Hameg Hm 203-7 User manual

Instruments

MANUAL

Oscilloscope

HM

203-7

Table

of

contents

Oscilloscope

datasheet

with

technical

details

.

P

1

Accessories

.Z

1

Operating

Instructions

General

Information

.Ml

Use

of

tilt

handle.

Ml

Safety.Ml

Operating

conditions.M2

Guarantee

.M2

Maintenance.M2

Switching

over

the

mains/line

voltage.M2

Type

of

the

signal

voltage

.M3

Amplitude

Measurement.M3

Time

Measurements.M

4

Connection

of

Test

Signal

.M

6

First

Time

Operation.M

7

Trace

Rotation.

M

7

Probe

compensation

and

use.

M

7

1

kHz

compensation.M

8

1

MHz

compensation.M

8

Operating

modes

of

the

vertical

amplifiers

....

M

8

X-Y

Operation.

M

9

Phase

difference

measurement

in

DUAL

mode

.

M

9

Measurement

of

an

amplitude

modulation

....

M10

Triggering

and

time

base.M10

Automatic

Triggering.M10

Normal

Triggering,

Slope.Mil

Trigger

coupling.

Mil

Alternate

Triggering.Ml

2

Line

Triggering.Ml

2

Triggering

of

video

signals.Ml

2

External

triggering,

Trigger

indicator.Ml3

Holdoff-time

adjustment.Ml

3

Component

Tester.Ml

3

Test

patterns.Ml

6

Short

instruction

K

1

Front

panel

elements

Folder

with

front

view

.K

2

Test

Instructions

General.T

1

Cathode-Ray

Tube;

Brightness

and

Focus,

Linearity,

Raster

Distortions.T

1

Astigmatism

Check.T

1

Symmetry

and

Drift

of

the

Vertical

Amplifier

.

.

.

.

T

1

Calibration

of

the

Vertical

Amplifier.T

1

Transmission

Performance

(Vertical

Amplifier)

.

.

.

T

2

Operating

Modes:

CH

I/ll,

DUAL,

ADD,

CHOP.,

INVERT

and

X-Y

Operation.T

2

Triggering

Checks

.T

3

Timebase.T

3

Holdofftime

.T

4

Component

Tester.T

4

Trace

Alignment.T

4

Mains/Line

Voltage

Checks.T

4

Oscilloscope

HM

203-7

Service

Instructions

General.SI

Instrument

Case

Removal.SI

Operating

Voltages.SI

Maximum

and

Minimum

Brightness.SI

Astigmatism

control.S

2

Trigger

Threshold.S

2

Trouble-Shooting

the

Instrument.S

2

Replacement

of

Components

and

Parts.S3

Replacementof

the

Power

Transformer.S3

Adjustments.S3

Circuit

Diagrams

Wiring

Diagram.D

1

Identification

of

electrical

components.D

2

Y-Inputs,

Attenuators,

Preamplifier

Channel

I

and

Channel

II.D

3

Y

Intermediate

Amplifier

Channel

I

and

Channel

II

Channel

Selection,

Component

Tester.D

4

Trigger

Circuit,

TV

Sync

Separator,

Calibrator.

.

.

.D

5

X

and

Y

Final

Amplifier.D6

Timebase

Circuit,

Trigger

Control.D

7

CRT

Circuit,

Unblanking

.D

8

Power

Supply.D

9

Component

Locations

EY

Board.DIO

Component

Locations

CO

(IF)

Board.DIO

Component

LocationsXY

Board.Dll

Component

Locations

TB

Board.D12

Subject

to

change

without

notice

5.91

•

203-7

OSCILLOSCOPE

HM

203-7

Specification

(

21

°

C;

ismin.)

Vertical

Deflection

Operating

modes;

Channel

I

orCh.

II

separate,

Channel

I

and

II:

alternate

or

chopped;

(Chopper

frequency

approx.

0.4

MHz).

Sum

or

difference

of

Ch.

I

and

Ch.

II.

(channel

II

invertible).

X-Y

Mode:

via

Channel

I

and

Channel

II.

Frequency

range:

2x

DC

to

20MH2

(-3dB).

Risetime:

approx.

17.5ns.

Overshoot:

^1

%.

Deflection

coefficients:

10

calibrated

steps

from

5mV/div.

to

5V/div

in

1-2-5

sequence.

Accuracy

in

calibrated

position:

±3%.

Variable

2.5:1

to

max,

12.5V/div.

Y-magnification

x5

(calibrated)

to

1

mV/div.

±5%

(frequency

range

DC

to

3.5MHz,

—3dB)

Input

impedance:

1

MQ

II

25pF.

Input

coupling:

DC-AC-GD

(Ground)

Input

voltage:

max.

400V

(DC

+

peak

AC).

Y-output

from

Ch.

I

or

Ch.

II

(optional)

Trigger

System

With

automatic;

10Hz-40MHz.

>0.5div.

normal

with

level

control

from

DC-40MHz.

Slope:

positive

or

negative.

ALT.

triggering

;

LED

indication

for

trigger

action.

Sources:

Ch.

I,

Ch.

II,

line,

external.

Coupling:

AC

(S10Hz

-10

MHz),

DC

(0

-10

MHz),

LF

(0

-

<50kHz),

HF

(>1,5kHz

•

40MHz).

Threshold

external

>0.3V.

Active

TV-Sync-Separator

for

line

and

frame.

Horizontal

Deflection

Time

coefficients:

18

calibrated

steps

from

0.2|is/div.

to

0.1

s/div.

in

1-2-5

sequence,

accuracy

in

calibrated

position:

±3%.

variable

2.5:1

to

max.

0.25s/div.,

with

X-Magnifier

x10

(±

5%)

to

==

20ns/div..

Hold-Off

time:

variable

to

approx.

10:1.

Bandwidth

X-Amplifier:

DC-3

MHz

(-3dB).

Input

X-Amplifier

via

Channel

II,

sensitivity

see

Ch.

II

specification.

X-Y

phase

shift:

<3°

below

220kHz.

Z

input

(optional)

Component

Tester

Test

voltage:

approx.

8.5Vm,5

(open

circuit).

Test

current:

approx.

8mA,(shorted).

Test

frequency:

^

line

frequency.

Test

connection:

2

banana

jacks

4mm

0.

One

test

lead

is

grounded

(Safety

Earth).

General

Information

Cathode-ray

tube:

D14-364

P43/123,

or

ER151

-GH/-,

rectangular

screen,

intern,

graticule.

8x10cm

Acceleration

voltage:

2000V,

Trace

rotation:

adjustable

on

front

panel.

Calibrator:

square-wave

generator

==

1

kHz

for

probe

compensation.

Output:

0.2Vand2V

+1

%.

Line

voltage:

110,

125,

220,

240

V~

±10%.

Line

frequency:

50Hz

to

400Hz.

Power

consumption

:

=

37

Watt

(at

50

Hz).

Max.

ambient

temperature:

-(-10°C...-T40°C.

Protective

system:

Safety

Class

I

(lEC

348).

Weight:

approx.

7.5kg.

Colour:

techno-brown.

Cabinet:

W

285,

H

145,

D

380mm.

Lockable

tilt

handle.

20

MHz

Standard

Oscilloscope

2

Channels,

max.

1

mV/div.

sensitivity;

Component

Tester

Timebase:

0,1s/div.

to

20ns/div.;

Variable

Holdoff;

Alternate

Triggering;

Triggering:

DC-40MHz;

TV

Sync

Separator;

Trigger

LED

The

HM

203-7

is

Western

Europe's

best

selling

oscilloscope

because

it

responds

thoroughly

to

customer

demands

for

reliability,

superior

perfor¬

mance,

and

ease

of

operation.

The

outstanding

transient

response

of

the

HM

203-7,

particularly

when

displaying

square

wave

signals,

is

one

of

the

pre-eminent

features

of

this

quality

instrument,

the

integrity

of

the

signals

reproduced

by

this

oscilloscope

reflect

a

dedication

to

engineering

excellence

normally

only

found

in

expensive

labora¬

tory

instruments.

As

an

aid

to

ensure

the

correct

polarities

when

displaying

the

sum,

difference,

or

video

signals,

an

"invert"

control

is

provided

on

channel

II.

Technically

advanced

triggering

circuits

enable

the

user

to

attain

clear,

stable

displays

from

DC

to

over

40

MHz,

with

input

levels

as

low

as

0.5

divisions.

The

Holdoff

control

enables

even

complex

asynchronous

waveforms

to

be

solidly

displayed.

Trigger

action

is

indicated

by

an

LED,

which

illuminates

whenever

the

trigger

threshold

point

is

crossed.

And

for

the

display

of

video

signals,

the

HM

203-7

has

a

low

distortion

active

TV

sync

separator,

which

allows

for

auto¬

matic

synchronizing

with

line

and

frame

frequencies.

"Alternate

triggering"

mode

enables

the

display

of

two

asynchronous

signals

simulteneously.

The

CRT's

8x10

cm

internal

graticule

enhances

parallax-free

viewing

over

a

wide

field.

In

addition,

the

CRT

is

fully

shielded

with

mumetal

to

prevent

display

distortion

in

the

presence

of

magnetic

fields.

As

a

practical,

built-in

feature,

the

component

tester

enables

the

operator

to

quickly

identify

faulty

semiconductors

and

a

large

variety

of

individual

compo¬

nents,

both

in

circuit

and

out.

The

HM203-7

was

specifically

designed

for

use

in

production

lines,

general

service

applications,

and

for

technical

training

facilities.

The

multiplicity

of

display

modes,

the

easy-to-understand

front

panel,

and

the

operational

simplicity

of

the

HM203-7

make

it

also

an

ideal

training

scope

for

educational

purposes.

Accessories

supplied

Two

10:1

probes.

Line

cord.

Operators

Manual.

Subject

to

change

without

notice.

OSCILLOSCOPE

ACCESSORIES

Test

Cable

Banana-BNC

HZ32

Coaxial

test

cable;

length

1.15m,

characteristic

impedance

50fl.

Cable

capacitance

120pF.

Input

voltage

max.

500Vp.

Test

Cable

BNC

-

BNC

HZ34

Coaxial

test

cable;

length

1

m,

characteristic

impedance

50J1.

Cable

capacitance

126pF.

Input

voltage

max.

500Vp.

Adapter

Banana-BNC

HZ20

Two

4mm

binding

posts

(19mm

between

centers)

to

standard

BNC

male

plug.

Input

voltage

max.

500Vp.

son

Through-Termination

HZ22

For

terminating

systems

with

50

Q

characteristic

impedance.

Modular

Probes

Maximum

load

2W.

Max.

voltage

lOVp^s-

The

clear

advantage

over

ordinary

probes

are

field

replaceable

parts

and

the

HF-compensation

feature

on

the

10:1

attenuator

pro¬

bes.

For

the

first

time,

probes

in

this

price

range

allow

adjustments

of

their

FIF-characteristics

to

match

individually

the

input

imped¬

ance

of

each

scope.

This

is

particularly

important

for

scopes

with

higher

bandwidths

(>50MFIz),

as

otherwise

strong

overshoot

or

rounding

may

occur,

when

measuring

fast-rising

square

waves.

An

exact

FIF-compensation,

however,

is

only

possible

with

square-

wave

generators

having

a

risetime

<5ns.

Most

FIAMEG

scopes

already

feature

such

a

calibration

generator.

For

other

oscillo¬

scopes,

it

is

available

as

accessory

item

FIZ60-2.

At

present

the

following

Modular

Probes

are

available

(FIZ36

without

HF-com-

pensation);

Type

HZ36

selectable

Attenuation

Ratio

1:1/10:1

Bandwidth

min.

(MFIz)

10/100

Risetime

(ns)

35/3.5

Inp,

Capacitance

(pF)

47/18

Inp.

Resistance

(Mil)

1/10

Inp.

Voltage

max.

(Vp)

600

Cable

Length

(m)

1.5

Spare

Cable

for

HZ36

Spare

Cable

for

HZ51.

HZ54

Sparepart

Kit

(2

sprung

hooks.

2

HZ51

HZ52

HZ53

HZ54

selectable

10:1

10:1

(HF)

100:1

1:1/10:1

150

250

150

10/150

<2

<1.4

<2

35/<2

16

16

6,5

40/18

10

10

100

1/10

600

600

1200

600

1.2

1.5

1,5

1.2

HZ

39

HZ57

tips,

1

ground

cable)

HZ40

Demodulator

Probe

HZ55

Special

probe

for

AM-demodulation

and

wobbulator

measure¬

ments.

HF-Bandwidth

lOOkFIz

-

500MFIz

(±1dB).

