HP 651B Service manual

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OPERATING

(HP

AN

PART

D

SERVIC'E

NO.

00651-90004)

MAN

UAL

MODEL

TEST

SERIALS

651B

OSCILLATOR

PREFIXED:

647-

01810-1

Copyright

P.O.

Box 301,

Hewlett-Packard

Loveland,

Colorado,

Company

80537

1966

U.S.A.

Printed:

OCT

1966

Model651B

TableofContents

Section I GENERAL INFORMATION .

1-1.

Description. 1-5.Accessories 1-7. 1-8. 1-10. 1-12.

Options

Instrument

... Option 01 Option 02

Identification.

Section

n INSTALLATION .

2-1.

Inspection

2-3.

Power

2-5.

Three-Conductor

2-8.

Installation.

2-10.

Rack/Bench

2-12.

Repackaging

Section

ill

OPERATING 3-1.

Introduction

3-3.

Controls

3-5.

AdjustmentofMechanical

3-7.

Operation.

Section IV

THEORYOFOPERATION 4-1.

General

4-3.

Circuit 4-5. 4-13. 4-17. 4-19.

4-21. 4-24.

Oscillator

Peak Power Monitor Output

Regulated

Section V MAINTENANCE .

5-1.

Introduction

5-3.

Required

5-5.

Performance 5-7. 5-8. 5-9.

Dial Output Output

. . . . . .

Requirements.

Power

. .

Installation.

for

Shipment

INSTRUCTIONS

.••...

and

Indicators

. . . . . . . . . . .

Description

Circuit.

Detector

..

Amplifier

Circuit

..

Attenuator

Power

. . • . . . .

Test

Equipment

Checks

Accuracy

Monitor Voltage

Check.

• .

Supply

...

Cable

Zero

TABLE

Page

OF

1-1 1-1 1-1 1-1 1-1 1-1 1-1

2-1 2-1 2-1 2-1 2-1 2-1 2-1

3-1 3-1 3-1 3-1 3-1

4-1

4-1 4-1 4-1 4-2 4-2 4-2 4-2 4-3

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

CONTENTS

Section V MAINTENANCE (Cont'd)

5-10. 5-11. 5-12. 5-13. 5-14. 5-15.

Output Monitor Frequency Distortion Attenuation

Adjustment

Impedance

Procedure 5-17. 5-20. 5-21. 5-22.

Cover

Removal.

Power

Supply Voltage Frequency X100, X1K, and XlOK

Frequency 5-23. 5-24.

X10 X1M

Range

Calibration 5-25.

X100K

Range

Calibration 5-26. 5-27. 5-30. 5-31. 5-32. 5-37. 5-39. 5-41. 5-43.

10 MHz Output

Adjustment Minimum Output

Monitor

Troubleshooting

Troubleshooting Servicing Servicing Servicing

Section

VI

CmCUIT 6-1.

DIAGRAMS.

Introduction.

Section

VII

REPLACEABLE

-1.

Introduction.

7 7-4. 7-6.

Ordering Non-Listed

Information

Appendix

OF

A CODE LIST

MANUFACTURERS

B SALES AND SERVICE

Flatness

Response

Check.

Check

and

Calibration.

.....

Dial

Calibration

Frequency

Flatness

Distortion

Etched Rotary Tuner

.

PARTS

Parts.

OFFICES

Check.

Check ..

Calibration

Frequency

Adjustment

Adjustment.

Calibration

Procedure.

Information.

Circuit Switches.

Assembly.

Adjustment

Range

. .

.

. .

Boards

. .

Page

5-2 5-2 5-3 5-3 5-4

5-4 5-4 5-4 5-4

5-7 5-7

5-7

5-8 5-8 5-8 5-9 5-9 5-9 5-9

.5-11

.5-12 .5-12

Page 6-1/6-2 6-1/6-2

Page

'1-1

7-1 7-1 7-1

Number

1-1.

Specifications.

1-2.

Accessories

5-1.

Required

5-2.

Dial

Accuracy

5-

3.

Monitor

Number 1-1.

Model 651B

3-1.

LocationofControls

3-2.

Impedance

4-1.

RC 4-2. 5-1. 5-2. 5-3. 5-4.

Network

Peak

Detector

Dial

Accuracy Output Monitor Distortion

Test

Flatness

Test

Correction

Characteristics

Monitor,

Flatness

Check

. . . . . .

Equipment. Test

. . .

Check.

Oscillator.

and

Graph

Circuit. Check

. . . .

Voltage

Check.

.

Indicators.

. . .

Check

.

LIST

OF

Page

1-0

1-1

5-0 5-1 5-3

OF

ILLUSTRATIONS

Page

1-0 3-0 3-2 4-1 4-2 5-1 5-2 5-3 5-3

TABLES

Number 5-4. 5-5.

7

-1.

Number 5-5. 5-6. 5-7. 5-8. 6-1. 6-2.

6-3. 7-1. 7-2.

Frequency Frequency

Resistors

Replaceable

Attenuation A2TP2

LocationofInternal Troubleshooting Block Oscillator Monitor

Response Range

....

Parts

Check

Test

Lead

Diagram.

