TFT 723 Manual de usuario

www.SteamPoweredRadio.Com

R

Q

E CY A ODULA

TIO

- 0 OR

MODEL 723

TIME AND FREQUENC't

TECHNOE.OGY;

INC.

www.SteamPoweredRadio.Com

•

TO:

FROM:

DATE:

MODEL

723/734

FM

MONITOR USERS

TFT

16

September

1974

We

are

pleased

to

enclose

the

final

version

of

the

Instruction

Manual for

your

monitor.

Older

manuals

and

supplements

have

been

replaced

by

the

new

manual.

If

you

have

any

questions

or

if

you

would

like

to

let

us

know how

your

monitor

is

performing,

don't

hesitate

to

call

or

write

TFT

.

09164rd

3000

Olcott

Srreet, Santa Clara, California 9

50

5 1 (

408

} 2

46

-6

365

www.SteamPoweredRadio.Com

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CY AND MODULATIO MO

ITOR

MODEL 723,

A , R Q E. CY

TEC

O OGY, I C . .

3000

Olcott

treet

San.

ta

Cla

a,

Califo

nia

95051

408

-24'6-636

www.SteamPoweredRadio.Com

I

••

TABLE

OF

CONTENTS

I

Section

1

General

Information

I 1. 1

1.

2

1.3

General

Description

- - - - - - - - - -

1-1

Specifications

- - - - - - - - - -

1-2

Accessory

Equipment-

- - - -

1-4

I

1.4

1.5

Warranty

----------

1-5

Claim

for

Damage

in

Shipment-

1-5

I

Section

2

Installation

2

.1

Unpacking

and

Inspection

- - - - - - - -

2-1

I

2.2

2.3

2.4

Power

Requirements

----------

2-1

Installation

Remote

from

Transmitter

- -

2-1

Installation

at

Transmitter

Site

- - - - -

2-1

I

2.5

2.6

2.7

Model

724

Stereo

Monitor

Connection

- - -

2-2

Model 730 SCA

Monitor

Connection

- - - -

2-2

Model

704

Remote

Readout

Panel

Connection

(Optional)- - - - - - - - - - - - - - - -

2-2

ll

2.8

2.9

2.10

Automatic

Logging

Connection

(Optional) - -

2-2

Off-Frequency

Alarm

Connection

(Optional)-

2-3

Carrier-Off

Alarm

Connection

- - - - - - -

2-3

te

2.11

Section

3

Modulation

Alarm

Connection

(Optional) - - - -

2-3

Operation

I

3.1

3.2

General

- - - - - - - - - - - - - - - -

3-1

Controls,

Connectors,

and

Indicators

- - -

3-1

3.3

Turn-On

and

Warm-Up

- - - - - - - - -

3-7

'

3.4

3.5

Calibration

of

Modulation

Meter

and

Peak

Flashers

-------------

3-7

Measurement

of

Frequency

Modulation

I

3.6

Using

the

Modulation

Meter

-------

3-7

Measurement

of

Frequency

Modulation Using

the

Peak

Flashers

- - - - - - - - - - -

3-7

3

.7

I 3. 8

Main

Carrier

Frequency

Error

Measurements

---------------

3-7

Stereo

Pilot

Carrier

Frequency

Measurement

-------------

3-8

I

3.9

3

.10

SCA

Subcarrier

Frequency

Measurement

-

3-8

Use

of

the

Model 723

as

a

General

Purpose

Counter

- - - - - - - - - - - - - -

3-8

I

3.11

3.12

Audio Output - - - - - - - - - - - - - -

3-8

Operation

of

Model 723

from

External

5MHz

Time

Base-

- - - - - - - - - - -

3-8

3.13

Carrier-Off

Alarm

-----------

3-9

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3.14

Carrier

Off-Frequency

Alarm

(Optional) 3-9

••

3.

15

Model

704

Remote

Reado

ut

Panel

3-

9

3.16

Automatic

Logging

Outp

ut (Optional)

3-9

3.17

Measurement

of

Amplitude

Modulation

3-

10

I

Section

4

Theory

of

Operation

I

4.1

General

Block

Diagram

Disc

u

ssion

4-1

4.2

Crystal

Oscillator

(AS)

4-3

4.3

Fixed

Frequency

Board

(Al)

4-3

4.4

Local

Oscillator

Generator

(A2)

4-4

I

4.5

IF

Board

(A3) 4-4

4.6

Discriminator

Board

(A4)

4-5

4.7

Meter

Amp

and

Peak

Flasher

Board

(AS) 4-6

I

4.8

Channel

Filter

4-6

4.9

Power

Supply (A6)

4-6

4.10

Counter

and

Display

Board

4-7

4.11

Digital

to

Analog

Converter

(A9) (optional)

4-8

I

4.12

Carrier

Frequency

Alarm

(All)

(optional) 4-8

4.13

BCD

Automatic

Logging (optional) 4-9

4.14

Modulation

Alarm

(Al0) (optional)

4-9

I

Section

5

Maintenance

5.1

General

5-1

I

5.2

Access

5-1

5.3

Periodic

Maintenance

5-1

5.4

Master

Oscillator

Calibration

5-1

5.5

Calibration

of

the

Modulation

Meter

5-2

,_

5. 6

Calibration

of

the

Peak

Flashers

5-3

5.7

Adjustment

of

the

Internal

Calibration

Circuits

5-3

I

Section

6

Schematic

Diagrams

6.1

General

Block

Diagram

I

6.2

Front

Panel

and

Main

Chassis

Wiring

Diagram

6.3

Rear

Panel

Wiring

Diagram

6.4

Fixed

Frequency

Board

(Al)

6.5

L.