AC

Input

Volt¬

age

250mV

-

50Vrms-

DC

Isolation

Voltage

200V

DC

including

peak

AC.

Cable

length

1.2m.

High

Voltage

Probe

HZ58

For

measurement

of

voltages

up

to

15kVpp.

Input

resistance

approx.

500mQ.

Recommended

load

resistance)

MQ/10MQ

(switchable).

Attenuation

ratio

1000:1.

Bandwidth

1

MFIz.

Cable

length

1.5

m.

BNC

connector.

Carrying

Cases

For

HM103

HZ95

For

HM

203,

HM204,

HM205,

HM208,

HM408,

HM604,

HM605

and

HM

1005

HZ96

Viewing

Hood

HZ47

ForHM203,

HM204,

HM205,

HM208,

HM408,

HM604,

HM605

and

HM

1005

Scope-Tester

HZ

6

O

-2

For

Checking

the

Y

amplifier,

timebase,

and

compensation

of

all

probes,

the

HZ

60-2

is

a

crystal-controlled,

fast

rising

(typ.

3

ns)

square-wave

generator

with

switchable

frequencies

of

DC,

1-10-

100Hz,

1-IO-IOOkHz,

and

1

MHz.

Three

BNC

outputs

provide

sig¬

nals

of

25

mVpp

into

50

Q,

0.25

Vpp

and

2.5

Vpp

(open

circuit

for

10x

and

lOOx

probes);

accuracy

±1%.

Battery-powered.

Component-Tester

HZ65

Indispensable

for

trouble-shooting

in

electronic

circuits.

Single

component

and

in-circuit

tests

are

both

possible.

The

HZ65

oper¬

ates

with

all

scopes,

which

can

be

switched

to

X-Y

operation

(ext.

horizontal

deflection).

Non-destructive

tests

can

be

carried

out

on

almost

all

semiconductors,

resistors,

capacitors,

and

coils.

Two

sockets

provide

for

quick

testing

of

the

3

junction

areas

in

any

small

power

transistor.

Other

components

are

connected

by

using

2

banana

jacks.

Test

leads

supplied.

Examples

of

Test

Displays:

Short

circuit

CapacitorSS^F

Junction

E-C

Z-Diode<8V

Printed

in

West

Germany

5/90

zi

Operating

Instructions

General

Information

Safety

This

oscilloscope

is

easy

to

operate.

The

logical

arrange¬

ment

of

the

controls

allows

anyone

to

become

familiar

with

the

operation

of

the

instrument

after

a

short

time,

however,

experienced

users

are

also

advised

to

read

through

these

instructions

so

that

all

functions

are

understood.

Immediately

after

unpacking,

the

instrument

should

be

checked

for

mechanical

damage

and

loose

parts

in

the

in¬

terior.

If

there

is

transport

damage,

the

supplier

must

be

in¬

formed

immediately.

The

instrument

must

then

not

be

put

into

operation.

Check

that

the

instrument

is

set

to

the

correct

mains/line

voltage.

If

not,

refer

to

instructions

on

page

M2.

Use

of

tilt

handle

To

view

the

screen

from

the

best

angle,

there

are

three

dif¬

ferent

positions

(C,

D,

E)forsetting

up

the

instrument.

If

the

instrument

is

set

down

on

the

floor

after

being

carried,

the

handle

remains

automatically

in

the

upright

carrying

posi¬

tion

(A).

In

order

to

place

the

instrument

onto

a

horizontal

surface,

the

handle

should

be

turned

to

the

upper

side

of

the

oscillo¬

scope

(C).

For

the

D

position

(10°

inclination),

the

handle

should

be

turned

in

the

opposite

direction

out

of

the

carry¬

ing

position

until

it

locks

in

place

automatically

underneath

the

instrument.

For

the

E

position

(20°

inclination),

the

handle

should

be

pulled

to

release

it

from

the

D

position

and

swing

backwards

until

it

locks

once

more.

The

handle

may

also

be

set

to

a

position

for

horizontal

carry¬

ing

by

turning

it

to

the

upper

side

to

lock

in

the

B

position.

At

the

same

time,

the

instrument

must

be

moved

upwards,

because

otherwise

the

handle

will

jump

back.

This

instrument

has

been

designed

and

tested

in

accor¬

dance

with

lEC

Publication

348,

Safety

Requirements

for

Eiectronic

Measuring

Apparatus,

and

has

left

the

factory

in

a

safe

condition.

The

present

instruction

manual

contains

important

information

and

warnings

which

have

to

be

fol¬

lowed

by

the

user

to

ensure

safe

operation

and

to

retain

the

oscilloscope

in

safe

condition.

The

case,

chassis

and

all

measuring

terminals

are

connected

to

the

protective

earth

contact

of

the

appliance

inlet.

The

instrument

operates

ac¬

cording

to

Safety

C/ass

/

(

three-conductor

power

cord

with

protective

earthing

conductor

and

a

plug

with

earthing

con¬

tact).

The

mains/line

plug

shall

only

be

inserted

in

a

socket

outlet

provided

with

a

protective

earth

contact.

The

protec¬

tive

action

must

not

be

negated

by

the

use

of

an

extension

cord

without

a

protective

conductor.

Warningl

Any

interruption

of

the

protective

conductor

inside

or

outside

the

instrument

or

disconnection

of

the

protective

earth

terminai

is

iikely

to

make

the

instru¬

ment

dangerous.

Intentional

interruption

of

the

protec¬

tive

earth

connection

is

prohibited.

The

mains/line

piug

should

be

inserted

before

connections

are

made

to

measuring

circuits.

The

grounded

accessible

metal

parts

(case,

sockets,

jacks)

and

the

mains/line

supply

contacts

(line,

neutral)

of

the

in¬

strument

have

been

tested

against

insulation

breakdown

with

2000Vr.m.s.

(50Hz).

Under

certain

conditions,

50

Hz

or

60

Hz

hum

voltages

can

occur

in

the

measuring

circuit

due

to

the

interconnection

with

other

mains/line

powered

equipment

or

instruments.

This

can

be

avoided

by

using

an

isolation

transformer

(Safety

Class

II).

When

displaying

waveforms

where

the

"low-level"

side

of

the

signal

is

at

a

high

potential,

even

with

the

use

of

a

protective

isolation

transformer,

it

should

be

noted

that

this

potential

is

connected

to

the

oscillo¬

scope's

case

and

other

accessible

metal

parts.

High

volt¬

ages

are

dangerous.

In

this

case,

special

safety

precautions

are

to

be

taken,

which

must

be

supervised

by

qualified

per¬

sonnel

if

the

voltage

is

higher

than

42

V.

Most

cathode-ray

tubes

develop

X-rays.

However,

the

dose

equivalent

rate

falls

far

below

the

maximum

per¬

missible

value

of

36pA/kg

(O.SmR/h).

Whenever

it

is

likely

that

protection

has

been

impaired,

the

instrument

shall

be

made

inoperative

and

be

secured

against

any

unintended

operation.

The

protection

is

likely

to

be

impaired

if,

for

example,

the

instrument

-

shows

visible

damage,

-

fails

to

perform

the

intended

measurements,

-

has

been

subjected

to

prolonged

storage

under

un¬

favourable

conditions

(e.g.

in

the

open

or

in

moist

envi¬

ronments),

-

has

been

subject

to

severe

transport

stress

(e.g.

in

poor

packaging).

Subject

to

change

without

notice

Ml

Operating

conditions

Maintenance

The

instrument

has

been

designed

for

indoor

use.

The

permissible

ambient

temperature

range

during

opera¬

tion

is

-I-10°C...

-t-40°C.

It

may

occasionally

be

subjected

to

temperatures

between

-l-10°Cand

-10°C

without

degrad¬

ing

its

safety.

The

permissible

ambient

temperature

range

for

storage

or

transportation

is

-40°C

...

-I-70°C.

The

maximum

operating

altitude

is

up

to

2200

m

(non¬

operating

15000

m).

The

maximum

relative

humidity

is

up

to

80%.

If

condensed

water

exists

in

the

instrument

it

should

be

acclimatized

before

switching

on.

In

some

cases

(e.g.

extremely

cold

oscilloscope)

two

hours

should

be

allowed

before

the

instrument

is

put

into

operation.

The

instrument

should

be

kept

in

a

clean

and

dry

room

and

must

not

be

operated

in

explosive,

corrosive,

dusty,

or

moist

environ¬

ments.

The

oscilloscope

can

be

operated

in

any

position,

but

the

convection

cooling

must

not

be

impaired.

The

ven¬

tilation

holes

may

not

be

covered.

For

continuous

opera¬

tion

the

instrument

should

be

used

in

the

horizontal

posi¬

tion,

preferably

tilted

upwards,

resting

on

the

tilt

handle.

The

specifications

stating

tolerances

are

only

valid

if

the

instrument

has

warmed

up

for

30

minutes

at

an

ambient

temperature

between

-h15C°and

+30C°.

Val¬

ues

not

stating

tolerances

are

typical

for

an

average

instrument.

Guarantee

Each

instrument

runs

through

a

quality

test

with

10

hour

burn-in

before

leaving

the

production.

Practically

every

early

failure

is

detected

in

intermittent

operation

by

this

method.

However,

it

is

possible

that

a

component

fails

only

after

a

lengthy

operating

period.

Therefore

a

functional

guaran¬

tee

of

2

years

is

given

for

all

units.

The

condition

for

this

is

that

no

modifications

have

been

made

in

the

instrument.

In

the

case

of

shipments

by

post,

rail

or

carrier

it

is

recom¬

mended

that

the

original

packing

is

carefully

preserved.

Transport

damages

and

damage

due

to

gross

negligence

are

not

covered

by

the

guarantee.

In

the

case

of

a

complaint,

a

label

should

be

attached

to

the

housing

of

the

instrument

which

describes

briefly

the

faults

observed.

If

at

the

same

time

the

name

and

telephone

number

(dialing

code

and

telephone

or

direct

number

or

department

designation)

is

stated

for

possible

queries,

this

helps

towards

speeding

up

the

processing

of

guarantee

claims.

Various

important

properties

of

the

oscilloscope

should

be

carefully

checked

at

certain

intervals.

Only

in

this

way

is

it

largely

certain

that

all

signals

are

displayed

with

the

accu¬

racy

on

which

the

technical

data

are

based.

The

test

methods

described

in

the

test

plan

of

this

manual

can

be

performed

without

great

expenditure

on

measuring

instru¬

ments.

However,

purchase

of

the

new

HAM

EG

scope

test¬

er

HZ

60,

which

despite

its

low

price

is

highly

suitable

for

tasks

of

this

type,

is

very

much

recommended.

The

exterior

of

the

oscilloscope

should

be

cleaned

regularly

with

a

dusting

brush.

Dirt

which

is

difficult

to

remove

on

the

casing

and

handle,

the

plastic

and

aluminium

parts,

can

be

removed

with

a

moistened

cloth

(99%

water

-Fl

%

mild

detergent).

Spirit

or

washing

benzine

(petroleum

ether)

can

be

used

to

remove

greasy

dirt.

The

screen

may

be

cleaned

with

water

or

washing

benzine

(but

not

with

spirit

(alcohol)

or

solvents),

it

must

then

be

wiped

with

a

dry

clean

lint-free

cloth.

Under

no

circumstances

may

the

cleaning

fluid

get

into

the

instrument.

The

use

of

other

cleaning

agents

can

attack

the

plastic

and

paint

surfaces.

Switching

over

the

mains/line

voltage

The

instrument

is

set

for

220

V

line

voltage

on

delivery.

It

can

be

switched

over

to

other

voltages

at

the

fuse

holder

combined

with

the

3-pole

appliance

inlet

at

the

rear

of

the

instrument.

Firstly

the

fuse

holder

printed

with

the

voltage

values

is

removed

using

a

small

screw

driver

and

-

if

required

-

provided

with

another

fuse.

Refer

to

the

table

below

for

the

prescribed

value

of

the

fuse.

Then

replace

the

fuse

holder

so

that

the

impressed

white

triangle

points

to

the

desired

voltage.

Here

pay

attention

that

the

cover

plate

is

also

correctly

engaged.

The

use

of

repaired

fuses

or

short

circuiting

the

fuse

holder

is

not

allowed.

Damage

arising

because

of

this

is

not

covered

by

the

guarantee.

220

R

\

ir>

N>

CM

1-

o

0

0

1

oil

V-

y

Fuse

type:

Size

5

x

20

mm;

250

V~,

C;

lEC

127,

Sheet

III;

DIN

sheet

3).

