Iwatsu Sc7101 User manual

FREQUENCY

COUNTER

SC7101/SC-7102

INSTRUCTION

MANUAL

FREQUENCY

COUNTER

SC-7I01/SC-7102

F697-816151(L)

F271-816151(L)

SC-7101

/SC-7102

Cautions

on

Operations

When

using

the

Frequency

Counter

SC-7101/SC-

7102,

take

care

on

the

following

items.

Ambient

Temperature

and

Ventilation

The

instrument

operate

normally

in

the

ambient

temperature

of

O°C

to

+40°C.

Be

sure

to

use

the

instrument

within

this

range.

Use

beyond

the

limits

of

this

range

can

result

in

some

trouble.

Do

not

place

anything

near

the

venti-

lating

hole

in

the

cover

to

improve

the

efficiency

of

heat

dissipation.

Check

the

Supply

Voltage

Before

plugging

the

power

cord

to

an

electrical

output,

be

sure

to

check

its

voltage.

The

instru-

ment

can

be

used

on

the

line

voltage

shown

in

Table

1,

which

can

be

selected

with

the

voltage

selector

plug

on

the

rear

panel.

Operating

the

instrument

on

other

than

the

specified

voltages

can

result

in

breakdown.

In

case

of

switching

the

voltage

selector,

remove

the

power

cord.

Then

remove

the

fuse

holder

cap

by

turning

it in

the

direction

shown

by

an

arrow.

Pull

and

remove

the

voltage

selec-

tor,

then

insert

into

the

desired

center

voltage

value.

Table

1

Center

voltage

Voltage

range

AC

100

V

90

to

110

V

AC

120

V

108

to

132

V

AC

220

V

198

to

242

V

AC

240

V

216

to

264

Vv

Do

Not

Apply

Excessive

Voltage

The

maximum

allowable

input

voltage

is

200

V

(DC

+

peak

AC).

Never

apply

any

voltage

beyond

these

voltages.

Connection

of

Input

Signals

Use

a

supplied

coaxial

cable

for

connection

of

input

signals.

Use

of

single

core

wires

may

cause

an

incorrect

measurement

by

electric

noises

due

to

induction.

When

there

is

any

fear

of

mixing

of

noises,

etc.,

check

input

signals

with

the

oscilloscope.

Start

measuring

only

after

confirming

that

there

is

no

mixing

of

noise,

etc.

di

Switch

on

the

Rear

Panel

The

10

MHz STD

OUT-IN

switch

on

the

rear

panel

is

set

to

OUT

side

at

the

time

of

shipment.

When

this

switch

is

set

to

"IN"

side,

no

signal

of

the

internal

reference

oscillator

is

connected.

Be

sure

to

set

this

switch

in

"OUT",

since

setting

in

"IN"

will

not

allow

measurement

without

apply-

ing

external

reference

signal.

Earth

a

Protective

Ground

Terminal

When

supplying

the

line

voltage

from

the

power

consent

using

a

two-conductor

type

power

cord,

ensure

to

connect

the

ground

terminal

on

the

rear

panel

to

the

earth

in

order

to

prevent

a

danger.

When

supplying

the

line

voltage

from

the

power

consent

using

a

supplied

three-conductor

type

power

cord,

grounding

is

provided

with

an

earth-

ing

wire

attached

to

the

power

cord.

Type

of

Input

Circuit

The

input

circuit

of

the

instrument

is

not

of

the

floating

type

but

the

circuit

type

apply-

ing

the

unbalanced

signal

against

the

earth

poten-

tial.

Never

perform

measuring

the

primary

power

source

with

an

unclear

earth

potential,

which

causing

significant

danger.

Ensure

to

Replace

a

Fuse

with

the

Requied

Rated

Current

0.3

A

fuse

is

used

in

the

instrument

in

order

to

prevent

the

damages

to

the

circuit

due

to

excessive

voltage.

If

it is

fused,

make

sure

to

replace

only

fuse

with

the

required

rated

current

after

closely

checking

the

cause

of

fusing

and

repairing

the

defective

portion.

Never

use

those fuses

other

than

the

rated,

as

it

may

result

in

failure

of

the

instrument.

TABLE

OF

CONTENTS

Cautions

on

Operations

..

SECTION

1

SPECIFICATIONS

.

1-1

GENERAL

1-2

SPECIFICATION

.

1-2-1

Frequency

Measurement

.

1-2-2

General

csccescceccceee

1-2-3

Physical

Characteristics

-3

ENVIRONMENTAL

CHARACTERISTICS

-4

ACCESSORIES

..eeeeesseseeee

1

SECTION

2

OPERATING

INFORMATION

..cccccscccccccccccscvccccssccsccscccsssssssecsssssssssssssceees

2-1

FRONT

PANEL

.....

2-1-1

Power

Supply

aa

2-1-2

Display

of

Measured

Results

2-1-3

Input

ceccceee

2-1-4

Measuring

Condition

Setting

2-2

REAR

PANEL

wesccccccccescccesece

.

