Bruel & kjaer 2033 User manual

Instruction

Manual

High Resolution Signal Analyzer Type

2033

033-0579

A spectrum analyzer

with

a

10

K input me-

mory and featuring three modes

of

opera-

tion. In baseband mode, 1 K time sampl~s

are transformed to produce a constant band-

width spectrum in

400

lines across a fre-

quency range

which

is selectable from 0 -

10

Hz

to

0 -

20

kHz

in a

1-2-5

se-

quence. In high resolution mode, the full

contents

of

the 10 K sample memory are

used to produce a times ten zoom, includ-

ing the possibility of generating a

4000-line

spectrum from a single

10

K sample time re-

cord. In scan analysis mode, a 1 K sample

analysis

window

is stepped along the

10

K

samples,

with

the 1 K samples selected

producing a

new

400-line

spectrum

with

each step. This enables changes in the spec-

tral content

of

the 10 K samples

to

be ob-

served. All the results produced are dis-

played on an

11"

calibrated display screen,

either

with

or

without

averaging to improve

the stability

of

analyzed results.

+

Bri.iel

&

Kj~r

l,

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-

o--

In:,

D

o--

I

'-'

'-.

_I

..

o

....

-

r---~

----,

0-

-1

;,

1;

,·,

•O

•--

-

-'

,_,

-•

+

BrUel

&

Kjaer

DK-2850

N/ERUM, DENMARK · Telephone,+

452800500

·Telex, 37316

brukadk

Printed

in

Denmark

by

Nil!rum

Offset

Instruction

Manual

High Resolution Signal Analyzer Type

2033

033-0579

A spectrum analyzer

with

a

10

K input me-

mory and featuring three modes

of

opera-

tion. In baseband mode, 1 K time sampl~s

are transformed to produce a constant band-

width spectrum in

400

lines across a fre-

quency range

which

is selectable from 0 -

10

Hz

to

0 -

20

kHz

in a

1-2-5

se-

quence. In high resolution mode, the full

contents of the

10

K sample memory are

used to produce a times ten zoom, includ-

ing the possibility of generating a

4000-line

spectrum from a single

10

K sample time re-

cord. In scan analysis mode, a 1 K sample

analysis

window

is stepped along the

10

K

samples,

with

the 1 K samples selected

producing a

new

400-line

spectrum

with

each step. This enables changes in the spec-

tral content of the

10

K samples to be ob-

served. All the results produced are dis-

played on an

11"

calibrated display screen,

either

with

or

without

averaging to improve

the stability of analyzed results.

+ Briiel & Kjrer

HIGH RESOLUTION

SIGNAL

ANALYZER

TYPE

2033

(from serial no.

935014)

Revision May 1981

This

apparatus

has been designed and tested according

to

class

II

of

IEC

publication

348,

Safety

Requirements

for

Electronic

Measuring

Apparatus,

and

has

been

supplied

in

safe

condition.

The present

instruction

manual

contains

information

and

warnings

which

should

be

followed

by

the

user

to

ensure

safe

operation

and

to

retain

the

apparatus

in

safe

condition

.

CONTENTS

1.

INTRODUCTION

AND

SPECIFICATIONS

(PRODUCT

DATA)

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

1

2.

CONTROLS

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

13

2.1.

FRONT PANEL

OF

THE

HIGH RESOLUTION SIGNAL ANALYZER

TYPE

2033

..

13

Controls used

for

Analog Input and General Operation ................................ 13

Controls used to set the Triggering Conditions ............................................ 15

Controls used in Recording and Transformation

of

Data ............................... 16

Controls used in Averaging

of

Data ........................................................... 17

Controls used in

the

Display

of

Data ... ....................................................... 18

Controls used in

the

Input/Output

of

Data .................................................

20

2.2.

THE

2033

DISPLAY

SCREEN

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

...

..

..........

21

The

2033

Display Screen in Display

of

a Time Function

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

..

..........

21

The

2033

Display Screen in Display

of

a Spectrum

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

22

2.3.

REAR

PANEL

OF

THE

HIGH RESOLUTION SIGNAL ANALYZER

TYPE

2033

....

23

3.

INSTALLATION

AND

CALIBRATION

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

26

3.1.

INSTALLATION AND PRELIMINARY ADJUSTMENTS

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

26

Environment

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

26

Mounting

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

....

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

26

Connection of

Mains

Supply

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

27

Grounding Considerations

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

.

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

28

3.2.

INITIAL CONTROL SETTINGS

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

28

3.3.

CALIBRATION

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

.

.......

29

Calibration in dB using a Sinusoidal Reference

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

29

Calibration in dB using an External Noise Source

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

31

Calibration in Volts

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

32

Calibration in Engineering Units

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

32

Calibration in

the

Analysis

of

Transient Data

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

...

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

32

3.4.

GENERAL OPERATIONAL PROCEDURE

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

33

4.

RECORDING

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

34

4.1.

SELECTION

OF

TRIGGER SOURCE

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

35

4.2.

INFLUENCE

OF

THE

TRIGGER

"Samples

after

Trig."

CONTROL

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

35

The "Samples after

Trig."

Control in High Resolution Mode

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

36

The "Samples after

Trig."

Control in Baseband Mode

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

36

The Transformed Record Length in Baseband and High Resolution Mode

.......

37

4.3.

CONTROL

OF

RECORDING

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

37

Baseband Mode

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

38

High Resolution Mode .....

..

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

..

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

.. ..

....

.. ..

....

.. ..

........

38

Use

of

RECORD

"Single"

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

..

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

..

....

.. ..

....

..

.......

..

.

38

Manual Selection

of

RECORD

"Stop"

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

39

4.4.

DISPLAY

OF

TIME DOMAIN DATA

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

·

39

Control

of

Time Domain Data Display

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

:

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

40

Use

of

the

2033

LINE SELECTOR

to

read Time Domain Data

from

the

2033

Display Screen

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

41

5.

ANALYSIS

AND

DISPLAY OF SPECTRA,

BASEBAND

MODE

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

43

5.1.

CONTROL

OF

AVERAGING, BASEBAND MODE

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

.

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

43

Linear Averaging

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

44

Exponential Averaging

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

-

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

45

Hold Max. ..

.-

.......

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

...

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

46

5.2.

DISPLAY

OF

BASEBAND SPECTRA

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

.

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

..

......

46

Display of a Spectrum

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

46

Use of

the

Reference

Memory

................................................................... 47

Display of

the

Ratio

between

Spectra

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

48

5.3. USE

OF

AN EXTERNAL SAMPLING FREQUENCY

IN

BASEBAND MODE

.........

48

Use

of

the Tracking Frequency

Multiplier

Type

1901

with

the

2033

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

49

6.

ANALYSIS

AND

DISPLAY OF SPECTRA, HIGH RESOLUTION

MODE

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

50

6.1.

ANALYSIS

OF

SPECTRA, HIGH RESOLUTION MODE .

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

50

6.2.

AVERAGING AND DISPLAY

OF

SPECTRA

IN

HIGH RESOLUTION MODE

........

51

6.3.

MEASUREMENT

OF

4000-LINE

SPECTRA

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

.

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

..

..........

52

6.4.

USE

OF

AN EXTERNAL SAMPLING FREQUENCY

IN

HIGH RESOLUTION MODE .....

..

.....

..

..........

..

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

...

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

.

52

·

6.5

. TRACKING ZOOM

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

..

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

.....

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

55

7.

ANALYSIS

OF

TRANSIENT

AND

NON-STATIONARY

SIGNALS

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

.

...........

57

7.1.

ANALYSIS

OF

TRANSIENT AND NON-STATIONARY SIGNALS,

BASEBAND MODE ..................................................................................

58

Analysis of Single Transients

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

59

Automatic

Transient Averaging

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

:

..

...

