHz

or

more

(from

450kHz)

6dB

band

width

+7.5kHz

or

more

(from

455kHz)

50dB

band

width

+15.0kHz

or

less

(from

450kHz)

50dB

band

width

+15.0kHz

or

less

(from

455kHz)

Ripple

2dB

or

less

(within

450+5kHz)

Ripple

2dB

or

less

(within

455+5kHz)

Insertion

loss

6dB

or

less

(at

minimum

lost

point)

Insertion

loss

6dB

or

less

(at

maximum

output

point)

Guaranteed

attenuation

35dB

or

more

(within

450+100kHz)

Guaranteed

attenuation

35dB

or

more

(within

455+100kHz)

vO

matching

1.5kO

VO

matching

1.5kQ

terminating

impedance

terminating

impedance

Table2

Ceramic

filter(L72-0979-05)

(TX-RX

Unit

CF101)

Table5

Ceramic

filter(L72-0981-05)

(TX-RX

Unit

CF401)

terminating

impedance

2.0kQ

terminating

impedance

Item

Rating

Item

Rating

Norminal

center

450kHz

Norminal

center

455kHz

requency

frequency

6dB

band

width

+4.5kHz

or

more

(from

450kHz)

6qB

band

width

+4.5kHz

or

more

(from

455kHz)

50dB

band

width

+10.0kHz

or

less

(from

450kHz)

50dB

band

width

+10.0kHz

or

less

(from

455kHz)

Ripple

2dB

or

less

(within

450+3kHz)

Ripple

2dB

or

less

(within

455+3kHz)

Insertion

loss

6dB

or

less

(at

minimum

lost

point)

Insertion

loss

6dB

or

less

(at

maximum

output

point)

Guaranteed

attenuation

35dB

or

more

(within

450+100kHz)

Guaranteed

attenuation

35dB

or

more

(within

455+100kHz)

I/O

matching

1/O

matching

2,0kQ

Table3

Ceramic

filter(L72-0971-05)

(TX-RX

Unit

CF100)

(E

type

only)

Table6

Ceramic

filter(L72-0980-05)

(TX-RX

Unit

CF400)

(E

type

only)

TM-D700A/E

CIRCUIT

DESCRIPTION

2-5.Audio

Circuit

The

detected

VHF

audio

signal

is

amplified

by

Q108

and

de-

emphasized

by

Q110.

The

UHF

audio

signal

is

amplified

by

Q402

and

de-emphasized

by

Q405.

One

of

these

audio

signals

is

selected

with

a

cross

point

switch

(IC702).

The

signal

passes

through

the

electronic

variable

resistor

(1C804),

is

amplified

by

the

AF

amplifier

(IC806),

and

fed

to

the

speaker

or

the

external

speaker

jack.

The

VHF

or

UHF

audio

signal

selected

by

the

cross

point

switch,

passes

through

the

filter

circuit

(C701)

and

goes

to

the

CPU

(IC604)

for

CTCSS

and

DCS

decoding.

The

signal

buffered

by

Q701

is

output

to

the

PR1

terminal

of

the

DATA

connector,

and

the

signal

buffered

by

Q700

is

output

to

the

PR9

terminal.

The

1200bps

and

9600bps

packet

signals

pass

through

CN600

from

the

cross

point

switch,

go

to

the

TNC

unit

(X52-331).

They

are

used

for

the

TNC

circuit.

In

the

X52-331

unit,

the

1200bps

packet

signal

is

amplified

by

the

AF

amplifier

(IC7),

passes

through

the

audio

filter

(Q5),

and

is

rectified

to

a

rectangular

wave

by

the

comparator

(IC4).

Then,

the

reshaped

signal

goes

to

the

TNC

ASIC

(IC2).

It

passes

through

the

filter

(Q4,

Q7)

and

the

comparator

(IC6).

Then

it

goes

back

to

IC2.

Then

it

is

converted

to

digital

data

and

output

to

the

COM

terminal

at

the

TNC

CPU

(IC3).

The

9600bps

packet

signal

is

amplified

by

the

AF

amplifier

(IC7),

passes

through

the

audio

filter

(Q6).

It

is

reshaped

to

a

rectangular

wave

by

the

comparator

(IC4).

Then

it

goes

to

the

TNC

ASIC

(IC2),

converts

to

digital

data

and

output

to

the

COM

terminal

at

TNC

CPU

(IC3).

X52-331

SP

AF

AMP

CROSS

POINT

Sw

DE-EMPHASIS

—

AF

AMP

FIC

-~<]-

#

IC100

iF

IC

Q405

Q402

C806

1C804

2804617 2804617

(R) (R)

BUFFER

ic400

Q701

PRI

O

(a)

1702

Ye)

BUFFER

(3700

PRI

O«

2804617

Ko)

TO

X52-331~<—-O.

Fig.6

Audio

circuit

AF

FILTER

Qs

I

2804617

(A)

|

AF

AMP

AF

FILTER

COMPARATOR

TNC

ASIC

TNC

CPU

I

man

CPU

DAT

DATA

IC7

IC4

|}

Ic2

IC3

IC604

O-—>|

TA75w

TA75W

TGT02100

c>

TMT021Q

c>

O1FU

393FU

~;-]

1200bps

|

AF

LPF

AF

LPF

COMPARATOR

|

IC6

TA75S

|

393F

I

X57-586

Fig.7

TNC

unit

circuit

TM-D700A/E

CIRCUIT

DESCRIPTION

2%

RAV

and

RAU

is

de-emphasized

audio

signal.