2-3

DISPLAY

UNIT

sescsscseccccccccscscseces

2-4

HOW

TO

USE

THE

CARRYING

HANOLE

(STAND)

NNNNNNNNN

SECTION

3

MEASURING

PROCEOURES

3-1

POWER-ON

.

3-2

ON

RESET

.

3-3

MEASUREMENT

.

3-3-1

Frequency

Measurement

.

3-3-2

DIFF

Calculation

.

3-4

MEASUREMENT

USING

AN

EXTERNAL

REFERENCE

OSCILLATOR

3-5 USE

AS

THE

SECONDARY

FREQUENCY

STANDARD

UUUwnWwaww

SECTION

4

ADJUSTMENT

OF

REFERENCE

OSCILLATOR

sesseeeseeccccccccenccccecccencesssceassssssesessees

4-1

PREPARATION

FOR

ADJUSTMENT

...

4-1-1

Removing

the

Upper

Cover

.

4-1-2

External

Reference

Oscillator

.

4-2

ADJUSTMENT

PROCEDURE

«.sseeeeeeeeee

SECTION

5

SCHEMATIC

DIAGRAM

.

'

PEEUNNA=

'

OUFENNZA245

'

BE

ENN=AS5

'

Nese

MEMO

iv

SC-7101

/SC-7102

Section

1

Specifications

1-1

GENERAL

The

frequency

counter

SC-7101/SC-7102

are

compact

and

light

weight

electronic

measuring

instrument

which

can

measure

frequency

of

wide

range

from

10

Hz

to

200

MHz.

Use

of

large

and

high

luminousity

LED

in

the

display

makes

reading

easier.

This

instrument

is

provided

with

follow-

ing

features.

Use

of

Easy-to-read

Large

Light

Emitting

Diode

The LED

display

is

decimal

9

digits

+

1

digit

of

exponent

and

employs

Zero-blanking

methode.

Capability

of

Measurement

of

Low

Frequency

Signals

with

High

Resolution

This

instrument

allows

measurement

of

signals

of

low

frequencies

with

high

resolution

(normally

7-digits

per

1

s)

in

a

very

limited

time

by

the

reciprocal

methode

frequency

measurement.

Automatic

change

to

direct

frequency

measure-

ment

for

input

signals

of 10

MHz

or

more

enables

this

instrument

to

perform

measurement

of

input

signals

with

the

heightest

resolution.

Provision

of

DIFF

Calculation

Function

This

instrument

can

calculate

and

display

differences

between

the

values

of

input

signals

and

the

reference

value

by

a

simple

operation.

Allows

Easy

Systemization

of

Measuring

Since

mounting

of

an

optional

GP-IB

interface

or

a

centronix

type

parallel

interface

enables

output

of

measured

results,

external

reset,

remote

control

of

the

time

base, etc.,

this

instrument

can

be

built

into

a

systemized

configuration.

Built-in

Highly

Stabilized

Reference

Oscillator

and

Capability

for

External

Connection

The

SC-7101

and

SC-7102

have

built-in

high

stability

reference

oscillator

of

+3

x

10~’/month

and

#2

x

1078/day

respectively.

In

addition,

external

input

of

reference

sig-

nals

of

high

accuracy

is

possible.

4-Step

Setting

of

Sample

Rate.

(SC-7102)

Sample

rates

can

be

set

in

4-steps

of

200

msec

x1,

x2,

x

4

and

x

8

Improved

Shielding

Effect

The

specially

treated

cases

provide

better

shielding

effect

than

that

of

metal

cases

though

these

cases

are

made

of

light

weight

plastics.

Easy

Mounting

of

Optional

Supplies

Following

optional supplies

can

be

easily

mount-

ed.

(For

the

SC-0108

and

the

SC-0110,

select

either

one

only.

No

mounting

of

both

of

them

is

permitted).

*

Parallel

interface

SC-0108.

*

GP-IB8

interface

SC-0110.

On

SC-7102,

there

are

further

additional

op-

tions.

*

High

stability

reference

oscillator

the

SC-

0114.

(10

MHz

+

5

x

10-°/day).

*

High

stability

reference

oscillator

the

SC-

0115.

(10

MHz

+

2

x

10-$/day).

Out

of

the

above

options,

when

SC-0114

is

mount-

ed,

on

the

Name

plate

on

the

rear

panel

showing

the

Model

No., "B"

is

printed,

while

when

SC-

0115

is

mounted,

"C"

is

printed.