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

59

Manual

Averaging

of

Transients

with

Rejection

of

Bad Data

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

59

Analysis of

Machine

Cycles

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

60

7.2. ANALYSIS

OF

TRANSIENT AND NON-STATIONARY SIGNALS,

HIGH RESOLUTION MODE

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

61

Measurement

of

the

4000-line

Spectrum

of

a Transient ..............................

61

7.3.

SCAN ANALYSIS

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

..

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

61

Operation

of

a Scan Analysis ....................................................................

62

Scan Analysis

with

Manual

Control ...........................................................

63

Scan Averaging .......................................................................................

63

8.

OUTPUT OF

DATA

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

65

8

.1

. ANALOG OUTPUT FROM

THE

2033

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

65

Analog Output

to

a Level Recorder Type

2307

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

65

Analog

Output

to

an X-Y Recorder Type

2308

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

68

Exchange

of

the

Level Recorder and X-Y Recorder interfaces

.. .. ..

......

..

.. .. .. .. ..

69

8.2.

DIGITAL READ-OUT UNDER

MANUAL

CONTROL

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

71

Read-out to an

Alphanumeric

Printer Type 231 2 ........................................

71

Read-out to and Read-in

from

a Digital Cassette Recorder Type

7400

..

...

..

71

9.

DIGITAL

DATA

TRANSFER

AND

REMOTE

CONTROL

VIA

THE IEC INTERFACE

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

73

9.1.

IEC

FUNCTIONS IMPLEMENTED

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

74

9.2.

SELECTION

OF

ADDRESSES

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

74

9.3.

CODES

FOR

ADDRESSING

2033

CONTROLS

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

75

F.S. FREQUENCY

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

76

TRIGGER

"Samples

after

Trig."

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

76

AVERAGING

"No.

of

Spectra"

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

76

TRIGGER

''Level''

...

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

77

INPUT

"Att.

0 -

100

dB"

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

77

TIME FUNCTION

"Move"

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

78

SPECTRUM GAIN .

..

.........

..

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

78

LINE SELECTOR ......................................................................................

79

Centre Frequency ....................................................................................

79

Other

Controls, Upper Front Panel

of

2033

.'

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

80

Other

Controls,

Lower

Front Panel

of

2033

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

81

Differences Between Remote and

Manual

Control

of

the

2033

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

81

9.4.

REQUIRED FORMATS

FOR

DIGITAL INPUT AND OUTPUT

OVER

THE

2033

IEC

INTERFACE

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

82

Mode #

0,

Digital

Input/Output

of

an ASCII Encoded Spectrum ....................

82

Mode # 1, Remote Setting

of

Pushkeys and

Output

of

Pushkey Settings ........

83

Mode # 2, Digital

Input/Output

of

a Time Record .....................................

..

84

Mode # 3, Block Transfers

MSBY

-LSBY to and

from

the

2033

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

85

Mode #

4,

ASCII Sensing

of

Pushkeys

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

86

Mode # 5, Digital

Output

of

2's

Complement Encoded Spectrum

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

86

Mode # 6, Block Transfers LSBY

to

and

from

the

2033

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

87

Mode # 7, Block Transfers MSBY

to

and

from

the

2033

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

87

Mode # 8, Carry On processing

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

87

Mode # 9, Reset

10

K Time Function

Buffer

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

87

Other

Input/Output

Modes,

Manual

Digital

Input/Output

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

87

Other

Input/Output

Modes,

Input

of

Text

to

the

IEC

Text Line ......................

88

Other

Input/Output

Modes,

Output

of

Text from

2033

Text Line ..................

89

9.5.

USE

OF

INTERRUPTS

IN

2033

DATA TRANSFERS

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

,....

89

Read-out

of

the

Complex Spectrum

with

Interrupt

Control ............................

90

Use

of

Service Request in Read-out

of

Instantaneous and Averaged Spectra ..

90

9.6

. FORMATS USED

IN

BLOCK TRANSFERS ........

..

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

...........

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

91

Format of a Time Record ..........................................................................

91

Format of

the

Complex Spectrum ..............................................................

91

Format of

the

Instantaneous Power Spectrum .............................................

92

Format of

the

Averaged Power Spectrum

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

92

Format of

the

Reference

Memory

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

93

Format of Display

Buffer

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

94

9.7. SPEED

OF

DIGITAL INPUT AND OUTPUT

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

94

10.

SERVICE

AND

REPAIR

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

95

USES:

•

High

resolution

analysis

of

acoustical

and

vibrational

signals

•

Analysis

of

non-stationary

signals

such as speech,

rapid

machine

run-ups

and

run-downs,

etc.

•

Measurement

and

analysis

of

shock and

transient

signals

•

Analysis

of

vibration

from

both

rotating

and

cyclic

machines

•

Measurement

of

4000-

line

spectra

•

Order

Analysis

FEATURES:

•

Constant

bandwidth

baseband

frequency

analysis

in

400

frequency

lines

• Eleven selectable

baseband

frequency

ranges

from

O - 10

Hz

through

O-

20

kHz

•

10

K

sample

input

memory

with

internal,

external

or

free

running

trigger

and

adjustable

after

trigger

recording

giving

exceptional

transient

analysis

possibilities

• 1 K

sample

window

can be

moved along 10 K

sample

recorded

time

function

to

permit

automatic

"slow

motion"

analysis

•

Built-in

10

x zoom

to

allow

measurement

of

high

resolution

spectra

with

zoom

frequency

range

controlled

by

line

selector

084-81

type

2033

High Resolution

Signal

Analyzer

• Display

of

spectrum

over

80

dB,

40

dB or

linear

display

range

with

variable

display

gain

•

Memory

allows

storage

of

spectrum

for

comparison

with

later

data

•

Alphanumeric

read-outs

directly

from

display

screen

using

line

selector

•

Major

control

settings

displayed on

display

screen

•

Output

of

displayed data

via analog

output

•

Connection

to

IEC

625-1

/

IEEE

Std.

488

interface

bus

•

Digital

input

and

output

of

data and

front

panel

control

settings

via

IEC

interface

iiii

-

iiii

--

f-

";"

!:':"~':"-:'7

....

L..--__J

..... ...• .•

• Display

of

time

signal,

instantaneous

spectrum,

averaged

spectrum

and

spectrum

ratio

on

11"

display screen

•

Greater

than

70

dB

dynamic

range

•

Built-in

antialiasing

filters

•

Overlap

processing

where

calculation

time

allows

it

• Exponential

and

linear

averaging over 1

to

2048

spectra and

hold

max

.

facility

• Scan averaging

for

analysis

of

10

K

transient

signals

• Flat or

Hanning

weighting

selectable before or

after

recording

• Read-out

of

amplitude

in

relative

or

engineering

units

Introduction

The

High

Resolution

Signal

Anal-

yzer Type

2033

represents

a

signifi-

cant

innovation

in

the

world

of

real-

time

FFT

analysis.

An

input

memory

which

has been

considerably

en-

larged

with

respect

to

that

found

in

a

conventional

FFT

analyzer

greatly

enhances

the

capability

of

the

2033

in

the

analysis

of

transient

and

non-stationary

signals.

Further,

a

unique

zoom

feature

which

pre-

serves

the

time

function

allows

a

4000-line

spectrum

to

be

generated

from

a

single

time

record.

This

is in

marked

contrast

to

the

usually

im-

plemented

zoom

transforms

which

require

that

the

time

function

be re-

recorded

for

each

new

zoom

fre-

quency

range.

The

2033

consists

of

a

combined

transient

recorder

and

Fourier

anal-

yzer. The

transient

recorder

has a

10

K

sample

memory,

(1

K =

1024),

and

is

equipped

with

an

extremely

flexible

trigger

allowing

the

2033

to

analyze both

continuous

and

tran-

sient

data. The

transient

recorder

combines

with

the

Fourier

analyzer

to

give

the

2033

two

modes

of

oper-

ation.

