Dolby Laboratories SR 280 User Information

[](I

DolbY

SR

Cat. Spectral

User

No. 280

Information

Recording

Module

USER

INFORMATION

FOR

SPECTRAL

RECORDING MODULE

CAT. NO. 280

Dolby

U.S.A. 100

Tel: (415) 558-0200; Telex: 34409;

U.K.

Tel: 01 720-1111; Telex: 919109;

Laboratories

Potrero

346

Clapham

Avenue,

Road,

San

Incorporated

Francisco,

Fax:

London

(415) 863-1373

SW9

Fax:

01 720-4118

CA

9AP

94103

WARRANTY defects

01'

warranty defective,

distributor.

inadequate

Dolby

circumstances

All

ill1986

in

implied

Laboratories'

requests

Dolby

materials

warranties

period

provided

packing

INFORMATION:

and

workmanship

and

Dolby

Defects

shall

for

repairs

Laboratories

the

unit

caused

for

service

obligation Dolby

or

information

Inc.

Equipment

no

warranty

is

shipped,

by

modifications,

return,

is

restricted

Laboratories

manufactured

for

one

year

of

merchantability

will

repair

prepaid,

are

not

covered

to

the

be

liable

should

include

from

or,

at

to

misuse

repair

for

any

its

the

or

by

other

the

accidents,

this

or

unit

by

Dolby

date

of

purchase.

or

fitness

option,

manufacturer

warranty.

replacement

damage,

serial

for a

replace

and any

number

Laboratories

There

particular

components directly

further

of

defective

either

direct

to

ensure

is

warranted

are

no

other

purpose.

which

or

via

an

damage

parts

and

or

consequential.

rapid

service.

against express

During

prove

authorized

caused

S871741717493

the

to

under

be

by

no

This Cat. basic familiarity

information

No. 280

principles

spectral

of

with

Dolby

is

intended

recording

audio

A-type

to

serve

module.

recording,

noise

as

an

introductory

It

assumes

complementary

reduction

and

interface

user's

processing,

frames.

guide

knowledge

for

and

the

of

the

some

The both Cat. Dolby Cat.

Cat.

No.

A-type

No.

No. 22 22

module established the

rear

of

appropriate

280

and

A-type

module

and

studio

the

frame

Important

spectral

level

module.

user

can

with

continue

procedures.

Cat.

No.

type.)

Note

recording

compatible

In

most

simply

the

recording

(A

280

must

module

with

cases,

replace

Cat.

switch

be

set

No.

using

to

is the the the

280

on

the

Dolby®

Cat.

No.

280

Spectral

Recording

Module

Co",pare

DOlbY

••

Noise

Ref Tape

Auto

DD

DoibySR

The

Cat.

No.

280 module is the first commercially available embodiment recording process developed Dolby has been designed for ease of installation M-Series frames from Laboratories.

Dolby

new

audio recording technique which provides audible signal integrity superior to other

recording performance of contemporary

tape recorders stands tensive scrutiny. module has been designed to allow easy operational use of the SR process, using existing frames, with

no

changes

of the

new

Laboratories.

in

existing 360-Series

spectral recording

major

or

capital expenditure.

The

that method Dolby

analog professional

The

Cat. No. 280

studio equipment

spectral

module

Dolby

of

in use.

SR

up

to ex-

by

and

is

a

any

The

with

Dolby

The

Cat.

No.

280 spectral recording logic similar to Cat. No. 22 A-type noise reduction module; consequently the control facilities of 360, 361 units operate normally, such as IN/OUT, RECORD/PLAY input

Dolby

a

new verification tool called Compare generator in the module applies

bursts of noise (Dolby Noise) at a calibrated level to the recorder. The signal is used

tape to identify the use of

SRI

bration

recording process

of

input/output Dolby During playback, the pare nates the the

module

/output

SR modules incorporate

recorder alignment

. A built-in

and

to assist in recorder cali-

(however, the spectral

A-type noise reduction).

circuitry automatically alter-

monitor

Dolby

Noise off-tape

utilizes function

that

of the

and

M-Series

gain controls.