Section

1

Specifications

SC-7101

/SC-7102

1-2

SPECIFICATION

1-2-1

Input

Frequency

Measurement

Measuring

range

10

Hz

to

200

MHz

1

kHz

to

200 MHz

with

time

base

of

1

ms

100

Hz to

200 MHz

with

time base

of

10

ms

Input

voltage

At

ATTEN

1:

20

mrms

to

1

Vrms

(1

kHz

to

100

MHz)

50

mUrms

to

1

Vrms

(10

Hz

to

200

MHz)

At

ATTEN

1/20

:

0.4.Vrms

to

20

Vrms

(1

kHz

to

100

MHz)

1

Vrms

to 20

Vrms

(10

Hz

to

200

MHz)

Maximum

input

voltage

200

V

(OC

+

peak

AC)

Input

RC

Approximately

1

M2//25

pF

or

less

Attenuator

1

or

1/20

Input

coupling

AC

Sc-7101

SC-7102

Time

base

10

ms,

0.1

s,

1s,

10s

|

ims,

10

ms,

0.1

s,

1s,

105

Resolution

10

MHz

or

more

100

Hz/10

ms,

10

Hz/O.1

s,

|

1

kHz/1

ms,

100

Hz/10

ms,

1

Hz/1

s,

0.1

Hz/10

s

10

Hz/0.1

s,

1

Hz/1

s,

0.1

Hz/10

s

10

MHz

or

less

S

digits/10

ms

4

digits/1

ms

6

digits/0.1

s

5

digits/10

ms

7

digits/

1s

6

digits/0.1

s

8

digits/10

s

7

digits/1

s

8

digits/10

s

Reading

unit

EXPONENT

(0,

#3,

+6,

#9)

Hz

Error

10

MHz

or

more

Accuracy

of

reference

oscillator

+

1

count

10

MHz

or

less

Accuracy

of

reference

‘

Trigger

error

+

1

reference

time

oscillator

Measured

frequency

x

Time base

SC-7101/SC-7102

1-2-2

General

Calculating

function

Display

method

Display

digits

Display

time

Sample

rate

Reference

oscillator

Oscillation

frequency

Aging

rate

Rise

time

Temperature

Vibration

Impact.

Output

of

reference

frequency

Frequency

Released

voltage

50

terminal

Input

of

reference

frequency

Frequency

Input

voltage

Maximum

input

voltage

Input

resistance

Input

coupling

Power

supply

Supply

voltage

Section

1

Specifications

OIFF

$X-Xref

X

:

Measured

value

X-ref

Storage

display

method

At

mantissa

DIFF

Calculation

mal

8

digits

Reference

value

using

the

light

emitting

diode,

zero

blanking

decimal

9

digits

when

the

result

is

negative,

-

sign

and

deci-

At

exponent

21

digit

(0,

+3,

+6,

+9)

Time

base

+

sample

rate

or

infinite

display

SC-7101

Sc-7102

Approximately

200

ms

10

MHz

+3

x

10°7/month,

#10

x

10°?/year

(On

the

basis

of

1

hour

after

Power

on)

+3

x

10%

(On

the

basis

of

1

hour

after

Power

on,

from

immediately

after

power

on)

#3

x

1078/0

°C

to

+40

°C

#1

x

107

or

less

(For

30

minutes

each

in

three

direction

at

frequency

of

10 Hz

to

55

Hz

and

with

am-

plitude

of

1.5

mm)

#1

x

1077

or

less

(Dropping

from

height

of SO

mm

above

a

hard

wood

three

times

each

in

three

directions)

Approximately

200

ms,

400

ms,

800

ms

or

1.6

s

10

MHz

+2

x

10°8/day,

#10

x

10°°/year

(On

the

basis

of 24

hour

after

power

on)

+5

x

107°

(On

the

basis

of

1

hour

after

power

on,

from

10

minutes

after

power

on)

+5

x

10°8/0

°C

to

+40

°C

+5

x

1078

or

less

(For

30

minutes

each

in

three

direction

at

frequency

of

10 Hz

to

55

Hz

and

with

am-

plitude

of

1.5

mm)

+5

x

1078

or

less

(Dropping

from

height

of

50

mm

above

a

hard wood

three times

each

in

three

directions)

10

MHz

2

Vp-p

or

more

350

mVp-p

or

more

10

MHz

1

Vrms

to

5

Vrms

10

Vrms

Approximately

10

k®

AC

Center

voltage

Voltage

range

AC

100

V

90

to

110

V

AC

120

V

108

to

132

V

AC

220

V

198

to

242

V

AC

240

V

216

to

264

V

Selected

with

the

voltage

selector

plug

Section

1

Specifications

SC-7101

/SC-7102

Frequency

range

50

Hz

to

400

Hz

Power

consumption

Approximately

11

w

(SC-7101)

Approximately

15

w

(SC-7102)

1-2-3.

Physical

Characteristics

Weight

Approximately

2.5

kg

Dimension

(210#2)W

x

(1002)H

x

(310+2)L

[mm]

1-3.

ENVIRONMENTAL

CHARACTERISTICS

Operating

temperature

0

°C

to

+40

°C

Operating

humidity

85

$RH

or

less

(0

°C

to

+40

°C)

Storage

temperature

-20

°C

to

+70

°C

Storage

humidity

90

#RH

or

less

(0

°C

to

+70 °C)

1-4

ACCESSORIES

Power

cord

+s.

