Geospace vlf 12 schematic

,-

\--

.-f

DEPARIMENT

DEPARTMENT
DEPARTMENT

I

oFTHE ARMY TEcHNIcAt,VIANUAI

IHE

OF

OF IHE

OPERATOR,

GBIIRAI. SUPPORT, AND DEPOT MAhTTENAI{CE

NAVY TECHNICAL

AtR FORCE TECHNICAL

ORGANIZATrcNAI., DIRTCT SUPFORT,

MANUAT

ORDER

Trrt I t-5895-4t3-t5/3

NAVSH'IPS

T0

0967-30t-5230

3rs5-2rYQ42-r6r

TIANUA1

-f

REGEIVER.PHASE

COMPARAT(IR

J-

.l

CM.364IG

\-_

DEPARTilEIIS OT THE

ARTIY, THE NAW

OCIO.BER 1968

AND

T}IE

AIR FORC

?i^

I I

-5895-413-1

5/3/NAVSH|P5

O967-3ol-523OItO 3155-2FyQ42-t6l

TECHNICAL

No.

11-5895-413-15/3

TECHNICAL

NAVSHTPS

TECHNICAL

TO

31S5-2FYQ42-161

CHAPTEB

Section

1. INTRO

f, General

II. Description and

CHAPIER

Section

CHAPTEB

Section

2. INSTALLATION

I. Installation

3. PRINCIPLES

I. General

IL

III. Individual

MANUAL

MANUAL

0967-301*5230

ORDER

Operotor,

RECEIVER-PHAsE

DUCTION

Scope

Indexes of equipment

Forms

and records

data

Major

components

Uses and

VLF tihe

Technical
Physical

Generel

Unpacking

Tools

Installation procedure

Operation

Generial

Preoperational

Utilizing the vlf-12B

Stopping

Introduction

Functional

Simplified

Detailed

General

Local

Second

Mechanical

Basic

Power

Plus

capabilities

service stations

characteristics

description

AND OPERATION

and

and equipment

description

block description

oscillat r synthesizer

mixer

si8nal

control

20-volt

checking the equipment

procedure

procedure

OF OPERATION

description

block diagram

servo system

circuit analysis

circuits

protective

and

dc operation

THE

WASHINGToN,

Orgonizotionol, Direct

Support, Generol

ond Depot Moinlenonce Monuql

COIY1PARAIOR CM-364 /

publications

-------_--

(PARI

_ ___

ill OF ill)

------

----

required for installation

for frequency source

cilcuits

(optional)

--

comparison

DEPARTMENTS

NAVY, AND THE

D. C,, 14

Support,

G

and adjustment

--------

OF THE ARMY,

AIR FOBCE

October

P!t!etr!& Prc!

1-1

l-2

1-3

1.1

1-6

l-6

t-7

1-8

7

2-4,

2-6

2-6

2-A

3-1

3-2

8-4

3-6
3-6

3-7

3-{

3-9

3-10

1968

1-1
1-1
1-1

t-2

1-3

1-6

1-6

1-10

2-t

2-l

2-7

2-t

2-6

2-$

8-1
3-1

3-2

3-5
3-6

3-6

3-17
3-77

I

Tir r r-5895{r Lr5/3/NAVSHTPS 0967-301-5230/|0

3I S5-2FYO42-l6t

CHAPTEB a.

Section I.

MAINTENANCE

Preventive maintenance

General

Scope of

Tools and

Preventive

II.

Corrective

General

Trouble analysis

Removal

preventive

materials required

maintenance

maint€nance

and replacement

Alignment and calibration

CHAPIER 5. ILLUSTRATIONS

Part III

in Part I

(TM

11-5896-413-15,/2)

APPENDIX

Illustrations in
Illushations

II

Part

BEFERENCES

maintenance

procedures

procedures

(TM

procedures

(TM

11-5895-413-16/3)

11-5895-,413-15,/1)

and

4-1
4-2
4-3

44

4-5
4-4

4-7

4-{

5-1

5-2

,l-1

4-7

4-t

4-7

L4

,1-16

4-19

6-1

6-1

A-1

Ti't

I t-5895-41r3-1S/3/NAVSH|PS

O96t-3Ot

-S2SO

3155-2FYO42-t

ltO

6t

TIST

1-1

1_2

2-2

3-1

'

3-4

3_6

3:6

3-8

3-9

3-10
3-11

3-t2

3-14

3-15
3-16

3-17
3-18
3-19
3-20

3-21

3-26

3-27

3-28

3-29

3_30

4-1

4-2

4-3

5-1

5-2

34

:

5-5
5-6

5-7
6-8

5-9
5-10

D-11

5-t2

5-13

5-14

VLF-12Breeeiver-phasecomparator

Typical

illustrating

Typical

VLF-128
VLF-128

Functional

Simplif ied

Response

Detailed
Phase
Detoiled
Sampling

Schematic,

VLF-128

Schematic,

Characteristic

Schernatic,
Schematic,
Schematic,
Schematic,
Schematic,
Schematic, four
Schematic,
Schematic,
Schematic,
Schematic,
Schematic, 1-kc

Schematic,
Schematic,
Schematic,
Schematic, output
Schematic,

Schematic,76.8

Schematic,
Schematic,

Coaxial cable repair

Multiconductor

Loading

RF amplifier

12.25-kc IF
Second mixer
45-kc

(part

Local
MOD-10
and

!'our flip-flops

One-shot and

S1'nthesizer

(part

S''nthesizer

(part

100-kc
Servo and agc
1-kc IF arnplifier
Servo

vlf-12B

rcceiver-phase

diurnal

packing

for export

receiver-phase
receiver-phase

diagram

diag"am,

curve

30-kv low pass

block

detector

diagTam, vlf-128

wavefonns

block

diag?am,

technique

vlf-128 receiver-phase

receiver-phase

RF

amplifier

curve

12.25-kc

second lnixel

three

flip-flops

local oscillator

MOD-10

flip-flops

one-shot
synthesizer

s]'nthesizer

servo and

lF amplifier

servo

cutout assembly,

audio amplifier

plus

and minus

buffer

100-kc arnplifier

to 100-kc converter

servo-motor
dc-to-dc

chart r€corder

and agc amplifier

to 11,250-kc

No. 200160)

oscillator assembly,

counter assembly,

(part

A23

phase

No. 200171)

phase

No. 200168)

arnplifier and

cutout

convert€r

cable repair

and firct hixer

assembly,

three flip-flops

No. 200022)

assembly,

reset assembly,

detector
det€ctor

--

phase

assembly,

a$sembly, A17

shift

comparator

shipment

compalator,

comparator,

of basic

vlf-128

vlf-12B

receivet-phase

filter

mechanical

phase

of

of

IF

counter assembly,

and rcset assembly,

agc

detectors

comparatol,

and first

crystal filter FL1

and agc

phase

phase

amplifier assembly,

assembly,

gates

and

and

VCO assembly,

assembly,

detector

detector

phase

det€ctors assembly, A15

assembly,

assembly,

1z-volt

assernbly, A25

phase

and

driver

assembly,

-------

assembly, A1A1

assembly, A2

(part

A4

and

(part

A6

A7, A8, A,21, A22,

----

(pa*

A9

A10

(slow-loop)
(fast-loop)

phase

shifter

detectors

assembly, A15

(part

A16

(part

receiver-phase

servo

comparator

mixer assembly,

A4

Ag __

A17

power

assembly, A24

No, 200151)

gates

No. 200163)

No. 200016)

(part

assembly,

assembly, A14

No. 2001?7)

ITTUSTRATIONS

OF

chart rccord,

panel

front

panel

rear

receiver-phase

comparator

compatator

top view

A1

assembly, Ab

A6

A7, A3, AZt,

-

A10

(slowloop)

(fast-loop)

A16

A19

supply assembly,

assembly,
assembly,

shifter assembly,

A18

(part

(part

assembly, A5

No. 200180)

No. 200139)

No. 20015?)

assernbly,

A12

A13

(part

(part

No. 200433)

No. 200142)

comparator

A2

A22, and AZI

A12
A13

A20

A14

---

No. 200154)

---_----

Plge

1-11

7-72

2-A

3-18
3-19

3-20

3-2t

.3-24

q-25

3\27

3-29
3-30
3-31

3-34
3-35
3-36

3-38
3-39
3-40
3-41

342

3-43

344

3-45
3-46

347

3-48
3-49
3-60

4-2r

4-22

4-23

6-2

54

5-5

F4

6-7

5-€
5-9

5-10
5-11

5-t2

5-13
5-14
5-16

llt

rM l t-5895-{r

}|'5/3/NAVSHIPS

O967-3()1-523Olt

3t

O

55-2FYO42-I6I

5-15

Servo-motor

5-16 Audio

5-17

5-18
5-19

5-20
5-21

5-22

Plus and

(part

?6.8-kc to 100-kc converter

Output buffer

Servo

Thumbv/heel

VLF-12B

driver assembly,

amplifier

minus 12-volt

200124)

No.

assembly,

switch

receiver-phase

tlST OF

assembly, A19

power

assembly,

assembly, A25

(part

A27

assembly,

No. 330034)

comparator,

A18

(part

supply

(pa!t

A28

IttUSTRAI

(part

No.

assembly, A20

A24

No. 200165)

(p-art

No.

200136)

(part

No.

bottom

200174)

IONS-Continued

200394)

No.

3301011)

riew

PlsE

5-16
5-L7

5-18
5-19

5-20

5-2t

6-23

TM I I

-5895-4r

ts-t 5/3/NAV5H

IPS @57

-3Ot

-5230

/

3l

lO

S5-2FYO42-I 6

|

CHAPTER

INTRODUCIION

Section

I-1. Scope

This manual contains

maintenance

and

Phase

called the vlf-12B receiver-phase

or simply

ponent

Digital Message

42(V)L

AN/FYQ-42

automatic d,igital network

manual is

1 contains

characteristics;

procedures

tions;

operation; chapter 4

maintaining

and chapter 5 explains location of illustrations

which support this

l-2.

Publ;icatiotu.

