Trio Sg-402 User manual

~TRIO

RF

SIGNAL

GENERATOR

~~

I H

10

;

SOLID-STATE

SG

402

WIDE

BAND

•

INSTRUCTION

MANUAL

CONTENTS

GENERAL

&

FEATURES

...................

.

SPECIFICATIONS.

. . . . . . . . . . . . . . . . . . . . . . . . 2

CIRCUIT

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . 3

OPERATING

INSTRUCTIONS

. . . . . . . . . . . . . . . . . 4

APPLICATIONS

. . . . . . . . . . . . . . . . . . . . . . . . . . 6

MAINTENANCE

..........................

10

ADJUSTMENT

...........................

12

CAUTIONS

.............................

14

BLOCK

DIAGRAM

........................

15

EXTERNAL

VIEW

........................

16

SCHEMATIC

DIAGRAM

.....................

17

GENERAL

& FEATURES

~]

THIO

S6

401

-o·-·_

-

/"

.

' -

o

All

solid-state construction.

o Compact, easy-to-look-at frequency

scale

with

smooth mechanism_

o 100kHz

to

30MHz frequency coverage in six

ranges,

each

in

different

color on

scale

plate

for

easy, quick

reading.

o

Output

voltage

of

more than

0.1

V rms, continuously

adjustable

to

any desired magnitude through com-

- 1 -

Thank you very much

for

purchasing the

TRIO

SG-402.

The

TRIO

SG-402

is

a radio frequency signal gener-

ator employing a Hartley

circuit

and

covers a frequency

range

of

from

100kHz

to

30MHz in six

ranges.

The

output

voltage available

is

more than

0.1

V rms

and continuously adjustable through combined

use

of

the

RF

GAIN

control and HIGH-LOW attenuator, the

latter giving a fixed attenuation

of

approximately 20dB.

The

output

can

be

AM-modulated, either internally

(approximately 40% at 400Hz)

or

externally (1.5V rms

for

40% modulation

or

more between 50Hz and 10kHz),

when switched.

bined

use

of

20dB (approximately 1/10) attenuator

and RF

OUTPUT

control.

o

Modulation

possible either internally approximately

40% at 400Hz

or

externally (50Hz to 10kHz) when

selected

by

means

of

MODULATION

switch.

o High

stability

against power voltage fluctuations.

o Markings on

scale

plate

for

convenience in amateur

band, and

TV

and

AM

receiver IF adjustments.

SPECIFICATIONS

Oscillating frequency:

Frequency accuracy:

Output

voltage:

Attenuator:

Internal

modulation

frequency:

Internal

modulation

degree:

External

modulation

frequency:

External

modulation

voltage:

Operating temperature:

Power requirements:

Power consumption:

Dimensions:

A band 1OOkHz

to

250kHz

B band

250kHz

to

650kHz

C band

550kHz

to

1.5MHz

0 band

1.5MHz

to

4MHz

E band

4MHz

to

11

MHz

F band 10MHz

to

30MHz

±1.5%

More than

0.1

V rms (20°C)

HIGH-LOW,

(Provide approx-

imately 20dB change)

Approximately

400Hz

40% ±

5%

50Hz

to

10kHz

1.5V rms

for

40%

modulation

or

more

0

to

50°C

100V,

117V

or

230V

AC

±1

0%,

50

or

60Hz

2.8W

186(W) x

220(0)

x

131

(H)

mm

-

2-

Weight:

Accessories

or 190(W) x

245(0)

X 154(H)

mm when all protrusions

are

included.

2.2kg

(

1)

Sh1elded lead

With

clothed

cl1p

and

banana plug.

(2) Fuse (0 1

A)

Fuse

(0

2A)

(3)

Instruction manual

..

····· . 2

·······

.... 2

copy

,

c

CIRCUIT

DESCRIPTION

1.

OUTLINE

Please

refer

to

the

block

diagram

of

Fig. 1 iP.

151

and

circuit

diagrarn

(P.

171.