Cutoff:

time

lag

(T).

Line

voltage

110V~±10%

125V~±10%

220V~±10%

240V~±10%

41

662

(possibly

DIN

41

571

Fuse

rating

T0.63

A

T0.63

A

T0.315A

T0.315A

M2

Subject

to

change

without

notice

Type

of

the

signal

voltage

With

the

HM

203-7,

practically

all

periodically

repeating

sig¬

nals

with

the

frequency

spectrum

below

20

MHz

can

be

examined.

The

display

of

simple

electrical

processes,

such

as

sinusoidal

RF

and

LF

signals

or

line

frequency

hum

volt¬

ages

is

straightforward.

When

recording

square-wave

or

pulse-type

signal

voltages,

it

must

be

noted

that

their

har¬

monics

must

also

be

transmitted.

The

repetition

frequency

of

the

signal

must

therefore

be

significantly

smaller

than

the

upper

limit

frequency

of

the

vertical

amplifier.

Accurate

evaluation

of

such

signals

is

only

possible

up

to

approxi¬

mately

2

MHz

repetition

frequency.

Displaying

composite

signals

can

be

difficult,

especially

if

they

contain

no

repetive

higher

amplitude

content

which

can

be

used

for

triggering.

This

is

the

case

with

bursts,

for

instance.

To

obtain

a

well-triggered

display

in

this

case,

the

assistance

of

the

variable

holdoff

and/or

variable

time

con¬

trol

may

be

required.

Television

video

signals

are

relatively

easyto

trigger

using

the

built-in

TV-Sync-Separator

with

correct

trigger

slope

setting.

For

optional

operation

as

a

DC

or

AC

voltage

amplifier,

the

vertical

amplifier

input

is

provided

with

a

DC/AC

switch.

The

DC

position

should

only

be

used

with

a

series-con¬

nected

attenuator

probe

or

at

very

low

frequencies

or

if

the

measurement

of

the

DC

voltage

content

of

the

signal

is

absolutely

necessary.

When

displaying

very

low

frequency

pulses,

the

flat

tops

may

be

sloping

with

AC

coupling

of

the

vertical

amplifier

(AC

limit

frequency

approx.

1.6

Hz

for

-3dB).

In

this

case,

DC

operation

is

preferred,

provided

the

signal

voltage

is

not

superimposed

on

a

too

high

DC

level.

Otherwise

a

capacitor

of

adequate

capacitance

must

be

connected

to

the

input

of

the

vertical

amplifier

with

DC

coupling.

This

capacitor

must

have

a

sufficiently

high

breakdown

voltage

rating.

DC

cou¬

pling

is

also

recommended

for

the

display

of

logic

and

pulse

signals,

especially

if

the

pulse

duty

factor

changes

con¬

stantly.

Otherwise

the

display

will

move

upwards

or

down¬

wards

at

each

change.

Pure

direct

voltages

can

only

be

measured

with

DC-coupling.

Amplitude

Measurements

In

general

electrical

engineering,

alternating

voltage

data

normally

refers

to

effective

values

(rms

=

root-mean-

square

value).

However,

for

signal

magnitudes

and

voltage

designations

in

oscilloscope

measurements,

the

peak-to-

peak

voltage

(Vpp)

value

is

applied.

The

latter

corresponds

to

the

real

potential

difference

between

the

most

positive

and

most

negative

points

of

a

signal

waveform.

If

a

sinusoidal

waveform,

displayed

on

the

oscilloscope

screen,

is

to

be

converted

into

an

effective

(rms)

value,

the

resulting

peak-to-peak

value

must

be

divided

by

2xy~2

=

2.83.

Conversely,

it

should

be

observed

that

sinusoidal

volt¬

ages

indicated

in

(Veff)

have

2.83

times

the

potential

dif¬

ference

in

Vpp.

The

relationship

between

the

different

volt¬

age

magnitudes

can

be

seen

from

the

following

figure.

Voltage

values

of

a

sine

curve

V,ms

=

effective

value;

Vp

=

simple

peak

or

crest

value:

Vpp

=

peak-to-peak

value:

'^mom

=

momentary

value.

The

minimum

signal

voltage

which

must

be

applied

to

the

Y

input

for

a

trace

of

1

div.

height

is

ImVpp

when

the

Y

MAG.xS

pushbutton

is

depressed,

the

VOLTS/DIV.

switch

is

set

to

BmV/div.,

and

the

vernier

is

set

to

CAL

by

turning

the

fine

adjustment

knob

of

the

VOLTS/DIV.

switch

clockwise

all

the

way.

However,

smaller

signals

than

this

may

also

be

displayed.

The

deflection

coefficients

on

the

input

attenuators

are

indicated

in

mV/div.

or

V/div.

(peak-to-peak

value).

The

magnitude

of

the

applied

voltage

is

ascertained

by

multiplying

the

selected

deflection

coefficient

by

the

vertical

display

height

in

div.

If

an

attenuator

probe

xIOis

used,

a

further

multiplica¬

tion

by

a

factor

of

10

is

required

to

ascertain

the

correct

voltage

value.

For

exact

amplitude

measurements,

the

variable

con¬

trol

on

the

attenuator

switch

must

be

set

to

its

calibra¬

ted

detent

CAL.

When

turning

the

variable

control

ccw,

the

sensitivity

will

be

reduced

by

a

factor

of

2.5.

Therefore

every

intermediate

value

is

possible

within

the

1-2-5

sequence.

With

direct

connection

to

the

vertical

input,

signals

up

to

lOOVpp

may

be

displayed

(attenuator

set

to

5V/div.,

vari¬

able

control

to

left

stop).

With

the

designations

H

=

display

height

in

div.,

U

=

signal

voltage

in

Vpp

at

the

vertical

input,

D

=

deflection

coefficient

in

V/div.

at

attenuator

switch,

the

required

quantity

can

be

calculated

from

the

two

given

quantities:

U-DH

H.U

D

=

U

Subject

to

change

without

notice

M3

203-7

However,

these

three

values

are

not

freely

selectable.

They

have

to

be

within

the

following

limits

(trigger

threshold,

accuracy

of

reading):

H

between

0.5

and

8div.,

if

possible

3.2

to

8div.,

U

between

1

mVpp

and

40Vpp,

D

between

1

mV/div.

and

5V/div.

in

1-2-5

sequence.

Examples:

Set

deflection

coefficient

D

=

50mV/div.

^

0.05

V/div.,

observed

display

height

H

=

4.6

div.,

required

voltage

U

=

0.05

-4.6

=

0.23

Vpp.

Input

voltage

U

=

5Vpp,

set

deflection

coefficient

D

=

1

V/div.,

required

display

height

H

=

5:1

=

5div.

Signal

voltage

U

=

220\/,^,-2-VY

=

622

Vpp

(voltage

>

40Vpp,

with

probe

x

100:

U

=

6.22

Vpp),

desired

display

height

H

=

min.

3.2div.,

max.

8div.,

max.

deflection

coefficient

D

=

6.22:3.2

=

1.94V/div.,

min.

deflection

coefficient

D

=

6.22:8

=

0.78V/div.,

adjusted

deflection

coefficient

D

=

1

V/div.

If

the

applied

signal

is

superimposed

on

a

DC

(direct

voltage)

level

the

total

value

(DC

+

peak

value

of

the

alternating

voltage)

of

the

signal

across

the

Y-input

must

not

exceed

±400V

(see

figure).

This

same

limit

applies

to

normal

xIO

attenuator

probes,

the

attenuation

ratio

of

which

allows

signal

voltages

up

to

approximately

400Vpp

to

be

evaluated.

Voltages

of

up

to

approximately

2,400Vpp

may

be

measured

by

using

the

HZ53

high

voltage

probe

which

has

an

attenuation

ratio

of

100:1.

It

should

be

noted

that

its

ACpeak

value

is

derated

at

higher

frequencies.

If

a

normal

xIO

probe

is

used

to

measure

high

voltages

there

is

the

risk

that

the

compensation

trimmer

bridging

the

attenuator

series

resistor

will

break

down

causing

damage

to

the

input

of

the

oscilloscope.

However,

if

for

example

only

the

residual

ripple

of

a

high

voltage

is

to

be

displayed

on

the

oscilloscope,

a

normal

xIO

probe

is

sufficient.

In

this

case,

an

appropriate

high

voltage

capacitor

(approx.

22-

68

nF)

must

be

connected

in

series

with

the

input

tip

of

the

probe.

Voltage

Total

value

of

input

voltage

The

dotted

line

shows

a

voltage

alternating

at

zero

volt

level.

When

superim¬

posed

a

DC

level,

the

addition

of

the

positive

peak

and

the

DC

voltage

results

in

the

max.

voltage

(DC

-i-

ACpeaJ.

It

is

very

important

that

the

oscilloscope

input

coupling

is

set

to

DC,

if

an

attenuator

probe

is

used

for

voltages

higher

than

400V

(see

page

IVI6:

Connection

of

Test

Signal).

With

Y-POS.

control

(input

coupling

to

GD)

it

is

possible

to

set

a

horizontal

graticule

line

as

reference

line

for

ground

potential

before

the

measurement.

It

can

lie

below

or

above

the

horizontal

central

line

according

to

whether

posi¬

tive

and/or

negative

deviations

from

the

ground

poterntial

are

to

be

measured.

Certain

switchable

xIO/xl

attenuator

probes

also

have

a

built-in

ground

reference

switch

posi¬

tion.

Time

Measurements

As

a

rule,

most

signals

to

be

displayed

are

periodically

repeating

processes,

also

called

periods.

The

number

of

periods

per

second

is

the

repetition

frequency.

Depending

on

the

time

base

setting

of

the

TIME/DIV.

switch,

one

or

several

signal

periods

or

only

a

part

of

a

period

can

be

dis¬

played.

The

time

coefficients

are

stated

in

ms/div.

and

\>s/

div.

on

the

TIME/DIV.-switch.

The

scale

is

accordingly

divided

into

two

fields.

The

duration

of

a

signal

period

or

a

part

of

it

is

deter¬

mined

by

multipiying

the

reievant

time

(horizontal

dis¬

tance

in

div.)

by

the

time

coefficient

set

on

the

TIME/

DlM.-switch.

The

variabie

time

control

(identified

with

an

arrow

knob

cap)

must

be

in

its

caiibrated

position

CAL.

(arrow

pointing

horizontally

to

the

right).

With

the

designations

L

=

displayed

wave

length

in

div.

of

one

period,

T

=

time

In

seconds

for

one

period,

F

=

recurrence

frequency

in

Hz

of

the

signal,

Tc

=

time

coefficient

in

s/div.

on

timebase

switch

and

the

relation

F

=

1

/T,

the

following

equations

can

be

stated;

H

II

1“

t-

II

II

P-lH

F

-

,

1_

L

-

.1

T

-

^

L’Tc

F-Tc

LF

With

depressed

X-MAG.

x10

pushbutton

the

Tg

value

must

be

divided

by

10.

However,

these

four

values

are

not

freely

selectable.

They

have

to

be

within

the

following

limits:

L

between

0.2

and

lOdiv.,

if

possible

4

to

lOdiv.,

T

between

0.02

[xs

and

1

s,

F

between

0.5

Hz

and

20

MHz,

Tc

between

0.2[is/div.

and

0.1

s/div.

in

1-2-5

sequence

(with

X-MAG.

xIO

in

out

position),

and

Tc

between

20ns/div.

and

10

ms/div.

in

1-2-5

sequence

(with

pushed

X-MAG.

x

10

pushbutton).

M4

203-7

Subject

to

change

without

notice

Examples:

Displayed

wavelength

L

=

7div.,

set

time

coefficient

=

0.2

^is/div.,

required

period

T

=

7

0.2-10”®

=

1.4(is

required

rec.

freq.

F

=

1

;(1.4-10”®)

=

714

kHz.

Signal

period

T

=

0.5s,

set

time

coefficient

=

0.2s/div.,

required

wavelength

L

=

0.5:0.2

=

2.5div..

Displayed

ripple

wavelength

L

=

1

div.,

set

time

coefficient

=

10

ms/div.,

required

ripple

freq.

F

=

1

:

(1

-lO-IO”®)

=

100

Hz.

TV-line

frequency

F

=

15

625

Hz,

set

time

coefficient

Tc

=

lO^rs/div.,

required

wavelength

L

=

1

:(15

625

-10“®)

=

6.4div..

Sine

wavelength

L

=

min.

4div.,

max.