Comparatoi

vlf-128), which

the

of

Station

Switching Centers

throush

(V)

T1, which are

divided

Eeneral

chapter 2 contains installation

and complete operating

chapter 3 describes

and overhauling the equipment;

lndexes of Equipmeni Publicotions

u,. Neu; E tl,,itions, Changes, or Additiona|

Determine whether there are

operating

procedures

C.Vr364/G

Timing Units

AN/FYQ-4Z(V)12 and

(AUTODIN).

into five chapters. Chapter

information and technica:l

the

provides

equipment.

any new editions, changes, or additional

formation

pertaining

to

your

referring to DA Pam

NAVSANDA Pub
Index

(Air

latest

whether

Orders

I

Report

witl

and Requirement Table T. O. 0-1-01N

Force).

b. Motlification

edi.tion of DA Pam

there are

(MWO's)

Forms ond Records

-3.

a. Repor-t

unsatisfactory

procedures

of Unsatisfactory E

pertaining

in TM

(Navy),

2002

Work

Orders. Refer to the

310-7 to determine

any Modification Work

equipment in

3&750

instructions

for Receiver-

(hereinafter

comparator,

is a major com-

for Automatic

AN/FYQ-

part

principles

instructions for

equipment

310-4

or Numerical

to the equipment.

(Army),

of the

This

instruc-

in-

(Army),

quipment.

accordance

NW

I

l.

GENERAL

00-35-546

Force).

b. Report of

Deficiencies, Fill out

(Report

6

ciencies)

NAVSUP Pub 378

(Air

Force).

DiscrepancE

c.

out and forward

(DISREP) (SF

poit

55-38

or AFM

d,. Report of Maintenance. Records

ports

must

of

be

in TM

Subject: Planned Maintenance System

back Report

Force).

e. Report

ments.
mendations

individual

(Navy),

of Packaging

prescribed

as

in Shi,pment

Discrepancy in Shipment

(Army),

75-34

preventive

of

made in

38-750

Report of errors, omissions,

NAVSUP

(Air

accordance

(Army),

(Navy),

of Equipment

for improving this

is

user

encouraged.

TO-00-35D-54

or

Packaging

and forward

and

in AR 700-58

(Navy),

361) as

prescribed

Pub 459

Force).

maintenance

with

OPNAV

or AFM 66-1

Mantals

and

Handling

or

manual by the

Repofts should

be submitted on DA Form 2028

by

mended

forwarded

Army

Changes

to Commanding General, U. S.

Electronics Command,

ME-NMP-AD

07703

10-67)

forwarded

System Command, ATTN: 0451C, Washington

D.

22

ficiency

er, Oklahoma
OCNDT

73145

(Army);

(Formenly

to: Commander,

C. 20360

(Technical

Report) and forwarded to: Command-

(B-F),

(Air

Force).

to DA Publications)

ATTN: AMSEI-

Fort Monmouth,

NAVSHIPS 5600/2

NAVSHIPS

Naval Electronics

(Navy);

Order System Publications

Air Materiel Area,

City

Tinker Air Force

AFTO Form

or

(Air

Hand.ling

Form

DD

Defi-

(Army),

AFR 71-4

Report. Fill

Re-

in AR

(NavY),

re-

and

and repairs

procedures

Form

4700,

Feed-

(Air

Improrte-

and recom-

(Recom-

and

New

Jersey

(REV

4914) and

De.

ATTN:

Base,

Ok.

t-t

Tll t I

-5895-4

I 3-l

s/S/NAvSHl

PS

09

67

-3or

-s23o

ltO

3I

55-2FYO42-I

6I

I

Mojor

-4.

Table

1-1

ponents,

number

parator,

The items

by

an

asterisk

to which

12B,

have

matics

1-2

in

cl6tuE

serial

been indicated,

and

lists

serial

A1

A2
A4
.4.5
A6
A7

A8
Ag
A10

Al2

Components

of this manual

by nomenclature,

of the

serial

in

changes have

the

num,bers

RF

First

IF and AcC

fiers.

Normal-Mode

Mixe!.

Three Flip-Ftops

and

focal

vco.

Mod-10

Mod-10

Four

One-Shot
Slow-Loop

and Phase

vlf-l2B receiver-phase

numhrs

part

the

indicate

numbers

parts

differences

Table

Amplifier

Mixer.

number

printed-circuit

been made

179-180.

as alternates,

pla.ement

between circuit boards

722-Lg2

1-1, Maior

N,m

and 330039-101

Ampli-

Second

Gates,

Oscillator

and

Counter

Count€r

Flip-Flop8

and

Reset

Synthesizer

Detector.

Seclion

lists

the

name,

12?-132

and 179-180.

column followed

All

diagrams. Table

and 179-180.

Cotnponetuta

Psrr

lilo.

200139-101

200151-101

200160-101

200163-101

2O\OZZ-|OT

2OOOZZ-7O}

200016-102

ZO}L'7-LOL

2001?1-101

ll. DESCRIPTION

major

in

on the sche-

and

boards

the vlf-

changes

.

,i

*

com-

part

com-

AND

Table 1-1, Majot

A13

414

A15

A16
A1?

A18

A19

A20

.{21

422

A23

424
425

421

A28

L1

T]

?6.8-Itc-to-100-

Output Buffers

Servo Assembly

cHANNELSELEC-

RF Int€rfelence

Chart

Accessory

DAIA

Cortupotuents-Co[finued

Nme

Fast-Loop

and Phase Det€ctor.

100-KC.

and Phase Shift€r.

Servo

Phase

1-KC IF

Servo
Servo-Motor

Audio

I

lz-Volt Power

Supply.

Mod-10

10-KC

Synthesizer

Amplifier

and AGC

Detectors.

Amplifier

Cutout

Driver

Amplifier

10G

KC-to- 200022-log

Divider.

Mod-1010-KC-to-

1-I(C

Divider.

Mod-10

Loudspeaker

l-[C-to-

100-PPS

KC

Converter.

TOR

Thumbwheel

Switches.

Becorder

Cable,

Card Extrac-

tor,

and Card Ex-

t€nder).

Divider.

Kit

Fitter

(Power

Psrt

No.

2001G8-101

200154-101

200433-101

200142-70L

2001?7-101

20017

4-L0t

200136-101
240724-101

2OOO22-1O\

2OOO22-|O3

200394-101

200165-101
300034-101

460063-101

+

*

+

*

*

+

*

Circuit

A2

Al3

415

1-2

A1

At2

AL4

s18l

slRil

s1B6

S1R7

s1n9

R8

Rl9

Q6

Q7,

QlA

L1

cR4-CR7

Q1

q2

Q?

Rl6

Table

1-2. Di,fferenooe

S€dal No.

122-L32

3480

ohms

348

ohms

34.8

ohme

3,48

ohns

0,5

ohm

390 ohms

6.2

K

2N2222

25

mh

1N270
2N1169

2N1319

2N1996

2.2K

in

Circuit Boardl

Sed.l No.

170-180

ii,3K

330 ohms
33

ohms

3.3

ohms

0.51 ohm

180 ohms

3K

2N3643

2N3643

22 ri\

1N625
sM8481
2N2334

sM8481

1.6K

(sensistor)

I I-5895-.{I&I6/3/NAVSHIPS

Tl

O967-{1-5t3o

O 3155-2FYQ42-I6I

lt

To,bl.e 1-2.

Cilcuit

At?

A18

A19
A20

I

-5.

a.

1-1, is a highly
ment
tracking

transmissions.

vlf-128 is to

cumulative frequency

quency

standard. The

microseconds on

a chart recorder

This information

frequency standard and to determine

d6

R26
R28

811
R12

Q7, Q9

Q8, Q1O
R12

R7

R2,817

cR20

cR19,

Copobilities

ond

Uses

GeneNLL

designed

The vlf-12B,

for

of vlf

standard time

sensitive,

The

provide

time transmission

frequency offset

a

located on the

is used to calibrate

shown

ultra-stable

phase-locked

major

application

representing

data

offset between

and

time difference

tal oscillator aging characteristics.

part

of 1

measurement

a 24-hour observation
tainable. Uses of the vlf-12B

comparator include the following:

and

in 10" over approximately

interval and 2

parts

interval

(1)

Frequency measurement, calibration,

performance

monitoring of

Dillercncea in

No,

S€ri,l

tz2-132

21.5K

3,6 meg

3K
3K

2N3638
2N3646
68 ohms

None

Not used

None

in

reception

frequency

and

vlf fre-

a

a local

frequency

is recorded

register

front

the local

the crys-

Accuracies

a

B0-minute

in 10" over

readily

are

receiver-phase

precision

figure

instru-

and

of the

the

panel.

ob-

crys-

tal oscillators, atomic frequency standards,

and other

cision

nomena,

carrier

b. Frequency M eosurement,

Standnrdizattion.

calibration

comparably

(2)

Timing and synchronization

clock systems.

(3)

Investigation

(4)

Navigation through

techniques.

(1)

Us€ of the vlf-lZB for frequency

of any frequency standard having:

an available 100-kc
and direct.

tween

The relative

the local frequency

stable frequency

of

or

propagation phe-

vlf

use

Cakbratinn,

l-mc

output

frequency error

standard and the

sources.

pre-

of

of stabilized

atd,

is

simple

be-

Circuit

Boar.ls-Continued

received

vlf carrier

Hrl

20.6K

2,7 tueg

2.1K
(sensistor)

1.5K

2N4L27

2N3567
82

ohm8

200

ohms
Removed
1N270

No.

1?9-rE0

signal

may be observed on

the time difference register

ONDS counter). Rate a

be directly interpreted as a

error in

1 psec

of

sents a fractional frequency deviation of 1

local standard; thus, a

the

in a 1O0-second lime

in 10".