Auto

pink

at

the

head

is

more tolerant

gain errors

Auto

output

between

and

Dolby

and

noise

Dolby

than

Com-

of a

the

internal noise generator. LED indicators indicate the current dition. recorder set-up alignment, additionally provides a method track

Dolby livered over 80,000 Cat. No. 22 noise reduction modules throughout availability of interfaces accepting the Cat. No. 280 modules will facilitate Dolby

are available, including No. and

two testers are available to as sist process evaluation performance verification.

about process,

describing other Dolby

and from Dolby Laboratories.

on

the module front

monitor

Auto

Compare

of checking a recorder

by

ear

during a session.

Laboratories

the

world, and

adoption

SR process.

Other

Dolby SR configurations

431

, a module for Dolby SP-

XP-Series units.

Full descriptive information

the

Dolby spectral recording

and

product

testers are available

assists in

but

rapid

has

de-

this widespread

of the

new

the

Cat.

In

addition,

and

module

leaflets

SR

modules

on

request

con-

Dolby®

Cat.

No. 280

Specifications

INTERFACES:

The

Cat. No. 280 module can be installed

in the following frames:

Models 360 and 365

All

module

functions available, including simultaneous if

two

Model

and

Record

Model

Auto

361

Compare

record/play

360s are used in dedicated

Play

modes.

functional

Auto

durin

Compare

g tape-playback following recording, not

during

simultaneous recording.

M-Series Units

Simultaneous The

Cat. 280 requires a special top cover

No

(Cat. 18 of M-Series interface.

CAT.

record/play

Auto

. 359) to fit in Channels 2, 10,

NO.

280 MODULE

Compare

SPEGFICATIONS:

Layout:

A

pair

of printed circuit cards

togeth

er

output

form the module. Signal

and

control functions compatible

with Cat. No. 22 noise reduction

mounted

input/

modul

Input Circuit:

680 k

ohms

unbalanced, 300 mV rms for

reference leve

l.

Peak Encode Input Level:

3.0 V rms (20

Peak

3.0 V rms from

5.0 V

Decode

rms

from

dB

above

reference level).

Output Level:

Output

1,

Output

2.

Line Amplifier:

When

mounted

output

+ 22 into 600 (0

dB = 0.775 V rms).

in interface,

dB

into bridging load, +

ohms

maximum

(A 6 dB higher level is possible using

V line-amplifier supply voltage.)

+ 36

Overall Frequency Response:

± 1 dB, 20

Hz-20

kHz

(encode/decode).

but

21

and

e.

dB

Bandwidth Limitation:

Internal filters: 10

Hz-50

kHz.

Overall Harmonic Distortion:

2nd & 3rd below Negligible higher ponents

Overall SR

105 noise level. 93 weighted noise level. 105

A- weighted noise

.

95 dB - clipping level to unweighted noise level, 20

peak

harmonic

level, 20

each 0.3% Hz-20

order

at

any

level.

Dynamic

System (typical}:l

dB-clipping

dB

- clipping level to NAB

Hz-20

level to

level to CCIR Rec. 468-2

leve

kHz.3

distortion com-

Range

CCIR/ARM

}2

Typical Obtainable Dynamic Range,

90-95 dB.

15

ips:

Matching Between Units:

±1

dB

at

any

level

20

Hz-20 kHz.

and any

Signal Delay:

Approximately

J.l.S

overall, encode/decode, plus delay

14 of interfaces used.

7.0

J.l.s

per channel,

Calibration Facilities:

Dolby

Noise

generator

correct levels

and

built-in meter amplifier

Output

meter.

signal

external analysis facilities.

audible

Auto

comparison

with

internally generated reference

pink

noise.

Compare

of

for establishing

frequency response, via

and

can

also be fed to

Automatic

function, allowing

Dolby

Noise from tape

Status Indicators:

Yellow LED Dolby Auto status indicated on

front of module. (LED control signal available for remotely situated LEDs

on

front of module indicates

Noise mode,

Compare

or

Reference/Tape function

by

red

and

lamps.)

at

3 dB

kHz.

of

frequency,

interface

green LEDs

Control Inputs:

External + 18 to + mode

(provided in interface). External single pole switch for process in/out

(provided in interface).

External single pole switch for

mode

Noise Internal three position switch to adjust operating logic to Model 361,

30 V to actuate record

Dolby

(provided in interface).

Models

360

or

M-Series interfaces.

and

365,

Stability:

System

is

highly stable - does

not

require routine alignment (no adjustable internal controls).