RDV

and

RDU

is

not

de-emphasized.

RAV

from

IF

mm

Loe]

bot!

bos!

Los!

Lect!

Les}

Le!

Le]

RDV

from

IF

Lt)

Lot!

Le!

Leal

Le

L6I

1)

RAU

from

IF

mm

Lal

Los!

Let!

Le!

Lal

Le!

Lal

Ls)

RDU

from

IF

sn

Lol

Los!

Led

Le!

Lal

1]

BEEP

sound

from

CPU

=“

Ll

Los!

Let!

Led

Leal

Lal

Le!

Le)

VS-3

vocal

sound

of

option

Ll

Los!

Let

Leal

Lal

Ler

Le]

DTMF/1750

signal

from

CPU

Los)

Los! Les!

Los!

Lal

Le!

Le]

DTMF

sound

from

MIC.

Lot!

Lesl

Led

Le!

Lal

Le!

1)

V

Y

VY

V

Y

V

\

Al

AO

To

DTMF

decoder

To

built-in

TNC

To

CPU

for

DCS/CTCSS

decode

'

To

PR9

(DATA

terminal)

y

To

PR1

(DATA

terminal)

To

modulation

line

to

transmit

OTMF/1750

Fig.8

Cross

point

switch

(Audio

switching

circuit)

C702

z

#

To

SP1/INT

SP

side

AMP

To

SP2

side

AMP

TM-D700A/E

CIRCUIT

DESCRIPTION

3.

Transmitter

system

3-1.Modulation

Circuit

The

audio

modulation

input

from

the

microphone

is

amplified

by

|1C801.

The

1200bps

packet

signal

generated

by

the

X52-331

goes

to

iIC801.

The

DTMF

signal

and

1750Hz

tone

signal

(E

type

only)

generated

by

the

CPU

are

also

mixed

by

IC801.

The

modulation

signal

from

the

DATA

terminal

is

switched

by

IC803.

It

is

directed

to

C801

in

1200bps

mode

and

to

1C802

in

9600bps

mode.

The

signal

amplified

by

IC801

is

pre-emphasized

by

Q801

and

Q802,

and

its

level

is

adjusted

PRE-EMPHASIS

AF

AMP

MIC

AMP

C801

NJM2100V4

MIC

[}———

X§2-331

1200bps

DTMF

1750

TONE

AMP

by

IC804,

and

the

resulting

signal

goes

to

each

of

the

VHF

and

UHF

VCOs

as

a

modulation

signal.

The

TONE/CTCSS/DCS

signal

generated

by

the

CPU

is

fed

to

IC802

in

the

same

way

as

the

9600bps

mode

signal

from

the

DATA

terminal.

The

signal

amplified

by

C802

is

distributed

and

the

level

is

adjusted.

The

modulating

signal

goes

to

each

of

the

VHF

and

UHF

VCOs.

The

signal

is

amplified

by

IC300

and

modulates

the

reference

oscillation

circuit.

M62364FP

IC804

‘

AMP

IC300

YUM2904V;

sw

IC802

CPU

TA75501F

Ba

PKD

OF

B

1200bps

IC803

BU4066

BCFV

TONE/CTCSS/DCS

Fig.9

Modulation

curcuit

3-2.Transmitter

circuit

The

VHF

VCO

output

is

amplified

by

3-stage

amplifier,

RF

amplifier

(Q6)

and

driver

amplifier

(Q8,

QQ).

It

is

amplified

to

the

final

output

by

the

power

module.

The

signal

passes

through

antenna

switch

(D14,

D15)

and

low-pass

filter

and

is

fed

to

the

antenna.

The

UHF

VCO

output

is

amplified

by

4-stage

amplifier,

RF

amplifier

(Q304)

and

driver

amplifier

(Q307,

Q309,

and

Q310).

It

is

further

amplified

to

the

final

output

by

the

power

module.

The

signal

passes

through

antenna

switch

(D314),

low-pass

filter

and

high-pass

filter.

Then

it

is

fed

to

the

antema.

ANT

VHF

VCO

RF

AMP

DRIVER

POWER

AMP

_

Y

Ic2

as

~Le

KCH38

2802954

M67746

|

;

AIT

UHF

VCO

POWER

AMP

LPF

HPF

IC302

:

i

—~

Fig.10

Transmitter

curcuit

TM-D700A/E

CIRCUIT

DESCRIPTION

10

3-3.APC

circuit

The

Automatic

transmission

Power

Control(APC)

circuit

has

a

differential

amplifier

(\C200)

that

compares

the

DC

voltage

generated

by

detecting

part

of

the

transmission

output

using

diodes

(VHF:

D18,

D19;

UHF:

D317,

D318)

with

the

reference

D18

:

voltage

output

from

the

CPU.

The

output

signal

is

amplified

by

Q209

and

Q208

and

fed

to

the

power

module

to

keep

transmission

output

constant.

VHF

AW

D19

k

DC

AMP

I

comparator

PCA

DC

AMP

1C200

2Se4617

TA75S01F

(R)

D317

k

t

CPU

UHF

AM,

0318

:

Fig.11

APC

circuit

3-4.Overheating

protection

circuit

To

protect

from

the

thermal

destruction

of

the

power

module,

the

voltage

of

the

thermistor

(TH1)

near

the

power

module

is

monitored

by

the

CPU

(IC604).

If

it

becomes

high

temperature,

the

APC

voltage

is

controlled

to

cool

down

the

temperature.

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