(2)

To

appreciate

in

time ratios involved,

on

t hr

1

I

1 psec/hr : 2.78

L psec/

Corresponding

:

1 min

:

day

=

/,sec/min

60 sss

3600 sec

day

:

:

8.64 x 10'sec

and

:

1.66? x l0-"

:

1.16 x 10-"

frequmcy ernors ar€

pressed:

Fractional frequency error

Difference in

time difference can

fractional irequency

interval repre-

the magaitude of the

consider

10'Asec

x 10'ssec

3.6

that:

:

8.64 x 10"

x 10-'"

=

psec

x 10-'

Elapsed bime in sec

(3)

Calculotion can

time-difference

information taken from

chart recorder. Full-scale deflection of

chart

either
and frequency comparisons to an accuracy

parts

can be obtained w,ithin an interval of 10 to 30

minutes.

represents

tra,ce

positive

in

10'

a

or negative as the

relative

to bhe

made

be

100-psec

received

phase

(MICROSEC-

phase

rate

part

l6ec

ex-

Af

:

f

-

using

case may be,

vlf carrier

the
the
the

change,

of

IJ

(4)

In reading the chart

accumulated

the recorder displays a

that

mental range

phase

obtained,

full

parsion

over an elapsed time

excursions of the

phase

however,

with

error, it

100 psec. The total change

of

keeping

by

recorder and by

the digital

ter. A discontinuity in the
the flyback

recording

because the trace

posite

aging
be visualized by converting the basic data to

a

characteristics of the

daily

(5)

makes

of

local

a

periods.

tion

a

crystal oscillator

aging rate. That

for example, higher

rate. During

is changing rapidly,

several

(6)

four months

placed

be

turned off; the entire

be repeated

(7)

recorder,

indicates
the chart

function

time

is frequency,

is frequency

is

chairge in rate

determined

short

monitoring

(8)

tion

of observation

chart

trace

or

the

local

oscillator

periods

For

crystal

able. An

procedure

ment

point

on the continuous-rotation

potentiometer,

will

continue

edge of the chart.

"frequency

Proper use of the vlf-128 record

possible

it

precision

error"

to determine the

oscillator between calibra-

After an initial run-in

has

a

its

is,

each d,ay at a uniform

the run-in

period

but can be

days.

The

run-in

period

of continuous

in operation

each time the

In

using the vlf-l2B

it

is important

change in

indicates this

of time.

(.rate)

by continuous monitoring

Precision of

width

perriod

of one day,

oscillator

example of measurement

the oscillator should never

phase;

change in

Change

so the slope

error.

error. These

periods

measurement

noise, which

and the

between

predictable

is

a typical high-quality

can

be assumed

given

is

below.

records of the

must

maximum incre-

time-difference regis-

recognized

be

interval

record of

a

can be

the

com-

record occurs at

trut no data

from the

Frequency drift

oscillator can best

plot.

is lost

op-

performance

period,

relatively constant

frequency becomes,

the aging rate

projected

consists of one to

operation.

run-in

oscillator is restafted.

to know that the

period

with

its

for

Once

must

chart

pen

the movement of

phase

phase

in

of the

Change in the slope

errors

per

pen

can

as a

unit

line

or by

at regular intervals.

is a func-

is related to

period

observations, if

of

observation

between

to be

and adjust-

the

periods.

predict-

(9)

Assume that observations

once a day. On the

quency

in

day

the

ter

observations

one

from nominal

f.

or

The frequency for that

f : f"

error.

ard

markings in incrernents of 1

the knob 5 divisions
The next day's observation
curacy of this adjustment

slope of the

gained
and,

be

out

between' observations

sirable

compensated
quency

if

to

oscillator may

standard was

(t')

chart

of

+

there

50

is an indicated

recorder and

psec. If the elapsed

was

the eror

day),

(f")

50 x 10' sec erroill

f"x

=

(10)

will

(11)

if

adjusted

making

(12)

10' sec elapsed timo

f",

+

assuming

Ordinarily,

have

an adjustment

line.

After the

each day

necessary, the

with

a new ob,servation, or

In

some applications

that the oscilrlator be

rather than set exactly on

whenever an adjustment is

experience indicates that the oscillator tends

(age)

drift

toward a higher frequency, the

be adjusted so that it starts off

with a negative frequency

The overcompensation

be

in the maximum

adj ustment

oscillator

(13)

used

for frequency

pends

global

in

be

instructed

mitter

ceiving

ary stations

will be required

within specified

Selection of

upon many

network operation

to monitor

that can be reliably

sites.

Selection of one

is

advisable so that no receiving

made

are

firsb day

not adjusted.

(t')

time-difference

10' smonds

in the frequency

ll-as:

local fre-

the

The second

error on

time

between

time

(slightly

standard

regis-

over

:f"x5x10"

24-hour

no appleciable

local

frequency

the

knob with

pp

to correct

run-in

the

indicates

the

by

period,

will be vidually

frequency standard

considerable

can be increased.

confidence

period

10'".

frequency.

the

lvas

aging

stand-

dial

Adjust

the ac-

resulting

time

the

constant,

may

with-

period

it may be de-

slightly over-

fre-

made. Thus,

deviation

technique will

time interval before another

maintain

to

tolerances.

the vlf

correlation

factors.

station

purposes

Groups

will undoubtedly

particulat

some

tracked

more

or

error.
result

to be

involved

trans-

at all

second-

the

de-

re-

l-{

TM I t-5E95-41i3-15/3/NAVSHIPS

0967-30l-5230

lto

3,I

S5-2FYQ42-I6I

site is wholly dependent

mitter. The

stations are listed in

upon a single trans-

t-I.

c.

Clock Synchronization It is

use

the vlf transmissions directly for time-of-

day

information

example,

second intervals.

tion

slow

mitted
The

in

the neighborhood

cause

700. This

radiating

Nevertheless,

able

slope

and

clock

d., Itwestigation

nomem,o,.

phenomena
agencies,

ies

of

transmits timing

envelope of the keyed

rise time that the

time

NBA

transmitted sigxral

of

transmitting

a

is required

efficiency at the low frequency.

synchronization

of

the

are being

settings.

(1)

Investigations

here

the diurnal

vlf-reflecting

ies

of

the effects of magnetic

ospheric

reception

sions is true

agation

ness,

more

sunset

(36

determined

tween

by

the seasonal

twilight;

longitude,

disturbances;

of the various

(2)

The

path

with

daytime

stable. During

there is a shift

psec

at 18 kc).

by the

the transmitter

if

the shift will

purposes.

Station

pulses

Unfortunately,

carrier

beginning of the trans-

pulse

is difficult to recognize.

has

of 15 milliseconds be-

antenna

Q

to achieve

various

modulation

schemes to obtain reli-

points

on the leading

have been

used successfully

of VLF Propagation

of vlf

are being

and abroad. These include

D layer

ultra

for cases where

is

either

there is

carried out

change

of altitude in the

of

the atmosphere; stud-

and sudden ion-

and

comparisons of

vlf

transmissions.

stability of vlf

the entire

in daylight

transmissions being

periods

in

period

The

difference

and

variations

of sunrise or

phase

of about 200o

of the shift is

in longitude

the receiver,

in

the length

a difference

occur over.

or

at

the

a r,ise time

propagation

paragraph

possible

NBA, for

precise

modula-

has

such

of roughly

reasonable

developed,

to achieve

Phe-

by various

stud-

transmis-

prop-

in

dark-

the

be-

and

of

of

approxi-

T5o

in

mately
and sunset)

posite

to

only real

sonal valiation

night

little

1-

predicted

be

a

accomplished

the shifts

period).

effect on
transmission

ionospheric
phase

with

effects

be identified

covery,
removed
parison.

'

tration

disturbance
rise

and sunset

mitter

er. An

e. Nattigation.

used for

LORAN

received.

quency

chart

for

radial

tions
dead-reekoning
mile

conditions.

I-6.

a. VLF stations which

of conbrolled

table

hours.

5

These diurnal shifts

are equal in magnitude and

in

direcbion, and extremely

changes are due to the ordinary

in the length of the day and

and the duration

local

experience, the diurnal shifts can

and fretluency calibration can be

even during the shifts

cancel for a 24-hour observation

(3)

Lagnetic

stolms

nighttime

is virtually

disturbances

shifts as large

recovery

cannot

and can

taking

predicted,

be

by

the sharp rise
then either be

analltically

(4)

A typical

of diurnal

is

about

30' longitude

S.I.D. is shown

vlf-l2B

shift and sudden

shown in figur.e

effects

VLF

navigation

C or

OMEGA

For

this application

standand,

record€r,

velocity

are required.

two vlf-12B's,

and some forrn

with respect

It has

transmission, but daytime

about

from the frequency

purposes

twilight.

of

produce

unaffected. Sudden

(S.I.D.)

as 100o in 5 minutes,

an

of course, but can

chart record illus-

shown

are

west of

occurring

transmissions

in areas

transmissions

of compensation

been reported

navigational

or

Iess can

VLF Time

be realized

Service

Stotions

during

transmit on a basis

carrier frequencies are listed in

1-3.

(sunrise

regular.

With

(of

course,

turbulent

a

produce

can

hour. The

and slow re-

discounted or

1-2. The

for

at 10 o'clock.

preeision

a

a dual-channel

to the

accuracy

S.I.D.

ionospheric

a trans-

the receiv-

can be

where

are not

vlf sta-

of 1

all daylight

op-

The

sea-

a

com-

sun-

fire-

that

OMEGA

GBN,

FUB

Table 1-3. VLF

70.2

16.0

16.8

fi,rna Seruice

Various; Clobal

Rugby, England

Paris, Fralrce

Statimu

Net

U.S. Navy

RNOUK

IJ

rr I t

-5895-413-I5/3/NAVSHIPS

NAA
NPG/NKL

GQD

GBZ

wwvL

NSS

NBA

NPM

wwvB

The U.S.

b.

subject

are

quencies

1965.

listed

AII stations

UT2 Time

c. The
and the United
time and

in the

tions

ters stabilized

pulses

Time

lized carrier

Navy

change

to

those

are

except

Base: WWVB

Time Service

Kingdom

frequency

coordination

Atomicron

by

synchronized

are

frequency,

A-1 to minimize the

frequency

and UTZ.

constant throughout

ified as follows:

nominal

the

s is the

most

fractional

mined,
Observatory

The value for

10-".

d.

broadcast

The

F:

frequency

fractional

nearly

equal

offset

in

advance,

The value of

each 15

offset

to the

for any

the U.S.

and

both 1964 and

0967-.gJ1-523ol10

Tabte 1-3.