In baseband mode,

the

2033

op-

erates

like a

conventional

400-line

FFT

analyzer by,

sampling

the

input

signal

and

transforming

it,

1 K

sam-

ples

at

a

time,

into

the

frequency

do-

main

. The

spectrum

produced

by

each

transformation

is a

constant

bandwidth

spectrum

measured

at

400

equally

spaced

frequency

inter-

vals, (or lines), across a

frequency

range

which

is selectable in a

1-2-

5

sequence

from

OHz

(nominal)

to

Features and Uses

Use

of

zoom

in

the analysis

of

vi-

bration

One

of

the

major

applications

of

real-time

narrow

band

spectrum

an-

alysis is

in

the

study

of

vibration

from

rotating

machines.

Such

analy-

sis can be

instrumental

in

pin-

-pointing

faults

as

they

occur,

en-

abling

repairs

to

be

made

before ca-

tastrophic

failure

takes place. In

many

measurements,

e.g.,

the

vibra-

tion

from

rotating

shafts,

the

base-

band

spectrum

gives

sufficient

reso-

lution

to

enable

the

speedy

identifi-

2

10 Hz

through

OHz

(nominal)

to

20

kHz. The selected

frequency

range

is

referred

to

as

the

base-

band

of

the

2033,

and

spectra

mea-

sured

using

baseband mode as re-

ferred

to

as baseband spectra. The

sampling

frequency

used in

the

2033

is

always,

(in both baseband

and

high

resolution

modes),

2,56

times

the

selected baseband

fre-

quency

range.

In high resolution

mode,

the

2033

operates on

10

K

samples

rather

than

1 K

samples

of

the

in-

put

signal,

i.e.,

a

10

times

longer

time

function

. This can

then

be

used

to

produce

a

10

times

"zoom"

whereby

part

of

the

baseband

fre-

quency

range is expanded by a fac-

tor

of

10

such

that

the

entire

400

lines

of

the

spectrum

lie

within

a

frequency

range

which

is

one

tenth

of

the

baseband

frequency

range.

This zoom can be applied

anywhere

within

the

baseband

frequency

range, by

positioning

the

2033

line

selector

on

the

line

of

the

baseband

spectrum

which

corresponds

to

the

centre

of

the

required

zoom

fre-

quency

range. Spectra

measured

us-

ing zoom are

referred

to

as high res-

olution spectra.

Another

method

of

analysis

is a

"scan"

analysis

. Here,

10

K

sam-

ples

of

the

input

signal

are recorded

and stored in

the

2033

input

me-

mory.

A

time

window

1 K

samples

long can

then

be

automatically

or

manually

stepped

along

the

10 K

sample

time

function,

the

1 K

sam-

ples

of

the

time

function

selected by

the

window

with

each step

being

analyzed. The

frequency

range

and

resolution

of

each

of

the

spectra

cation

of

key

components

in

the

vi-

bration

spectrum

. In

some

measurements,

however,

and

in

par-

ticular

in

the

analysis

of

sideband

structures

typical

of

gearbox

vibra-

tions,

a

greater

resolution

can be

beneficial.

It is

here

that

the

high

resolution

mode

of

the

2033

can be used.

Pressing

the

zoom

pushkey,

shown

in Fig.1, causes

that

part

of

the

baseband

spectrum

centered

around

the

line

selector

to

be ex-

panded by a

factor

of

1

0,

hence

will

be

the

same

as

of

the

baseband

spectrum.

This

method

of

analysis

gives

the

possibility

of

"scanning

through"

the

10 K

sample

time

func-

tion

to

give a

"slow

motion"

analy-

sis,

allowing

any

changes

in

the

baseband

spectrum

to

be observed

as

the

time

window

is stepped

along

the

10

K

samples

.

The spectra

produced

by

the

2033

in

both

baseband and

high

resolution

mode

can be

linearly

or

exponentially

averaged,

or

their

maxima

can be stored. These re-

sults

as

well

as

the

instantaneous

spectrum

and

the

time

function

can

then

be displayed on an

11"

cali-

brated

display

screen,

and

the

dis-

played

values

read via a

line

selec-

tor.

The

2033

incorporates

a

me-

mory

where

a

spectrum

can be

stored

and

then

recalled

to

the

dis-

play screen

allowing,

e.g.

the

com-

parison

of

baseband

and

zoomed

data. The

amplitude

ratio

between

the

input

data

and

the

memory

can

also

be

displayed

.

Output

of

displayed

data can be

made

to

an

X-Y

or

level recorder.

The

2033

is also

equipped

with

an

extremely

sophisticated

IEC

625-1

standard/IEEE

Std

.

488

compatible

interface.

The

analysis

modes

and

other

fea-

tures

described

above

allow

the

2033

to

be used in a

wide

range

of

applications

in

the

analysis

of

both

stationary

and

non-stationary

sig-

nals.

The use

of

these

modes

and

features

is

further

described

in

the

section

"Features

and

Uses".

1

Spectrum

Range

II

Reference 7

Time

or

Level

Linear

40

dB

80

dB

Relative

Se't

--

~-

,.

-.

,:_-

V"

--0

~

-~

390

1K

10K

~Time

Function--...--

....

1

une

Selector

7

-4

Move

.,

-4

.,

0

••

-

--

-

~

Y

10

dB A Zoom

...._

__

Spectrum

___J

Fig.1.

Pushkeys used

to

control

the

2033

high

resolution

mode

Fig.2 .

Example

of

the

use

of

zoom

to

expand

spectra

data.

The

upper

spectrum

is

the

baseband

spectrum.

In

the

lower

spectrum,

the

range

from

900

to

1100

Hz

has

been

expanded

to

fill

the

entire

screen

giving

10

times

improved

resolution.

This

is

illustrated

in Fig.

2,

where

the

baseband and

high

resolution

vi-

bration

spectra

from

a large gearbox

are

compared

. The

400-line

base-

band

spectrum

shows

a

frequency

range

of

0-2

kHz,

while

in

the

high

resolution

spectrum,

the

400

lines

are

centered

around

the

third

harmonic

of

the

toothmeshing

fre-

quency

in a

frequency

range

of

900

Hz

to

11

00

Hz. In

the

high

res-

olution

spectrum,

a sideband

structure

around

the

third

harmonic

which

is

indicative

of

faulty

gears

becomes

clearly

apparent.

It is

interesting

to

note

here

the

optimal

nature

of

the

zoom

factor

10 in

this

type

of

measurement,

in

that

it is

sufficient

to

bring

out

the

required

information

.

Higher

zoom

factors,

on

the

other

hand,

would

cause

increased

"smearing"

of

the

spectral peaks,

this

arising

from

small

variations

in

machine

speed.

Measurement

of

4000

line spectra

A

feature

of

the

2033

is

that

when

it

is

switched

to

its

high

reso-

lution

mode,

once

10

K

samples

of

the

input

signal

have been re-

corded,

multiple

zoom

transforms

may

be made on

the

same

10

K

samples.

Each zoom

transform

takes

approximately

1 s.

This

al-

lows,

for

instance,

10

contiguous

400-line

high

resolution

spectra

to

be

generated

from

the

same

10 K

samples,

allowing

a

4000-line

spec-

trum

of

a

single

time

record

to

be

obtained

.

This

spectrum

will

extend

across

the

entire

2033

baseband

frequency

range

.

High speed zoom

The

feature

described above, i.e.,

that

the

2033

can process

multiple

zoom

transforms

from

the

same

10 K

time

record, can

make

the

2033

considerably

faster

than

an

analyzer processing

conventional

zoom

transforms

in

obtaining

high

resolution

spectra.

With

conven-

tional

zoom

transforms,

the

zoom

frequency

range

must

be selected

before

the

time

function

is re-

corded, and

hence

the

time

function

must

be re-recorded each

time

a

new

zoom

frequency

range is re-

quired

.

