Tft 844 User manual

www.SteamPoweredRadio.Com

TECHNICA

MANU,~L

FOR

MODEL

844

FM

MODULATION

AND

STEREO

MONITOR

www.SteamPoweredRadio.Com

P/N

5004-0844

Rev

C

October 16,

1985

Equipment

Serial

No.

-----

Shipping

Date

--------

TECHNICAL

MANUAL

FOR

MODEL

844

FM

MODULATION

AND

STEREO

MONITOR

T F T

Inc.

3090

Oakmead

Village

Drive

Santa

Clara,

CA

95051

(408) 727-7272

TWX

910-338-0584

www.SteamPoweredRadio.Com

SECTION

1

SECTION

2

SECTION

3

TABLE

OF

CONTENTS

GENERAL

INFORMATION

1.1

1.2

1.3

1.

3.1

1. 3.2

1.4

1.5

General Description

Specifications

Accessory

Equipment

Model

730A

SCA

Monitor .

Model

804

Remote

Metering Panel

Warranty

.•...

Claim

for

damage

in Shipment

INSTALLATION

2.1

Unpacking

and

Inspection . . . .

2.2

Power

Requirements . .

. . .

2.3

Installation

and

Connections

2.4 Connection of Accessory

Equipment

2.4.1

Connection

of

Model

730A

SCA

Monitor .

2.4.2

Connection of

Model

804

Remote

Metering

Panel . . .

. .

.

. .

2.5 Field

Installation

of

Options . . . . .

OPERATION

3.1 General . . . . . . . . . . .

3.2

Turn-On

and

Warm-Up.

. .

.

. .

3.3 Controls, Connectors

and

Indicators

3.3.1

Model

844

Front Panel

3.3.2

Model

844

Rear

Panel

3.4 Calibration . . . . . . . . . .

3.4.1

Meter Calibration .

. .

3.4.2

Peak

Modulation

Calibration.

. . . .

3.5 Measurements . . . . . . .

3.5.1

Main

Channel

Modulation

(L

+

R)

. .

3.5.2 Stereo Subchannel Modulation

(L

-R).

3.5.3

Pilot

Carrier Modulation

3.5.4

38

KHz

Subcarrier Suppression ..

3.5.5 Stereo Separation . . . .

3.5.5.1

Stereo

Channel

Separation

(left

Channel

Modulated) . . . . .

.

. . .

3.5.5.2

Stereo

Channel

Separation (Right

Channel

Modulated) .

. .

.

. .

3.5.6

Main

Channel

to

Subcarrier Crosstalk

3.5.7

Subcarrier

to

Main

Channel

Crosstalk

3.5.8

FM

Noise

3.5.9

Distortion . . . . . .

3.5.

10

Pilot

Frequency.

.

3.5.

11

Peak

Modulation .

.

3.5.12 Incidental

And

Residual

AM

3.5.13

Multipath

Noise.

. . . .

.....

3.6

Absence

of Modulation

Alarm

(Optional).

3.7 Carrier Failure

Alarm

(Optional). . . .

3.8

Use

of

Remote

Metering Panel.

Model

804

-2-

.

. . .

.

3

5

6

7

8

9

12

13

14

15

16

17

18

19

www.SteamPoweredRadio.Com

SECTION

1

GENERAL

INFORMATION

1.1 General Description

The

TFT

Model

844

FM

Modulation

stereo

monitor

provides both

on-the-air

and

off-the-air

monitoring of

FM

broadcast

stations

operating in

the

frequency range

of

88

to

108

MHz.

The

three

meter format allows

stereo

measurements

while monitoring

total

modulation, Left

and

Right channels.

Push

button switches allow monitoring of the following functions

on

the

LEFT/TEST

Meter:

left

Channel, Right Channel, 38

kHz,

19

kHz

pilot,

L+R,

L-R,

Total modulation,

AM

noise,

and

multipath.

Front panel

indicators

show

when

a preset

modulation percentage

is

exceeded

on

either

positive

or

negative

peaks.

Front panel controls allow the monitoring of

two

different

frequencies without

resetting.

Absence

of modulation

and

carrier

failure

alarms

are available

as

options.

1.2

Specifications

RF

SECTION

Frequency range

.....

On-site

RF

input voltage

Antenna

input voltage

Tuning

.

.......

.

AGC

range

.......

.

Input impedance, antenna

Input connector, antenna

MODULATION

METERS,

TOTAL

Deviation

for

100%

indication

Meter

Range

.•...••

AC

Voltmeter range .