Operating Temperature:

Up to 45 degrees

C.

Construction:

Fiberglass printed circuits, solid state devices

throughout;

aluminum

covers, black characters.

clear anodized

Size:

192 x 155 x

20

mm

(7.6

x 6.1 x 0.8 inches).

Weight:

500 gm

(18

oz.).

Power Requirements:

SR

circuit:

+20

V to

+28

V,

Line amplifier:

+18

V to

100-140 mA.

+36

V,

13-17 mA.

D[] Dolby

Dolby

Laboratories

San

Francisco,

Teleph

one

346

Clapham

Teleph

one

"Dolby"

and

Dolby

Laboratories

5871741717493

Specifications

CA

94103-4813,

(415)

558-0200,

Road,

(01)

720

-1111, Telex 919109.

the

double

subject

Inc.,

100

London

-D

licensing

to change

Potrero

Telex

34409.

SW9

symbo

Corporation.

without

Avenue

9Ap,

l are

,

trademarks

notice.

of

1.

Processor alon

l

evels use

2.

Weighting

pass

filter

3.

Rms

or

d.

filter

to

ensure

average

e; in interfaces,

supplemented

that

only

audible

responding

may

by

meter,

depend

25

kHz 4-pole

nois

e is

4-pole

on

line

low measured. filters.

-

II

SECTION

1

INTRODUCTION

1.1 Dolby

1.2 Dolby

1.3 Dolby

Spectral SR

SR

1.4 Dolby SR

Cat.

1.5

No. 280

360

M-Series . SP/XP Cinema

2 CAT. NO. 280

2.1

2.2

2.3

2.4

General Configuration Interface Optional

3 CAT. NO. 280

3.1 Dolby

3.2

3.3

3.4

3.5

Auto Auto Auto Auto

Noise. Compare Compare Compare Compare

3.6 Dolby Tone

Recording.

Packaging

. . Compatibility Calibration.

Applications.

Series

Products

. . . . . . . .

(CP50,

INSTALLATION

Installation

Switch

Frame

Switch

External

. . . . .

and

Connections

CALIBRATION

. 3-1 Control Metering Synchronization.

and

the

Cat.

TABLE

OF

CONTENTS

Page

1-1

1-1 . .

1-1

1-2

1-3

CP100,

CP200)

1-3

2-1

Indicators

Labeling

2-2 2-2 2-3

3-1 3-2

3-2 3-2

No. 280 3-3

SECTION

APp(i~NnIX

APP(i~NUIX

4

5

A

B

SYSTEM

4.1

ALIGNM(i:N'I'

General

System

4.2 Recording

4.3

4.4

4.5

PRACTICAL

General Using

VU

Aligning

Alignment

OP~:RA'I'ION

5.1 Model 360

5.2

Auto

Compare

5.3 Model 361

5.4

5.5

5.6

Auto M-Series Auto

Compare Compare

Technical

Optional

Alignment

Levels

Meters

with

for Dolby

with

Peak

Operation

in

the

Operation.

in

the

Operation

in

the M Series

Aspects

Cat.

No. 280

SR

Using

VU

High

Level

Program

. . . .

Model

360

. . .

Model 361 .

.

Connections.

. 4-1

4-1

Meters

Reference

Meters

Tapes.

4-2 4-3 4-3

5-1

.

5-1 5-2 5-3 5-5

5.5

A-I

B-1

1-1

SECTION 1

INTRODUCTION

1.1

Dolby

modern implementation frames widespread

1.2

To

facilitate same This

will

Series

unit

due

SR

module, multi-track

While is

one (about existing cards packaging This

long panel used

in

Dolby

spectral

professional

manufactured

introduction

Dolby

easy

card

profile

allow

and

M-Series

to

incompatibilities

the frames.

the

Cat.

major

.15

have

by

close-pitch

difference:

inch, 3 mm)

Cat.

No. 22

been

adaptation

but

thin

about 7 112

Spectral

recording,

recording.

of

this

new

by

SR

Packaging

interchange,

and

the

process to be

interface

Cat.

No. 431,

No. 280

is

applications.

mounted

of

adaptation

inches,

situations.