This

is in

contrast

to

the

2033

zoom

transform,

where

the

zoom

frequency

range need

not

be

chosen

until

after

the

time

function

has been recorded,

allowing

re-

peated zoom

transforms

to

be

per-

formed

on

the

same

data.

An

indication

of

the

possible

dif-

ferences

in processing

times

may

be had by

comparing

the

two

trans-

forms

in a 10

times

zoom on a O

to

10

Hz

baseband

frequency

range

.

Both

will

require

400

s

of

time

do-

main

data,

(assuming

a

400

line

high

resolution

spectrum)

.

Thereaf-

ter

,

the

2033

can make as

many

zoom

transforms

as are

required

from

the- same

400

s

of

data, each

taking

about

1 s. A

conventional

zoom

transform

,

however,

requires

a

new

400

s

of

data

for

each

new

zoom

transform,

making

it in

this

case

about

400

times

slower.

Use

of

scan

in

the analysis

of

non-

stationary signals

The scan

function

is

of

excep-

tional

value

in

the

analysis

of

non-

stationary

signals

such

as speech,

fast

machine

run-ups

and

run-

downs,

music,

etc. It has

the

effect

of

producing

a

"slow

motion"

analy-

sis

such

that

rapid

changes

in

the

spectrum

of,

e.g.,

a

word

of speech

can be seen

and

understood

directly

from

the

2033

display

screen

.

Oth-

erwise,

as in

for

instance

a real-

time

analysis

,

these

changes

might

occur

so

rapidly

as

to

make

their

vis-

ual

comprehension

impossible.

3

10 K samples

are

recorded in the 2033

input

memory

I ' I

I I I

~1¢::).~l~~~

l /

·,

\ , \ , ,

i"

'\I

.

----

A

flat

or Hanning weighting time

window

is

--

t'

..,.._......,...._,.._....,...._

1 _ stepped along the 10 K samples

~:

:

I I 1 K samples

are

selected

with

ea

ch

step

for

analysis

-A

spect,om

;,

obta;oed

of

the

relected 1 K

~mples

790997

Fig.3. Illustration

of

scan analysis, where a 1 K sample time

window

is

stepped along the 1

OK

sample

time

function to give a

"slow

motion"

analysis

In

operation

of

a scan

analysis

,

1

0240

samples

of

the

input

signal

are recorded

and

stored

in

the

2033

input

memory

. The scan

func-

tion

then

allows

a 1 K

sample

time

window

to

be stepped

along

the

10 K

samples,

while

producing

a

new

400

-

line

spectrum

for

each

step.

Either

a

flat

(rectangular)

or

a

Hanning

weighting

can be applied

as

the

window

function

. The pro-

cess is

illustrated

in

Fig.3

. The scan

is

non-destructive

,

allowing

re-

peated scans

on

the

same

10 K

samples,

e.g.,

with

a

changed

weighting

function,

etc..

The scan can

be

controlled

auto-

matically

or

manually

. In an auto-

matic scan

the

window

is stepped

across

the

entire

10 K

samples,

producing

and

displaying

a

new

spectrum

for

each step. The

num-

ber

of

steps is selectable in a se-

quence

of

8

values

from

10

to

1153,

(these

values

corresponding

to

a step size selectable in a

binary

sequence

of

from

1024

to

8

sam-

ples),

the

duration

of

each step be-

ing

approximately

110

ms

. The ef-

fect

is

to

produce

a

"live"

display

of

the

spectrum

changes

which

occur

as

the

time

window

moves

along

the

10

K

samples

. The

total

time

taken

for

the

scan

varies

from

about

1 s

to

about

2

min.

depending

on

the

number

of

steps.

In a manual scan,

the

time

win-

dow

is chosen by

manually

position-

ing

the

required

1 K

samples

on

the

2033

display

screen.

and

then

se-

lecting

instantaneous

spectrum

dis-

4

play

to

show

the

spectrum

. (An ex-

ample

is

shown

in Fig.4). In a

man

-

ual scan.

the

step size

from

window

to

window

is in

multiples

of

30

sam-

ples.

Signals

from

200

ms

to

400

s

du-

ration

can be analyzed

in

the

above

manner

.

depending

on

the

base-

band

frequency

range

selected

.

With

a 5 kHz baseband

frequency

range

,

for

instance,

the

10

K

sam-

ples

would

correspond

to

800

ms

of

time

domain

data,

and

the

mini-

mum

step size

from

one

window

to

the

be

about

1

ms

for

an

automatic

scan and

about

2,5

ms

for

a

manual

scan. The

time

window

would

in

this

case

corre-

spond

to

80

ms

with

rectangular

weighting

selected,

and

about

40

ms

with

Hanning

weighting

se-

lected, (use

of

Hanning

weighting

reduces

the

effective

time

window

by

approximately

50%).

Triggering facilities

The

2033

incorporates

very

ad-

vanced

and

flexible

triggering

facili-

ties.

In

the

free running

trigger

mode.

the

2033

analyzes data at a

rate

which

is

only

limited

by

the

cal-

culation

procedures

. In

the

lower

baseband

frequency

ranges,

(0

to

2 kHz

and

less),

this

gives

overlap

processing

whereby

overlapping

time

records are analyzed

to

update

the

instantaneous

spectrum

at

least

5

times

a second,

making

it

easier

to

follow

changing

spectral

compo-

nents

. Use

of

a

free

running

trigger

is

principally

associated

with

the

an-

alysis

of

continuous

signals

.

Internal

trigger

mode

is

primarily

applied

in

the

analysis

of

transient

signals

. Here,

the

input

signal

itself

is used

to

trigger

the

analysis,

the

trigger

level

being

adjustable

in

200

steps across

the

maximum

in-

put

voltage

swing.

The

trigger

level

set is

displayed

when

the

2033

dis-

play

screen

is set

to

show

a

time

function.

In external

trigger

mode,

an

externally

applied

pulse

is used

to

control

the

recording

. The

major

use

of

this

is

to

synchronise

the

an-

alysis

with

a

repetitive

process.

After

trigger recording

Associated

with

internal

and

ex-

ternal

triggering

is an

adjustable

de-

lay called

after

trigger

recording.

It

is used

to

select

precisely

which

part

of

the

input

signal

is analyzed

with

respect

to

the

time

when

the

trigger

occurs

. It

operates

by

allow-

ing

the

2033

to

continue

recording

new

samples

after

it

has been

trig-

gered

until

a

preset

number

has

been reached.

Then,

the

recording

process is stopped,

and

the

2033

operates

on

whichever

time

func-

tion

is

standing

in

its

memory

at

that

ti

me. The

after

trigger

record-

ing

enables

the

2033

to

analyze

events

occurring

both

before

and

af-

ter

the

trigger

, (an

example

of

its

use is

given

in

the

section

"Analy-

sis

of

machine

cycles")

.

Up

to

a

further

64

K

samples,

ad-

justable

in steps

of

0,

1 K

samples,

can be recorded

after

the

2033

is

triggered

.

This

allows

the

2033

to

analyze

events

occurring

from

10

K

samples

before

the

trigger,

(after

trigger

recording

set

to

0,0

K), up

to

64

K

samples

after

the

trigger,

(af-

ter

trigger

recording

set

to

64

K).

For

instance,

with

a baseband

fre-

quency

range

of

10 kHz

this

repres-

ents

a

timespan

of

0,4

s

before

the

trigger

up

to

2,

56 s

after

it. (The

sampling

frequency

is

2,56

times

the

baseband

frequency

range). On

the

2 kHz

range,

the

corresponding

figures

would

be 2 s and

12,8

s re-

spectively

.

Transient analysis

The

trigger

and

after

trigger

re-

cording

facilities

described

in

the

sections

make

the

2033

an

extremely

flexible

system

in

the

analysis

of

transient

signals

.