17.8

18.6

19.0

19.6

20.0

21.4

24.0

26.7

60.0

frequency

without

in use

assignments

notice.

as

WWVB

A.1

uses

Stations

vlf links.

by

are

plan

of

coordinated

All the

have transmit-

(cesium)

with

which

difference

one

any

(1

F"

of

is

between

transmitted

year,

5),

+

transmitter

the

which

gives

rate of

year

is

iointly

by the Royal

Naval Observatory.

1965

the fractional

minutes

in International

Time Serrice

VLF

fre-

The

of January

operate

Base.

Time

U.S.

the

sta-

clocks.

the stabi-

offset

and

where

was

from

A.1

remains

is spec-

F, is

and

rate

a

UT2.

Greenwich

The

deter-

-150

offset

3rl

Cutler,

Jim Creek,

Anthorn,
Liverpool, U.

Ft. Collins,

-q.nnapolis,

Balboa, Canal

Laulualei,

Boulder, Colorado

Morse Code,

from the

on

the carrier

pulses

at all

in

milliseconds on the

changes

FYQ42-I

55-2

Stotiorrs-Continued

Maine

Washington

Scotland

K.

Colorado

Maryland

Zone

Hawaii

received carrier

e. Seconds

depart too

the transmitting

are

Greent"ich Obselvatory

Observatory.

changes

l.

will

U. S.

Bulletins A and
transmitted

UTO and A.1.

and

Apparent and

(the

"equation

the equinoxes",

the American

nac,

x

is

Technicol Chorocteristics

l-7.

Table l-4 lists

for

the

vlf-128.

6I

Navy

U.S.
U.S. Naqy

NATO

KNOUK
National

U.S.
U.S.

U.S.

National

A.l can readily

so

pulses

frequency.

are locked

far from

Whenever

Bureau

Standards

Navy

Navy
Navy

Bureau

Standarde

frequency'

UT2,

stations are

of a

first

jointly

determined

and the

No more than

be necessary

ever

one or

Naval Observatory

give

B

frequencies

final

obtain UTz,

to

The differences

Mean

of time" and

respectively)

Ephemeris and

Solar

and

the "equation

are tabulated

Nautical

the technical

of

of

determined

be

in

phase

the

the

with

seconds

clocks

shifted

trvo

The

Royal

Naval

such

year.

month.

by the

U. S.

in one

Time Signal

corrections

UTf,

between

Sidereal

characteristics

Times

Alma'

50

to

of

in

rrequency Coverage

IJ

tr .tur!

Table 1-1,.

Techtuical Characteri.stiaa

VLF channel tracking

ments for all

spectrum betwe€n
is entirely
detent, Channel

without the use of

adjustment of

any other frequency-determining

A 60-kc channel,

front-panel switrh, is also
required for optimum operation,

possible

by thumbu'heel

selection

the local oscillator,

selectable

Oher8ctet{lnica

provided

is

channels

10 kc and

is

plug-in

in

in the

30 kc. Channel

sivitches

positive

filters and

with

and accurate

rf selectivity,

circuits.

by m€ans of

provided.

No tuning

100-cps incre-

frequency

selection

position

without further

or

a sepalate

is

rfrt I I

-5895-4lrlls/3/NAVSHIPS

@67-@1-5230

3lS5-2FYO42-I6t

llo

Randlvidths

Beceiver Sensitivity

Signal Level Operating Range

.\utomatic Gain

Response to Undersirable Sigaals

Control

(AGC)

Adjacent Channel

Rejection

Spurious Responses

Image

Rejection

Desensitization

Tabte 1-1.

Technical

Charactedsiics-Continued

Ch.ruteriltica

Bandwidth

cations

handling

RF module

image rejection: 8 to 30 kc

restriction

within

capability

pass

the

is supplied

receiver to ensure

of each

(single

band

l'irst inter:mediate frequency

200 cps

Second intermediate

(nominal)

50

cps

Phase-tracking servo

frequency

bandwidth:

at appropriate

the desired siShal-

function described:

filter) for 60-db

(12.25

kc)

(1

pass

kc)

0.006 cps

(nominal)

input tevel of 0.01

An

and a sigaal-to-noise
measured in a 1-kc bandwidth)

phase

tracking

0.006 cps.

The noise figure of the

internal receiver noise

and

recorder

more than

caused by internal receiver noise,

receiver is
coherent
is 0.006
The total operating range of

cps.

u'ith a nominal

o! the time difference

microsecond

0.3

tracking

generator

microvolt across

ratio of

-50

servo bandwidth

receiver

will result in accurate

will not cause

register

jitt€r.

a 0.ol-microvolt

and the nominal

signal level

This range is accomplished by the

step attenuat r having

steps coupled lvith

gain

contml

A stable

over a

(agc).

agc circuit

40-db

range

than 0.5 microsecond of

the agc sigral

is

ture detector designed

phase

between the receiyed

standard.

The follorving characteristics are
a normal input level of 1 microvolt

signal, and assuming

a range of 80

a minimum of 40 db

assures reliable

of input carrier

phase

shift. The

accomplished

to

by the

provide

station and

that all receiver controls

is Iess than 20 db,

50

(Gaussian

db

to display

The limit on

when

exists

sigral from a

servo bandwidth

is 120 db'

a manual

use of

db in 10-db

of automatic

phase

level with less

detection of

use of a

regardless of

agc,

the local

given

assuming

for the desired

optimized:

.A. coherent siglal 100 cps

and 30 db larger

affect the

in amplitude will not adversely

phase

tracking

Similarly, a signal 200 cps or

signal and

phase

the
The

spectral

vlf-128

the

responses, 100 cps or more from

hy

the thumbwheel switches, from limiting the

cent channel rejection charact€ristics specified.
Image rejection is 60 db or
frequencies without the use of

larger in amplitude

60 db

tracking

purity

are sufficient

ftom the desired sigaal

of the desired sigrral.

more from the desired

urill not affect

of the desired sigTlal.

mixing frequencies within

of the

provide

to

greater

any undeeired

the

channel

at

plug-in

all selected

filters and

without repositioning the local oscillator.

With

the receiver

and undesired sigral
frequency from the desired

larger in amplitude, will not lowe! t}re

receiver to the desired sigaal by mole thatr 3 db.

properly

located 200

to a desired channel,

tuned

channel,

or more in

cps

and 60 db

gain

Io-

pass

band:

band:

ohms

noise

of

the chart

iitter,

the

tracking

quadra-

are

selected

adja-

of the

t-7

rM r l

-5895-41

3-|5/3/NAVSH|PS 0967-30l-5234/10

l'eature

Intermodulation and Harmonic Dist rtion

Response

Fr.equency

Coherent Signal lladiation

Receiver Inputs

Receiver

Synthesizer

Outputs

IJ

3lS5-2FYO42-l6r

Tabte 1-1. T echnical C haracte?1istics-Continued

-{11 second- and third-order

and undesired channels are 60 db lower

than the input signal.

Tbe

choice of the first intermediate frequency and

the desigr of the frequency synthesizer

local-oscillator injection frequency that is locked in

100-cps increments

rnal

100-cps

24.45 kc. The frequency offset

oscillator signals radiated by the antenna from inter-

fering $'ith other

discrete frequencies are not

normal vlf

selecting
and

channel frequencies. The frequency-

srvitches set the desired 100-cps

provide

station frequency.

frequency and then

the synthesizer

second,

phase-coherent

The
antenna input

(0.001

microvolt).

Trvo separate

are supplied with

panel.

rear

A 100-kc frequency standard input is

means

of a BNC

nominal 10K input

betrr-een 0.5 volt

The following
panel

BNC connectors:

Amplified

quency

same
100-kc square

and

phise

carrier and is

10-kc square

carrier

1-kc

and is a nominal

square wave

carrier and is

100-cps square wave

carrier and is

DC

output voltage

to the

relative

standard

1-ma

and

external

reai chassis

calibration to obtain a full-scale

that reptesents

panel

A rear

phase

difference

ternal

The

panel:

or int€rnal

following
built-in

-{

and a chart

calibration

Built-in

if. A

range

speaker for

front-panel

to shut off

but offset by 50 cps

incremcnt;

coherent

direct indication of the desired vlf

After

returned to an

phase

signal level

connector is Iess than

rf inputs, 50 ohms and 10K nominal,

BNC connectors mounted on

connector on the rear

accommodates a signal level

and 15 volts rms,

outputs are available on the rear

vlf

carder

200-cps

information

potentiometer

outputs are available

chart recorder with

speed of 1 inch

of the

band$'idth

wave that is coherent with the vlf

a nominal t volt

rvave that is

that is coherent with the vlf

nominal

a

nominal

a

that is accurately

phase

vlf

the

recorder or the intemal recordet.

100 microseconds

switch is

output voltage

recorder,

chalt

volume

tlle audio

Chara.teriotie

products

e.g,,24.25 kc,24.35 kc,

phase

phase-coherent

of the desired

in

amplitude

produce

from

prevents

any locai-

detector, since the

the

to the

incremert

being

switched to

another

original settilg,

is

shift

less than 0.5

present

at a 1-kc intermediat€

at the

dbm

-16?

provided

panel.

micro-

50-ohm

The

fre-

that carries the

as the

leceived sigral.

pp

across 50 ohms.

coherent with the vlf

pp

volt

1

1 volt

that is

1 volt

across 60 ohms.

pp

across 50 ohms,

coherent

pp

across 50 ohms.

with

the

proportional

difference between the local

carrier, for driving

adjustment

nominal

a

provides

chart deflection

provided

of

to connect the

change.

phase

to eiiher the ex-

on the front

inkleBs

pet

paper

is 100 microseconds,

aural monitoring

control

hour.

Full-scale

provides

stylus

of the 1-kc

adequate

signal completely

a

nor-

the

by

vlf

A

span

TM

r-58954lr3-r

I

5/3'INAVSH|PS 0967--30I-5230

3',tS5-2FYQ42-|

O

lt

6r

\*

Phase-Tracking

Servo

l\Ieter Display

Interrupt Warning

Time Difference Register

Calibration

Accuracy

llnvironment

Power

Requirements

T@ble 1-t,

Technical

Characteristics-Continued

provide

or t,o

ventional

An

electromechanical servo maintains a

shifted

reference sigral in a

relative

Servo

Phase-tracking
mum fractional frequency offset

Manual

panel,

servo

at approximately tw'ice the rate

sufficient audio

operating

to a select€d vlf carrier.

deadband is

servo slewing switch, located

advances or retards the

Char&tenisti6

environments.