Recording

or

Dolby SR,

recording

Dolby

ofthis

generally

the

than

the

out

as

frames. with will

standard

the

close

Cat.

extends

or

new

190

has

The

Laboratories

high-quality

the

conveniently

the

be

compatible

Cat.

To together, No. 280

mm,

Cat.

process.

Dolby familiar

The

Cat.

available

Cat. No. 22,

address

has

the

thereby

been

developed to

No. 280

It

can

recording

SR

circuit

Cat.

used

Cat.

No. 280

No.

230

for

with

No. 280

and

situations

such

Dolby

as

been

allowing

SR

module

be

used

and

the

SR

will,

format.

has

been

No. 22 noise

in

commonly

cannot

carrier

the

module

therefore

in

developed,

circuits

card.

existing

Cat.

is

where

the

Model

Dolby

answer

in

existing

therefore,

reduction

be

SP-

No. 22

physically

will

the

forward

the

is

packaged

available used

A specific Dolby

and

XP-Series

module,

not

fit

the

Cat.

362, a special

Cat.

No. 280-L.

of

SR

modules

needs

the

first

interface

allow

in

the

module.

360-

in

the

SP

there

thicker

in

some

No. 22

the

front to be

of

a

The

increased

in

a few

and

modules

18,

special

channels

used

1.3

Electrically,

Both decoded noise or compatible--Dolby cards

Dolby

properly,

reduction

transmission

and

1.4

As

with correctly accomplished new,

easily

DN,

is

always

thickness

module

in

these

Dolby

the

Dolby

A-type

systems

channel.

vice

versa.

Dolby

A-type

set

identifiable

noise

in

level

using

used

of

the

of

the

M-Series

covers

channels

SR

Compatibility

SR

process

NR

and

give

excellent

in

its

Dolby

SR

encoded

SR

Calibration

reduction,

with

Dolby Tone;

alignment

to

establish

Cat.

frame.

(Cat.

only.

Dolby

ability

A-type

tapes

respect

with

correct

No. 280

No. 359)

is

very

SR

are

results.

to

improve

should

Dolby

to

the

signal:

decode

will

not

allow

To

accommodate must

different

complementary

Dolby

and

SR

encode

Dolby

be

SR,

the

Dolby

not

be decoded

requires

module.

SR

Noise.

level.

process,

standard

M-series

installed

from

A-type

however, overall SR

are

the

Dolby

modules

channels

on

the

noise

processes

goes

quality

not

with

decode

With

it

of a recording

considered

Dolby

module

A-type,

is

achieved

Noise,

to fit

1,10

Cat.

No. 280

reduction.

that,

far

abbreviated

when

beyond

cross-

A-type

to be

this

using

is

a

In

addition

generator,

The

Auto

gain

and Compare signal verify noise

fully

and

the

with

in

Section 3 --

to

the

Cat.

No. 280

Compare

frequency

mode

the

performance

the

circuit,

response

allows

internally

Dolby Noise from

Calibration.

Dolby

an

automatic

of

the

spectral

contains

using

generated

Dolby Noise

information

recording

the

1-2

recording

an

important

about

aural

pink

system

tape.

comparison

The

circuits

as a signal,

the

noise.

by

Auto

and

new

feature--Auto

gives

recording

of

the

The

user

comparing

Compare

the

Dolby

Compare.

the

user

valuable

channel.

recorded Dolby

can

quickly,

the

feature

The

by

reference

is

discussed

Noise

Auto

Noise

ear,

pink

1.5

The

following interface covered

Cat.

No. 280

is a summary

frames.

in

Section 5 -360

Series

Model

The encode two simultaneous Compare record

Model 361 The

single Cat. playback Auto back

360

Model

Cat.

and

Model

No. 280

Compare

previously

Applications

A

full

Practical

360

or

decode

No.

280

feature

playback.

361

module

signal

of

how

discussion

Operation.

is

intended

operation.

modules

record

is

sequence

and

can

designed

for

both

is

paths

recorded

the

Cat.

of

Cat.

for

single-channel,

Two

are

required

playback

be

fully

switched

just

is

Dolby Noise.

operational

for

changeover

record

as

with

available

No. 280

interface

for

operation.

and

playback.

into

the

Cat.

only

can

be

used

operation

dedicated

frames

one

channel

The

during

operation

record

No. 22.

when

playing

in

specific Dolby

in

these

and

of

Auto

both

of

a

The

and

The

units

is

Model

The modules, Due modules the must circuit module, results length,

7t

M-Series

The A-type accommodate Dolby

362

Model

to

height

cannot

Model

be

cards

with

in a module

therefore

inches

M-Series

modules.