The

range

of

adjustment

of

the

inter-

nal

trigger

level reduces

the

likeli-

hood

of

a

false

trigger,

while

where

(a) (b)

(c) (d)

Fig.4.

Illustration

of

transient

analysis

possibilities

with

the

2033,

a)

10

K

sample

time

function,

b) 1 K

samples

selected

using

manual

scan, c) an-

alysis

of

the 1 K samples,

d)

scan average

of

the

10

K samples

a

suitable

trigger

signal

is available,

an

external

trigger

can be used.

Use

of

the

after

trigger

recording

en-

ables

the

2033

to

analyze data oc-

curring

both

before

and

after

the

trigger.

This

makes

the

2033

equally

suitable

in

analysis

across

the

entire

range

of

transient

signals

from

short

,

highly

impulsive

signals

such

as

gunshots,

to

long,

low

fre-

quency

signals

like

seismic

waves.

Fig

.4

illustrates

the

possibilities

available

in

the

analysis

of

transient

signals.

It

shows

an

analysis

in

the

10 kHz baseband

frequency

range

of

punch

press

noise

.

First

the

10

K

sample

time

function

is displayed,

which

is

of

400

ms

duration,

this

being

sufficient

to

describe

the

en-

tire

punch

press cycle. Next, a 1 K

sample

section

of

the

10

K

time

function

is displayed,

this

having

been selected

using

a

manual

scan

from

that

part

of

the

time

function

where

the

amplitude

was

at a

maxi-

mum,

(as i

ndicated

by

the

line

selec-

tor

in Fig .4(a)). The

shows

an

analysis

in

the

baseband

frequency

range

of

those

1 K

sam-

ples.

Finally,

a scan average, (see

the

section

"Scan

averaging"),

ac-

ross

the

entire

transient

is

shown

.

A

further

possibility,

not

illustrated,

would

be

to

measure

the

4000

line

spectrum

of

the

transient.

Averaging

Spectrum

averaging

is

performed

in signal

analysis

in

order

to

reduce

the

effects

of

random

variations

and

to

produce

a

statistically

reliable

re-

sult.

The

2033

has

three

averaging

modes,

the

first

two

of

which,

namely

exponential averaging

and

linear averaging give a

true

RMS

av-

erage. From 1

to

2048

baseband

or

(400

line)

high

resolution

spectra

can be averaged

coming

from

both

continuous

and

transient

data. The

third

averaging

mode

is a maxi-

mum

hold,

where

the

maximum

le-

vel

occurring

in each

line

of

the

spectrum

is held.

Maximum

hold

can operate on an

unlimited

num-

ber

of

spectra.

When

the

2033

is in its base-

band mode, and

Hanning

weighting

is selected,

the

effective

time

win-

dow

is

reduced

by

about

50%.

The

2033

takes advantage

of

this

to

re-

duce

the

time

required

to

produce

a

statistically

reliable

result,

by aver-

aging

spectra

which

come

from

50%

overlapping

time

records.

Hence,

the

time

required,

for

in-

stance

to

linearly

average

64

spectra

with

a 1 kHz

full

scale

fre-

quency

is reduced

from

25,6

s

to

1

2,8

s

but

with

the

relative

error

re-

maining

at

approximately

±

0,5

dB.

Averaging

with

flat

weighting

in

the

baseband

mode

or

with

flat

or

Han-

ning

weighting

in

the

high

resolu-

tion

mode is

carried

out

without

overlap.

Scan averaging

When

the

2033

makes

an

auto-

matic

scan

analysis

of

a

10

K

sam-

5

Indication

of

major

control

settings.,_

__

Read-out

of

Line

Selector--------

Indication

of

selected

line

--------1

Indicators

of

overload

or

upper

10

dB

For

entry

of

signal

from

co-axial

sources

For

input

of

signals

from

most

B & K

Microphone

Amplifiers

Allows

adjustment

of

the

reference

level in 10 dB steps

Gives

continuous

adjustment

of

the

input

gain

--

_,.__

S,gnal°""""'j

f

·-··

·--·~

,

.•.

••••

1

4.

1'

UJ

:

•

Selects

whether

the

signal

analyzed

_________

__,

comes

from

the

Preamplifier

or

Di-

rect

input

.

Also

selects

the

internal

calibration

signal

6

Control

trigger

mode

Set

input

attenuation

in

steps

of

10

dB

-I

• - - ,c -

...,.

____

,_.....,_..,,..___.

-

---

.

.,.......,

----.

...

---

..--..

u.

....

,...

._.

I

•

----J

,.

.... 1 r,.•.,....-., r -.....- 7

Off

........

0...\ltl

Select

time

weighting

function

Select

number

of

spectra

to

be

aver-

aged

Select

baseband

full

scale

fre-

quency

Select

after

trigger

recording

from

0,0

to

64

K

samples

after

trigger

---

Select

external

sampling

and

allow

the

antialiasing

filters

to

be by-

passed

----••

Control

trigger

level

..

-

....

--------,•

Select

digital

input

or

output

--------

Control

the

analog

output

Control

which

data

is

displayed

or

output

Control

entry

of

data

to

the

memory

Control

entry

of

data

to

the

display

screen

For

setting

a

reference

on

the

dis

-

play

screen

For

selecting

spectrum

display

range

or

number

of

samples

dis

-

played

of

a

time

function

Control

display

gain

and

move

a

dis

-

played

time

function

--------•

Controls

line

selector

-----Selects

high

resolution

mode

Control

the

appearance

of

the

2033

display

---

Resets

the

2033

to

a

preset

state

Control

recording

----------Control

averaging

7

pie

time

function

,

it

simultaneously

produces a scan average.

This

is a

linear

average

of

the

spectra

gener-

ated by

the

scan, and

it

can

be

seen

by

setting

the

2033

display

screen

to

show

the

averaged

spectrum

.

Scan

averaging

is used

to

obtain

a

400-line

averaged baseband spec-

trum

from

a

10

K

sample

time

func-

tion.

In

this

respect

it

can be used

with

both

stationary

and

non-sta-

tionary

signals

and

both

transient

and

continuous

signals

.

Analysis

of

machine cycles

The

application

,

of

the

2033

to

the

analysis

of

machine

cycles,

men-

tioned

previously

, can be

extended

by

appropriate

use

of

the

trigger

,

af

-

ter

trigger

recording,

and

averaging

facilities

. Fig .5

shows

a typical re-

sult

,

this

being a

three

dimensional

plot

of

the

vibration

at

the

cylinder

head

covering

one cycle

of

a

4-cylin-

der

4-stroke

diesel

engine

,

operat-

ing

at

1

500

rpm

with

delayed

injec-

tion

. Each

spectrum

in

the

plot

re-

presents

about

4

ms

of

the

entire

80

ms

cycle,

(8

ms

of

record

weighted

with

a

Hanning

weight

-

ing),

and

is an average

over

64

cy-

cles.

Synchronisation

between

the

2033

analysis

window

and

the

en-

gine

was

obtained

using

a

once-per

-

cycle

tachometer

pulse

as an

exter-

nal

trigger

,

the

analysis

window

be-

ing stepped in

1,6

ms

steps

along

the

engine

cycle by

incrementing

the

after

trigger

recording

.

The

var-

ious

events

in

the

cycle can be

clearly

seen.

Tracking and order analysis

The

frequency

range

of

the

2033

can also be

controlled,

both

in base-

band and

high

resolution

mode,

from

an

external

sampling

fre-

quency

. By

deriving

this

external

sampling

frequency

from

the

rota-

tional

speed

of

a

machine,

order

an-

alysis

whereby

the

2033

tracks

the

machine

speed can be

carried

out

.

In

such

an

analysis,

the

frequency

range displayed varies in

sympathy

with

the

machine

speed

such

that

the

rotationally

stay in fixed

positions

on

the

2033

display

screen

. A

suitable

set-up

for

this

,

utilising

the

Tracking Fre-

quency

Multiplier

Type

1901

is

shown

in Fig.6.