0.1

=

error is less than 5

power

phase-null

nominal.

tsec,

phase-tracking

for use in

phase-

condition

Asec

(1 pp

on the front

experienced

at the maximum fractional frequency offset

given

a

leceiver

.{ front-panel rneter,

markings,

observe

receive!.

METER

independent

monitors signals that the

to determine the

The sigral or level

FUNCTION switch to allow

time

constant.

1trith

special calibrated

performance

operator must

status of the

is selected by the

individual and

monitodng of the following

signalB:

Belative carrier level

Phase

Positive

det€ctoi

gupply

error:

voltage

voltage

Negative supply voltage
Indication

quency

Indication

sizer signal

The front-panel indicator

inteuuption

standard input
manually

to normal

Another

carrier,

and will automatically turn off

carrier is
A front-panel

driven

by the servo, displays the relative time differ-

ence between

carrier,

seconds.

The
is

specified

The

calibration accuracy, relative to a received carrier,

better than a 1 x 101r on a 24-hour basis, over the

variation

The vlf-12B

+65"

to

ceiver

psec

receiver is

C at a relative humidity of 95%, Total re-

phase

over

tion encountered

The vlf-12B

95 to

130 volts rms, 48 t

of less

than 25 watts. All of the

are maintained

If a

recorder is supplied,

must be

128 may

source to

the ac

chosen to suit the line frequency.

power

proper

of

operation of 100-kc f!e-

standard input

proper

of

in the ac

has occurred. Only the

operation of

provides

power

100-cps synthe-

a u'arning if

or the local frequency-

indication

resettable; the vlf-128 returns automatically

operation when service is restored.

front-panel indicato|warns of any loss of

when the

returned.

MICROSECONDS

digiial

the local standard and the vlf

counter

is cumulative to 9999.9

countcr,

temperature range and input ac line-voltage

t lerance,

operates

shift from all causes

a temperature range of 0o C

desigred to withstand the shock and vibra-

operates from an ac

also be

enable automatic

should

properly

over a range of

is less than t

durirg normal shipping.

power

600 cps, at

over these

basic specifications

line-voltage variations.

ac

the s,'nchronous motor

connected to a

24-volt

operatiolr

fail.

to

50o C. The

source of

power

a

The vlf-

dc standby

in

the event

con-

at the maxi-

10').

or for

dial

is

micro-

-20o

1.0

level

C

I-9

Til t t

-5895-4

M 5/3/NAVSHIPS 09 67

-3ol -523)

TO 3l S5-2FYO4il-l 6I

I

l-8.

Physicol Description

o. The vlf-12B is designed to be

in

a slandar:d

than 7 inches high, and requires no

l9-inch rack

position

18 inches in depth behind the front

The net weight is

b, The unit is constructed of functional

modules arranged for ease of maintenance

approximately

mounted

not more

more

pounds.

45

than

panel.

and troubleshooting. Each module

quate

particular

a

for monitoring

operation. An extender card is

incircuit testing, and a card extractor

vided to allow easy removal of

cards.

test

points

to

module. All

without

isolate any trouble

points

interrupting normal

has ade-

are accessible

pmvided

printed-circuit

within

pro-

is

for

t-to

rM I t

-5895-4t3-r

5/3

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2-1. Generol

This

section

unpacking and

phase

comparator.

2-2.

Unpocking

Equipment

When

packed

is contained
figure 2-1.
during

below:

a. Transport

location.

b.

Cut

c. Remove

wooden box

pry

to

lids.

d, Open

the

carton

carton.

e. Open carton

proof

barrier

Remove inner carton. Open

l.

and

remove equipment.

Caution:

strum€nts when opening

cause

damogr

g.

Upon

containers,

shipped agree with

terior for any

as dents,

loose control knobs.

mediately.

contains

installing

for export shipment,

in a tlpical

To avoid damage

unpacking,

fold back

and

nails from top

with nail

moisture-proof barrier

inside

within the carton.

Never use sharp tools

to the equ,ipment.

removal of equipment

check

visible signs of damage, such

nricks,

detailed instructions

ond Checking

carefully

package

the wooden box, and

and second

to see

packing

or scratches,

Report any

INSTATLATION

the vlf-12B

lhe

package

to equipment

follow

to desired

metal straps.

and one

puller.

Do

moisture-vapor-

inner carton

cartons,

whether

list. Inspect ex-

and broken or

CHAPTER

Section

l. INSTAIIAIION

for

receiver-

vlf-12B

the

shown

as

the steps

operating

of

side

not attempt

covers

that

remove

or in-

as they may

from the

items

all

defects im-

2

AND

in

OPERATION

Tools

2-3.

lnstollotion

o. For vlf-12B's

intended for bench
is required

b. VLF-12B's

a standard

commodated

panel

be
clearance. Tools and

height. The depth

least 22 inches

at

Equipmenl

ond

supplied

mounting,

therefore

and

intended

l9-inch equipment

in a space adequate

install the equipment

following:

(1)

Screwdrivers,

no tools

for

of

to allow

hardware

in the

common

head,6and8inch

(2)
(3)
(4)

l/16

to l/4 inch

(5)

rack

used)

(6)

split

lockwashers

c. Ancillary

of small sockets

Set

power

-inch

l/

Assortment of

in

Countersink

drill

drill bits

32nds

bit

Nuts, bolts, and assorted

equipment

required

a long-wire, whi'p, or loop antenna; a

(normally

cord

two

50-ohm coaxial

length

antenna

receiver,

in

with BNC

table

and local frequency

A list of mating

2-1.

2-4. lnstollotion

a. If

the vlf-128

necessary

antenna

local standard

only to connect the

leadin, and the coaxial

supplied with receiver); and

cables of appropriate

connectors

connectors

Procedure

is

cabinet

to the desig:nated

Required

with

for

a cabinet

installation

no

are

required.

installation

be ac-

can

rack

for the

the rack

for

7-inch

should

connector

required

rack include

Phillips

and

(1/4-inch

(for

drive)

metal),

(depending

flat and

includes:

power

to conneot the

standard to the

is

mounted, it

power

cord, the

line from the

connectors

in

to

the

upon

given

is

IM

I

r

-5895-4

3-l

I

5/3/NAVSHIPS

0967

-*t

-523o

tO 31 55-2 FYQ42-I 6l

I

at the rear of t}re chassis.

na is

whip

50o input. It

coaxial

connect to the HI

used,

or loop antenna

is

not necessary to use

lead-in

with the long-wire ant€nna,

but use of a shielded

minimize

strong

local interference

If a long-wire anten-

Z input.

is used, connect

line, of some type,

is rrecom-

mended.

Tabb

Ohr..i!

50-ohm

Hi Z antenna

100-kc
10-kc
1-kc

0.1-kc

Local standard input

1-kc if.

Extcrnal

AC

art€nna

coherent

coherent

coherent

coherent

recorder

po\f,er

Notc 1: With RC-174/U cable use Gremar t]?e 6399.

RG-68/U cable use BNC typB UG-88/U.

With
With RG-62/U cable

Nota 2: Chassis connector

BNC type UG-1094/U

BNC

type

BNC type UG-1094/U
BNC type UG-1094/U
BNC type UG-1094/U
BNC type UG-1094/U
BNC tlTe UG-1094/U

BNC t,'pe UG-1094/U

BNC

type

Note 2

use BNC type-260/U.

is integral

part

b. For installation of a vlf-128

If a with

to the

mounting instructions supplied with the

drawer

slides, consult the

50-oh,m ticular rack used. With

able racks, it is necessary only

to bo

2-1. Liat ol

conn6to!

UG-1094/U

UG-L094/V

of rfi filter.

predrilled

necessary

the s'lides.

Mating

to drill

Connectorc

rack bars. With

special holes to accommodate

ll&tlns clnnlotor

Note 1

Note 1

Note 1

Note 1

1

Note

Note 1

Note 1

1

Not€

1

Note

MS 3106A 105I-36

equipped

equipment

par-

most commonly avail-

to bolt the

some racks

(C)

slides

it is

2-5.

Generql

This section

provides

information on all

erating controls, ind'icators, and

plus

instructions for operating the

Refer to

and to table 2-2

indicators,

2{. Preoperotionol

When the vlf-12B is to be

ice,
ried

a. Connect the

to the AC POWER

the

b, Plug the

a nominal 120

from 48

be used, conneot

D.C.

c. Connect an

propriate

figures 2-2 ar,d 2-3 for

for functions of the controls,

and connectors.

Procedure

put

into actual serv-

the following instructions should

out step by step.

three-conductor line cord

connector

panel.

rear

to 600 cps.

POWER

input,

into

cord

volts ac at any line

If standby

the

+24

connector on the rear

available antenna to the ap-

50o or HI Z, depending upon

outlet

an

dc

volt dc source to the

Section

connectors,

vlf-12B.

locations,

be car-

provided

providing

frequency

power

is to

panel,

ll.

OPERATION

op-

on

the impedance of the antenna

wire-Hl Z; Toop or

d.

Connect either

signal

(0.5

to 15

whip-50o).

the

volLs, rms) from a

standard frequency source

STD connector on

kcl100 kc selector switch,

and to the right of the connector,

propriate

e.

open

on

the chart

located on

Position
screwdriver

(The

snap button hole

recorder
knurled

l.

s.

db.

local

Loosen

the recorder

the rear

recorder stylus,

adjust, to the center

mechanical adj,ust

panel.)

thumbscrew.

Set AUDIO volume

Set DB ATTENUATION control to 80

the rear

reference frequency.

the knurled thumbscrew

panel

to discharge

paper;

then set

panel,

to the

with

is

plug

at the top center

Close

panel

control at

circuit

100-kc or 76.8-kc

to the

panel.

which

the record switch,

INT.

the

of the scale.

located

and

(long

local

LOCAL

the 76.8

Set

is

adjacent

to the ap-

the static

position.

mechanical

under a

of

tighten

midrange.

and

the

the

2-2

v

N.D.