Circuit

Check

Switch

. . . . . . . .

Connection . .

Adjustments

Tree

. . . . . .

. . . . . . . . . . .

and

Power FrequencyTuningAssembly Chassis

Mechanical

Parts.

Padding

6-4

Supply

. . .

and

5-10

..

6-5/6-6 6-7/6-8

Page

5-3 5-7

7-4

Page

5-4 5-5 5-6

6-3

7-2 7-3

iii

Section

I

Model 651B

Frequency

calibration:1to

Frequency

Flat

Range: 10 Hz to10MHz, 6

10.

Response:

within:

±2%

100 Hz to 1 MHz ±3%10Hzto100 Hz ±4%

1 MHz to10MHz*

Dial

Accuracy:

±10%

line

±2%,

(Including

voltage

variation).

100 Hz to 1 MHz

±3%,10Hzto100 Hz, 1 MHzto10

Output: 200

(3.16V)into 600

mW

(3.16V)

ohms;6.32

into50ohms;16mW

Attenuator:

Range: Overall

range;

90

dBin10dBsteps

Accuracy:

±O.2dB

±D.

. 1 mV

1 dB.3mV

Figure

warm-up

Vintoopen

range

1-1.

bands.

drift

to 3V

Model 651B

Table

and

MHz

circuit.

1-1.

Specifications

dial

Test

Oscillator

Amplitude

Control:

Output Monitor:

put of

attenuatorinvoltsordB. Top calibratedinvolts, in dB.

Accuracy:

Flatness:

Distortion:

less

and

Hum

rated

Less

than2%at10MHz.

Noise:

output.

Temperature

20dBrange

Voltmeter

±2%atfull

±1%atfull ±2%atfull

4 MHz

than

Less

monitors

bottom

scale

scale, scale.

20Hzto 10Hzto20Hz,

to10MHz

1%,10Hzto5 MHz,

than

0.05% of

Range: 00to+500C.

(nominal).

levelatin-

scale

calibrated

4 MHz

maximum

1-0

*This

put. The ohms

specification

applies

response

outputisaffected

above

onlyat50

1 MHzatthe

by

capacitive

ohm

out600

loads.

Power:

115V/230V

Dimensions:

deep

(132,6 x 425 x 336 mm).

5-7/32"

±10%,

high.

50

to 1000 Hz,

16-3/4"

wide.

30watts.

13-1/4"

01810-1

Model 651B

Section I

1-1.

DESCRIPTION.

1-2.

The torisa eringafrequency oscillator adjustable 600 in

Figure Table Model 651B

for

differences

Options 01 and 02.

1-3.

panel vides with The50ohm source

1-4. is

constantly byaninternal scales erencedto1 ATTENUATOR,inconjunction control, when

Hewlett-Packard

wide

range

capacitance-tuned

range

hasastable

from10microvoltsto3.16

ohms.

transmission

The Model 651B

1-1

and

the

1-1.

This

manualiswritten

Test

Oscillator;

between

Two output output an output

impedanceisdesired.

The

Model 651B

for

RMS voltage

providesamonitored

matched

impedances

connectors.

withanimpedance

lines

connector

monitoredatthe

voltmeter.

milliwatt

into a50or

Model 651B

from10Hzto10

sine-wave

Test

specifications

the

standard

The

and

many

providesanoutput

Test

Oscillator

The

readings

into50ohms.

600 ohm load.

GENERAL

Test

oscillator output Oscillatorisshown

for

refertoparagraph

instrument

are

providedatfront

600 ohm

thatiscompatible

distribution

input of

voltmeter

and

adBm

with

the

output of

Oscilla-

MHz.

signal

volts

into50or

are

given

the

standard

connector

systems.

where

output voltage the

attenuator

has

scale

The

OUTPUT

AMPLITUDE

desired

SECTION

INFORMATION

1-7.

cov-

The

that

1-7

and

pro-

a low-

two

ref-

level

is

in

1-8. 1-9.

Oscillator tor panel been the

1-10. OPTION 02. 1-11.

Oscillator ohms. referencedto1

1-12.

1-13. serial of with sheets between in

I

OPTIONS.

OPTION 01. Option 01isa

that

referencedto1

OUTPUT ATTENUATOR dBm

changedtocorrespond

600n

output

Option 02isa

that

has

Also,

INSTRUMENT

Hewlett-Packard

number

the

serial

those

supplied

this

manual.

the

(000-00000).

numberonyour

on

the

your

instrument

standard

has

the

milliwatt

connector

standard output output

milliwatt

title

with

the

dBm

(-80to+10

impedancesof75

monitor

into 75

IDENTIFICATION.

usesatwo-section

pageofthis

manual

and

-hp-

Model 651B

scaleofthe

into 600

with

the

-hp-

Model 651B

has

ohms.

If

the

first

instrument

manual,

will

define

the

Model 651B

output

ohms.

markings

signal

DBM).

ohms

the

dBm

eight-digit three do not

differences

described

Test

moni-

Thefront

have

level

at

Test

and 600

scale

digits

agree

change

1-5.

ACCESSORIES.

1-6.