10div.,

Frequency

F

=

1

kHz,

max.

time

coefficient

T;,

=

1:

(4-10®)

=

0.25

ms/div.,

min.

time

coefficient

Tc

=

1

:(10-10®)

=

0.1

ms/div.,

set

time

coefficient

=

0.2

ms/div.,

required

wavelength

L

=

1

(10®

0.2

10“®)

=

5div.

Displayed

wavelength

L

=

O.Sdiv.,

set

time

coefficient

T,,

=

0.5pis/div.,

pressedX-MAG.

xIO

button:

=

0.05^is/div.,

required

rec.

freq.

F

=

1:

(0.8-0.05-10“®)

=

25

MHz,

required

period

T

=

1:

(25

-10®)

=

40

ns.

If

the

time

is

relatively

short

as

compared

with

the

complete

signal

period,

an

expanded

time

scale

should

always

be

applied

(X-MAG.

xIO

button

pressed).

In

this

case,

the

ascertained

time

values

have

to

be

divided

by

10.

The

time

interval

of

interest

can

be

shifted

to

the

screen

center

using

the

X-POS.

control.

The

following

figure

shows

correct

positioning

of

the

oscil¬

loscope

trace

for

accurate

risetime

measurement.

100

%

90%

10

%

0

With

a

time

coefficient

of

0.2ns/div.

and

pushed

X-MAG

xIO

button

the

example

shown

in

the

above

figure

results

in

a

measured

total

risetime

of

t,ot

=

1.6div.-0.2ns/div.:

10

=

32ns

When

very

fast

risetimes

are

being

measured,

the

rise-

times

of

the

oscilloscope

amplifier

and

of

the

attenuator

probe

has

to

be

deducted

from

the

measured

time

value.

The

risetime

of

the

signal

can

be

calculated

using

the

fol¬

lowing

formula.

In

this

ttot

is

the

total

measured

risetime,

tosc

is

the

risetime

of

the

oscilloscope

amplifier

(approx.

17,5

ns),

and

tp

the

risetime

of

the

probe

(e.g.

=

2

ns).

If

ttot

is

greater

than

100

ns,

then

t^t

can

be

taken

as

the

risetime

of

the

pulse,

and

calculation

is

unnecessary.

Calculation

of

the

example

in

the

figure

above

results

in

a

signal

risetime

When

investigating

pulse

or

square

waveforms,

the

critical

feature

is

the

risetime

of

the

voltage

step.

To

ensure

that

transients,

ramp-offs,

and

bandwidth

limits

do

not

unduly

influence

the

measuring

accuracy,

the

risetime

is

generally

measured

between

70%

and

90%

of

the

vertical

pulse

height.

For

peak-to-peak

signal

amplitude

of

6div.

height,

which

are

symmetrically

adjusted

to

the

horizontal

center

line,

the

internal

graticule

of

the

CRT

has

two

horizontal

dot¬

ted

lines

±2.4div.

from

the

center

line.

Adjust

the

Y

attenuator

switch

with

its

variable

control

together

with

the

Y-POS.

control

so

that

the

pulse

height

is

precisely

aligned

with

these

0

and

100

%

lines.

The

10

%

and

90

%

points

of

the

signal

will

now

coincide

with

the

two

lines,

which

have

a

distance

of

±2.4div.

from

the

horizontal

center

line

and

an

additional

subdivision

of

0.2

div.

The

risetime

is

given

by

the

product

of

the

horizontai

distance

in

div.

between

these

two

coincidence

points

and

the

time

coefficient

setting.

If

magnification

is

used,

this

product

must

be

divided

by

10.

The

/a/Zf/meof

a

pulsecan

also

be

measured

by

using

this

method.

tr

=

y

32®

-

17.5®

-

2®

=

26.27

ns

The

measurement

of

the

rise

or

fall

time

is

not

limited

to

the

trace

dimensions

shown

in

the

above

diagram.

It

is

only

par¬

ticularly

simple

in

this

way.

In

principle

it

is

possible

to

measure

in

any

display

position

and

at

any

signal

amplitude.

It

is

only

important

that

the

full

height

of

the

signal

edge

of

interest

is

visible

in

its

full

length

at

not

too

great

steepness

and

that

the

horizontal

distance

at

10%

and

90%

of

the

amplitude

is

measured.

If

the

edge

shows

rounding

or

over¬

shooting,

the

100%

should

not

be

related

to

the

peak

val¬

ues

but

to

the

mean

pulse

heights.

Breaks

or

peaks

(glitches)

next

to

the

edge

are

also

not

taken

into

account.

With

very

severe

transient

distortions,

the

rise

and

fall

time

measurement

has

little

sense.

For

amplifiers

with

approxi¬

mately

constant

group

delay

(therefore

good

pulse

trans¬

mission

performance)

the

following

numerical

relationship

between

rise

time

tr

{in

ns)

and

bandwidth

B

(in

MHz)

applies;

tr

=

3|0

B

tr

Subject

to

change

without

notice

M5

203-7

Connection

of

Test

Signal

Caution:

When

connecting

unknown

signals

to

the

oscillo¬

scope

input,

always

use

automatic

triggering

and

set

the

DC-AC

input

coupling

switch

to

AC.

The

attenuator

switch

should

initially

be

set

to

5

V/div..

Sometimes

the

trace

will

disappear

after

an

input

signal

has

been

applied.

The

attenuator

switch

must

then

be

turned

back

to

the

left,

until

the

vertical

signal

height

is

only

3-8div.

With

a

signal

amplitude

greater

than

lOOVpp,

an

attenuator

probe

must

be

inserted

before

the

oscilloscope's

vertical

input.

If,

after

applying

the

signal,

the

trace

is

nearly

blanked,

the

period

of

the

signal

is

probably

substantially

longer

than

the

set

value

on

the

TIME/DIV.

switch.

It

should

be

turned

to

the

left

to

an

adequately

larger

time

coefficient.

The

signal

to

be

displayed

can

be

connected

directly

to

the

Y-input

of

the

oscilloscope

with

a

shielded

test

cable

such

as

HZ

32

and

HZ

34

or

attenuated

through

a

xIO

or

xlOO

attenuator

probe.

The

use

of

test

cables

with

high

imped¬

ance

circuits

is

only

recommended

for

relatively

low

fre¬

quencies

(up

to

approx.

50

kHz).

For

higher

frequencies,

the

signal

source

must

be

of

low

impedance,

i.e.

matched

to

the

characteristic

resistance

of

the

cable

(as

a

rule

50

Ohm).

Especially

when

transmitting

square

and

pulse

signals,

a

resistor

equal

to

the

characteristic

impedance

of

the

cable

must

also

be

connected

across

the

cable

directly

at

the

Y-

input

of

the

oscilloscope.

When

using

a

50

Ohm

cable

such

as

the

HZ

34,

a

50

Ohm

through

termination

type

HZ22

is

available

from

HAMEG.

When

transmitting

square

signals

with

short

rise

times,

transient

phenomena

on

the

edges

and

top

of

the

signal

may

become

visible

if

the

correct

ter¬

mination

is

not

used.

A

terminating

resistance

is

some¬

times

recommended

with

sine

signals

as

well.

Certain

amplifiers,

generators

or

their

attenuators

maintain

the

nominal

output

voltage

independent

of

frequency

only

if

their

connection

cable

is

terminated

with

the

prescribed

resistance.

Here

it

must

be

noted

that

the

terminating

resis¬

tor

HZ

22

will

only

dissipate

a

maximum

of

2

Watts.

This

power

is

reached

with

10

V^ms

or

-

at

28.3

Vpp

with

sine

sig¬

nal.

If

a

x10

or

x100

attenuator

probe

is

used,

no

termination

is

necessary.

In

this

case,

the

connecting

cable

is

matched

directly

to

the

high

impedance

input

of

the

oscilloscope.

When

using

attenuators

probes,

even

high

internal

imped¬

ance

sources

are

only

slightly

loaded

(approx.

10

MQ

II

16

pF

or

100

MQ

II

7

pF

with

HZ

53).

Therefore,

if

the

voltage

loss

due

to

the

attenuation

of

the

probe

can

be

compen¬

sated

by

a

higher

amplitude

setting,

the

probe

should

always

be

used.

The

series

impedance

of

the

probe

pro¬

vides

a

certain

amount

of

protection

for

the

input

of

the

ver¬

tical

amplifier.

Because

of

their

separate

manufacture,

all

attenuator

probes

are

only

partially

compensated,

therefore

accurate

compensation

must

be

performed

on

the

oscillo¬

scope

(see

"Probe

compensation"

page

M7).

Standard

attenuator

probes

on

the

oscilloscope

normally

reduce

its

bandwidth

and

increase

the

rise

time.

In

all

cases

where

the

oscilloscope

band

width

must

be

fully

utilized

(e.g.

for

pulses

with

steep

edges)

we

strongly

advise

using

the

modular

probes

HZ

51

(x10)

HZ52{x^

0

HF)

and

HZ54

(x1

and

xIO,

see

oscilloscope

accessories,

page

Z1).

This

can

save

the

purchase

of

an

oscilloscope

with

larger

bandwidth

and

has

the

advantage

that

defective

compo¬

nents

can

be

ordered

from

HAMEG

and

replaced

by

one¬

self.

The

probes

mentioned

havea

HF-calibration

in

addition

to

low

frequency

calibration

adjustment.

Thus

a

group

delay

correction

to

the

upper

limit

frequency

of

the

oscilloscope

is

possible

with

the

aid

of

an

1

MHz

calibrator,

e.g.

HZ60.

In

fact

the

bandwidth

and

rise

time

of

the

oscilloscope

are

not

noticably

changed

with

these

probe

types

and

the

wave¬

form

reproduction

fidelity

can

even

be

improved

because

the

probe

can

be

matched

to

the

oscilloscope's

individual

pulse

response.

If

a

xIO

orxIOO

attenuator

probe

is

used,

DC

input

cou¬

pling

must

always

be

used

at

voltages

above

400

V.

With

AC

coupling

of

low

frequency

signals,

the

attenuation

is

no

longer

independent

of

frequency,

pulses

can

show

pulse

tilts.

Direct

voltages

are

suppressed

but

load

the

oscil¬

loscope

input

coupling

capacitor

concerned.

Its

voltage

rat¬

ing

is

max.

400

V

(DC

-F

peak

AC).

DC

input

coupling

is

therefore

of

quite

special

importance

with

a

xlOO

attenua¬

tion

probe

which

usually

has

a

voltage

rating

of

max.

1

200

V

(DC

+

peak

AC).

A

capacitor

of

corresponding

capaci¬

tance

and

voltage

rating

may

be

connected

in

series

with

the

attenuator

probe

input

for

blocking

DC

voltage

(e.g.

for

hum

voltage

measurement).

With

all

attenuator

probes,

the

maximum

AC

input

volt¬

age

must

be

derated

with

frequency

usually

above

20

kHz.

Therefore

the

derating

curve

of

the

attenuator

probe

type

concerned

must

be

taken

into

account.

The

selection

of

the

ground

point

on

the

test

object

is

impor¬

tant

when

displaying

small

signal

voltages.

It

should

always

be

as

close

as

possible

to

the

measuring

point.

If

this

is

not

done,

serious

signal

distortion

may

result

from

spurious

cur¬

rents

through

the

ground

leads

or

chassis

parts.

The

ground

leads

on

attenuator

probes

are

also

particularly

critical.

They

should

be

as

short

and

thick

as

possible.

When

the

attenuator

probe

is

connected

to

a

BNC-socket,

a

BNC-

adapter,

which

is

often

supplied

as

probe

accessory,

should

be

used.

In

this

way

ground

and

matching

problems

are

eliminated.

Hum

or

interference

appearing

in

the

measuring

circuit

(especially

when

a

small

deflection

coefficient

is

used)

is

possibly

caused

by

multiple

grounding

because

equalizing

M6

203-7

Subject

to

change

without

notice

currents

can

flow

in

the

shielding

of

the

test

cables

(voltage

drop

between

the

protective

conductor

connections,

caused

by

external

equipment

connected

to

the

mains/line,

e.g.

signal

generators

with

interference

protection

capacitors).

First

Time

Operation

Check

that

the

instrument

is

set

to

the

correct

mains/

line

voltage.

(Refer

to

page

M2).

Before

applying

power

to

the

oscilloscope

it

is

recom¬

mended

that

the

following

simple

procedures

are

per¬

formed:

-

Check

that

all

pushbuttons

are

in

the

out

position,

i.e.

released.

-

Rotate

the

variable

controls

with

arrows,

i.e.

TIME/DIV.

variable

control,

CH.I

and

CH.II

attenuator

variable

con¬

trols,

and

HOLD

OFF

control

to

their

calibrated

detent.