Coaxial

cable

Fuse

(FSA-0.3A)

Accessory

bag

.-

Instruction

manual

Figure

1-2-4.

Dimension

(SC-7102)

r

230

-

|

21022

=

10H

|

oe

aaa

1

:

31082

+

[=

gesgeesee

6

<|'

|

el

(SC-7101

and

SC-7102

are

of

the

same

dimensions)

SC-7101

/SC-7102

Section

2

Operating

Information

CAUTION

©

Check

mode

and

measurement

mode

In

this

manual,

the

status,

where

LED

located

above

the

|CHECK|

key

is

turned

on,

is

called

a

“check”

mode

and

the

status,

where

such

LED

turns

out,

is

called

a

“measurement”

mode.

With

the

“check’””

mode

selected,

performs

self-check

and

displays

the

frequency

(10MHz)

of

the

internal

refer-

ence

oscillator.

With

the

“measurement”

mode

selected,

measures

a

signal

applied

to

INPUT

A

or

B.

©

Hold

mode

and

sample

mode

In

this_manual,

the

status,

where

LED

located

above

the

|HOLD|

key

is

turned

on,

is

called

a

“hold”

mode,

and

the

status,

where

such

LED

is

turned

out,

is

called

a

“sample”

mode.

With

the

“hold”

mode

selected,

measurement

is

stopped,

while

such

measurement

already

started

be-

fore

the

|HOLD]

key

is

pressed,

is

continued

until

completion.

With

the

“sample”

mode

selected,

the

SC-7101

repeats

measuring

at

the

rate

of

approximately

200

msand

the

SC-7102,

at

the

preset

sample

rate.

2-1

FRONT

PANEL

This

paragraph

describes

the

switches

and

keys

on

the

front

panel

and

the

display

which

indi-

cates

measured

results.

See

to

Figure

2-1-1-(1)*(2)

2-1-1

Power

Supply

@

POWER

ON-OFF

Selects

line

voltage

on

or

off.

2-1-2

Display

of

Measured

Results

@

Numerical

display

LED

Indicates

the

measured

results

in

9

digits

of

the

mantissa

(or

8

digits

with

a

negative

sign)

and

one

digit

of

the

exponent

with

-

sign.

@

STATUS

LED

Indicates

operating

status,

which

are

REMOTE,

OVER,

GATE

and

OVEN

(for

SC-7102)

statuses.

REMOTE

:

Turns

on

in

only

GP-IB

remote

status.

OVER

Turns

on

when

the

measured

results

causes

overflow.

GATE

+

Turns

on

at

the

measuring

gate

open.

QVEN

+

Indicates

to

use

a

high

stability

crystal

oscillator

with

thermostat

(for

SC-7102

only).

Section

2

Operating

Information

2-1-3.

Input

@®

BNC

connector

Signal

input

connector

to

measure

frequency

from

10

Hz to

200

MHz.

Input

Voltage

is

200

V

(DC

+

AC

peak).

©

FILT

NORM-10

kHz

Selects

the

low

pass

filter

of 10

kHz

on

or

off.

In

such

a

case

where

noises

of

high

frequencies

are

contained

in

low

frequency

signals,

attenuate

frequency

higher

than

10

kHz.

©

ATTEN

1/20-1

Selects

attenuator

of

1/1

or

1/20.

X1

position

connects

input

signal

directly

to

input

amplifiers,

X20

position

attenuates

input

signal

by

a

factor

of

20

(nominal).

SC-7101/SC-7102

2-1-4

Measuring

Condition

Setting

@

TIME

BASE

Selects

a

TIME

BASE.

The

TIME

BASE

are

displayed

by

1

ms

(for

SC-7102

only),

10

ms,

0.1

s,

1

s

and

10

s

(im

black

color)

which

locate

above

the

keys.

Mounting

of

the

GP-IB

interface

(optional

supply)

allows

the

external

remote

control.

CHECK

Selects

the

"check"

mode

or

"measure"

mode.

When

the

LED

located

above

the

[CHECK]

key

turns

on,

the

"check"

mode

is

selected

and

the

instrument

performs

self-checks

with

frequency

(10

MHz)

of

the

internal

reference

oscillator.

When

the

LED

located

above

the

[CHECK]

key

turns

out the

"measure"

mode

is

selected

and

the

instrument

measures

input

signals

applied

to

BNC

connector

of

INPUT.

Figure

2-1-1-(1).

Front

Panel

(SC-7101)

Figure

2-1-1-(2).

Front

Panel

(SC-7102)

SC-7101

/SC-7102

©

DIFF

Performs

DIFF

calculation

(X-Xref)

while

LED

located

above

the

[DIFF]

key

turns

on,

indicates

that

the

instrument

is

put

in

DIFF

calculating

status,

while

this

LED

turns

out,

the

DIFF

calculation

is

released.