Accuracy

(5-KHz

tone)

Frequency response

Characteristics

.

Remote

output .

. 88-108

MHz,

tunable in

50

KHz

steps

. 1

to

10

volts

rms

250

uV

to

lOOmV

Two

4-digit

switches

and

a push-

button switch for

selecting

station

Aor B.

. 60

dB

75

ohms

Type

F

• +

75

KHz

peak

to

peak

•

1Y

to

133%

modulation

.

Oto

-50

dB

in

10

dB

steps

. +

2%

at

all

modulation

levels

+ 0.1

dB

typical,+

0.

25

dB

max

from

50

Hz

to

120

KHz

-

Quasi-peak reading

circuit

Suitable for driving remote readout

meter panels.

-3-

www.SteamPoweredRadio.Com

MODULATION

METERS,

RIGHT

Right channel modulation

MODULATION

METER,

LEFT/TEST

Left channel modulation .

Right channel modulation

Main

channel

..•.

L + R • • • • •

L - R • • • •

Indicates

and

measures

right

channel

modulation

. Indicates

and

measures

left

channel

Modulation

.

Same

as

right

modulation meter

.

Same

as

total

modulation meter

• + 0.35

dB,

50

Hz

to

15

KHz

. + 0.35

dB,

23

KHz

to

53

KHz

38

KHz

1

eve

1• • • • • • •

Pilot

level

..

••.•

'Reasure

down

to

-60

dB

•

Measure

down

to

-60

dB

Phase

calibration

. .

For

optimization of

stereo

measurements

AM

noise

..•.

Multipath

indicator

. .

Measures

AM

noise

PEAK

MODULATION

INDICATORS

Deviation for

100%

indication

.

Peak

level

........

.

Accuracy

(5-KHz

tone) .

Frequency response

Response

time accuracy

Remote

flasher

output

Peak

counter

.

For

adjustment of antenna to minimize

multipath

distortion

. +

75

KHz

.

-S-et

by

a

front

panel

3-digit

thumb-

wheel

switch in

1%

steps

from

0%

to

199%

on

both

positive

and

negative

peaks

. +

2%

at

100%

modulation

. +

2%

from

30

Hz

to

120

KHz

. Adjustable,

10

cycles

of

10

KHz

or

faster

. Suitable for driving

two

remote meter

panels

Registers

number

of

peaks

per minute

MODULATION

CALIBRATOR

Built

in frequency synthesized

calibrator

for

meter

and

peak

flasher

calibration

of

100%

modulation

from

the

front

panel . Accuracy

,::1%

.

MEASUREMENT

OF

RESIDUAL

AM

Range

. . . . • . . • . .

Accuracy

(at

-30dB)

...

OUTPUTS,

FRONT

AND

REAR

PANEL

Main

channel output with

75

sec de-emphasis

*Signal

to

noise

ratio

..

.

*Harmonic

distortion

..

. .

*Intermodulation

distortion

*Frequency response . . . . .

. 0

to

70

dB

• + 1

dB

5

volts

rms

into

SK

ohms

at

400

Hz

.

78

dB

at

400

Hz

with de-emphasis

.

0.1%

max

(de-emphasized)

• 0.

1%

max

per

SMPTE

standard

+0.25

dB

from

30

Hz

to

120

KHz

composite

-4-

www.SteamPoweredRadio.Com

*Balanced audio output level

...

*Balanced audio frequency

response

.......

.

SCA

output

at

rear

panel

Audio

(with de-emphasis)

left

and

right

.....

Audio

(without de-emphasis)

1

eft

and

right

Pilot

carrier

(19

KHz).

Composite

. .

Remote

meter

Connectors

Meter

output

Carrier-failure

alarm. optional

Absence

of

modulation

a1

arm.

optiona1 • •

STEREO

SEPARATION

AND

CROSSTALK

Separation L-to-R

and

R-to-L.

Crosstalk

(L+R)

to

(L-R)

or

(L-R)

to

(L+R)

•..

Crosstalk

SCA

to

(L+R)

or

SCA

to

(L-R)

...•

Pilot

carrier

measurement

leve1 accuracy . . . .

MECHANICAL

AND

ENYIROtf'IENTAL

Input

power

.....

Operating temperature • •

Size . . . . .

Net

Weight

Shipping weight .

0

dBm

into

600

ohms.