-

Set

all

controls

with

marker

lines

to

their

midrange

posi¬

tion

(marker

lines

pointing

vertically).

-

The

TV

SEP.

lever

switch

and

the

TRIG,

selector

lever

switch

in

the

X-field

should

be

set

to

their

uppermost

position.

-

Both

GD

input

coupling

pushbutton

switches

for

CH.

I

and

CH.

II

in

the

Y-field

should

be

set

to

the

GD

position.

Switch

on

the

oscilloscope

by

depressing

the

red

POWER

pushbutton.

An

LED

will

illuminate

to

indicate

working

order.

The

trace,

displaying

one

baseline,

should

be

visible

after

a

short

warm-up

period

of

10

seconds.

Adjust

Y-POS.I

and

X-POS.

controls

to

center

the

baseline.

Adjust

INTENS.

(intensity)

and

FOCUS

controls

for

medium

brightness

and

optimum

sharpness

of

the

trace.

The

oscillo¬

scope

is

now

ready

for

use.

If

only

a

spot

appears

{CAUTION!

CRT

phosphor

can

be

damaged.),

reduce

the

intensity

immediately

and

check

that

the

X-Y

pushbutton

is

in

the

released

(out)

position.

If

the

trace

is

not

visible,

check

the

correct

positions

of

all

knobs

and

switches

(particularly

AT/NORM,

button

in

out

position).

To

obtain

the

maximum

life

from

the

cathode-ray

tube,

the

minimum

intensity

setting

necessary

for

the

measure¬

ment

in

hand

and

the

ambient

light

conditions

should

be

used.

Particular

care

is

required

when

a

single

spot

is

dis¬

played,

as

a

very

high

intensity

setting

may

cause

damage

to

the

fluorescent

screen

of

the

CRT.

Switching

the

oscillo¬

scope

off

and

on

at

short

intervals

stresses

the

cathode

of

the

CRT

and

should

therefore

be

avoided.

The

instrument

is

so

designed

that

even

incorrect

operation

will

not

cause

serious

damage.

The

pushbuttons

control

only

minor

functions,

and

it

is

recommended

that

before

commencement

of

operation

all

pushbuttons

are

in

the

"out"

position.

After

this

the

pushbuttons

can

be

operated

depending

upon

the

mode

of

operation

required.

The

HM

203-7

accepts

all

signals

from

DC

(direct

voltage)

up

to

a

frequency

of

at

least

20MHz

(-3dB).

For

sinewave

voltages

the

upper

frequency

limit

will

be

30-35MHz.

However,

in

this

higher

frequency

range

the

vertical

display

height

on

the

screen

is

limited

to

approx.

4-5div.

The

time

resolution

poses

no

problem.

For

example,

with

25MHz

and

the

fastest

adjustable

sweep

rate

(20ns/div.),

one

cycle

will

be

displayed

every

2div.

The

tolerance

on

indicated

val¬

ues

amounts

to

±3%

in

both

deflection

directions.

All

val¬

ues

to

be

measured

can

therefore

be

determined

relatively

accurately.

However,

from

approximately

6MHz

upwards

the

measuring

error

will

increase

as

a

result

of

loss

of

gain.

At

12MHz

this

reduction

is

about

10%.

Thus,

approxi¬

mately

11

%

should

be

added

to

the

measured

voltage

at

this

frequency.

As

the

bandwidth

of

the

amplifiers

differ

(normally

between

20

and

25MHz),

the

measured

values

in

the

upper

limit

range

cannot

be

defined

exactly.

Addition¬

ally,

as

already

mentioned,

for

frequencies

above

20MHz

the

dynamic

range

of

the

display

height

steadily

decreases.

The

vertical

amplifier

is

designed

so

that

the

transmission

performance

is

not

affected

by

its

own

overshoot.

Trace

Rotation

TR

In

spite

of

Mumetal-shielding

of

the

CRT,

effects

of

the

earth's

magnetic

field

on

the

horizontal

trace

position

cannot

be

completely

avoided.

This

is

dependent

upon

the

orientation

of

the

oscilloscope

on

the

place

of

work.

A

centred

trace

may

not

align

exactly

with

the

horizon¬

tal

center

line

of

the

graticule.

A

few

degrees

of

mis¬

alignment

can

be

corrected

by

a

potentiometer

acessi-

ble

through

an

opening

on

the

front

panel

marked

TR.

Probe

compensation

and

use

The

attenuator

probe

must

be

matched

exactly

to

the

input

impedance

of

the

vertical

amplifier

to

ensure

an

undistorted

display

of

waveforms.

A

generator

built

into

the

HM

203-7

supplies

a

square

wave

signal

for

this

purpose

with

very

short

rise

time

(<60

ns)

at

1

kHz.

The

square

wave

signal

can

be

taken

from

the

two

eyelets

beneath

the

screen.

One

output

supplies

0.2Vpp

±

1

%

for

x10

attenuator

probes,

the

Subject

to

change

without

notice

M7

203-7

other

2Vpp

±1%

for

xlOO

attenuator

probes.

These

volt¬

ages

correspond

in

each

case

to

a

screen

amplitude

of

4

div.

provided

the

input

attenuator

switch

of

the

HM

203-7

is

set

to

the

deflection

coefficient

5

mV/div.

1

kHz

compensation

This

trimmer

adjustment

compensates

the

capacitive

load¬

ing

of

the

oscilloscope

input

(approx,

25

pF

for

the

HM

203-7).

After

compensation,

the

capacitive

attenuation

has

the

same

attenuation

ratio

as

the

ohmic

divider.

The

same

volt¬

age

attenuation

then

results

at

high

and

low

frequencies

as

for

direct

voltage

(for

x1

probes

or

probes

switches

over

to

x1,

this

compensation

is

neither

necessary

nor

possible).

The

trace

line

must

be

parallel

with

the

horizontal

graticule

lines

(see

"Trace

rotation

TR",

page

M7).

Connect

attenuator

probe

(10:1

or

100:1)

to

the

CH.I

input,

do

not

press

any

buttons

or

turn

any

knobs,

set

input

cou¬

pling

to

DC,

input

attenuator

to

5

mV/div.

and

TIME/DIV.

switch

to

0.2

ms/div.

(both

variable

controls

in

calibration

position

CAL),

connect

probe

to

the

corresponding

CAL.

eyelet

(x10

probe

to

0.2

V

eyelet,

x100

to

2

V

eyelet).

2

cycles

can

be

seen

on

the

screen.

The

compensation

trim¬

mer

must

now

be

adjusted.

It

is

generally

located

in

the

probe

itself.

It

is

located

in

the

x100

attenuator

probe

HZ53

in

the

small

box

on

the

BNC

plug.

Adjust

the

trimmer

with

the

insulating

screw

driver

provided

until

the

tops

of

the

square

wave

signal

are

exactly

parallel

to

the

horizontal

graticule

lines

(see

1

kHz

diagram).

The

signal

height

should

then

be

4

div.

±0.12

div.

(=

3

%).

The

signal

edges

are

invis¬

ible

during

this

adjustment.

1

MHz

compensation

HF

adjustment

is

possible

for

the

HZ51,52,

and

54

probes.

These

possess

resonance

correction

elements

(pots

in

combination

with

coils

and

capacitors)

with

which

it

is

pos¬

sible

for

the

first

time

to

simply

adjust

the

probe

in

the

upper

frequency

range

of

the

vertical

amplifier.

After

this

compensation,

not

only

the

maximum

possible

bandwidth

is

obtained

in

the

attenuator

probe

mode

but

also

a

largely

constant

group

delay

at

the

end

of

the

bandwidth.

In

this

way

transient

distortions

(such

as

over¬

shooting,

rounding

off,

ringing,

holes

or

humps

in

the

pulse

top)

in

the

vicinity

of

the

leading

edge

are

kept

to

a

minimum.

The

bandwidth

of

the

HM

203-7

is

therefore

fully

utilized

when

using

the

HZ51,

52

and

54

probes

without

having

to

accept

wave

form

distortions.

Prerequisite

for

this

HF

compensation

is

a

square

wave

generator

with

short

rise

time

(typically

4

ns)

and

low-

impedance

output

(approx.

50

Ohm)

which

also

supplies

a

voltage

of

0.25

V

or

2.5

V

at

a

frequency

of

1

MHz.

The

Scope

Tester

HZ60

fullfills

these

tasks

excellently

(see

Accessories,

page

Z1).

Operating

modes

of

the

vertical

amplifiers

The

desired

operating

mode

of

the

vertical

amplifiers

is

selected

with

the

3

buttons

in

the

Y

field.

All

three

buttons

out

for

mono

mode.

Only

Channel

I

is

then

operational.

The

button

CHI

/CHII

must

be

depressed

in

mono

mode

for

Channel

II.

The

internal

triggering

is

simultaneously

switched

over

to

Channel

II

with

this

button.

If

the

DUAL

button

is

depressed,

both

channels

are

work¬

ing.

Two

signals

can

be

displayed

together

in

this

button

position

(alternate

mode).

This

mode

is

not

suitable

for

dis¬

playing

very

slow-running

processes.

The

display

then

flick¬

ers

too

much

or

it

appears

to

jump.

If

the

CHOP,

button

is

depressed

in

addition

to

DUAL,

both

channels

are

switched

over

constantly

at

a

high

frequency

within

a

sweep

period

(CHOP

mode).

Slow

running

processes

below

1

kHz

or

with

time

coefficients

higher

than

1

ms/cm

are

then

also

displayed

without

flicker.

The

dual

mode

chosen

is

less

important

for

signals

with

higher

repetition

frequency.

If

the

ADD

button

is

depressed,

the

signals

of

both

chan¬

nels

are

algebraically

added

(I

±

II).

Whether

the

resulting

display

shows

the

sum

or

difference

is

dependent

on

the

phase

relationship

or

the

polarity

of

the

signals

and

on

the

position

of

the

INVERT

button.

In-phase

input

voltages:

INV.

CHII

button

released

=

sum.

INV.

CHII

button

depressed

=

difference.

Antiphase

input

voltages:

INV.

CHII

button

released

=

difference.

INV.

CHII

button

depressed

=

sum.

In

the

ADD

mode

the

vertical

display

position

is

dependent

upon

the

Y-POS.

setting

of

both

channels.

The

same

attenuator

switch

position

is

normally

used

for

both

chan¬

nels

with

algebraic

addition.

Differentiai

measure/nenf

techniques

allow

direct

meas¬

urement

of

the

voltage

drop

across

floating

components

(both

ends

above

ground).

Two

identical

probes

should

be

used

for

both

vertical

inputs.

Using

a

separate

ground

con¬

nection

and

not

connecting

the

probe

or

cable

shields

to

the

circuit

under

test

avoid

ground

loops

(hum,

common-mode

disturbances).

M8

203-7

Subject

to

change

without

notice

X-Y

Operation

For

X-Y

operation,

the

pushbutton

in

the

X

field

marked

X-Y

must

be

depressed.

The

X

signal

is

then

derived

from

the

Channel

II

(HOR.

INP.).

The

calibration

of

the

X

signal

during

X-Y

operation

is

determined

by

the

setting

of

the

Channel

II

input

attenuator

and

variable

control.

This

means

that

the

sensitivity

ranges

and

input

imped¬

ances

are

identical

for

both

the

X

and

Y

axes.

However,

the

Y-POS.II

control

is

disconnected

in

this

mode.

Its

function

is

taken

over

by

the

X-POS.

control.

It

is

important

to

note

that

the

X-MAG.

xIO

facility,

normally

used

for

expanding

the

sweep,

should

not

be

operated

in

the

X-Y

mode.

It

should

also

be

noted

that

the

bandwidth

of

the

X

amplifier

is

>3

MHz

(-3dB),

and

therefore

an

increase

in

phase

differ¬

ence

between

both

axes

is

noticeable

from

50

kHz

upwards.

The

inversion

of

the

X-input

signal

using

the

INVERT

button

is

not

possible.

Lissajous

figures

can

bedisplayed

in

the

X-Ymo</efor

cer¬

tain

measuring

tasks:

-

Comparing

two

signals

of

different

frequency

or

bringing

one

frequency

up

to

the

frequency

of

the

other

signal.

This

also

applies

for

whole

number

multiples

or

fractions

of

the

one

signal

frequency.

-

Phase

comparison

between

two

signals

of

the

same

fre¬

quency.

Phase

comparison

with

Lissajous

figure

The

following

diagrams

show

two

sine

signals

of

the

same

frequency

and

amplitude

with

different

phase

angles.