To

perform

calculation,

set

in

DIFF

calcula-

tion

status

and

then

register

the

reference

value

(Xref)

with

the

key.

For

further

details,

refer

to

"3-3-2

DIFF

Cal-

culation".

HOLD

Selects

the

hold

or

sample

mode.

Whi

lighting

of

LED

located

above

the

key,

the

instrument

is

put

in

the

hold

status

to

stop

measurement

and

keep

displaying

the_

results

measured

before

pressing

the

[HOLO}

key.

However,

such

measurement,

which

has

already

started

before

the

[HOLD]

key

is

pressed,

is

per-

formed

until

completion.

While

this

LED

turns

out,

the

instrument

is

put

in

the

sample

status

to

repeat

mea-

surement

in

accordance

with

the

preset

sample

rate

(SC-7101

is

fixed

at

200ms).

Section

2

Operating

Information

RESET

(LOCAL)

Performs

the

following

operation

by

pressing

key.

Interrupts

all

process

being

executed

when

the

key

is

pressed.

*

Clears

the

splay

of

the

measured

re-

sults.

*

Updates

measuring.

*

If

DIFF

calculation

is

selected,

resisters

internally

the

restarted

measuring

re-

sults

as

Xref

by

pressing

the

key.

*

In

GP-IB

mode,

it

is

recognized

as

key.

SAMPLE

RATE

x2,

x4,

x8

(sc-7102

only)

Selects

SAMPLE

RATE

time.

Each

pressing

the

[SAMPLE

RATE]

key

allows

selection

of

sample

rates

in

the

following

sequence.

All LED

LED

LED LED

turns

out

turns

on

turns

on

turns

on

ba

be

*

Gd

x1

>

x2

—>

x4

>

x8

Approxi- Approxi- Approxi-

Approxi-

mately

200

ms

400

ms

800

ms

1.6s

Section

2

Operating

Information

2-2

REAR

PANEL

Describes

switch

and

connectors

on

the

rear

panel.

Refer

to

Figure

2-2-1.

®

10

MHz

STD

IN-OUT

BNC

connector

Either

provides

10

MHz

of

the

internal

ref-

erence

oscillator

or

apply

external

signals

of

the

reference

frequency

of

high

accuracy.

OUT:

Provides

from

the

10

MHz STD

connector

immediately

when

10

MHz

internal

reference

oscillator

is

internally

connected.

IN:

Disconnects

internal

connection

of 10

MHz

internal

reference

oscillator.

In

this

case,

applies

10

MHz

of

an

external

refer-

ence

oscillator

to

the

10

MHz

STD

connec-

tor.

@

FUSE,

VOLTAGE

SELECTOR

Both

the

fuse

holder

and

the

power

supply

voltage

selector.

To

select

the

power

supply

voltage,

remove

the

fuse

holder

cap

and

then

select

it.

Figure

2-2-1.

Rear

Panel

SC-7101

/SC-7102

©

AC

LINE

INPUT

Connect

the

power

cord

to

it.

+

(GND)

Protective

grounding

terminal.

DATA

OUT

connector

installed

location

(option)

Installs

the

data

output

connector

for

the

Parallel

interface

SC-0108.

REMOTE

connector

installed

location

(option)

Installs

the

input/output

connector

for

the

GP-IB

interface

SC-0110.

:

Switch

installed

location

(option)

Installs

the

switch

for the

parallel

inter-

face

SC-0108

or

the

GP-IB

interface

SC-0110.

SC-7101

/SC-7102

2-3.

DISPLAY

UNIT

Section

2

Operating

Information

11

digits

LED

to

shows

measured

results

of

input

signals.

Turns

on

while

GP-IB

remote

status.

Turns

on

while

the

|

measurement

overflows.

Gate

Turns

on

while

the

=

4

oogc000

Indicates

the

high

stability

crystal

oscillator

with

a

thermostat

(SC-7102)

a

ETS

EI

TTT

>

oven

6

z

EXPONENT

gate

is

open.

Display

of

Hysteresis

in

a

Mantissa

In

measurement

of

the

signal

of 10

MHz

or

less,

resolution

is

determined

according

to

the

mea-

surement

time.

Thus,

if

MSD

value

of

the

mea-

sured

results

changes

from

9

to 10

or

vice

versa,

read-out

of

the

results

becomes

difficult,

since

the

position

of

decimal

point

and

exponent

change

while

the

number

of

digit

displayed

remains

same.

To

solve

this

problem,

when

MSD

value

changes

from

9

to

10,

the

display

of

the

mantissa

is

shifted

to

left

by

1

digit

to

blank

the

lowest

digit.

(For

the

external

output

data,

0

is

added

to

the

lowest

digit).

When

MSD

value

changes

from

10

to

9,

the

display

of

the

mantissa

is

shifted

to

right

by

omitting

1

digit.

Through

the

above

operations,

hysteresis

is

provided

with

display

for

easy

read-out.