The sine wave signal produced

rn

tt1e

RF oscrllator

circuit

is

drrect!y arnplrfred by the

rroduldted

arnplrfier

v:hen the

rv10UULJIT!U~

svvitch

:sat

CW

tr1en

passes

the

outcut

attenuator·, and appears at the

output

terminal. When the

~.1()0Ul.AT!Oi'-.J

switch

rs

set

to

INT.

the

output

can

be

rnternaily

modulated

to

approxrmate·

!y

40~

at

400H;

uv

sine wave s:gnal

from

the AF

oscrllatur

ururrt,

or

externally

modulilted

when the

switch

rs

shrfted

to

EXT.

Required level

of

the

moduiat

ing signal

is

more than 1.5V rms

for

40%

modulation

at

frequencres between 50Hz and 1OkHz.

2.

RF OSCILLATOR

CIRCUIT

The RF oscrllator

crrcuit

employs

a

Hartley

circuit,

the oscillating elements consisting

of

coils

(FREO.

RANGE),

which

are

switched in six ranges, and a

variable capacitor

(FREQUENCY

d1al), covering 2.5

times the

lower

edge

of

each

range

or

a

total

of

from

1OOkHz and

30M

Hz.

The

amplifier

circuit

for

the

oscillator

is

a high

input

impedance

circuit

employing

an

FET

(2SK55-E),

-

3-

and rncludes a feedback resistor

for

each range

so

that

output

may

be

equal

ill

ali ranges.

3.

MODULATED

AMPLIFIER

The signa!

from

the RF

oscillator

rcurt

rs

,Jr<rp!rfrecJ

by 0.2 i2SC535-f:3i. and

passes

the rnocJtAned ar;;p(:i:ccr

(cJ

gate

modulated

type

bu1lt around

03,

2S

and

then

an

RLC

type

low

pass

filter

before taken

out

through

an

ernitter

follower,

04

12SC458·Ci.

4.

AF

OSCILLATOR

CIRCUIT

Transistor

05

(2SC458·C) forms

an

HC:

oscillator

,,rcuit,

and its

output

is

coupled to the rnudulated

amplifier

adjusting

by

VR

1.

5.

POWER SUPPLY

Input

AC

voltage

(100V,

117V

or

230V

AC)

is

step·

ed

down

to

a required voltage by the

power

transformer,

rectified

in full-wave

rectification

by

rectifier

01,

and

passed

through

a

smoothing

circuit

to

obtain

the DC

voltage.

This

power

supply

section teeds

15V

DC

to

all

signal generator

circuits

as

"B"

voltage.

OPERATING

INSTRUCTIONS

FRONT PANEL

Ref.

No.

Controls,

Description

Connectors,

etc.

(

1)

(Neon

lamp)

Lights

up

when

POWER

switch

(2) is

turned

to

ON.

(

2)

POWER

Slide

switch

for

power

switching

and

turns

on

power

when

set

to

right-

hand

position.

(

3)

MODULATION

Selector

switch

for

modu-

lating

signal.

EXT

In

this

mode,

output

signal

can be

AM-modulated

at

any

frequency

between

50

Hz

and

10kHz

when

a

modulating

signal is fed

to

EXT

MOD

INPUT

termi-

nals (12) and

(13).

cw

This

is

the

central

position

of

the

MODULATION

switch,

and

produces

un-

modulated

output.

INT

Output

is

AM-modulated

by

the

built-in

AF

oscil-

lator

to

approximately

40%

at

400Hz.

(

4)

__j_(GND)

Grounding

terminal.

-

(

5)

OUTPUT

Any

output

can be

ob-

tained

from

this

output

terminal.

-4-

The controls

and

their

function

are

listed below.

Refer

to

EXTERNAL

VIEW

(P.

16)

Ref.

No.

Controls,

Description

Connectors,

etc.

(

6)

OUTPUT

ATT,

Output

attenuator

20d8

HIGH

In

this

position,

output

is

passed

directly

to

the

out-

put

terminal

without

at-

tenuation.

LOW

Gives an

attenuation

of

approximately

20d8.

(

7)

RF

OUTPUT

Permits

changing

output

voltage

continuously

be-

tween

0 and 0.1 V rms (sine

wave).

(

8)

FREO

RANGE

Used

to

select

frequency

ranges

indicated

on

scale

(10) and

pointer

(11)

as

follows.