Calculation

of

the

phase

angle

or

the

phase

shift

between

the

X

and

Y

input

voltages

(after

measuring

the

distances

a

and

b

on

the

screen)

is

quite

simple

with

the

following

for¬

mula

and

a

pocket

calculator

with

trigonometric

functions

and

besides

independent

of

both

deflecting

amplitudes

on

the

screen.

sin

cp

=

|

a

cp

=

arc

sin

^

The

following

must

be

noted

here:

—

Because

of

the

periodic

nature

of

the

trigonometric

func¬

tions,

the

calculation

should

be

limited

to

angles

<90°.

However

here

is

the

advantage

of

the

method.

-

Do

not

use

a

too

high

test

frequency.

The

phase

shift

of

the

two

oscilloscope

amplifiers

of

the

HM

203-7

in

the

X-

Y

mode

can

exceed

an

angle

of

3°

above

120

kHz.

-

It

cannot

be

seen

as

a

matter

of

course

from

the

screen

display

if

the

test

voltage

leads

or

lags

the

reference

volt¬

age.

A

CR

network

before

the

test

voltage

input

of

the

oscilloscope

can

help

here.

The

1

MQ

input

resistance

can

equally

serve

as

R

here,

so

that

only

a

suitable

capacitor

C

needs

to

be

connected

in

series.

If

the

aper¬

ture

width

of

the

ellipse

is

increased

(compared

with

C

short-circuited),

then

the

test

voltage

leads

the

refer¬

ence

voltage

and

vice

versa.

This

applies

only

in

the

reg¬

ion

up

to

90°

phase

shift.

Therefore

C

should

be

suffi¬

ciently

large

and

produce

only

a

relatively

small

just

observable

phase

shift.

Should

both

input

voltages

be

missing

or

fail

in

the

X-

Y

mode,

a

very

bright

iight

dot

is

dispiayed

on

the

screen.

This

dot

can

burn

into

the

phosphor

at

a

too

high

brightness

setting

(INTENS.

knob)

which

causes

either

a

lasting

loss

of

brightness,

or

in

the

extreme

case,

complete

destruction

of

the

phosphor

at

this

point.

Phase

difference

measurement

in

DUAL

mode

A

larger

phase

difference

between

two

input

signals

of

the

same

frequency

and

shape

can

be

measured

very

sim¬

ply

on

the

screen

in

Dual

mode

(DUAL

button

depressed).

The

time

base

should

be

triggered

by

the

reference

signal

(phase

position

0).

The

other

signal

can

then

have

a

leading

or

lagging

phase

angle.

Alternate

mode

should

be

selected

for

frequencies

>1

kHz;

the

Chop

mode

is

more

suitable

for

frequencies

<1

kHz

(less

flickering).

For

greatest

accu¬

racy

adjust

not

much

more

than

one

period

and

approxi¬

mately

the

same

height

of

both

signals

on

the

screen.

The

variable

controls

for

amplitude

and

time

base

and

the

LEVEL

knob

can

also

be

used

for

this

adjustment

-

without

influence

on

the

result.

Both

base

lines

are

set

onto

the

hori¬

zontal

graticule

center

line

with

the

Y-POS.

knobs

before

the

measurement.

With

sinusoidal

signals,

observe

the

zero

(crossover

point)

transitions;

the

sine

peaks

are

less

accurate.

If

a

sine

signal

is

noticably

distorted

by

even

har¬

monics,

or

if

an

offset

direct

voltage

is

present,

AC

coupling

is

recommended

for

both

channels.

If

it

is

a

question

of

pulses

of

the

same

shape,

read

off

at

steep

edges.

Phase

difference

measurement

in

duai

mode

t

=

horizontal

spacing

of

the

zero

transitions

in

cm.

T

=

horizontal

spacing

for

one

period

In

cm.

In

the

example

illustrated,

t

=

3cm

and

T

=

10cm.

The

phase

difference

in

degrees

is

calculated

from

(p^=—-360°=—-360°=

108°

^

T

10

Subject

to

change

without

notice

M9

203-7

or

expressed

in

radians

Relatively

small

phase

angles

at

not

too

high

frequencies

can

be

measured

more

accurately

in

the

X-Y

mode

with

Lis-

sajous

figures.

Measurement

of

an

amplitude

modulation

The

momentary

amplitude

u

at

time

f

of

a

HF-carrier

volt¬

age,

which

is

amplitude

modulated

without

distortion

by

a

sinusoidal

AF

voltage,

is

in

accordance

with

the

equation

Figure

2

Amplitude

modulated

oscillation:

F=

1

MHz;

f=

1

kHz;

m

=

50%;

Ut=

28.3

mV,„„.

If

the

two

values

a

and

bare

read

from

the

screen,

the

mod¬

ulation

factor

is

calculated

from

m=

-—-

bzw.

m

=

-—-

•100[%]

a

+

b

a

+

b

where

a

=

Uj

(1+m)

and

b

=

Uj

(1—m).

The

variable

controls

for

amplitude

and

time

can

be

set

arbitrarily

in

the

modulation

factor

measurement.

Their

position

does

not

influence

the

result.

Triggering

and

time

base

u

=

Uj-

sinSlt

+

0,5m

•

l/j-

•

cos(Q—o>)t

—

0,5m

•

Uf

•

cos(S2-hco)t

where

Uj

=

unmodulated

carrier

amplitude

Si

=

=

angular

carrier

frequency

(a

=

27rf

=

modulation

angular

frequency

m

=

modulation

factor

(g

1

^

100%).

The

lower

side

frequency

F—

fand

the

upper

side

frequency

F-/-f

arise

because

of

the

modulation

apart

from

the

carrier

Figure

1

F-f

F

F+f

Amplitude

and

frequency

spectrum

for

AM

display

(m

=

50%)

The

display

of

the

amplitude-modulated

HF

oscillation

can

be

evaluated

with

the

oscilloscope

provided

the

frequency

spectrum

is

inside

the

oscilloscope

bandwidth.

The

time

base

is

set

so

that

several

wave

of

the

modulation

fre¬

quency

are

visible.

Strictly

speaking,

triggering

should

be

external

with

modulation

frequency

(from

the

AF

generator

or

a

demodulator).

However,

internal

triggering

is

fre¬

quently

possible

with

normal

triggering

(AT-NORM.

button

depressed)

using

a

suitable

LEVEL

setting

and

possibly

also

using

the

time

variable

adjustment.

Oscilloscope

setting

for

a

signal

according

to

figure

2:

Depress

no

buttons.

Y.

CH.

I;

20mV/div.;

AC.

TIME/DIV.;

0.2ms/div.

Triggering:

NORMAL;

with

LEVEL-setting;

internal

(or

external)

triggering.

A

signal

can

be

displayed

only

if

the

time

base

is

running

or

triggered.

To

produce

a

stationary

display,

triggering

must

be

synchronous

with

the

test

signal.

This

is

possible

by

using

the

test

signal

itself

or

by

an

externally

supplied

but

synchronous

signal

voltage.

The

trigger

voltage

should

have

a

certain

minimum

amplitude.

This

value

is

called

the

trigger

threshold.

It

is

measured

with

a

sine

signal.

When

the

trigger

voltage

is

taken

internally

from

the

test

signal,

the

trigger

threshold

can

be

stated

as

vertical

display

height

in

mm,

through

which

the

time

base

generator

starts,

the

display

is

stable,

and

the

trigger

LED

lights.

The

internal

trigger

threshold

of

the

HM

203-7

is

given

as

^5

mm.

When

the

trigger

voltage

is

externally

supplied,

it

can

be

measured

in

Vpp

at

the

TRIG.

INP.

socket.

Normally,

the

trigger

threshold

may

be

exceeded

up

to

a

maximum

factor

of

20.

The

HM

203-7

has

two

trigger

modes,

which

are

charac¬

terized

in

the

following.

Automatic

Triggering

If

the

AT/NORM,

pushbutton

in

the

X

field

is

in

the

out

posi¬

tion

AT,

the

sweep

generator

is

running

without

test

signal

or

external

trigger

voltage.

A

base

line

is

always

displayed

even

without

a

signal

applied.

This

trigger

mode

is

therefore

Ml

0

203-7

Subject

to

change

without

notice

called

Automatic

Triggering.

Operation

of

the

scope

needs,

having

a

constantly

visible

trace,

only

a

correct

amplitude

and

time

base

setting.

A

LEVEL

adjustment

is

neither

necessary

nor

possible

with

automatic

triggering.

This

simple

AT

mode

is

recommended

for

all

uncompli¬

cated

measuring

tasks.

However,

automatic

triggering

is

also

the

appropriate

operation

mode

for

the

"entry"

into

dif¬

ficult

measuring

problems,

e.g.

when

the

test

signal

is

un¬

known

relating

to

amplitude,

frequency

or

shape.

Presetting

of

all

parameters

is

now

possible

with

automatic

triggering;

the

change

to

normal

triggering

can

follow

thereafter.

The

automatic

triggering

works

above

10Hz

up

to

at

least

40MHz.

The

changeover

to

the

break

down

of

the

automa¬

tic

triggering

at

frequencies

under

10Hz

is

abrupt.

How¬

ever,

it

can

not

be

recognized

by

the

TRIG.

LED;

this

is

still

blinking.

Break

down

of

triggering

is

best

recognizable

at

the

left

screen

edge

(the

start

of

the

trace

in

differing

display

height).

The

automatic

triggering

follows

immediately

all

variations

or

fluctuations

of

the

test

signal

above

10

Hz.

However,

if

the

pulse

duty

factor

of

a

square-wave

signal

changes

so

much

that

one

part

of

the

square-wave

reduces

to

a

needle

pulse,

switching

over

to

normal

triggering

and

using

the

LEVEL

control

can

be

necessary.

With

automatic

triggering,

the

trigger

point

lies

approx,

in

the

zero

voltage

crossing.

The

time

interval,

required

for

the

time

base

start,

can

be

too

short

at

a

steep

zero

crossing

of

the

needle

pulse.

Then

normal

triggering

should

be

used.

Automatic

triggering

is

practicable

not

only

with

internal

but

also

with

external

trigger

voltage.

Normal

Triggering

With

normal

triggering

(AT/NORM,

button

depressed)

and

LEVEL

adjustment,

the

sweep

can

be

started

by

signals

within

the

frequency

range

selected

by

the

TRIG,

coupling

switch.

In

the

absence

of

an

adequate

trigger

signal

or

when

the

trigger

controls

(particularly

the

LEVEL

con¬

trol)

are

misadjusted,

no

trace

is

visible,

i.e.

the

screen

blanked

completely.

When

using

the

internal

normal

triggering

mode,

it

is

possi¬

ble

to

trigger

at

any

amplitude

point

of

a

signal

edge,

even

with

very

complex

signal

shapes,

by

adjusting

the

LEVEL

control.

Its

adjusting

range

is

directly

dependent

on

the

dis¬

play

height,

which

should

be

at

least

O.Sdiv.

If

it

is

smaller

than

1

div.,

the

LEVEL

adjustment

needs

to

be

operated

with

a

sensitive

touch.

In

the

external

normal

triggering

mode,

the

same

applies

to

approx.

0.6V

external

trigger

voltage

amplitude.

Other

measures

for

triggering

of

very

complex

signals

are

the

use

of

the

time

base

variable

control

and

HOLDOFF

time

control,

hereinafter

mentioned.

Slope

The

trigger

point

can

be

placed

alternatively

on

a

rising

or

fal¬

ling

edge

of

the

test

signal.

This

is

valid

with

automatic

and

with

normal

triggering.

The

selected

slope

is

set

with

the

+/—

button.

The

plus

sign

(button

released)

means

an

edge,

which

is

coming

from

a

negative

potential

and

rising

to

a

positive

potential.

That

has

nothing

to

do

with

zero

or

ground

potential

and

absolute

voltage

values.

The

positive

slope

may

also

lie

in

a

negative

part

of

a

signal.

A

falling

edge

(minus

sign)

triggers,

when

the

+/—

button

is

depressed.

However,

with

normal

triggering,

the

trigger

point

may

be

varied

within

certain

limits

on

the

chosen

edge

using

the

LEVEL

control.

Trigger

coupling

The

coupling

mode

and

accordingly

the

frequency

range

of

the

trigger

signal

can

be

changed

using

the

TRIG,

selector

switch.

However,

this

is

possible

only

with

the

TV

SEP.

switch

in

OFF

position.

AC:

Trigger

range

>

10Hz

to

10MHz.

This

is

the

most

frequently

used

trigger

mode.

The

trigger

threshold

is

increasing

below

10

Hz

and

above

10MHz.

DC:

Trigger

range

DC

to

10MHz.