METER

Metei

Chart

SERVO

INTERRUPT

and

MICROSECONDS

ference

DB .{TTENUATION

Switch

Recorder

Lat hing

FUNCTION

Selector

Switah

WARNING

Relay

Regist€r

Time

Selector

Lamp

Dif-

TrrA r r

895{ tts-t

-5

iable 2-s.

R€f d6.

M1

ttIz

s8

P/O 427

AlSl or H0A1

5/3/NAV5H

Controta, Indioatofi,

A

rotaiy

of

six frequently

operational

The functions

-12V:

+12V:

CARRIER,

of the

PHASE:

the reference
input, within

100KC:

operation

100PPS:

correct operation

Proper

reading.

Provides

formance
switch.

An integral

tive

record

with

respect

recorder

inch per

1

Pemits

as follows:

Manual

lecting
Autornatic

an automatic
nect the
low

for

reconnected

OUT
tinuously.

When

either
terrupted,
button

Whenever

which

is normally

tracking,

and remain

information

inputs

when left

manually

device.

during

extinglish

rier

retuma.

A digital

difference

phase

shift

Permits

section in

rps O967-3Ot

and,

Cotunectofa

switch which

used test

when

checks

monitored

Output voltage

Output voltage

trhlctlon

permits

I

-s23O

selective honitoring

points

maintaining

are:

of

-12-volt

of +12-volt

: The instantaneous

carrier level. The

The instantaneous

frequency
a

range of t 0.5 radian.

The tocal

is indicated

The

operation

indications

as selected by

standard 100-kc input.

100-pps corrected output.

of the entire output

is indicated

total meter range is 60 db.

relative

witi respect to the

by a midscale meter

by a midscale meter

power

of

levels

the METER FUNCTION

chart recorder which

of local reference ftequency

to the incoming

has

an inkless stylus

hour,

operation of the

Sle}r'ing: Direction

either + or

Track:

servo if

reliable tracking. The servo is

position,

OFF

local standard input

the upper half

will

display PWR,zSTD

the carrier strength

the lower

lighted, The

rclated

teset by deprcssing

The

C.{RRIER indicator

the actual absence

In the CUTOUT

cutout

cauier fails or falls to a level

$'henever

required

half will indicate Ioss

to continuity of signal

unattended and witl

without manual

count€r

which

registration of

up to 9999.9 microseconds.

attenuation

10-db intervals

of the input

stendard signal, The

and a chart speed

servo in two

is determined by

SLEW.

-

is

activat€d which will

carrier

the

servo is connected

of the dual indicator

and remain lighted.

falls below a level

for r.eliable

PWR/STD indicator

the indicator/pushbutton

of the vlf

resetting whed

provides

frequency

the

over a rangB

tO

3l S5-2FyQ42_r

wheu

making

the vlf-128.

power

po$'er

relative strength

phase

Indicata8 the

divider chain.

and signal

provides

time shift

pre-

supply,

supply,

shift of

coherent

Proper

reading.

per-

a cuhula-

of

basic modes,

se-

position,

ON

discon-

too

automatically

retums, In the CUT-

con-

power

or ac

is in-

push-

phase

of carrier

stores

power

and

do so until

remains

lighted only

carrier and will

the car-

cumulative

signal of the

time

stand&rd

RF

of 0 to 80 db.

r

6

2-3

rrvl r r J895-4 r 3-r 5/3/NAV5H IPS 09

Table s.

N.D.

Controla

Ra,

67

-3()t -5;230

Indiaato$, ahil

U

tO 3t

/

55-2FYQ42-I 6l

Connectora-Qonnectrots

POWEB

Loudspeaker

ON Switch

CHANNEL SELECTOR Svritah

AUDIO Level

RANGE-KC

,A.NTENNA

COHERENT

trol

Co

Outputs

LOCAL STD Input

1KC IF Output

RECORDEB

D.C. POWER Input

AC

Fuse

POWER,

Input

s5

LS1

s1, s2, s3

s4

J1

J7(.rKC)

J6(1KC)

(10KC)

J5

J4(100KC)

J3

J8

R2

(Pot€ntiometer)

s/o

(toggle

J9

(Connector)

.I11

J10

F1

Sw)

pushbutton

A
for the entire vlf-128.

is illuminated,

Provides an aural indication of the

tion.
Permits frequency selection, which is

positioning

by
settings that correspond numerically

switch that turns ac

When

the three thumbwheel

porrer

power

is on, the Bwit h

vlf

accomplished

switches to

to the desired

input frequency. The entire 10- to 30-kc vlf

steps of 0.1 kc, is covered

Permits control of the audio modulation

Enables selection of the 10 to 30-kc band o!

60-kc channel.

Edr

DaD.l

The 50O input connector

vrith whip and loop antennas, The

(J2)

nector

tennas.

Four coherent

is intended for u8e with

sighal

for external use. The

KC, 1 KC,

10

a nominal 1 vott

vlf

to the

Provides for the connection of either

100-kc local frequency standard. Appropriate

tioning of the adjacent toggle

128 to the chosen local standard.

carrier.

A receptacle that

2nd if..signal which is

It may be

Calibration adjustment for

scale adjustment of tlle

The INT. and EXT. selector swit h

use of either

attached to the EXT. connector

enables sinultaneous monitoring of the cumulative

reference frequency shift time and amplitude

tion

Terminals

nection of a +24 volt dc standby source, Transfer

the stand-by

u6ed

signal6.

0.1 KC furnish square

and

peak-to-peak.

provides

for extarnal

internal or an extemal chart recorder

the

provided

po$r'er

tith

(r1)

buffered outputs

receptacles labeled

buffered access

coherent

FS

internal

on the rear

source is accomplished automatical-

ly, without interruption or loss ol

power

if ac

A 3-pin

primary power

1/2-ampere slo-blo fuse

ac

Power

should fail.

connector

to the Ylf-128.

input,

vrhich accepts the 120-volt ac

in

series with t}re

selector,

this

is intended

HI-Z ilput con-

long-wire at-

All are

a ?6.8-kc o! a

switch adapts the

with the

monitoling.

ADJ

st

(Jg).

panel

phase

(R2)

p
(S10)

chart recorder.

This

for the con-

on and off

carrier

modula-

band, in

volume.

the

for use

provided

are

100 KC,

waves at

phase-locked

posi-

to the

vlf

carrier.

is for fult-

pemits

provision

indica-

tracking,

primary

vlf-

tD

i.. Set SERVO

position.

ON

selector switch

i. Set RANGE-KC selector

position.

KC

Set the digital thumbwheel CHANNEL

r.

SELECTOR

desired

vlf station frequency.

switch

on the

front

to

switch to

panel

24

CUTOUT

10-30

to the

/r. Depress the indicator/pushbutton

ER

switch to apply

primary power

to the vlf-

r2B.

l.

the METER FUNCTION

Set

switch successively to each of the six

positions.

ing

as follows:

Normal

conditions

are indicated

POW-

selector

monitor-

7

g-r

at-

control,

of car-

DB

step

allorving

to charge

metel

rela-

particu-

of the

re-

switch

Mater Function

-12V
+72V

CARRIER

PHASE

l

OOKC

100PPS

rn. Adjust

if

necessary,

to bring

rier level into

ATTENUATION

sufficient time

between steps, until

reads

approximately

Metor

Red mark on right of center

Red mark on

grcen

In

tenuator

green

In

l.ocked.

grecn

In

green

In

DB ATTENUATION

green

switch

for

agc

tive signal strength

lar

transmitting

location

and antenna

ceiving station,

can be

preset

station and the

DB ATTENUATION

to the desired

rM l t

-5

lttdi,cation

right of center

proper

when

area

position
area

area

area

meter indication

ar.ea. Slowly

time constant

the front

center

is

selected.
phase-

\r'hen

downward,

panel

scale.

is knorvn for

geographical

characteristics

position.

895-4 r

If the

the

z. Set AIIDIO volume control to desired

volume

eration

or

u'ill

cation of negative change can be

the time difference

position
tained.

for continuous

Make

o.

SLEW. When

+

slew in a negative direction, and

quick

a

by setting

opposite indication will be

an

When the slew

monitoring.

check of

selector

set at

proper

switch to

-SLEW,

register. In the

check

is completed,

servo

op-

-SLEW

the servo

an indi-

observed at

SLEW

+

ob-

the SERVO selector switch should be re-

turned

procedure

mine u'hether the servo is tracking the
transmission. When the switch is returned

CUTOUT

should indicate the original reading or

which
mal
OUT ON. In this

automatically

falls

tracking,

carrier returns

can be made

tioning

this

and will

are below the

circuit.

to an automatic tracking

will enable the operator to deter-

the time difference

ON,

closely approaches the value. The nor-

position

below the level required for reliable

position

for the selector switch is CUT-

position

disconnected if the carrier level

and will be reconnected when the

to the

remain

to

the selector to

the servo is

allow tracking of weak

threshold level

proper

in operation by

CUTOUT OFF.

activated at all times

position.

the servo

level. The servo

signals

of the

This

vlf

register

number

will

posi-

which

cutout

5/3/NAVSHI

2-7.

been explained
most

and adjusting

equipment by deterrnininE

error drift of

with respect

quency

ments have

mined

comparison

fretluency

rived

follows:

ister readings
the interval

standard

difference

reading

the reading

to which

If

zero

once

difference

until

relative

quency

as an integral

A maximum

seconds

to

reading

recorder.

difference

be

uled

results

of

record.

calculated

In

PS 09 67

Utilizing

Source Comporison

o. Various

often used,

-3Ol -5230

VIF-I28

applications

previous

in

however, is that

precision

the local frequency

vlf standard

to a

broadcast.

b. After

preliminary

made

been

the vlf-lZB

that

measurements may be made and

standard corrections

by recording and

(1)

(2)

up a chart of time difference

Set

versus time, date,

recommended

manufacturer.