If

this

operations

are

performed

8

times

continu-

outly

or

if

the

MSD

value

becomes

any

one

of

2

through

8,

results

will

be

displayed

without

such

operations.

In

the

RECIPROCAL

mode

measurement,

where

the

result

is

obtained

by

calculating

the

count

data,

there

may

be

1

digit

difference

in

the

effective

digit

due

to

calculated

error

even

in

measurement

in

the

same

range.

Also,

in

such

a

case,

the

same

processes

as

above

are

performed

to

ensure

easy

read-out.

—

Mantissa

Exponent

On

Displays

*

The

highest

9

digits

indicate

the

mantissa.

However,

in

the

case

when

the

measured

result

is

negative,

the

first

digit

(the

left-end

of

the

mantissa

display)

takes

"-"

sign

and

the

display

of

the

measured

result

is

maximum

8

digits.

*

The

lowest

two

digits

(10th

and

11th

digits

from

the

left)

display

the

sign

of

the

exponent

and

1

digit

of

the

exponent.

The

displays

of

the

exponent

are

by

such

multi-

ples

of

3,

as,

-9, -6,

-3,

0,

3, 6,

9.

When

the

sign

of

the

exponent

is

+,

this

position

is

left

blank.

*

For

display

of

the

mantissa,

the

leading

zero

blanking

occurs.

°

When

the

measurement

overflows,

normally

the

OVER

LED and

the

date

display

indicates

overflow

mark

"Uuueee".

However,

though

counting

has

been

10

or

more

digits,

the

data

display

shows

the

mantissa

in

9

digits

from

the

lowest

digits

and

indicates

the

overflow

by

turning

on

the

OVER

LED.

Section

2

Operating

Information

2-4

HOW

TO

USE

THE

CARRYING

HANDLE

(STAND)

The

lock

of

the

carrying

handle

is

released

by

pulling

both ends

of it

outward,

allows

turning

of

the

handle

approximately

every

20

degree.

When

fixed

at

the

bottom

of

the

instrument,

the

handle

serves

as

the

stand.

Figure

2-4-1.

How

to

Use

the

Carrying

Handle

SC-7101/SC-7102

When

this

carrying

handle

is

not

used

as

the

stand

or

the

instrument

is

stored,

turn

the

handle

to

the

instrument

rear

side,

via the

bottom

and

store

the

handle

as

shown

in

Figure

2-4-2.

Figure

2-4-2.

Storing

of

the

Carrying

Handle

SC-7101

/SC-7102

Section

3

Measuring

Procedures

3-1

POWER-ON

When

the

POWER

switch

is

turned

on,

display

tests

of

LEDs

are

performed

in

the

following

sequence.

1.

All

LEDs turn

on

and off

three

times

in

suc-

cession

except

GATE

and

OVEN

(for

SC-7102)

LEDs.

2.

Mumeral

display

LEDs

display

each

number

from

0

to

9

in

this

order

once

for

each

number,

except

the LED

which

indicates

-

sign

of

the

exponent.

3.

Set

the

keys

as

follows:

*

TIME

BASE

key

1s

(LED

turns

on)

*

CHECK

key

CHECK

MODE

(LED

turns

on)

4.

The

data

display

indicates

the

frequency

of

the

internal

reference

oscillator

as:

"10,000,000

6Hz"

(Refer

to

Figure

3-1-1.)

Mounting

of

the

parallel

interface,

the

SC-

0108

(optional

supply)

enables

any

selection

of

initial

values

of

TIME

BASE

and

CHECK

ON-OFF.

Any

selection

of

INPUT

SELECT

initial

value

is

also

possible.

Figure

3-1-1.

The

Display

of

Initial

Setting

3-2

ON

RESET

following

operations

by

pressing

of

key.

*

Interrupts

all

process

being

executed

when

the

RESET]

key

is

pressed.

Clears

the

display

of

the

measured

results.

Updates

measuring.

S

°

If

OIFF

calculation

is

selected,

resistors

internally

the

restarted

measuring

results

as

Xref

by

pressing

the

[RESET]

key.

In

the

GP-IB

mode,

it

is

recognized

as

a

[LOCAL]

key.

Bee

sc-7102

rreouency

counter

=

(@0000000

6

ow

Section

3

Measuring

Procedures

3-3.

MEASUREMENT

3-3-1

Frequency

Measurement

Internal

Self-check

With

turning

on

the

power

switch,

after

perform

ing

"power

on

self-check",

measuring

the

10

MHz

of

the

internal

reference

oscillator

with

TIME

BASE

1

s,

displays

"10.000

000

6

Hz".

Then,

the

display

is

changed

by

TIME

BASE

as

listed

in

Table

3-3-1.

Table

3-3-1.

TIME

BASE

Count

display Display

unit

Mantissa

1

ms

10.000

Hz

10

ms

10.0000

Hz

O1s

10.00000

Hz

1s

10.000000

Hz

10s

10.0000000)

Hz

<Note>

1

ms

of

TIME

BASE,

available

for

the

SC-7102

only.