DC

triggering

is

recommended,

if

the

signal

is

to

be

triggered

with

quite

slow

processes

or

if

pulse

signals

with

constantly

changing

pulse

duty

fac¬

tors

have

to

be

displayed.

Always

work

with

normal

triggering

and

LEVEL

adjustment.

Otherwise

there

is

the

possibility

in

the

AT

posi¬

tion

(automatic

triggering)

that

the

trigger

point

may

change

or

that

triggering

may

not

occur

with

signals

without

zero

crossing

(e.g.

with

DC

offset).

Sometimes

triggering

is

easier

with

AC

input

coupling,

because

the

signal

then

has

its

average

value

exactly

at

the

oscilloscope's

ground

potential.

HF:

Trigger

range

1.5

kHz

to

40

MHz

(high-pass

filter).

The

HF

position

is

suitable

for

all

radio-frequency

signals.

DC

fluctuations

and

low-frequency

excess

noise

of

the

trigger

voltage

are

suppres¬

sed,

giving

a

stable

display.

The

trigger

threshold

increases

below

1.5

kHz.

LF:

Trigger

range

DC

to

50kHz

(low-pass

filter).

The

LF

position

is

often

more

suited

for

low-fre¬

quency

signals

than

the

DC

position,

because

the

(white)

noise

in

the

trigger

voltage

is

strongly

sup-

Subject

to

change

without

notice

Mil

203-7

pressed.

So

jitter

or

double-triggering

of

complex

sig¬

nals

is

avoidable

or

at

least

reduced,

in

particular

with

very

low

input

voltages.

The

trigger

threshold

increases

above

1

kHz.

Alternate

triggering

With

alternate

triggering

(ALT.

button

depressed)

it

is

possible

to

use

normal

triggering

from

both

channels

simul¬

taneously

(1

and

II)

in

alternate

DUAL

mode.

The

two

signal

frequencies

can

also

be

asymc/ironous

with

respect

to

one

another

when

doing

so.

So

that

the

two

signals

can

be

shifted

about

independently

of

one

another

on

the

scope

screen,

if

possible

AC

input

coupling

should

be

used

for

both

channels.

In

this

case

the

same

trigger

threshold

of

O.Bdiv.

holds.

The

trigger

pulse

is

derived

from

the

signal

being

written

at

that

point

in

time,

i.e.

alternately

from

the

two

signals.

It

is

not

posible

to

view

a

single

waveform

in

alternate

mode

with

this

triggering

type

Line

triggering

A

part

of

a

secondary

winding

voltage

of

the

power

trans¬

former

is

used

as

mains/line

frequency

trigger

signal

(50

to

60

Hz)

in

the

~

position

of

the

TRIG,

selector

switch.

This

trigger

mode

is

independent

of

amplitude

and

frequency

of

the

Y

signal

and

is

recommended

for

all

mains/line

syn¬

chronous

signals.

This

also

applies

-

within

certain

limits

-

to

whole

number

multiples

or

fractions

of

the

line

fre¬

quency.

Line

triggering

can

also

be

useful

to

display

signals

below

the

trigger

threshold

(less

than

5

mm).

It

is

therefore

particularly

suitable

for

measuring

small

ripple

voltages

of

mains/line

rectifiers

or

stray

magnetic

field

in

a

circuit.

Magnetic

leakage

(e.g.

from

a

power

transformer)

can

be

investigated

for

direction

and

amplitude

using

a

search

or

pick-up

coil.

The

coil

should

be

wound

on

a

small

former

with

a

maximum

of

turns

of

a

thin

lacquered

wire

and

con¬

nected

to

a

BNC

connector

(for

scope

input)

via

a

shielded

cable.

Between

cable

and

BNC

center

conductor

a

resistor

of

at

least

100Q

should

be

series-connected

(RF

decou¬

pling).

Often

it

is

advisable

to

shield

statically

the

surface

of

the

coil.

However,

no

shorted

turns

are

permissible.

Maximum,

minimum,

and

direction

to

the

magnetic

source

are

detectable

at

the

measuring

point

by

turning

and

shift¬

ing

the

coil.

Triggering

of

video

signals

The

built-in

active

TV-Sync-Separator

(separation

of

the

sync

pulses

from

the

video

signal

and

following

amplifica¬

tion)

even

allows

the

display

of

noisy,

changing

in

amplitude

or

distorted

video

signals,

alternatively

triggered

with

line

(or

horizontal)

frequency

or

frame

(or

vertical)

frequency.

The

TV

SEP.

lever

switch

has

three

positions.

The

OFF

position

serves

to

all

normal

operations;

the

TRIG,

selector

switch

is

operative.

The

TV:

H

position

(horizontal

^

line)

and

the

TV:

V

position

(vertical

^

frame)

are

used

for

video

triggering.

The

TRIG,

coupling

switch

is

inoperable

in

these

both

positions.

In

the

TV:

V

position

(frame

triggering),

a

low-pass

filter

or

integrating

network

is

connected

into

cir¬

cuit,

which

forms

a

trigger

pulse

sequence

with

frame

fre¬

quency

from

the

vertical

sync

pulse

(incl.

pre-

and

post¬

equalizing

pulses).

For

accurate

function

of

the

sync

separator,

the

slope

of

the

sync

pulses

should

correctly

be

adjusted

(corresponding

to

the

position

of

the

sync

pulses

in

the

composite

color

sig¬

nal.

If

the

sync

pulses

are

placed

above

the

picture

content,

the

-F/—

button

should

be

released.

The

trigger

point

lies

on

the

rising

front

edge

of

the

sync

pulse.

If

they

are

below

the

picture

content,

the

-F/—

button

should

be

depressed.

The

trigger

point

lies

on

a

falling

(negative)

front

edge

of

the

sync

pulse.

This

setting

of

the

slope

is

valid

for

line

and

frame

fre¬

quency.

An

incorrectly

set

slope

results

in

an

unstable

dis¬

play.

The

trigger

slope

cannot

be

changed

using

the

INVERT

buttons.

The

+/—

button

relates

always

to

the

input

signal!

Video

signals

are

triggered

in

the

automatic

mode.

Therefore

the

adjustment

of

the

trigger

point

with

LEVEL

knob

is

superfluous.

The

internal

triggering

is

virtu¬

ally

independent

of

the

display

height,

which

may

differ

from

0.8

to

8div.

Depressing

the

AT/NORM,

button

results

in

an

incorrect

working

of

TV

triggering.

Aside

from

the

TV

SEP.

switch

and

the

-F/—

button

setting,

a

time

coefficient,

adequate

to

the

measuring

purpose,

should

be

selected

on

the

TIME/DIV.

switch.

The

basic

positions

for

H

(horizontal

^

line)

and

V

(vertical

^

frame)

are

marked

on

the

scale

of

the

TIME/DIV.

switch.

How¬

ever,

the

TIME/DIV.

knob

may

be

turned

more

to

the

right

(without

break

down

of

the

triggering),

if

more

details

in

the

video

signal

should

be

required.

More

adventageous,

because

one

video

field

is

suppressed,

is

the

use

of

the

10-

fold

expansion

with

the

X-MAG.

xIO

button

and

the

HOLD-

OFF

time

setting.

Disconnecting

the

trigger

circuit

(e.g.

by

rapidly

pressing

and

releasing

the

EXT.

button)

can

result

in

triggering

the

consecutive

(odd

or

even)

field.

Setting:

TV:

V,

2

ms/div.,HOLDOFF

knob

at

the

right

stop,

X-MAG.

xIO

button

depressed,

searching

the

picture

detail

with

X-POS.

knob.

So

the

International

Insertion

Test

Sig¬

nals

including

Video

Text

and

VPS

etc.

in

the

vertical

blank¬

ing

interval

are

fully

visible

with

a

10:1

expansion

ratio.

The

sync-separator-circuit

also

operates

with

external

trig¬

gering.

It

is

important

that

the

voltage

range

(0.3

Vpp

to

6

Vpp)

for

external

triggering

should

be

noted.

In

addition,

the

cor¬

rect

slope

setting

is

again

critical,

because

the

external

trig-

M12

203-7

Subject

to

change

without

notice

ger

signal

rnay

not

have

the

same

polarity

or

pulse

edge

as

the

test

signal.

This

can

be

checked,

if

the

external

trigger

voltage

itself

is

displayed

at

first

(with

internal

triggering).

Generally,

the

composite

video

signal

has

a

high

DC

con¬

tent.

With

a

constant

video

information

(e.g.

test

pattern

or

color

bar

generator),

the

DC

content

can

be

suppressed

easily

by

AC

input

coupling

of

the

oscilloscope

amplifier.

With

a

changing

picture

content

(e.g.

normal

program),

DC

input

coupling

is

recommended,

because

the

display

varies

its

height

on

screen

with

AC

input

coupling

at

each

change

of

the

picture

content.

The

DC

content

can

be

compensated

using

the

Y-POS.

control

so

that

the

signal

display

lies

in

the

graticule

area.

Then

the

composite

video

signal

should

not

exceed

a

vertical

height

of

6cm.

External

triggering

The

internal

triggering

is

disconnected

by

depressing

the

EXT.

button.

The

timebase

can

be

triggered

externally

the

TRIG.

INP.

socket

using

a

O.SVpp

to

5Vppvoltage,

which

is

in

syncronism

with

the

test

signal.

This

trigger

voltage

may

have

completely

different

form

from

the

test

signal

voltage.

Triggering

is

even

possible

-

in

certain

limits

-

with

whole

number

multiples

or

fractions

of

the

test

fre¬

quency,

but

only

in

locked

phase

relation.

The

input

impedance

of

TRIG.

INP.

socket

is

approx.

1

MQII35pF.

The

maximum

input

voltage

of

the

input

cir¬

cuit

is

100V

(DC-f

peak

AC).

Only

5Vpp

maximum

are

required

for

a

good

external

triggering.

Trigger

indicator

An

LED

on

condition

(to

the

left

of

the

TRIG,

switch)

indi¬

cates

that

the

sweep

generator

is

triggered.

This

is

valid

with

automatic

and

with

normal

triggering.

The

indication

of

trigger

action

facilitates

a

sensitive

LEVEL

adjustment,

par¬

ticularly

at

very

low

signal

frequencies.

The

indication

pulses

are

of

only

100

ms

duration.

Thus

for

fast

signals

the

LED

appears

to

glow

continuously,

for

low

repetition

rate

signals,

the

LED

flashes

at

the

repet¬

ition

rate

or

-

at

a

display

of

several

signal

periods

-

not

only

at

the

start

of

the

sweep

at

the

left

screen

edge,

but

also

at

each

signal

period.

Holdoff-time

adjustment

this

off

period

cannot

trigger

the

timebase.

Particularly

with

burst

signals

or

aperiodic

pulse

trains

of

the

same

amplitude,

the

start

of

the

sweep

can

be

delayed

until

the

optimum

or

required

moment.

A

very

noisy

signal

or

a

signal

with

a

higher

interfering

frequency

is

at

times

double

displayed.

It

is

possible

that

LEVEL

adjustment

only

controls

the

mutual

phase

shift,

but

not

the

double

display.

The

stable

single

dis¬

play

of

the

signal,

required

for

the

evaluation,

is

easily

obtainable

by

expanding

the

holdoff

time.

To

this

end

the

HOLDOFF

knob

is

slowly

turned

to

the

right,

until

one

signal

is

dispiayed.

A

double

display

is

possible

with

certain

pulse

signals,

where

the

pulses

alternately

show

a

small

difference

of

the

peak

amplitudes.

Only

a

very

exact

LEVEL

adjustment

makes

a

single

display

possible.

The

use

of

the

HOLD-OFF

knob

simplifies

the

right

adjustment.

After

specific

use

the

HOLD-OFF

control

should

be

re-set

into

its

calibration

detent,

otherwise

the

brightness

of

the

display

is

reduced

drastically.

The

function

is

shown

in

the

following

figures.

Function

of

var.

HOLD-OFF

control

Fig.

1

shows

a

case

where

the

HOLD-OFF

knob

is

in

the

minimum

position

and

various

different

waveforms

are

overlapped

on

the

screen,

making

the

signal

observation

unsuccessful.

Fig.

2

shows

a

case

where

only

the

desired

parts

of

the

signal

are

stably

dis¬

played.

If

it

is

found

that

a

trigger

point

cannot

be

located

on

extremely

complex

signals

even

after

repeated

and

careful

adjustment

of

the

LEVEL

control

in

the

normal

triggering

mode,

a

stable

display

may

be

obtained

using

the

HOLD¬

OFF

control

(in

the

X-field).