Take an initial reading of the time

register, and record and

versus

time. The numerical value of

is of importance only as a reference

all subsequent readings

preferred,

the

dial can be

at the beginning of

the reference

register must not

the entire

frequency

standard

possible.

is

(3)

Mark

near

(4)

Make

register

interval has

as before,

the

reading is

An

by use of

procedure

error between the local fre-

and the vlf signal is observed

time

difference in

cumulative error of 9999.9 micro-

the date

the stylus

a second

after

passed.

and make

also recorded

initial rate

the following

Af

:

--

Fractional

t

Difference

Elapsed

in

time in sec

I

lO

3 I

55-2

FYO42-I

6l

for Frequency

Adiustment

ond

for the vlf-12B

paragraphs.

frequency

rate of time

the

time and

have

rating

of

source

standard

The

fre-

checks and adjust-

it has been deter-

and

is tracking

properly,

may be de-

interpreting data as

reg-

and hour for

by the frequency

plot

the

compared.

are

manually set to

sequence,

the

but

is established, the time

readjusted

be

is completed. The

microseconds.

and time of initial

on the vlf-12B chart

reading of the time

previously

the

Record and

sure that the

sched-

plot

the

time

of the chart

of drift error

frequency

p

sec

x

10-

can be

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initial

reading

ard frequency is

in

the reading would imply

standard

comparison

lected vlf

tained from

realized,

of

the chart recorder

microsecond

scale

readings

indicates

in

frequency

register,

nent

record

frequency

sources

of

frequency

that the

particular

a

same day

difference in microseconds

and

15 minute

the fractional

and implies that the

register reading

day is 4376.5

the reading is 4323.2.

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or

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:

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-2.i]7

was

low. Conversely, an

frequency is high with respect to the

frequency derived from

carnier. Similar results

the chart recorder. It

however,

an increase

the

of

or

being

that

each

change. The

is important,

and the

error. Unlike

chart recorder

all variations

phase

compared,

difference

as s'ell

represents

direction of the off-

the time difference

drift trends

at 8:00

and at 2il5

over the

seconds)

mricroseconds.

x 10'

lower than

that the

local

inter-

is:

reading

the

stand-

increase

local

the se-

can be ob-

must be

off-scale reading

100-

a

since one direction

other a decrease

provides

in

as

and of

perma-

a

rerlative

the

bet*'een

indications

diurnal

the

changes

should
computed

ings.

steps

adjustments

along

be referred

from

(5)

The information

above

determine

standards.

oscillator

procedure.

2-8.

Although

lowing

it

helpful

is

for

the next

dure

can

a.

Set DB

db.

b.

Set SERVO

oN.

c.

Set

See instructions accompanying

standard

Stopping Procedure

no damage can

predetermined

a

be used.

AUDIO

d. Depress

power.

mary

Note.

\f

dc

battery

when

the equipment

drain

during

lt,e vlf-128

pack,

periods

the v,lf

propagation

path.

to when rate of drift

time difference register read-

obtained from the

can be used directly to make initial

on

the frequency standard or to

aging characteristics of crystal

the

for complete

be done by not fol-

shutdown

preset

to

operation.

ATTENUATION

POWER

the

the controls to be ready

The following

selector

volume

switch

control

switch

is supplied

power

dc

is shut

of inactivity.

should

down to

adjustment

procedure,

proce-

control to 80

to CUTOUT

midrange.

at

to shut off

with an

be

prevent

extemal

disconnected

battery

pri-

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6l

CHAPTER

PRINCIPTES OF OPERATION

Section

l. GENERAT

3-l, lnlroduclion

This chapter

provides

eration for the vlf-128.

resses

frrom a

general

a detailed description of the various circuits

on a signal flow level. The block diagram dis-
cussion explains the

eration,

detailed functional theory of

the vlf-12B.

x'hile the circuit description furnishes

general principles

3-2. Funclionol Description

o. The underlying

can

best be understood by

operation
kilocycles, respectively.

plified

phase-shift

the

three frequencies

analogous

at

the selected incoming

servo

ficult

It is much

if

an input

I'esponse

assumed to have

with input signals of 10, 20, and 30

block diagram

principle

to a single

system is

to

consider under dynamic conditions.

easier to understand

condition is stated and the

js

assumed. Then after the servo is

individual leactions

can be checked

resDonse

can be assumed

(1)

In

and if

case I,

a convenient 10-microsecond

is assumed.

achieved

standard

to compensate

seconds.

After the

a null condition,

signal will have

for

will

This

principle

as it applies to each of

wherein the vlf-l2B is

phase

a closed-loop device, it is dif-

come to

through-out the system

proved
10-kc

a

the time shift

have occurred

principles

tt e

The

block

discussion

diagram

of

pmg-

level to

of op-

each element

of the vlf-12B

examination

Figure 3-1 is a sim-

of the

that demonstrates the

detector, operating

frerluency.

Since

the

the operation

proper

rest,

the resulting

correct the entire

to be correct,

input

signal with

step

phase

shift

servo system has

the corrected 100-kc

rotated

full

a

10

of

because

360"

micro-

when

3

DESCRIPTION

the vlfJ2B is tuned to 10 kc,

op-

100 kc is divided by

synthesizer
quency.

As

to
a

4.494 in

pmvide

the

the

proper

result of this division

the input to the 1st mixer is shifted
by 80.1'. Since both the incoming signal and

the

local oscillator have

resulting

a

ized at the first if. The mixing

of

quired

requires that the corrected 100

by 8.889. This

phase

tive

of the

phase

phase

by

the

shift

second

relationships are

difference

second mixer is 11.25

division ratio results in a

of 40.5'at the oscillator

mixer.

increasetl in

of

Once

again, since

increasing, a difference

of 3.6' will result in the l-ke IF signal. Since

the corrected 100-kc standard

by 100

frequency for

shift has

to achieve

result€d

kc inputs to the

by 3.6", a null

reached.

(2)

In case II, when the vlf-12B is tuned

to 20 kc,

phase

sent 72o. The servo system $'ill move until a

null has

it can

shift in the incoming signal will repre-

been

the required

phase

the

in

this

phase

condition has in fact

be

seen that a

reached,

compensating

has been divided

1-kc reference

detector, a 3.60

signal.

detector

l0-microsecond

time shift. This compensation is rrpresented

by 360' of the

synthesizer

by

3.101 rvith a resulting 116.10

in the local

phase

the di',rision factors of

difference of 44.10 in

tion signal

signal remain

resulting

phase

shifter.

In

lvill divide the corrected 100 kc

oscillator signal that

the first if.

the second mixer injec-

and the

the same, it can

phase

phase

changes are 40.5o

detector

be seen that the

the

corrected

local oscillator

process,

phase

in

phase,

is real-

kc.

This

divided

posi-

input

both

phase

both 1-

shifted

been

for

this

fre-

mixing

44.1"

frequency re-

kc be

Since

have

this case the

phase

produces

shift

Since

reference

and 360,

a

!!

respectively,

again

tion

has changed

has been

(3)

at the

ered

microsecond

of the input

the corrected

local oscillator

mixer output

logically,

and

same as

the

b. These

phase

quencies

rotations

the

standard

3-3.

tracking

time ermr

Simplified

e. General.

simplified
illustrates the

actual

are

gram

servo motor

shifting,

vlf-12B.

also represented.

shows a

ble to

electronic

sections

(1)

RF, lst and

audio

amplifiers,

(2)

the servo

cutout, sel,o

porting

The output

achieved

In case

input

time

signal.

1.00 kc

phase

will

the

in the

three

has

in the band

the

at

experienced

or the

The

block

main

All major

mechanical

to

the discussion

vlf-l2B's

servo systems.

are :

Receiver

2nd

Comparator

phase

motor

circuits.

logic

(3)Local

sisting

(VCO), phase

divider

needed to

oscillator signal.

rligital divider

100-kc signal

ternal

b. Recehser Section.

the simplified

of the

circuiLs

(4)

Reference

reference

synthesize

circuits that

from the

block

of the second

by 36',

III, a 30-kc

of the

shift

The

and a

the servo

by

signal

vlf-128 and

is reprcsented

synthesizer

by 2.367

of 1521''

shift

phase

a

har/e

remaining

previous

examples

been achieved

of

phase

incnming

Diogrom

Block

heavy black

diagram

signa'l

Although

provide

with

section----consisting

mixer stages,

agc circuits.

and

section-consisting

detector, servo

phase

oscillator

voltage-controlled

comparator,

and thumbwheel

the

divider

signals and

diagram

phase

two

demonstrate

interest, and

shifter

in either

signal.

shown

path

supporting

servo

necessary

the

follows

that

either mechanical

The major

amplifier,

shifter, and

synthesizer----con-

and

phaseJocked

chain-a series

divide

phase

shifter

buffered

For the discussion

(figure

mixer

null condi

system.

is consid-

10-

a

108"

by

will divide

+a

produce

The first

shift of

cases.

M.l"

shifts

are

that

fre-

all

at

the

that

will represent

local

the

in the

line

in figure

throuS:h

the block

that

is

functional

3-2

the

functions

dia-

utilizes

phase

applica-

or

of the

IF amplifiers,

of

servo

sup-

oscillator

the digital

switches

local

of

the corrected

into in-

outputs.

of

3-2),

is assumed

nected

is applied to

nal

former that

l0-kilohm input

the

amplifier.

gain

the rf

a

upon selection,

ing

bandpass

filter

illustrated

of the vlf

band.

a single

ter has

filter, the

the
attenuator

ments

switch.

a balanced

to

lator frequency

increments)
vide a

12.25

kc IF amplifiers

a

center

a

-r-

of

rapidly to 80

off
of center.

crystal

gain

Following

nal is applied

11.25-kc

corrected

dividing

mediate

the

coupled

amplifier,

,bandpass

the

c, Comparator Section.

1J<c filter

to the

and

nal from the

of the

the servo cutout

disconnect the
'level

it

servo

that a

to the 50-ohm

loop or

an antenna

couples

input.

the 50-ohm

circuit

The transfotmer

..,/-10,0-00760

of

amplifier,

filter.

has a bandpass

figure 3-3,

in

frequencies

If the

60-kc

channel

a bandpass

signal

that

by means

The attenuated

mixer.

above

first

kc. The stages

100 cps at the

intermediate

frequency

:

signal

the

either

to

At the 3-db

of from

in the

bandpass

at 60

approximately

of

is applied

adjustable

is

of the

The applied

is always

the

that follow

a crystal

and

of 12.25

3-db

db at

The if. amplifiers

filter are

of the

1-kc signal

falls too low for

phase

signal

amplification

signal,

5 kc

again by

frequency

to an output

and

is

servo

L2.25-kc if. amplifier

detector compares

used to

over a

to the

from the

second

obtained

provides

4,

of 1 kc.

is further

connector,

1-kc

to a

nominal 50

to a

applied

phase

to

phase

detector

that is used

servo system

whip antenna

The received

matching

broadband

of a

provides

14.14,

or

is

applied,

a 30-kc

points,

kc to

8

allowing

10-kc

filtel

is received.

kc

is

antenna

voltage

a

23 db.

depend-

or 60-kc

the 30-kc

30

coverage

to 30-kc

is selected,

This

2 kc. From

to an

10-db

in

front

signal

panel

is then

selector

local

(in

(IF)

the

which

pass

a

either

100-cps

to

12.25

incoming

frequency

filter

kc and

point's.