Measurement

Procedure

*

Press

the

[CHECK]

key

and set

to

the

"MEASURE"

mode.

(LED

turns

out).

Operate

ATTEN

and

FILT

switches.

Connect

the

signals

to be

measure:d

to

the

input

connector.

Connect

the

signals

to

be

measured

to

the

input

connector

selected

with

the

INPUT

SELECT

key.

Select

the

most

suitable

TIME

BASE.

In

case

of

holding

the

measured

results,

press

the

key.

Then

the

LED

located

above

the

key

turns

on

and

holds

the

results.

.

SC-7101

/SC-7102

Reference

for

Frequency

Measurement

When

the

signals

to be

measured

are

higher

than

10

MHz;

The

measuring

gate

opens

for

the

time

selected

as

the

TIME

BASE,

and

counts

and

displays

frequencies

of

input

signals

during

this

period.

When

signals

to

be

measured

are

lower

than

10

MHz;

Measure

by

the

RECIPROCAL

method.

REFERENCE

RECIPROCAL

Method

.

The

reference

gate

opens

for

the

time

selected

as

the

TIME

BASE,

then

the

measuring

gate

opens

in

triggering

the

input

signals,

After

closing

of

the

reference

gate,

the

measuring

gate

closes

triggering

with

the

input

signals.

The

instrument,

counting

the

measuring

gate

open

term

“t”

with

the

reference

clock

(10

MHz)

also

counts

a

number

of

period

“n”

of

the

signals

to

be

measured

within

this

term

and

obtains

the

frequency

by

executing

calculation

of

f

=

n/t

and

displays

the

result.

(reciprocal

of

the

average

period

measurement).

When

this

method

is

used,

irrespective

of

the

input

frequency,

resolution

of

the

results

is

determined

by

the

measuring

time

(displays

7

digits

for

1s

gate,

normally).

SC-7101/SC-7102

Section

3

Measuring

Procedures

Errors

in

Measurement

When

average

values

of

input

signals

during

Fi

:

-

Errors

in

frequency

measurements,

there

are

N

period

are

measured:

igure

3-3-2.

Frequency

and

Error

in

Frequency

Measurement

I

errors

due

to

accuracy

of

the

reference

oscil-

2a

1

En

1

(Sinewave;

when

S/N

is 40

dB)

(SC-7101)

lator",

"+

1

count

error"

and

the

"Trigger

error".

NT

7

*

es

*

Ww

.

Showing

1/N

reduction

in

error.

Consequently,

Error

due

to

accuracy

of

the

reference

oscil-

measurements

of

average

values

of

various

periods

My

lator":

are

advantageous

as

they

can

reduce

influence

Since

the

counting

time

(gate

time)

of

the

of

noise.

+

10

MHz

or

more

frequency

measurement

are

determined

by

dividing

1

kH2/1

ms,

10

H2/O.1

sy

1

Hz/1

5,

O61

Hz/10

s

the

oscillation

frequency

of

the

reference

oscil-

How

do

these

errors

appear

in

the

actual

mea-

10

fie

on

Less:

lator

(crystal

oscillator),

this

error

depends

surement.

Figure

3-3-2

and

3-3-3

shous

relation

‘an

aah

ria

tack

aca

shee

on

the

accuracy

of

the

reference

oscillator.

between

input

signal

and

error

frequency

after

cee

calibration

of

the

reference

oscillator

and

[

"Error

of

+

1

count":

errors.

Although

the

digital

measuring

instrument

is

a

measuring

instrument

of

high

accuracy,

on

in-

Figure

3-3-1.

Trigger

Error

[

struments

which

count

by

opening

and

closing

of

gates,

a

quantization

error

of

+

1

count

oc-

curs.

Limit

due

to

accuracy

of

the

internal

reference

oscillator

Noiseless

Es

signal

"Trigger

Error":

Normally

the

measuring

error

due

to

the

trigger

error

is

proportional

to

the

noise

level.

This

error

is

larger

when

the

slope

of

the

area

set-

———1

period

4

eale

ting

the

trigger

level

of

the

input

signal

wave-

form

is

less

sharper.

This

error

is

the

minimum

when

the

trigger

level

of

a

sine

waveform,

as

shown

in

Figure

3-3-1,

is

set

in

the

center

level

of

the

waveform.

Relation

of

the

input

signal

voltage,

noise

volt-

age and

the

error

can

be

expressed

by

the

follow-

ing

equation.

2aT

1,

£0

(..fn

27s,

Teo

Es

at”

TT

A

i

H

1

.

Signals

with

noise

Figure

3-3-3.