When

the

2033

is set

to

track

in

baseband mode,

wherever

the

calcu-

8

20

kHz

790964

Fig.5. Analysis

of

one cycle of a 4-cylinder diesel engine

Accelerometer

4368 -

-=

-

•

..

"-

Magnetic Pick-up

MM 0002

Charge Amplifi

er

2635

High Resolution Signal

Analyzer 2033

~------

)•.

(3)

iii

,

.....,,

________________

~

Tracking Frequency

Multiplier

1901

790966

Fig .6. Use

of

the Tracking Frequency Multiplier Type

1901

with

the

2033

lation

time

allows

it,

overlap

pro-

cessing is

employed

making

it

ea-

sier

to

follow

a spectral

component

from

one

spectrum

to

the

next,

(the

instantaneous

spectrum

will

be up-

dated at least 5

times

a second). In

high

resolution

mode, a

unique

fea-

ture

is

that

the

zoom process

effec-

tively

provides

the

2033

with

a

tracking

antialiasing

filter.

This

en-

ables

the

2033

to

track

over

approx-

imately

a 15:1 speed range

without

the

danger

of

the

introduction

of

dis-

turbing

aliasing

distortion.

Overlap

processing,

however,

is

no

longer

possible.

Data

Input

The

2033

input

is

designed

to

en-

sure

the

integrity

of

analyzed data.

A

full

B & K

measuring

amplifier

in-

put

is

built

in,

allowing

the

connec-

tion

of

signals

from

most

B & K

mic-

rophone

preamplifiers

and

other

sig-

nal

sources

.

Detection

of

overload

takes place

at

two

points,

namely

before

the

antialiasing

filter

to

guard

against

undetected

saturation

of

the

input

amplifier

,

and

at

analog

to

digital

conversion

to

guard

against

clipping

of

samples

at

the

ADC. Evidence

of

saturation

or

clip-

ping

is

later

used

during

averaging

to

prevent

data

influenced

by an

overload

from

entering

an

on-going

average.

Data

Display

The

2033

utilises

an

11"

cali-

brated

raster

scan

display

screen

en-

abling

important

details

in displayed

data

to

be

quickly

and

precisely

iden-

tified

.

Both

time

functions

and

spectra can be displayed.

In baseband mode,

the

2033

gives a

"live

"

display

of

the

enve-

lope

of

the

1 K

sample

time

func-

tion

on

which

it is

operating

, and in

high

resolution

mode,

the

10 K

time

function

can be displayed. If record-

ing is stopped,

either

the

10 K

time

function

or a 1 K or

390

sample

window

selected

from

it

can be

dis-

played.

Selection

of

the

display

win-

dow

is via

the

line

selector,

which

is also used

to

read

the

time

corre-

sponding

to

each

sample

in

the

time

function

. The displayed

win-

dow

can also be moved back and

forth

along

the

time

function

using

the

Move

push

keys.

The

time

function

display

facili-

ties

are also used

to

manually

con-

trol

a scan

analysis

of

a recorded

10 K

time

function

. The 1 K

sam-

ples

required

for

analysis

are

first

positioned

on

the

2033

display

screen.

Selecting

instantaneous

spectrum

display

gives

their

spec-

trum

.

Display

of

the

instantaneous or

averaged spectrum is in

terms

of

linear

or

logarithmic

amplitude

, (lo-

garithmic

amplitude

display

range

selectable

between

40

dB and

80

dB),

with

variable

display

gain

,

against

linear

frequency

. The

line

selector

may

now

be used

to

read

the

frequency

in

Hz

and

the

ampli-

tude

in dB

or

V

of

any

line

in

the

spectrum

.

Any

line

in

the

spectrum

can be set

to

read OdB

or

1

unit,

(as can

any

sample

of

the

time

func-

tion

be set

to

read Os). The

line

se-

lector is also used

to

select

the

zoom

frequency

range

in

high

reso-

lution

mode.

An

example

of

a

linear

spectrum

display

is

given

in Fig.7 .

Engineering Units

calibration

of

the

2033

can be

obtained

using

the

internal

100

mV

reference

with

the

Reference

Adjust

dB

and

Gain

Con-

trol

potentiometers

. The

calibration

level is

adjustable

across a range

of

Fig.

7.

Example

of

a linear spectrum display. The amplitude

of

the selected line can

be

read

in

volts. engineering units. or in linear units referred to any·line

of

the spectrum

Broel &

Kjzr

Time F

unction

Start

:

Full

Scale

Level

:_12~0

___

dB

,.

..

+

F.S.

Frequency

: ~

Weighting:~

Average Mode:~

No

.

of

Spectra

:_ 3_2 _

10

~-

Comments:

Typical X- Y Recorder

read-out from 2033

Record No:

__

_

Oat"

10

/ 1

0/79

Sign

.:

RMV

.

OP

1

002

2

1

0.5

End: N

ot

Expanded: + . Expanded: t

Measuring

Objec

1·

___________

_____

____

790969

Fig .

8.

Example

of

a

2033

spectrum recorded using an

X-Y

Recorder Type

2308

approximately

1

00

µV

/

unit

to

ap-

proximately

30

V/

unit.

Associated

with

the

display

screen is a

memory

,

where

a spec-

trum

can be stored

for

its

later

re-

call,

allowing,

e.g.,

the

comparison

of

baseband and

high

resolution

spectra. The amplitude ratio be-

tween

the

input

spectrum

and

the

memory

contents

can also be

dis-

played

allowing

the

estimate

of

the

magnitude

of

a system

frequency

re-

sponse.

Data

Output

Analog

outputs

can be made

to

a

B & K Level Recorder Type

2307

or

to

an X-Y Recorder Type

2308,

(specify

which

output

is

required

when

ordering)

.

Any

function

which

is displayed can be

output

,

the

re-

cording

being

made on

graduated

paper. Fig .8

shows

a

spectrum

re-

corded

using

an X-Y Recorder Type

2308

.

IEC Interface

A

further

unique

feature

of

the

9

2033

is an

extremely

flexible

and

sophisticated

interface

which

allows

total

access

to

the

2033

controls

and

data

memory.

This

interface,

which

conforms

to

the

IEC

625-1

standard

(compatible

with

IEEE

Std.

488),

allows

simple

connection

of

a

calculator

to

the

2033,

to

form

a

powerful

system.

So

connected,

a

calculator

has access to,

amongst

other

things:

All

the

2033

pushkeys

and

the

line

selector

.

The

time

function

.

The

complex

spectrum

.

The

instantaneous

power

spec-

trum

.

The averaged

power

spectrum.

The stored

spectrum.

The

display

screen

alphanumeric

text

line

.

Examples

of

more

complex

process-

ing

which

can

then

take place

in-

clude

:

Automatic

spectrum

comparison.

Inverse

Fourier

Transform

.

Cepstrum

.

Hilbert

Transform

.

An

interesting

combination

is

the

2033

with

the

Digital Cassette Re-

corder Type

7400,

(shown

in

Fig.

10)

. The

7400

connects

directly

to

the

2033,

and

as

well

as being

able

to

record spectra,

the

7

400

can record

the

time

function,

(1

K

or

10

K), held by

the

2033

.

This

al-

lows

the

total

documentation

of

re-

sults,

in

that

everything

generated

10

•ioo no 1.iiov

110

.......

SO

IOI-I•

Fig.9. Rear Panel of the

2033

High Resolution Signal

Analyzer 2033 Digital Cassette Recorder

7400

190965

Fig.1

O.

Use of the Digital Cassette Recorder Type

7400

with

the

2033

from

that

time

function

can be ex-

actly

reconstructed

by

reading

the

recorded

time

function

back

to

the

2033.