A:

100kHz

to

250kHz

8:

250kHz

to

650kHz

C:

550kHz

to

1.5MHz

D:

1.5MHz

to

4MHz

E:

4MHz

to

11MHz

F:

10MHz

to

30MHz

(

9)

(Frequency

dial)

Used

to

set

for

a desired

output

frequency.

Mechanically

ganged

with

the

variable

capacitor

and

pointer(11).

c

Ref.

No.

Controls.

Description

Connectors.

etc.

(101 (Scale

plate)

Graduated

in

six

ranges

to

read

output

frequencies

be·

tween

100kHz

and

30MHz.

(11)

I

(Pointer)

I

Indicates

scale

settings.

c_______L_

REAR

PANEL

I

(12)

EXT

MOD

INPUT

Input

terminal

for

external

modulation

signals.

To

I

modulate

the

SG-402

w1th

I an

external

n1odulation

I signal.

feed

a signal

to

this

I

terminal

and

set

~J'.ODU·

!

LL\TION

switch

(3\

to

i

EXT.

Usable

rnodtJ

ldt1ng

~~,.

i

freouenc

ies

are

lJet-.vPert

bOHz and

1OkHz.

--

I

GND

Groundiny

termindl

fur

~;x-

I

i

ternal

rnodulat1on.

1141

{PnvJer

cord)

Power

scmply

cord.

--

(1)

Starting

With

power cord (14) connected

to

a

power

source,

turn

power

switch (2)

to

ON. This

turns

neon

lamp

(1)

on and places the signal generator in

the

running

condi-

tion.

Allow

2

or

3

minutes

for

the set

to

warm

up in

order

to

stabilize the

operation.

!

-5 -

(2) Setting

to

a desired

frequency

To

set

to

a desired

frequency,

select a

proper

range

with

FREO.

RANGE

switch

(8) and operate

FRE-

QUENCY

dial (9) unt1l its

pointer

(

11

I indicates the

desired

frequency

on scale I10). The

frequency

dial

is

ganged

with

the 'Jariable

capacitor

For

exarnple,

to

set

to

1

MHL.

Set

FREO.

RANGE

switch

18)

to

C.

and

pointer

1111

to

HJ1H; un

sc.ale

110).

(3) AdJUSting

output

voltage

Output

vulta~w

taken

out

from

outout

terrnrnal (:))

can be

continuously

adjusted

from

0

to

0.1V

rrns

by

rnecHlS

of

RF G;\lf,J · •Jntrol

171.

The RF

GA.I~~

rontrol

increases the

output

voltage

when

turned

clockw1se,

up

tD

0 1V rms at the

fully

rlrxkwrse

f'CJS!tron

1f

output

atlenuator

((:))

is

at

HIGH.

When

tt1e

atterluator

IS set to

LOW, the

output

vCJitage

1s

reduced

to

approxrrnately

1;10

( 2UdB). INhen

obta1n1r1g

a srnal! voltage, set the

dttf:r-HJator

to

LOW, srnce this rnakes

adjustments

'"asrer

at

such small voltages.

(4)

Use

of

EXT

MOD

INPUT

terminal

'v'Vhen

connected

to

an

external sine wave

s1gnal,

this

terminal

enat>les

the

output

voltage

to

be

AM-modulated

at

a desired

frequency

between

50Hz

and

10kHz,

vvhen

the

MODULATION

switch

(3)

is

at

EXT

Required

modulating

voltage

is

more

than

1.5Vrms

for 40%

modulation.

APPLICATIONS

In

this description,

it

is

assumed

that

radio receiver

intermediate frequency and

TV

intermediate frequency

are

445kHz

and

10.7MHz respectively.

The followings

are

the examples

of

the

uses

of

this

RF signal generator operated

for

measurements

of

the

RF ampI

ifier

and IF ampI

ifier

of

AM radio receivers.

(

1)

Al1gn

ing IF transformers

Set the SG-402

to

455kHz,

an

intermediate fre·

ANT. Tr1

~~

SG· 402

~...;o;._=_"'_++--'

Local

OSC

SG·402

OUT

- 6 -

quency

of

the radio receiver

to

be

aligned, and connect

the signal generator

to

the

base

of

transistor

Tr2,

a

mixer, in Fig.