Frequency

and

Error

in

frequency

Measurement

II

(Sinewave;

when

S/N

is

40

dB)

(SC-7102)

Maximum

period

-——|

10

MHz

or

more

|

1

kHz/1

ms,

10

Hz/0.1

s,

1

H2/1

s,

0.1

Hz/10

s

10

Mz

or

less

4

digits/1

ms,

6

digits/0.1

s,

7

digits/

1

s,

8

digits/

10

s

As

it

is

clear

from this

equation,

in

case

of

the

sinewave,

this

error

is

solely

determined

by

the

ratio

of

noiseless

signal

Es

and

noise

En,

irrespective

of

the

frequency.

For

example,

the

error

when

S/N

is 40

dB,

comes

to

0.3

%

when

ghee

60

cB,

0.03

%

from

the

above

equation.

Limit

due

to

accuracy

of

the

internal

reference

oscillator.

OOMHE

OH:

100Hz~=—«sTkHz

~=—«10kHz_-—=«100kHz»=«

MHz

©

10MHe

200MHz

Section

3

Measuring

Procedures

3-3-2

DIFF

Calculation

Performs

calculation

of

difference

between

the

measured

value

X

and

the

reference

value

Xref.

Register

the

reference

value

Xref

in

ad-

vance.

Measurement

1.

Apply

the

reference

value

Xref.

2.

Press

the

|

DIFF}

key

(LED

turns

on).

3.

Press

the

[RESET]

key

and

register

the

refer-

ence

value

Xref.

4.

Apply

the

measured

signal

X.

5.

"X-Xref"

is

displayed

on

the

data

display.

<Note>

*

To

re-register

the

reference

value

Xref,

apply

the

signal

of

the

new

reference

value

and

then

press

the

[Rt

key.

Registered

Xref

values

remain

unchanged

even

when

CHECK

mode,

MEASURE

mode,

INPUT

SELECT,

SAMPLE

RATE

and

TIME

BASE

are

changed.

When

DIFF

calculation

is

turned

on

again,

after

once

turned

off,

the

Xref

which

has

been

pre-

viously

registered,

remains

unerased.

(When

using

the

same

value

as

the

Xref,

no

new

re-

gistration

is

required).

Turning

on

line

voltage,

clears

Xref,

resetting

to

0.

SC-7101/SC-7102

3-4

MEASUREMENT

USING

AN

EXTERNAL

REFERENCE

OSCILLATOR

The

instrument

allows

measurement

of

higher

accuracy

by

using

external

reference

oscillator

which

has

higher

accuracy

than

the

internal

reference

oscillator.

In

this

case,

set

the

IN-OUT

switch

on

the

rear

panel

to

"IN"

and

apply

signals

from

the

external

reference

oscil-

lator

into

the

input-output

connector

of

10

MHz

STD.

CAUTION

Make

sure

to

set

the

IN-OUT

switch

to

“OUT”

except

when

applying

signals

of

the

external

reference

oscillator.

3-5

USE

AS

THE

SECONDARY

FREQUENCY

STANDARD

When

the

In-Qut switch

on

the

rear

panel

is

set

to

"QUT",

the

input-output

connector

of

the

10

MHz STD

provides

signals

of

the

10

MHz

reference

oscillator.

This

signal,

because

of

its

very

high

accuracy,

can

be

used

as

the

external

driving

signal

of

pulse

generators

or

time

markers

for

adjusting

the

oscilloscope.

SC-7101/SC-7102

Section

4

Adjustment

of

Reference

Oscillator

Though

the

SC-7101

and

the

SC-7102

counters

use

a

high

accuracy

crystal

oscillator,

when

continuous

measurement

of

high

accuracy

are re-

quired,

adjust

the

crystal

oscillator.

4-1

PREPARATION

FOR

ADJUSTMENT

Perform

adjustment

of

the

reference

oscillator

by

removing

the

upper

case.

4-1-1

Removing

the

Upper

Cover

Remove

the

upper

cover

by

the

following

pro-

cedures.

1.

Face

the

instrument

bottom

up

and

remove

3

screws

on

the

bottom.

(See

to

Figure

4-1-

1).

Hold

the

bottom

and

upper

covers

between

both

hands

securely

and

place

with

the

bottom

down.

Lift

the

upper

cover

rear

end

slightly

up

and

remove

the

upper

case

by

pulling

it

back-

ward.

(The

upper

cover

front

end

is

inserted

into

the

panel

frame).

(See

Figure

4-1-2).

2

3

Figure

4-1-1.

Screw

Location

on

Bottom

|

&

HAT

TMT

TE

HEH

f

o

6

&

o

2.

a

o

1g

WHT

<Note>

To

install

the

upper

cover,

reverse

the

above

procedures

to

remove

the

upper

cover.

4-1-2

External

Reference

Oscillator

Accuracy

of

the

reference

oscillator

is

as

follows:

Sc-7101

10

MHz

reference

signal

of

+1

x

10°’.

SC-7102

10

MHz

reference

signal

of

+1

x

1078.

Figure

4-1-2.

Removing

the

Upper

Cover

oF

ae

=

Right

side!

@

Iwatsu SC7101 User manual

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