0.

Board

(A2)

1

6.6

IF

Board

(A3)

6.7

Discriminator

Board

(A4)

6.8

Audio

Amp

and

Peak

Flasher

Board

(AS)

I

6.9

Power

Supply

Board

(A6)

6.10

Counter

and

Display

Board

(A

7)

6.11

Crystal

Oscillator

(AS)

I

6.12

D/ A

Converter

(A9) (optional)

6.13

Modulation

Alarm

(Al0) (optional)

6.14

Model 704B

Remote

Panel

(optional)

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I

1.1

General

Description

SECTION 1

GENERAL INFORMATION

The

Model

723

FM

Frequency

and

Modulation

Monitor

is

designed

for

continuous

monitoring

of

an

FM

broadcast

transmitter

operating

in

the

frequency

range

of

88 to 108 MHz.

The

monitor

is

factory-adjusted

for

the

cu

stomer's

assigned

transmitter

frequency

and

provides

digital

display

of

the

carrier

frequency

error*

as

well

as

quasi-peak

reading

meter

indication

of

total

modulation

percentage.

The

Model 723

can

be

used

with a

rooftop

antenna

for

off-the-air

monitoring,

or

it

can

be

connected

to the

transmitter

thro

ugh

an

attenuator

(furnished)

for

operation

at

the

transmitter

site

.

The

six-digit

frequency

display

on

the Model

723

can

also

be

used

as

a

10

MHz

general

purpose

counter

with

10

Hz

or

1 Hz

resolution.

Conversion

is

made

by

depressing

a

single

front-panel

pushbutton.

Other

features

of

the Model

723

include:

Frequency

stability

of

±100 Hz

per

year

Two

:flashers

that

indicate

when

modulation

peaks

exceed

a

preset

value

in

either

the

positive

or

negative

direction

Built-in

calibrator

for

modulation

indicators

Carrier-off

alarm

Outputs

for

remote

modulation

monitoring

IF

outputs

for

the

TFT

Model

724

Stereo

Monitor

and

the

TFT

Model 730 SCA

Monitor

Optional

analog

or

BCD

output

for

automatic

logging

of

carrier

frequency

error

Optional output

for

off-frequency

alarm

Provision

for

reading

pilot

and

SCA

carrier

frequencies

with

addition

of

Model

724

or

730

Residual

Amplitude Modulation

Measurement

at

the

Hi

level

R.

F.

input.

The

Model

723

complies

with

all

FCC

regulations

relating

to

FM

broadcast

monitors,

including

Section

73

. 331

pertaining

to FM

frequency

monitors

and

Section

73.

332,

Subsections

a,

b,

and

c,

pertaining

to

FM

modulation

monitors

.

*

Readout

indicates

frequency

error

and

not

the

carrier

frequency

itself.

1-1

www.SteamPoweredRadio.Com

In

addition,

the

Model 723,

when

used

with

the

Model

724

Stereo

Monitor,

meets

the

requirements

of

Section

73.332,

Subsections

d

and

e,

for

stereo

monitors;

and,

when

used

with

the

Model

730 SCA

Monitor,

meets

the

requirements

of

Section

73.332,

Subsections

f

and

g,

for

SCA

monitors.

1.2

Specifications

RF

Input

Frequency

range

- - - - - - - - - - - -

Sensitivity

- - - - - - - - - - - - - - -

Input

Level:

Low-level

input

- - - - - - - - - -

Hi-level

input

- - - - - - - - - - -

Selectivity:

3 dB bandwidth - - - - - - - - - -

40 dB bandwidth - - - - - - - - -

Input

impedance

-------------

Input

connector

-------------

Image

rejection

- - - - - - - - - - - - -

Signal

-

to-noise

ratio

----------

Carrier

level

meter

- - - - - - -

--

- -

Carrier

Frequency

Error

Measurement

Digital

readout

- - - - - - - - - - - - -

Accuracy

- - - - - - - - - - - - - - - -

Internal

frequency

standard

------

1-2

88

to

108

MHz

Approximately

250 µV, 60 dB

automatic

gain

control

range

250

µV

to

250 mV (75

ohms)

1V

to

10 V (50

ohms)

375

kHz

800 kHz

75

ohms

(nominal)

60 dB

70

dB

below

100%

modulation

at

400 Hz with 75

µs

de-emphasis

and 500 µV

input.