+0.5

dB

from

30

Hz

to

120

KHz

. T

volt

rms

into

600

ohms

. 1 V

RMS,

600

ohms

unbalance

at

100%

modulation

(400

Hz)

. 1 V

RMS,

600

ohms

unbalanced at

100%

modulation.

600

mV

RMS,

available

on

front

panel

5 V

RMS,

lOK

ohms

at

100%

modulation

.

For

Model

804

remote meter panel

BNC

Main

meter selected signal available

on

front

pane

1•

. Relay drive output capable of sinking

50

mA

to

30

V

DC

when

RF

carrier

drops

below

50%

of

nominal.

An

output capable

of

sinking

50

mA

at

30

V

DC

when

composite signal drops

below

30%

modulation for a period

of

time

between

2 sections

and

1 minute,

internally

adjustable.

60

dB

typical,

55

dB

minimum,

50

Hz

to

15

KHz

.

65

dB

min

•

70

dB

min

+0.5%

from

6%

to

12%

injection

117/230

+10%

VAC,

50

to

400

Hz.

40

watts-max

0°C

to

50°C

(32°F

to

122°F}

.

7"

(17.78cm) high x

19"

(48.26cm)

wide

x

15"

(38.10cm)

deep

Approximately

18.5

pounds

(8.4

Kg)

Approximately 22.5

pounds

(10.

2Kg)

1.3

Accessory

Equipment

1.3.1

Model

730A

SCA

Monitor

The

Model

730A

enables

FM

stations

broadcasting

SCA

information

on

the

carrier

to

meet

all

FCC

SCA

requirements.

The

model

844

provides

a

composite

input

to

the

model

730A.

-5-

www.SteamPoweredRadio.Com

1.3.2

Model

804

Remote

Metering Panel

The

Model

804

duplicates

flasher

and

meter readings

and

comes

with

50

feet

of cable

(TFT

Part

No

. 51160-0804)

1.4

Warranty

TIME

&

FREQUENCY

TECHNOLOGY,

INC.,

warrants each

of

the instruments of

its

manufacture to

be

produced

to

meet

the

specifications

delivered

to

the

BUYER;

and

to

be

free

from

defects

in

material

and

workmanship

and

will

repair

or

replace,

at

its

expense,

for

a period

of

one

year

from

the date

of

delivery

of

equipment,

any

parts

which

are defective

from

faulty

material or

poor

workmanship.

Instruments

found

to

be

defective during the

warranty period shall

be

returned to the

factory

with

transportation

charges prepaid

by

BUYER.

It

is

with respect to

any

nonconforming

equipment

and

parts thereof

and

shall

be

in

lieu

of

any

other

remedy

available

by

applicable

law.

All

returns

to the factory

must

be

authorized

by

the

SELLER,

prior

to

such

returns.

Upon

examination by

the

factory,

if

the instrument

is

found

to

be

defective,

the unit will

be

repaired

and

returned

to

the

BUYER,

with

transportation

charges

prepaid

by

SELLER.

Transportation charges for instruments

found

to

be

defective within the

first

thirty

(30) days

of

the warranty period will

be

paid both

ways

by

the

SELLER.

Transportation charges for warranty

returns,

wherein

failure

is

found

not

to

be

the

fault

of the

SELLER,

shall

be

paid both

ways

by

the

BUY"'tlr.'"

NO

OTHER

WARRANTY

IS

EXPRESSED

OR

IMPLIED.

TFT

IS

NOT

LIABLE

FOR

CONSEQUENTIAL

DAMAGES.

1.5

Claim

for

Damage

in shipment

Your

instrument should

be

inspected

and

tested

as

soon

as

it

is

received.

The

instrument

is

insured for safe

delivery.

If

the instrument

is

damaged

in

any

way

or

fails

to operate properly,

file

a claim with the

carrier,

or

if

insured separately, with the

insurance

company.

WE

SINCERELY

PLEDGE

OUR

IMMEDIATE

AND

FULLEST

COOPERATION

TO

ALL

USERS

OF

OUR

PRECISION

ELECTRONICS

INSTRUMENTS.

PLEASE

ADVISE

US

IF

WE

CAN

ASSIST

YOU

IN

ANY

MANNER.

T

FT

Inc.

3090

Oakmead

Village Drive

Santa Clara,

CA

95051

(408)

727-7272

-6-

www.SteamPoweredRadio.Com

2.1

SECTION

2

INSTALLATION

Unpacking

and

Inspection

Upon

receiving the instrument, inspect the packing

box

and

instrument for signs

of

possible shipping

damage.