SR

362

and

362, a special

used.

(190

in

is

designed

functions

restrictions, be

installed.

The

that

make

one

mounted

that

extending

mm).

chassis

24

all

was

Two

or

32

channels,

to

hold

two

as a dual-channel

two

standard

To

incorporate

adaptation,

Cat.

No. 280-L

up

the

behind

is

of

single

forward

designed

chassis

channels.

provided

the

standard

thickness

of

to

can

It

that

Cat.

No. 22

Cat.

contains

Cat.

the

other.

the

front

hold

16

be

is

possible

special

A-type

Model 360.

No. 280

Dolby

Cat.

SR

in

No. 280-L,

the

two

No. 280

This

but

double

panel

linked

by

No. 22 to

use

covers

to

are

installed channels Cat.

No. 280

in

all

other referred Dolby

product

1, 10

to

as

on

the

and,

modules

M-series

the

distributors.

with

Cat.

No. 359, will be

Cat.

No. 280

in

the

standard

channels.

M-24

modules

unit,

covers

The

special

available

used

channel

can

be

cover,

through

in

18.

used

SP/XP

The

use

electrical card. SP plug-in combination Cat.

Cinema

The

within however, CP50, Laboratories

Series

greater

in

the

incompatibilities

The

Cat.

and

XP

replacement

No. 331 A-type

Products

Cat.

No. 280

cinema

it

CP100

thickness

SP

Series.

No. 431,

multi-track

in

existing

module

(CP50,

requires

units.

may

be

necessary

or

a CP200.

for

more

of

the

Cat.

Additionally,

with

the

due

in

late

units.

for

the

SP

in

This

entire

the

CPI00,

minor

In

a few

to

use a Cat.

In

this

information.

No. 280

Cat.

1986,

module

units

newer

prohibits

there

No. 230

will

fit

Cat.

and

XP

frames.

CP200)

modification

special

No. 280

case,

contact

its

are

some

carrier

both

the

will be a

No. 230/22

for

the

for

use

situations,

in

Dolby

a

2-1

2.1

If

the

Cat.

No. 22 A-type module, therefore, interface plugging

For

optimum recording and

is

installed information

The

Cat.

No. 22 A-type

is

important particularly and

below

General

Dolby

interface

simply a matter

frame,

in

the

module.

performance

system

covered

at

in

the

same

regarding

No. 280

that

the

chassis.

Installation

frame

setting

and

interface

Section 4.

time,

connections, etc.

module

adequate

M-Series

has

the

system

of

removing

the

configuration

of

the

Dolby SR circuits, however,

frame

If

the

interface

refer

to

consumes

and,

therefore,

free

air

be provided

unit,

which

CAT.

been

the

roughly

previously

is

basically

the

input

frame

appropriate

has

should

NO.

ready

existing

switch

and

output

(360

the

same

the

same

around

always

280

INSTALLATION

aligned

for use

for use.

Cat.

No. 22 from

on

the

Cat.

calibration

levels

Series

interface

or

M Series)

frame

amount cooling

the

Dolby

requirements.

have a blank

SECTION

with

Installation

the

No. 280,

is

recommended

is

manual

of

power

interface

panel

as

frame,

2

the

is,

Dolby

and

of

the

being

for

the

It

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SECTION 4

SYSTEM ALIGNMENT

4.1

This

section

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OFF

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185 n

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4-2

4.3

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circuit

separate

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in

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detailed

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procedure

the

following pages.

PRACTICAL

alignment

the

Model 360, Model 361

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procedure

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Please

SECTION

OPERATION

the

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Typically,

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Spectral

Recording

Process

Technical

Aspects

Dolby San

S86/6825

Laboratories

Francisco

RMD

February

24,

and

1986

Inc.

London

- 2 -

Spectral Recordjng process

Brief

OutJ1ne

The

spectral

characteristics in

reduction

the

technical

systems.

papers

relevant.