200 cps on

kc

siCnal

arc

Response

following

provide

very

12.25

at

mixer,

increased

narrow band.

kc, the

where

by multiplving

divider chain

a

From

amplified

by 9 and

second

this

to an

filter that

cps,

output of

The

the agc

detector.

controls

and also

restricts

phase

detector

The agc sigl-

the

operates

to automatically

when the

reliable tracking.

l-kc carrier

the

con-

sig-

trans-

to

RF

From

kc, as

fil-

80-db

incre-

routed

oscil-

pro-

of

12.25­has

band

falls

side

the

sig-

the

a

inter-

point

and

audio

the

gain

carrier

The

v2

Trrl I I

."5

895-4 I

l3-r

5/3/NAVSH

CHAPTER 3

p5

r

A967

-3Ot

-5230

tO 31

I

55-2 FyO42-l

6t

PRINCIPLES OF

Section

3-1. lnlroduction

This

chapter

eratiotr for the vlf-lzB. The discussion

resses fmm a

a detailed

on a

signal

cussion

eration, while the

detailed functional

the vlf-12B.

provides

general

description of the

flow

level. The block diagram dis-

explains the

general

cilcuit description

theory of each element of

tLe

block

principles

diagram

various circuits

principles

furnishes

3-2. Functionol Description

a. The underlying

can best be understood

operation

liilocycles,

plified

phase-shift

the three

analogous

at the

setvo

ficult

It is

if

an input

lesponse

assumed

individual

can be
response

with input

respectively. Figure

block diagram that demonstrates the

principle

frequencies wherein

to a single

selected incoming frequency.

system is a closedJoop

to consider under dynamic conditions.

much

easier to understand the operation

condition is stated

is

assumed. Then after

have

to

leactions

checked and if

can be assumed

(1)

In case I,

a convenient l0-microsecond

is

assumed. After

achieved a null condition,

standard

to compensate for

seconds.

signal will have

This will have

principle

of the

by examination

signals of 10, 20, and 30

is

3-1

as it applies to each of

vlf-l2B is

the

phase

detector,

operating

Since the

device,

come to rest, the resulting

it is

and the

servo is

the

through-out the system

proved

correct the

to be correct.

a 10-kc input

signal with

step

phase

the servo system has

the

corrected 100-kc

the time

occurred

rotated

shift of 10 micro-

a full

because when

l.

GENERAT

of op-

priog:-

level to

of op-

vlf-12B

of

the

sim-

a

dif-

proper

entire

shift

360.

OPERAIION

DESCRIPTION

the vlf-l2B

100 kc

syntl.resizer to

quency.

the input to the lst mixeri is shifted

by

80.1". Since both the

is

tuned to 10

is divided by

4.49.1 in the local

provide

As a result of this division

kc, the corrected

proper

the

incoming signal

mixing fre-

oscillator

process,

in

the local oscillator have increased in

a resulting

ized

at the first if. The

quired
requires

phase

by the second mixer

that the corrected

difference of

mixing frequency re-

44.1o is real-

is 11.25 kc. This

100 kc be divided

by 8.889. This division ratio results in a

phase

tive

of the second

phase

of 3.6" will result in the l-kc

the

corrected

by 100 to achieve the required

frequency for the

shift

kc inputs

by 3.6",

reached.

to 20 kc, it can be seen

phase

sent

has

null
time shift. This

by 360"

synthesizer r.r,ilrl

by

3.101

in

the local oscillator

phase

the division

tion

signal

resulting

shift of 40.5'at the oscillator

mixer.

relationships

100-kc

Once again, since

increasing, a difference

are

IF

signal. Since

standard

has been divided

l-kc reference

phase

has

resulted in this signal. Since both

phase

the

to

null condition has in fact been

a

(2)

In case

II,

shift in the incoming signal will repre-

The

72o.

difference

signal and the

remain the

servo system {.ill

been reached, compensating for

compensation is represented

of the

phase

divide the corrocted 100 kc

rvith

a resulting 116.10

of 44.1" in

factors of the

same, it can be

phase

changes

detector, a 8.6'

detector

when the vlf-128 is tuned

that a

shifter. In this

signal that

second mixer injec-

phase

are 40.5o

have shifted

l0-microsecond

move

phase

produces

first

the

detector

seen that the

until a

case the

if.

reference

and 36.,

phase

and

phase,

posi-

input

both

phase

1-

this

shift

a

Since

Lt

Ti^ r I

-5895-4

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09

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-fi

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3I

S5-2FYO42-!

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respectively. The

again

tion

ered at the input

microsecond

of the input

the

local oscillator

mixer output

and
the

phase
quencies

rotations at the
the time error

standard or the

has ehanged

has been achieved

(3)

In case

time shift

signal.

corrected I00

phase

will

logically,

same as

b. These

tracking

the remaining

in the

three examples

has been achieved

in the band

experienced

3-3. Simplified

a. General.

simplified

illustrates the

actual

are
gram

servo motor

shifting,

ble to

electronic

sections are

vlf-l2B.

also

shows a

vtf-12B's

(1)

lst

RF,

audio

amplifiers,

(2)

the servo

cutout, servo
porting

log:ic

(3)

sisting

(VCO), phase

The heavy

block dia€ram

main sigaal

All

representd.

mechanical

to

the discussion

servo systems.

:

Receiver

2nd mixer

and

Comparator

phase

detector,

motor

circuits.

Local

of the

comparator,

output

III, a 30-kc signal

of

kc by 2.?67

have a

previous

phase

incoming

Block

provide

with either

section-consisting

and agc circuits.

osci'llator

voltage-controlled

of

the second

by 36', and a

the servo

by

vlf-l2B and

the

is represented

The synthesizer

tD

shift of

1521''

phase

shift of

phase

cases.

two

demonstrate

of interest, and

shifter

will represent

in either the

siSaal.

Diogrom

black

shown

path

major supporting

Although

servo that

the

that

The

stages,

line

in figure

through

the block

necessary

follows is applica-

mechanical

major functional

IF amplifiers,

seotion-consisting

servo amplifier,

phase

shifter, and

synthesizer---<on-

and

divider circuits and thumbwheel

needed to
oscillator signal.

(4)

digital divider circuits

100-kc signal from the

ternal reference signals and

b. Receioer

the simplified

synthesize the

Reference

divider chain-a series

Section,

block diagram

phaseJocked

that divide

phase

the corrected

shifter into in-

buffered

For the discussion

(figure

mixer

null condi-

system.

is consid-

10-

a

108'

by

will divide

produce

The first

44.1o

shifts

at

are

that

fre-

all

the

that

local

in

the

3-2

the

functions

dia-

utilizes

phase

or

of the

of

servo

sup-

oscillator

the disital

switches

local

of

outputs.

of

3-2),

is assumed that a

nected to the 50-ohm

nal is applied to an

former

the l0-kilohm input

amplifier.

gain

a

the

ing upon

bandpass

filter

illustrated

of the

band.

that couples

The transformer

of

r,/10-g-00750

rf amplifier,

selection, to

filter. At

has

a

in

vlf frequencies

If

the

a single channel

has a bandpass

ter

filter, the signal

the

attenuator

ments by means

slritch.

that

The attenuated

to a balanced

frequency

lator

increments) above

vide a first

kc. The stages that

12.25

IF

a

kc

a center

off

amplifiers

frequency

-r-

100 cps at the

of

rapidly to 80 db

of center.

crystal
gain

Following amplification

is

nal

11.25-kc

corrected

dividing

mediate frequency of

The if. amplifiers

filter are used

of the signal

applied

signal,

kc from the divider

5

again by

the 1-kc signal

coupled to an output

amplifier, and

the bandpass to a

c. Comparator Section.

loop or

the sigaal

bandpass

figure 3-3, allowing

60-kc bandpass

at 60

of

is adjustable

of the

mixer.

is

always

the

intermediate

and a

of 72.25

to the second

obtained by

4,

is further

to a

nominal

1*c filter is applied to the agc

and to the servo

nal from

of the

the

disconnect the servo

level falls too low for

it

servo

the

12.25-kc if. amplifier and

servo

cutout

phase

phase

phase

that is used to

detector compares

whip

antenna

input. The received

antenna

the 50-ohm

circuit

:

either a

the 3-db

of from 8

in

matching

antenna to

of a broadband

provides

14.14,

or 23 db.

is applied,

30-kc

points,

kc to

10-kc

the

filter is

kc is received.

approximately

is applied

to

in 10-db

front

signal

The applied

incoming

follow arc

crystal

points.

3-db

200

at

to

over a very

at

provides

panel

then

is

local oscil-

(in

kc

12,25

signal to

frequency

filter

kc

cps

a

a-nd

Response

on either

following

provide

narrow

12.25 kc, the

mixer, where

multiplying

chain

a second

1 kc. From

amplified

connector,

1-kc filter

'50

T)r.e

detector.

detector

system when

reliable tracking.

to an

that restricts

cps.

output

phase

The agc sig:-

controls the

also operates

automatically

the carrier

the 1-kc carrier

is con-

sig-

trans-

RF

voltage

a

From

depend-

or 60-kc

30-kc

the

30 kc,

coverage

as

to 30-kc

selected'

fil-

This

2 kc. From

an 80-db

incre-

selector

routed

100-cps

pro-

(IF)

of

72.25-

the

which

pass

this

has

band

falls

side

the

increased

band.

sig-

the

by 9 and

inter-

point

and

audio

the

of

detector

g:ain

The

a

3-2