This

facility

varies

the

hold-off

time

between

two

sweep

periods

approx,

up

to

the

ratio

10:1.

Pulses

or

other

signal

waveforms

appearing

during

Component

Tester

General

The

HM

203-7

has

a

built-in

electronic

Component

Tester

(ab¬

breviated

CTi.

which

is

used

for

instant

display

of

a

test

pat¬

tern

to

indicate

whether

or

not

components

are

faulty.

The

Subject

to

change

without

notice

Ml3

203-7

CT

can

be

used

for

quick

checks

of

semiconductors

(e.g.

diodes

and

transistors),

resistors,

capacitors,

and

inductors.

Certain

tests

can

also

be

made

to

integrated

circuits.

All

these

components

can

be

tested

in

and

out

of

circuit.

The

test

principle

is

fascinatingly

simple.

The

power

trans¬

former

of

the

oscilloscope

delivers

a

sine

voltage,

which

is

applied

across

the

component

under

test

and

a

built-in

fixed

resistor.

The

sine

voltage

across

the

test

object

is

used

for

the

horizontal

deflection,

and

the

voltage

drop

across

the

resistor

(i.e.

current

through

test

object)

is

used

for

vertical

deflection

of

the

oscilloscope.

The

test

pattern

shows

a

cur-

rent-voltage

characteristic

of

the

test

object.

Since

this

circuit

operates

with

mains/line

frequency

(50

or

60

Hz)

and

a

voltage

of

8.5

V

max.

(open

circuit),

the

indicat¬

ing

range

of

the

CT\s

limited.

The

impedance

of

the

compo¬

nent

under

test

is

limited

to

a

range

from

20

Q

to

4.7

kQ.

Below

and

above

these

values,

the

test

pattern

shows

only

short-circuit

or

open-circuit.

For

the

interpretation

of

the

dis¬

played

test

pattern,

these

limits

should

always

be

borne

in

mind.

However,

most

electronic

components

can

normally

be

tested

without

any

restriction.

Using

the

Component

Tester

The

CT

is

switched

on

by

depressing

the

CT

pushbutton

beneath

the

screen.

This

makes

the

vertical

preamplifier

and

the

timebase

generator

inoperative.

A

shortened

hori¬

zontal

trace

will

be

observed.

It

is

not

necessary

to

discon¬

nect

scope

input

cables

unless

in-circuit

measurements

are

to

be

carried

out.

In

the

CT

mode,

the

only

controls

which

can

be

operated

are

INTENS.,

FOCUS,

and

X-POS..

All

other

controls

and

settings

have

no

influence

on

the

test

operation.

For

the

component

connection,

two

simple

test

leads

with

4mm

0

banana

plugs,

and

with

test

prod,

alligator

clip

or

sprung

hook,

are

required.

The

test

leads

are

connected

to

the

insulated

CT

socket

and

the

adjacent

ground

socket

in

the

Y-Section.

The

component

can

be

connected

to

the

test

leads

either

way

round.

After

use,

to

return

the

oscilloscope

to

normal

operation,

release

the

CT

pushbutton.

Test

Procedure

Caution!

Do

not

test

any

component

in

iive

circuitry

—

remove

all

grounds,

power

and

signals

connected

to

the

component

under

test.

Setup

Component

Tester

as

stated

above.

Connect

test

leads

across

component

to

be

tested.

Observe

oscilloscope

display.

Only

discharged

capacitors

should

be

tested!

A

built-in

quick-acting

fuse

protects

the

CT

and

the

oscillo¬

scope

against

mis-operation,

e.g.

device

under

test

not

dis¬

connected

from

mains/line

supply.

In

that

case

the

fuse

will

blow.

For

fuse

replacement

the

oscilloscope

has

to

be

opened

(see

service

instruction

page

SI

"Instrument

Case

Removal").

The

fuse

is

located

on

the

bottom

side

of

the

instrument

(close

to

the

CT

pushbutton).

Make

sure

that

only

fuses

of

the

specified

type

are

used

for

replacement:

5x20mm,

quick-acting,

250V,

C,

50mA

(IEC

127/11

or

DIN

41661).

Test

Pattern

Displays

Page

M16

shows

typical

test

patterns

displayed

by

the

var¬

ious

components

under

test.

—

Open

circuit

is

indicated

by

a

straight

horizontal

line.

—

Short

circuit

is

shown

by

a

straight

vertical

line.

Testing

Resistors

If

the

test

object

has

a

linear

ohmic

resistance,

both

deflect¬

ing

voltages

are

in

the

same

phase.

The

test

pattern

expected

from

a

resistor

is

therefore

a

sloping

straight

line.

The

angle

of

slope

is

determined

by

the

resistance

of

the

resistor

under

test.

With

high

values

of

resistance,

the

slope

will

tend

towards

the

horizontal

axis,

and

with

low

val¬

ues,

the

slope

will

move

towards

the

vertical

axis.

Values

of

resistance

from

20Q

to

4.7kQ

can

be

approxi¬

mately

evaluated.

The

determination

of

actual

values

will

come

with

experience,

or

by

direct

comparison

with

a

com¬

ponent

of

a

known

value.

Testing

Capacitors

and

Inductors

Capacitors

and

inductors

cause

a

phase

difference

between

current

and

voltage,

and

therefore

between

the

X

and

Y

deflection,

giving

an

ellipse-shaped

display.

The

posi¬

tion

and

opening

width

of

the

ellipse

will

vary

according

to

the

impedance

value

(at

50

or

60

Hz)

of

the

component

under

test.

A

horizontal

ellipse

indicates

a

high

impedance

or

a

relatively

small

capacitance

or

a

relatively

high

induct¬

ance.

A

vertical

ellipse

indicates

a

small

impedance

or

a

rela¬

tively

large

capacitance

or

a

relatively

small

induct¬

ance.

A

sloping

ellipse

means

that

the

component

has

a

con¬

siderable

ohmic

resistance

in

addition

to

its

reactance.

The

values

of

capacitance

of

normal

or

electrolytic

capacitors

from

0.7p,Fto

lOOOpiF

can

be

displayed

and

approximate

values

obtained.

More

precise

measurement

can

be

obtained

in

a

smaller

range

by

comparing

the

capacitor

under

test

with

a

capacitor

of

known

value.

Induc¬

tive

components

(coils,

transformers)

can

also

be

tested.

The

determination

of

the

value

of

inductance

needs

some

experience,

because

inductors

have

usually

a

higher

ohmic

series

resistance.

However,

the

impedance

value

(at

50

or

60

Hz)

of

an

inductor

in

the

range

from

20

Q

to

4.7

k£2

can

easily

be

obtained

or

compared.

M14

203-7

Subject

to

change

without

notice

Testing

Semiconductors

Most

semiconductor

devices,

such

as

diodes,

Z-diodes,

transistors,

FETs

can

be

tested.

The

test

pattern

displays

vary

according

to

the

component

type

as

shown

in

the

figures

below.

The

main

characteristic

displayed

during

semiconductor

testing

is

the

voltage

dependent

knee

caused

by

the

junc¬

tion

changing

from

the

conducting

state

to

the

non

conduct¬

ing

state.

It

should

be

noted

that

both

the

forward

and

the

reverse

characteristic

are

displayed

simultaneously.

This

is

a

two-terminal

test,

therefore

testing

of

transistor

amplifica¬

tion

is

not

possible,

but

testing

of

a

single

junction

is

easily

and

quickly

possible.

Since

the

CT

test

voltage

applied

is

only

very

low

(max.

8.5Vrms),

all

sections

of

most

semicon¬

ductors

can

be

tested

without

damage.

However,

checking

the

breakdown

or

reverse

voltage

of

high

voltage

semicon¬

ductors

is

not

possible.

More

important

is

testing

compo¬

nents

for

open

or

short-circuit,

which

from

experience

is

most

frequently

needed.

Testing

Diodes

Diodes

normally

show

at

least

their

knee

in

the

forward

characteristic.

This

is

not

valid

for

some

high

voltage

diode

types,

because

they

contain

a

series

connection

of

several

diodes.

Possibly

only

a

small

portion

of

the

knee

is

visible.

Z-

diodes

always

show

their

forward

knee

and,

up

to

approx.

10V,

their

Z-breakdown,

forms

a

second

knee

in

the

oppo¬

site

direction.

A

Z-breakdown

voltage

of

more

than

12V

can

not

be

displayed.

Type:

Terminals:

Connections:

Normal

Diode

High

Voltage

Diode

Cathode-Anode

Cathode-Anode

(CT-GD)

(CT-GD)

Z-Diodel2V

Cathode-Anode

(CT-GD)

The

polarity

of

an

unknown

diode

can

be

identified

by

com¬

parison

with

a

known

diode.

Testing

Transistors

Three

different

tests

can

be

made

to

transistors:

base-emit¬

ter,

base-collector

and

emitter-collector.

The

resulting

test

patterns

are

shown

below.

The

basic

equivalent

circuit

of

a

transistor

is

a

Z-diode

between

base

and

emitter

and

a

normal

diode

with

reverse

polarity

between

base

and

collector

in

series

connection.

There

are

three

different

test

patterns:

P-N-PTransistor:

Terminals:

Connections:

b-e

(CT-GD)

b-c

(CT-GD)

(CT-GD)

N-P-N

Transistor

l|

If

-W-^—

For

a

transistor

the

figures

b-e

and

b-c

are

important.

The

figure

e-c

can

vary;

but

a

vertical

line

only

shows

short

cir¬

cuit

condition.

These

transistor

test

patterns

are

valid

in

most

cases,

but

there

are

exceptions

to

the

rule

(e.g.

Darlington,

FETs).

With

the

CT,

the

distinction

between

a

P-N-P

to

a

N-P-N

transis¬

tor

is

discernible.

In

case

of

doubt,

comparison

with

a

known

type

is

helpful.

It

should

be

noted

that

the

same

socket

connection

(CT

o

r

ground)

for

the

same

terminal

is

then

absolutely

necessary.

A

connection

inversion

effects

a

rotation

of

the

test

pattern

by

180

degrees

round

about

the

center

point

of

the

scope

graticule.

Pay

attention

to

the

usual

caution

with

single

MOS-

components

relating

to

static

charge

or

frictional

elec¬

tricity!

In-Circuit

Tests

Caution!

During

in-circuit

tests

make

sure

the

circuit

is

dead.

No

power

from

mains/line

or

battery

and

no

sig¬

nal

inputs

are

permitted.

Remove

all

ground

connec¬

tions

including

Safety

Earth

(pull

out

power

plug

from

outlet).

Remove

all

measuring

cables

including

probes

between

oscilloscope

and

circuit

under

test.

Otherwise

both

CT

test

leads

are

not

isolated

against

the

circuit

under

test.

In-circuit

tests

are

possible

in

many

cases.

However,

they

are

not

so

well-defined.

This

is

caused

by

a

shunt

connec¬

tion

of

real

or

complex

impedances

-

especially

if

they

are

of

relatively

low

impedance

at

50

or

60

Hz

-

to

the

compo¬

nent

under

test,

often

results

differ

greatly

when

compared

with

single

components.

In

case

of

doubt,

one

component

terminal

may

be

unsoldered.

This

terminal

should

then

be

connected

to

the

insulated

CT

socket

avoiding

hum

distor¬

tion

of

the

test

pattern.

Another

way

is

a

test

pattern

comparison

to

an

identical

cir¬

cuit

which

is

known

to

be

operational

(likewise

without

power

and

any

external

connections).

Using

the

test

prods,

identical

test

points

in

each

circuit

can

be

checked,

and

a

defect

can

be

determined

quickly

and

easily.

Possibly

the

device

itself

under

test

contains

a

reference

circuit

(e.g.

a

second

stereo

channel,

push-pull

amplifier,

symmetrical

bridge

circuit),

which

is

not

defective.

Terminals:

Connections:

b-e

(CT-GD)

b-c

(CT-GD)

(CT-GD)

The

test

patterns

on

page

Ml6

show

some

typical

displays

for

in-circuit

tests.

Subject

to

change

without

notice

Ml5

203-7

Test

patterns

Single

Components

Single

Transistors

Mains

transformer

prim.

Capacitor

33

(iF

Junction

E-C

FET

Single

Diodes

In-circuit

Semiconductors

Rectifier

Thyristor

G

+

A

together

Diode

paraiieled

by

680

Q

2

Diodes

antiparallei

Diode

in

series

with

51Q

B-E

paraiieled

by

680

Q

B-E

with

1

|rF

+680

Q

Si-diode

with

10(iF

Ml

6

203-7

Subject

to

change

without

notice

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