Description

When

it

is

operating

in its base-

band mode,

operation

of

the

2033

is

similar

to

that

of

the

Narrow

Band

Spectrum

Analyzer

Type

2031

. A

full

description

of

the

the-

oretical

principles,

etc

.

behind

this

may

be

obtained

by

reference

to

the

2031

product

data

sheet

. A

thor-

ough

discussion

of

FFT

techniques

is also given in

the

B & K

Technical

Review,

No.1,

1979.

The

technical

description

of

the

2033

will

here

be

limited

to

a

description

of

the

zoom

transform

used.

Although

it is

not

the

intention

to

describe it in

detail,

a

conventional

zoom

transform

depends on an

in-

itial

multiplication

of

the

time

signal

with

a

rotating

vector,

which

shifts

the

required

zoom

frequency

range

in

frequency

such

that

it lies

cen-

tered

around

DC

.

This

is

then

fol-

lowed

by a

digital

low

-pass

filtration

and

the

discarding

of

redundant

x(0)

x(,O)

__..

1 K G0(k)

FFT

x(,0230)

x(1)

x(11) 1 K G1 (k)

__.,

FFT

x(,0231)

samples

to make a

new

time

signal

which

is

the

one

which

is

actually

transformed

. The

advantage

of

this

method

is

that

very

high

zoom fac-

tors

can be

obtained

. The

disadvan-

tage is

that

since

the

zoom

fre-

quency

range is

partially

deter-

mined

by

the

frequency

of

the

multi-

plying

vector,

a

new

time

signal

must

be recorded

for

each

new

zoom

frequency

range,

this

often

be-

coming

a

lengthy

and

time

consum-

ing process.

An

alternative

zoom

transform

process

was

chosen

for

the

2033

for

two

reasons,

namely

:

i)

Very

high

zoom

factors

are

infre-

quently

necessary in

measure-

ments

of

vibration

from

rotating

machines

,

and,

in fact, are

often

detremental

to

measurement,

be-

cause

of

the

increased

sensitivity

to

"smearing"

of

spectral peaks,

due

to

small

variations

in

ma-

chine

speed.

ii)

An

alternative

zoom

transform

could

allow

the

time

function

to

be preserved.

9

1)

X(k)

= I w

lk

G1

(k)

i=0

10240

0

.;;;

k

.;;;

4000

W

lk

( .

2rrlk

)

10240

= exp

-J

10240

X(k)

W 9 k

10240

x(9)

x(19)

__.,

1 K

Gg(k)

FFT

x(,0239)

190967

Fig.11.

Block

diagram

representing

the

2033

zoom

calculation

The zoom

transform

implemented

by

the

2033

can be

described

with

reference

to

Fig.

11

.

This

shows

an

FFT

which

transforms

1

0240

real

valued

time

domain

samples

into

51

20

complex

spectral

lines.

It

uses

the

principle

whereby

a 10 K

FFT

can be decomposed

into

ten

1 K

FFTs,

decimation

being

performed

on

the

10 K

time

function

to

pro-

duce

ten

1 K

time

functions.

The

baseband

FFT

procedures

can

then

be applied to

obtain

the

spectra

of

the

ten

1 K

time

functions,

these

spectra being

manipulated

to

obtain

the

51

20

frequency

domain

points

Input Characteristics:

Input:

either

"Direct

Input

" or standard

B & K 7

"Preamplifier

Input"

Input

Impedance: "

Direct

1

MO

//

100pF

Input

"

Maximum

Input Voltage:

2033

is a

Safety

Class

II

instrument

(IEC

348)

. For

safe

operation

in accordance

with

IEC

348

,

the

voltage

of

the

signal or signal

ground

relative

to

earth

must

not

exceed

42

V RMS (sine). To

ensure

safe opera-

tion

within

IEC

348

at

higher

voltages,

the

user

must

limit

all

input

currents

to

0,7

mA

peak

Sensitivity:

11

full

scale

sensitivity

ranges

(overload

limit

of

ADC), 10 dB

steps

from

66

dB

to

166

dB RMS re 1

µV

(sine)

Input

Attenuator: 0

to

1

00

dB in 10

dB

steps,

accurate

to±

0,

1 dB

Gain Control: 0

to

10

dB

Sensitivity Adjustment (Direct):

+ 4,7 dB

to

- 10 dB

Sensitivity Adjustment (Preamp.):

+4

,7 dB

to

-1

0 dB

Amplitude

Reference: 1

00

dB referred

to

1

µV

. Frequency,

64

%

of

selected

baseband

full

scale

frequency

Antialiasing Filters:

11

filters

automati-

cally

selected

with

baseband

frequency

range.

Max

. ± 0 ,2 dB ripple in

the

pass-

band,

113

dB/oct roll

off.

Provide at

least

70

dB

attenuation

of

any

compo-

nents

in

the

input

signal

having

frequen-

cies

higher

than

1,

56

the

baseband

full

scale

frequency

. The

filters

can be by-

passed,

if

required

Sampling:

2,56

x baseband

full

scale fre-

quency

,

automatically

selected

with

the

baseband

frequency

range

for

internal

sampling

. External

sampling

sets the

baseband

full

scale

frequency

to

1/ 2,

56

of

the

external

sampling

rate

Analog

to

Digital Conversion:

12-bit

two

's

complement,

quantizing

error

maxi-

mum±

1/ 2 LSB

Overload Indicator:

indicates

overload in

either

the

input

amplifier

or

the

ADC

Upper

10

dB Indicator:

indicates

when

either

the

input

amplifier

or

the

ADC is

operating

in

the

upper 10 dB of i\s dy-

namic

range

associated

with

the

original

10 K

time

function.

Of

these

51

20

points,

due

to

the

roll-off

of

the

2033

antialiasing

filter,

only

the

first

4000

give valid data

hence

forming

a

4000

line

spectrum.

The

2033

performs

its

zoom

transform

by

following

the

above

procedure,

but

by

then

limiting

the

manipulation

to

obtain

51 2 spectral

lines, (by

allowing

k

of

equation

1

of Fig.11

to

vary over

51

2

conti-

guous

values),

this

saving

consider-

able

time.

The

frequency

range

of

the

lines

is set

according

to

the

posi-

Specifications

2033

Analysis Characteristics:

Baseband

Mode:

Full Scale Frequency:

10

Hz

to

20

kHz

selectable in a 1 - 2 - 5 sequence

Real

Time

Frequency Range: > 2 kHz

Number

of

Synthesised Filters:

400,

generated

from

1024

input

samples

Filter Spacing,

/3

: reciprocal of

the

input

time

function

duration,

or

the

full

scale

frequency

/

400

Overlap:

with

free

running

trigger

se-

lected

the

instantaneous

spectrum

is up-

dated at least 5

times

a second

High Resolution Mode:

Frequency Span: one

tenth

of

the

se-

lected baseband

full

scale

frequency

,

1

Hz

to 2 kHz selectable in a 1 - 2 - 5 se-

quence

. Frequency span

centre

fre-

quency

is selectable in steps of 1/

400

th

of

the

baseband

full

scale

frequency

within

the

baseband

frequency

range,

via

the

line

selector

Number

of

Synthesised Filters:

400

generated

from

1

0240

input

samples

,

i.e.

4000

filters

within

the

baseband

fre-

quency

range

Filter Spacing,

/3

: reciprocal of

the

input

time

function

duration

, or

the

baseband

tu

II

sea

le

frequency

/

4000

Baseband and High Resolution

Mode:

Weighting:

flat

(rectangular) or

Hanning

,

selectable before or

after

the

time

func

-

tion

has been recorded

3 dB Bandwidth:

0,88

/3

for

Flat

Weight

-

ing,

1,44

f3

for

Hanning

Weighting

Noise Bandwidth:

/3

for

Flat

Weighting

,

1,5

/3

for

Hanning

Weighting

Amplitude Linearity: (for

32

spectra av-

erage) ±

0,

1 dB or ± 0,01 %

of

full

scale

at overload,

whichever

is

greater

(no ad-

justment

necessary)

System Frequency Response: ±0 ,2 dB

with

antialiasing

filters

bypassed, or

± 0 ,3 dB

otherwise.