After

installation,

operate the instrument in accordance with the procedures

of Section 3 of

this

manual.

If

the instrument

is

damaged

or

fails

to

operate properly,

file

a claim with the transportation

company,

or with

the insurance

company

if

insured separately.

2.2

Power

Requirements

The

model

844

is

factory wired to operate,

from

either

a

117

volt or

230

volt source.

The

line frequency

must

be

between

50

and

400

Hz

.

Maximum

Power

required

is

40

watts.

2.3

through

Jl3.

operation.

Installation

and

Connection

(A)

Mount

the

Model

844

in the

equipment

rack.

(B)

AC

Power

is

applied

to

rear

of the unit

Either

117

VAC

or

230

VAC

are required for proper

CAUTION

THE

CIRCUIT

BOARD

BELOW

THE

FUSE

IN

Jl3

MUST

READ

THE

VOLTAGE

TO

BE

USED

AS

PRIMARY

POWER.

117

VAC

OR

230

VAC

.

THIS

BOARD

MAY

BE

REMOVED

AND

TURNED

FOR

PROPER

VOLTAGE.

CAUTION

FUSE

VALUES

DIFFER

AT

THE

VARIOUS

OPERATING

VOLTAGES

AND

MUST

BE

CHANGED

WHEN

CHANGING

INPUT

POWER

CONNECTION

IN

Jl3

.

(C)

For

continuous monitoring, connect

FM

antenna

to

low

level

RF

input

Jll

on

monitor rear panel.

{D)

For

off

air

{high Level)

measurements

connect

RF

high level input

(1

to

10

V

RMS)

to

high level

RF

input

J12

on

844

rear

panel . Adjust

RF

input

set

until green

LED

on

rear

panel

is

on.

NOTE

HIGH

LEVEL

INPUT

REQUIRES

PROPER

CRYSTAL

TO

BE

INSTALLED

IN

THE

MONITOR

2.4 Connection of Accessory

Equipment

-7-

www.SteamPoweredRadio.Com

2.4.1 Connection

of

Model

730A

SCA

Monitor

Connection to

Model

730A

SCA

Monitor

is

made

by

taking composite output

at

J4

(to

SCA

Monitor)

and

applyi

ng

to

the

Model

730A.

2.4.2 Connection

of

Model

804

Remote

Metering

Panel

Connection

to

Model

804

Remote

Metering

Panel

is

made

to

TBl

on

844

Rear

Panel.

2. 5 Field

Installation

of

Options

TO

BE

PUBLISHED.

-8-

www.SteamPoweredRadio.Com

3.1 General

SECTION

3

OPERATION

The

Model

844

FM

Modulation

and

Stero Monitor

enables

FM

station

personnel

to

monitor

FM

and

Stereo Transmissions

to

comply

with

FCC

rules

and

regulations.

The

monitor provides

all

the

test

functions required for modulation

and

stereo

proof-of-performance

tests.

When

used

with

model

730A

SCA

Monitor

SCA

proof-of-Permance

test

may

also

be

made.

Monitor displays the modulation percentage of the

selected

carrier

being monitored.

Two

front-panel

LED

1

s provide a

flashing indication

when

the modulation percentage exceeds a pre

set

limit

on

either

positive or negative peaks. Right

and

left

channel can

be

monitored simultaneously or the

LEFT/TEST

meter

can

monitor

any

of

the other

test

functions of th monitor.

3.2

Turn-On

and

Warm-Up

The

monitor contains

no

On-Off

switch,

and

is

on

whenever

it

is

plugged into the appropriate

power

source. Indications

of

the unit having

power

on

are

1)

Meter

lights

on.

2)

One

of

the

two

green channel

select

LED's

on.

3)

Peaks/Min

digital

readout on.

3.3

3.3.1

Ref.

No.

1.

2.

3.

Controls, connectors

and

Indicators

Model

844

Front

Panel

(See Fig. 3-1)

Name

Function

TOTAL

MODULATION

meter Indicates modulation

percentage of

carrier

being

monitored.

11

-

11

PEAKS

1

amp

PEAK

CALI

adjust

-9-

"-" peaks

lamp

shows

whenever

the negative

modulation peaks

exceed

the

percentage

which

the

thumb-

wheel

switchs

has

been

set.

Calibrate the

11

-

11

and"+"

peak

lamps

on

point.

TFT 844 User manual

Popular Monitor manuals by other brands