2.

The local oscillator must

be

kept in·

operative during this adjustment.

To

make

it

inoperative

shunt the

base

of

the local oscillator transistor

or

tt1e

tank

circuit

to

ground.

Connect

an

output

meter (or a VOM set

to

2.5

to

1

OV

DC range)

to

the

emitter

of

Tr3,

and measure the

emitter

voltage. The

emitter

voltage, which

is

high when

detuned,

will

drop

as

tuned

to

455kHz. This measure·

ment refers

to

intermediate transformer IFT1. From

this

point,

at which the IF transformer

is

accurately

Volt

meter

(VOM)

FIG2.

ALIGNING

IF

AMPLIFIER

)

tuned, gradually change the

oscillator

frequency

of

the

SG

402

to

both

sides

of

the

point

to

obtain

a curve,

which should

be

as

shown in Fig.

3.

A

detuning

width

between

points

that

give 3dB

difference

of

output

as

cornpared

to

that

of

the center frequency

(a

point

which

sr1.J•Ned

the

maximum

output

drop)

is

referred

to

as

the

paosband

of

the IF transformer. and

an

attenuation

olJcained when the IF

transformer

is

detuned ±1OkHz

frorn the center frequency

is

called rated selectivity.

lnter-

rned<ate

treq.

FIG3.

SELECTIVITY

-

7-

The frequency scale

of

the

SG-402

is

marked

455kHz

IF

(10.7MHz

for

FM receiver)

for

convenience

in

use.

In

this

way.

the overall selectivity characteristic and

gain

of

the

IF ampI

ifier

can

be

known

by

measuring IF

transformers one

by

one.

When

finding

a

maximum

point

on

the

AF

output

meter. set

MODULATION

switch (3)

to

INT

and

use

a

modulating

output,

or

to

EXT

when

modulating

ex·

ternally.

When

utilizing

the

tuning

meter

or

emitter

voltage, the SG-402 may

be

either

modulated

or

non-

modulated (CW). When measuring the

bandwidth

of

IFTs, however,

non-modulated

signal

will

be

better

since

it

indicates

their

characteristics rnore

faithfully.

(2)

Tracking

A test

circuit

for

tracking

is

shown

1n

Fig. 4.

Tune

the SG-402

to

the receiver frequency

to

be

tested, and

feed its

output

to

the antenna

circuit.

Three

different

frequencies are generally specified

for

this

test:

Three frequencies

tor

standard

tracking

LW MW

sw

180kHz

600kHz

4.0MHz

240kHz

l,OOOkHz

7.0MHz

320kHz

1.400kHz

lO.OMHz

Measure and adjust the RF

tuner

and local

oscillator

frequencies using these three testing frequencies. Con-

nect a

100pF

capacitor

to

the

antenna. This capacitor

serves

as

a

dummy

antenna and

without

this

capacitor, a

point

tuned

during

tracking

will

appear in a

different

place in normal reception.

Adjust

all

controls

of

the receiver

so

that

its

output

becomes

maximum

when a

400Hz,

40%

internally

modulated signal

is

received

from

the signal generator.

Practical receiver sensitivity

is

expressed in terms

of

a

minimum

input

signal voltage measured at the

AF

out-

put

for

20dB

of

signal-to-noise ratio. This sensitivity

can

ANT.

be

checked

by

measuring and adjusting the RF

amplifier

section.

Note

that

this receiver

will

produce

an

image signal

in

addition

to

its

true

signal because

of

its superhetero-

dyne

action. Such

an

image

will

be

910kHz

different

from

its

true

signal when the intermediate frequency

is

455kHz,

and may appear nearly

as

strong

as

the

true

signal in short wave bands. However,

it

can

readily

be

identified

from

the

fact

that

the image

is

always above

its

true

signal

as

checked

by

shifting

the

signal generator

frequency back and

forth,

or

below

the

true

signal on

the receiver dial.

llu

II

FIG4.