Referring to Encoder high main

whereby dedicated other

three

There

including action reproducibil1ty, about signalleveJ).

low

low-level

characteristic.

frequency

about

3

kHz.

and

Decoder", a main

level

signals.

signal in

an

overall

encoder

decoder

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SR

stage

levels

are

-30

of

various

dB,

frequency

stage stages,

200

Hz,

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overlap

the

configurations

action

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low

-48 For

circuits

is

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and

system.

recording

common

process

with

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on

these

the

figure called

systems;

signal

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side

chain

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and

decoder

are

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advantages

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dB,

and

-62

the

high-level

are

used,

high

frequency

is a significant

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high

frequency

the

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frequency

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path

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obtained.

laid

layout

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reference

paper

should

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Diagram -Spectral

responsible

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out

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the

decoding

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this

in switchable circuits.

of

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used:

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the

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overshoot.

reference crossover

with

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extending

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level (20

stages

frequency

800

region

thresholds

dB

both

high

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Hz

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the

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kHz, 6 dB

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frequency

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spectral

signal

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response

action is

signal

100Hz.

produced

networks.

at

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10

kHz

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is

an

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Hz

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Hz

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- 4 -

process

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J

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11

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- 5 -

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24

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obtained

- 7 -

At

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Hz

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for

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audio components, tape recorder bias; subsonic noise components,

room rumble from

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linear analogue transfer characteristic.

good

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10kHz). Strong spectral skewing actions

in

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traffic

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at

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of

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15

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(below

be

used

soft

inherently

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Low

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the clipping level): there

regions.

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joined together to create a compression

respect

the

total

High freQuencies: dynamic action occurs

respect

total

In the dynamic action ranges the

to

dynamic range

to

dynamic range

or

attenuaUonl or

for

steady-state dominant signals'

reference level); te. there

(starting

is

a linear dynamic characteristic

reference leve));

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is

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from the system noise level) but

dB

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dynamic range (ending

multi-level

2:

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to

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the lower 35 - 40

full

with

in

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two

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full

two

stages are

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with

dB

---

Spectral Recording - Description

---

- 8 -

Dynamic

Non-dominant dominant sHding

band

compression

components

(therefore

Thus,

amount

at attenuation of ends

even

range

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action for stead¥-state

signals

signal

towards

actions.

or

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effect prevails for

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SR

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---

Spectral

Recording

- Description

---

The

decoding

provide a whoHy

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restored

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able

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level

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high

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input.

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recording

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low

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also

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fifth

harmonic

order

harmonics

clipping characteristic,

levels is significantly

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system,

with

Regarding

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frequency

in

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encoded

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low

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---

Spectral

Recording

- Description

---

-

10

The

existence recording marginal system cartridge formats. Conventionallandlines the

new

with

and

for professional

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technical

AES

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the

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new

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process

at

the

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forthcoming Fall

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~

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Mid

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Low

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Signal Input

LF & HF

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586/6822

D--

Remote

Auto

OPTIONAL

Compare

Status

B-1

CAT.

Display

NO. 280

APPENDIXB

CONNECTIONS

Pin D can about

in

the

passed

+ 18

OFF

into

be

volts

(Auto

conveniently shown.

and

Higher

additional

CAT.

CONNECTOR

+18V

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used

to

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Compare

or

out

located

current

circuitry.

NO.

280

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-------

0

-

13

-

16

remotely

the

ftREF" mode, 0

inactive)

of

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near

the

remote

6.8K 9V

6.8K

display

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The

user

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in

the

ttTAPE" mode,

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controlled

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of

by

3 rna.

D to

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at

+ 9

current

status

control

display,

LEDs

external

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at

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relays

A--Pink

The

reference

volts

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C--External

In

the

record mode,

module

normally convenient Dolby Noise Cat.

No. 280

In

the

Model Dolby connector Cat. units.For linking ring

Tone

that

No. 22

standardization

Dolby Noise (or Dolby

used

for

Noise

pink

Auto

free

the

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the

external

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SR

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if

simultaneously.

modules.

360

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units

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use.

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coupling

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mark

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stereo

modules

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interface

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capacitor

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between

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accomplished

phone

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synchronization

frames,

Cat.

No. 22

'REF"

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pink

noise

will be

necessary.

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modules

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situations,

pink

linking

normally

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tip

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pin C on

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280

it

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and

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link

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for

the