2

Hz

to

20

kHz

Noise Level: (for

32

spectra average)

less

than

0 dB re 1

µV

or

76

dB

below

overload,

whichever

is

greater

Transient Analysis:

Trigger Modes:

Internal.

External or

Free-run

tion

of

the

line

selector.

Once

the

original

10 K

samples

have been re-

corded,

the

entire

process takes ap-

proximately

1 s.

In

the

above process,

the

sample

values used in

the

1 K

time

func-

tions

are

never

modified

with

re-

spect to

the

10 K

time

function,

and

thus

the

original

information

is pre-

served

allowing

further

zoom

trans-

forms

to

take place on

the

same

data

.'

Hence

the

requirement

for

re-

recording

the

time

function

is

avoided.

Trigger Level:

adjustable

in

200

steps ac-

ross

the

input

voltage range.

Trigger

le-

vel

indicated

on

the

display screen

Trigger Slope: positive

for

positive

trig

-

ger

level, negative

for

negative

trigger

level

After

Trigger Recording:

adjustable

in '

steps of 0,1 K samples

from

0,0

to

64

K

samples

Memory

Period: equal to in seconds

4000

/baseband

full

scale

frequency

in

Hz

Recording Control:

manual

transient

capture

or

automatic

capture

on

the

Transient Averaging:

automatic

averag-

ing

of

a succession

of

transients

or aver-

aging

with

manual

control

after

verifica-

tion

of

data

Scan Analysis:

Automatic

; 1 K

time

win-

dow

is stepped across

entire

10 K

time

function

producing

new

analysis

with

each step,

number

of steps selectable in

a sequence

of

8 values

from

10

to

1153

Manual

; 1 K

time

window

placed

manu

-

ally

, step size in

multiples

of

30

samples

Averaging:

Linear:

linear

average of a preset

num-

ber

of

spectra producing a

true

power

av-

erage. A

true

average is

always

displayed

and

the

number

of spectra aver-

aged is

indicated

on

the

display

Exponential:

the

number

of spectra

indi-

cated on

the

display gives

the

effective

averaging

time

No.

of

Spectra: 1 -

2048

in 12

binary

related ranges

Hold

Max.:

the

maximum

level

occurring

in each

line

is held

Overlap:

Hanning

weighting

selected,

50

%

where

calculation

time

allows

it.

Rectangular

weighting

selected,

no

over-

lap.

High

resolution

mode selected, no

overlap

Controls:

Start

, Proceed and Stop

Overload Protection: data

influenced

by

an overload is

automatically

excluded

from

an average

Scan Averaging:

linear

average of an au-

tomatic

scan

analysis

1 1

Memory:

"Store":

stores

the

instantaneous

or av-

eraged spectrum and corresponding al-

phanumerics

shown

on

the

display

"Protect":

prevents

further

updating

of

the

memory

Display:

The display screen

shows

the

input

func-

tion

, (i.e

.,

time

function,

instantaneous

spectrum, or averaged spectrum),

the

me-

mory

contents,

the

amplitude

ratio be-

tween

the

input

function

and

the

me-

mory

contents,

or

the

input

function

and

memory

contents

alternatively

displayed

with

a fast or

slow

alternating

frequency

Size:

11"

Display Area:

150

x

210

mm

(6

in x

8,25

in)

Scale Lines: 41 horizontal lines are elec-

trically

generated

directly

on

the

screen

for

parallax free readings

Spectrum Range: linear,

40

dB

or

80

dB

Spectrum Gain: in 10 dB steps over an

80

dB range

Alphanumeric Read-outs:

full

scale le-

vel,

frequency

span, samples

after

trig-

ger,

number

of

spectra averaged, se-

lected

frequency

line or sample

number,

selected

frequency

or

time,

selected level

Line Selector:

line

moved

either

continu-

ously or in single steps

to

the

right

or

to

the

left, indicated by an

intensified

co-

lumn

Amplitude at Line Selector:

shown

on

display in V, or in dB referenced

to

1µV,

or

dB referenced to 1

µV

±

50

dB, or dB

referenced to

the

RMS level in

any

chan-

nel

of

the

spectrum,

or

linear

units

refer-

enced to

any

channel

of

the

spectrum

Time at Line Selector:

shown

on display

referenced

to

first

sample or relative to

any

sample in

the

record

Time Function Display: envelope of

10 K samples or 1 K samples,

or

390

contiguous

samples

Level Recorder Output:

Output Impedance: 1 k 0

Maximum

Output

Voltage: +

15

V

(nomi-

nal

12

V)

Digital Input and Output:

Interface:

conforms

to

IEC

625-1

stan-

dard, compatible

with

IEEE

Std.

488

Functions:

SH

1, AH 1,

T5,

L3

,

SR

1,

RL0

, PP0, DC2 and

DT0

Data:

functions

selected by Display Se-

lector, or

with

controller,

any

main

me-

mory

block

Code: ISO

7-bit

code (i.e. ASCII

but

with-

out

the

parity bit) or binary, selected

from

controller

Remote Control:

front

panel

settings

can

be

input

and

output

via digital

inter-

face

Miscellaneous:

Power Supply:

100,

115,

125,

200,

220,

240

V AC, ±

10%,

50

to

60

Hz, con-

sumption

approx.

120

VA

. Complies

with

IEC

348

Safety

Class

II

Environment:

temperature

range (for op-

eration

within

specifications), + 5°C to

+

40°C

Storage Temperature:

-25°C

to +

75°C

Cabinet: Supplied as model A (light-

weight

metal cabinet) or C (as A

but

with

flanges

for

standard

19"

racks)

Dimensions and Weight: (A-cabinet

with

feet)

Height:

310,4

mm

(

12,2

in)

Width

:

430

mm

(16,9

in)

Depth:

500

mm

(19,7

in)

Weight

:

22

kg

(48,5

lb)

Accessories Included:

Mains

cable

1 B & K plug

1 BNC plug

Cam disc

for

2307

Remote control cable

for

2307

Cam

switch

cable

for

2307

and

AN

0020

JP

0101

JP

0035

OD

0253

AO

0035

remote 1 cable

for

2308

AO

0034

Signal

cable

for

2307

AO

0064

Signal

cable

for

2308

AO

0087

Spare fuses 0,

63

A

Spare fuses

1,25

A

VF

0032

VF

0027

X-Y

Recorder

Output

ZN

0204

(optional):

(replaces Level Recorder

Output)

X-Deflection:

Read-out time:

switch

selectable

45,

118,or263s

Output

Voltage: staircase

Oto

+

10

V

400

steps,

(linearity

better

than

0,

1%),

full

-scale deflection in

"Cal."

mode

Output

Impedance:

100

0

Y-Deflection:

Output

Voltage: 0 to +

10V,

in

256

steps (accuracy better

than

±10

mV),

full

scale

deflection

in

"Cal."

mode

Output

Impedance: 1

00

0

Accessories Available:

IEC 625-1 interface cable (2m) .... AO 0194

IEC (male, slide-lock)

to

IEC

625-1 interface cable (2m) .

..

........

AO

0184

Adaptor

to convert IEEE instru-

ment

to

IEC 625-1

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

AO 0195

Preprinted Level Recorder pa-

per

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

..

.

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

......

OP 1103

Preprinted X-Y Recorder

paper

..

QP

1002

Display

/Documentation

Program

BZ

0013

and Machine Health

Monitoring

Program

BZ

0014,

for

operation

in an HP

9825

calculator

when

it

is connected

to

a

2033

BRUEL & KJAER 2033 User manual

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