TRACKING

ALIGNMENT

-

8-

(3) Suggestions on short wave band

adjustment

To

adjust a short wave receiver operating

at

fre-

quencies above 10MHz, connect

an

actual antenna

to

the

receiver

as

normally

used, and

twine

the

hot

lead

of

the

signal generator

to

this antenna in

two

or

three turns,

to

form

a capacitive coupling

for

adjustment. This small

coupling permits effective adjustment

without

affecting

the actual

conditions

of

the receiver.

An excessively large

input

will

impair

adjustment.

Reduce the attenuator setting

as

much

as

possible and

fully

raise receiver sensitivity. The

AVC

(automatic

volume

control)

may

be

left

operating.

-

9-

MAINTENANCE

1.

REMOVING

THE

CASE

Remove 3 setscrews each on the

left

and

right

side

plates

with

a Phillips screwdriver. The

case

can

then

be

readily removed

by

lifting

it

up

by

the grip

on

top,

since

the

case

does

not

have a

bottom.

2.

ATTACHING

THE

CASE

To

replace the

case

onto

the chassis, loosely thread

-10-

2 setscrews (marked

*)

before

mounting

the

case.

Place the

case

onto

the chassis starting

with

the rear

side and

fit

cuts provided at the

middle

rear

edges

of

left

and

right

side plates

onto

the setscrews attached before-

hand (marked

*).

Press

down

the

case

over the chassis

while

thrusting

it

rearward by the

case

until

the

case

is

placed on

the

case

properly.

In doing this operation,

be

careful

not

to

allow

the

front

ends

of

the

case

to

strike

the panel and damage.

Then,

fix

the

left

and

right

side plates

of

the

case

to

the chassis by screwing 2 setscrews

into

the holes

)

provided

on the

front

and

bottom

edges

of

the srde

plates. The

case

itself

has

no

face

or

ba<.k.

CAUTION:

When rerTlovrng

1.he

CiJSe,

pay

attention

ncn

to

touch

the internal prrnted

,·ircuit

bodrd and

other

pares. Also.

never

fc.;il

to

disc_onnel11he

power

'~ord

because 100\1/\C

(117V

or

2:30V

AC)

is

at the

printed

circuit

boards.

3.

REMOVING THE FRONT PANEL

To

remove

lhe

frun;

02w:el,

ioosen the setscrews

for

-11-

3

knobs

on

trle

panel and remove

the

knobs. Then,

remove 2 setscrews each

from

left

and rrght sides These

screws are used also

to

fix

the

case.

Further

remov•· 2

setscrews

from

the

bottom

of

the panel.

Then,

hold

the

pc;nel

with

both

hands and Dui!

it

to1Nard

you.

The

panel

will

then

corne

off

the

chas~rs

When rernoving ttle panel,

pull

it

gently

whric•

ta>

rng

care

not

to

allov;

the panel

to

be caught

hy

the

t8rr;\irld\S,

s\tdt~

y.:

..

t'

he-:,,

ne,,Jn ldrrq;,

etc.

AD0USTMENT

Model SG-402

is

shipped

after

factory

adjusted

about

the

following

items. When

it

is

to

be

readjusted,

however, calibrate the

power

source voltage before

adjustment.

The test

equipment

to

be

used

for

calibration

should also be calibrated ones.

Prior

to

adjustment. set the

controls

as

follows

unless otherwise noted.

(1)

MODULATION

(3) at

CW

(2)

OUTPUT

ATT

(6) at

HIGH

(3)

FREO.

RANGE

(8) at C

(4) RF

GAIN

(7) at

maximum

output

(fully

clockwise

position)

(5)

FREQUENCY

dial (9) at

1MHz

Prior

to

proceed in the adjustment, make DC

voltage checks

to

all

circuits

of

this signal generator

to

make sure

that

all

circuits

are

operating

normally.

For

proper

checking, refer

to

the

circuit

diagram on page 17.

1.

ADJUSTING THE OUTPUT VOLTAGE

(

1)

Connect

an

RF

voltmeter

to

output

terminals

(4)

and (5).

(2)

Adjust

semi-fixed resistor

VR2

until

the RF volt-

meter reads

more

than

0.1V

rms.

(If

an

ordinary

AC

voltmeter

is

used

as

an

alternative,

use

range A

allowing

its

narrower

frequency response.)

-12-

2.