Front

panel

meter

to

indicate

relative

signal

level

Zero

to

± 10 kHz

in

1 Hz

increments

from

assigned

center

frequency

±100 Hz

per

year

Uses

a

precision

5 MHz

crystal

oscillator

in

a

proportionally

con-

trolled

oven.

A 1 MHz

output

is

provided

on

the

front

panel

for

calibration

against

WWVB

or

a

precision

frequency

source

.

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Off-frequency

alarm

- - - - - - - -

Automatic

logging

output

- - - - - -

Modulation

Meter

range

- - - - - - - - - - -

Accuracy

- - - - - - - - - - - -

Frequency

response

- - - - - - -

Meter

characteristics

- - - - - -

Remote

metering

- - - - - - - -

Peak

Modulation

Indicators

Variable

peak

indicator

- - - - - -

Accuracy

- - - - - - - - - - -

Response

time

- - - - - - - - -

Modulation

Calibrator

Available

as

an

option to

provide

contact

closure.

Can

be

wired

for

desired

frequency

limits.

Available

as

an

option. BCD

output

or

a

:1::1

Vdc

output

representing

:1::l

kHz

of

carrier

frequency

error.

0 to

:1::133%

on

positive

or

negative

peaks.

(±100%

=

±75

kHz

FM

deviation)

±4%

over

entire

scale.

O.

5

dB

from

50 Hz

to

75 kHz

Peak-reading

circuit,

scale

,

and

ballistics

conform

to FCC

requirements.

Output

provided

for

Model 704B

Remote

Readout

Panel.

Level

set

by

a

front-panel

3-dtgtt

thumbwheel

switch

in

1%

steps

from

50%

to 129% on

positive

and

negative

peaks.

100%

setting

corresponds

to

an

FM

deviation

of

±75 kHz.

±4%

20

µs

pulse

Built-in

modulation

calibrator

for

calibration

of

the

modulation

meter

and

peak

flashers

from

the

front

panel.

Six-Digit

Frequency

Counter

Frequency

range

- - - - - - - - -

Input

sensitivity

- - - - - - - - -

1-3

10

Hz to

10

MHz

200 mV to 2 V

rms

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Input

impedance

----------

Resolution

- - - - - - - - - - - - -

Display

accuracy

- - - - - - - - - -

Time-base

aging

rate

- - - - - - - -

Rear-Panel

O

utpu

ts

700 kHz

ou

tput

------------

Standard

Frequency

- - - - - - - - -

Remote

meter

and

peak

fl

asher

- - -

Audio

outputs

- - - - - - - - - - - - -

Amplitude

Modulation

Measurements

Range - - - - - - - - - - - - - - - - -

Frequency

Response

- - - - - - - - -

Signal

-

To

-

Noise

Ratio

--------

Physical

and

Environme

nt

Specifications

Power

required

------------

Operating

temperat

u

re

- - - - - - - -

Dim

ensi

ons

- - - - - - - - - - - - - -

Weight

- - - - - - - - - - - - - - - - -

c~~et

-----------------

1. 3

Accessory

Equipme

nt

1.

3.1

Accessories

Furnished

Instruction

Manual

1-

4

500

kilohms

sh

un

ted

by

25

pF

1 Hz

or

10

Hz,

front-panel

switchab

le

±1

count

- 8

1 x 10

/day

after

30

days

of

op

eratio

n

Output

to

drive

TFT

Model 724

Stereo

Monitor

1

kHz,

TTL

level

For

use

with

Model 704B

remote

readout

panel.

Two

outputs

are

provided,

one

with

de-emphasis

and one

without

Residual

AM

measurements

up

to

20%

can

be

made

on

the

R F

signal

at

the

high

l

eve

l

input.

75µsec

de-emphasis

network

is

incorporated

in

this

output

.

70dB

below

100% with

75µsec

de-emphasis

11

5/230

V,

50 to 400 H

z,

30

watts

maximum

0°

to

+50°C

1

9"w

x

7"h

x

16"d

17

pounds

Rack

mo

unt

ed

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1.

3. 2

Accessories

Available

Model 704B

Remote

Readout

Panel

.

Duplicates

meter

and

peak-flasher

readings

of

the

Model 723.

Model 724

Stereo

Monitor

.

For

use

by

stereo

FM

stations

to

meet

all

FCC

stereo

monitoring

requirements

.

Model 730 SCA

Monitor

.

Enables

FM

stations

broadcasting

SCA

informa-

tion

on

the

carrier

to

meet

all

FCC

SCA

monitoring

requirements

.

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

partf

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

ex-

pressly

agreed

that

replacement

and

repair

shall

be

the

sole

remedy

of

BUYER

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

BUYER.

This

warranty

does

not

apply

to

instruments

which,

in

the

opinion

of

the

SELLER,

have

been

altered

or

misused.

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

.

1-5

TFT 723 Manual de usuario

Manuales populares de Instrumento de medición de otras marcas