ADJUSTING

INTERNAL

MODULATION

DEGREE

If

an

oscilloscope

is

used,

adjustment

may

be

accomplished

either

in a wave-envelope

pattern

or

trape-

zoidal pattern method. In

either

case,

adjust at a fre-

quency

within

range A

of

the signal generator.

(1) Set the

MODULATION

switch

to

INT.

(2) Connect

an

oscilloscope

to

output

terminals (4)

and (5).

(3)

Adjust

the semi-fixed resistor VR 1

until

approx-

imately

40%

of

modulation

is

obtained.

rM~l

L I

___l

Wave

envelope

pattern

method

Trapezoidal

pattern

method

3.

ADJUSTING THE POINTER

(1)

Fix

the variable capacitor

to

provide a

maximum

value.

(2)

Adjust

the

pointer

to

a

proper

position.

If

the

pointer

alone cannot give a

proper

setting, adjust

the

scale

plate

after

loosening its setscrew.

4.

ADJUSTING THE OSCILLATION

FREQUENCY

(

1)

Connect

a

frequency

counter

to

output

terminals

(4) and

(5).

(2) Set

the

FREOUE~JCY

RANGE

to

C and the

pointer

to

550kHz.

Confirm

that

the

oscillation

frequency

is

accurate

to

±1.5%

of

550kHz.

It

not.

adjust L3.

13)

Then,

shift

the

pointer

to 1.fSMHz, and

confirm

that

the

oscillation

frequency

is

1.5MHz

±1

5%.

If

not,

adjust

trimmer

TC1,

located on the variable

c:apaCIWr.

(4)

Return

the

pointer

to

550kHz

and

reconfirm

that

the stgnal generator

is

osc:llating at 5:SOkH;

±1.:)~-G.

If

thc;re

!S

a greater

deviation.

reneat adJustments

(2) and

13)

until

a

correct

frequer1cy

is

obtamed.

15)

Calibrate

other

ranges than C w1th the

pointer

betng

set

to

the

lowest

frequency

of

the range

And,

adjust coil L1

for

range

A,

cotI

L2

for

range

B.

coil

L4

for

range

0,

coil

L5

for

range E and

coil

L6

for

range F.

Trimmer

TC1,

which

has

been

finished

in

adJUStments (2) and (3),

should

not

be

touched.

(6)

Other

intermedtate

scale

graduations

are auto-

matically

calibrated

by the above adjustments.

-13-

CAUTIONS

(

1)

The

primary

voltage

of

the power transformer

can

be

altered

as

foil

ows.

Connections at

printed

circuit

board terminals:

100V

AC: Connect

to

No.

35

and 32

117V

AC: Connect

to

No.

34

and 32

230V

AC: Connect

to

No. 33 and 32

Fuse

for

230VAC

operation

is

0.1

A.

AC230V

AC

117V

AC

IOOV

.l

35

34

I

33

Fuse

32

0

31

0

30

-14-

(2)

Although

this signal generator

will

start operating

as

soon

as

power

is

supplied, however,

allow

approx·

imately 3 minutes

for

the

set

to

warm up when

making

an

accurate measurement.

(3) Since the attached shielded lead

has

capacitance

of

approx. 100pF (between a

conductor

and shield) ,

per 1m length,

output

voltage

will

be

affected large-

ly.

For

instance, attenuation by

it

is

6dB at 30MHz.

If

the above attenuation

is

seriously considered,

use

a single lead shorten.

In this

case,

the lead

will

be

affective inductively.

(4)

Avoid

to

install this

set

in a place which contains a

strong magnetic

or

electrostatic field

as

well

as

high

temperature

or

humidity.

(

NOTE: T

he

C11cu

1t 1

,----

---

- e ements ma

-

--

- Y be changed w

- - - -

lthout

not

-

-----

-

ICe

OWing t

-----

o a

technical.

----

Innovation

il

SG-402

.

-

17-

A

product

of

TRIO-KEN'WOOD

CORPORATION

17-5, 2-chome,

Shibuya,

Shibuya-ku,

Tokyo

150,

Japan

05112

PRINTED

IN

JAPAN

850-0725-00

(G)

Trio SG-402 User manual

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