Table

which

will

-hp-

Model10110A, Converts connectors.

-hp-

Model 11004A

Provides

from

1-2

containsalist

increase

single-ended

the

a BNC

fully

of

the

accessories

usefulnessofthe

BNCtoBindingPostAdapter:

connectortobinding

Line-Matching

balanced

135nor600n

input.

Model 651B.

Transformer:

Table

post

output

1-2.

1-14. instrument States.

Accessories

-hp-

If

Model 11005A Provides single-ended

Model 11048B Precision male

a

and

letter

was

fully

input.

50n

female

prefixes

manufactured

Line

balanced

Feed-Thru

feed-thru

BNC

the

Matching

600n

termination

connectors.

serial

Termination:

number,

outside

Transformer:

output

the

from

with

the

United

01810-1

1-1

Model651B

Section

IT

2-1.

INSPECTION.

2-2.

This

instrument

mechanically

and

electrically shouldbephysically perfect this,

damageintransit.

sories. instrument

graph warranty

2-3. 2-4.

230 Vac, converted the

so

the

ere,

electrical

the

instrument

order

Also,

and

test

the

using

the

5-5.Ifthereisdamageordeficiency,

on

the

inside

POWER

REQUIREMENT.S.

The Model 651B

50

- 1000 Hz.

from

115to230 volt

positionofthe

that

the

designation

nominal

slow-blow

slide

voltage of

fuseisused

operation.

2-5.

THREE-CONDUCTOR

2-6.

To Electrical mends ed.

that

All

protect

Manufacturers'

the

Hewlett-Packard

operating

instrument

withathree-conductor

ged intoanappropriate strument. prong

2-7. ing

the three-prong green

2-8. 2-9.

forenospecial instrument temperature

The

offset

connectoristhe

To

preserve

instrument

pigtailonthe

INSTALLATION.

the

fromatwo-contact

to

two-prong

adaptertoground.

The Model 651Bisfully

coolingisrequired.

should notbeoperated

exceeds

INSTALLATION

was

carefully

before

freeofmarsorscratches

upon

receipt.

shouldbeinspected

check

electrical

procedure

front

coverofthis

will

operate

The

instrument

operation

switch

locatedonthe

appearingonthe

the

power

for

POWER

personnel,

Association

panel

and

instruments

power

cable,

receptacle.

pinonthe

ground

wire.

protection

adapter

transistorized;

550C (131

o

inspected

shipment.

To

for

supplied

performance

outlined in

from

either canbeeasily

by changing

rear

switch

source.

both

A

115 and 230 volt

CABLE.

the

(NEMA)

cabinetbeground-

are

equipped

which, whenplug-

grounds

power

cable

feature

when

outlet,

and

connect

However,

where

F).

the

SECTION

both

It

and

in

confirm

physical

acces-

of

the

Para-

see

the

manual.

115

or

panel,

matches

0.4

amp-

National

recom-

the

in-

three-

operat-

use

a

the

there-

the

ambient

II

2-10. 2-11.

type type) version accomplishedbyusing instructions

2-12. 2-13.

for local B

If

RACK/BENCH

The

Model 651Bisinitially

instrument

with

plastic

(unless

feet

toarack-mounted

furnished

REPACKAGING

The

followingisa

shipment.Ifyou have any

-hp-

Sales

and

for

office

locations.

------NOTE-----

If

the

instrumentistobeshipped

to

Hewlett-Packard

or

repair,

strument,

and

indicating repairtobe the

model

number numberofthe correspondence, strumentbymodel

a.

number Place

and

instrument available. able,asuitable your

nearest

original

containerisnot

b.

Wrap before

c.

Use

instrument

placinginan

plenty of

sidesofinstrument

with

cardboard

d.

Place

instrument

heavy

carton

strong

e.

Mark

tapeormetal

shipping

strument,""Fragile"

INSTALLATION.

shippedasa

ordered

and a

specificallyasa

tilt

standinplace.

instrument

the

rack

mounting

with

your

instrument.

FOR

SHIPMENT.

general

guide

questions,

Service

Office. (See Appendix

)

for

service

attachatagtothe

identifying

the

service

accomplished;

and

full

serial

instrument.

identify

the

number,

serial

If

original

one

-hp-

Sales

number in

prefix.

original

containerisnot

canbepurchased

and

used,

in

heavy

inner

container.

packing

and

material

protect

strips.

and

inner

or

wooden box and

bands.

container

with

etc.

bench-

rack

Con-

can

be

kit

and

for

repackaging

contact

your

in-

owner

or

include

In

any

in-

serial

container. if

avail-

from

Service

Office.

paperorplastic

around

panel

container

"Delicate

seal

all

faces

in a

with

In-

01810-1

2-1

Section

ill

OUTPUT

ATTENUATOR

AMPLITUDE

VERNIER

Model65lB

®- 0

"''i

@D@

II

o I

~~--

-'@

~o

FREQUENCY Dial: within 'multiplied by quency of

CD

Output Monitor (M1):

CD

of Mechanical

CD

tortobe mentisoff,

each

frequency

range

the

instrument.

FREQUENCY RANGE Switch (S1):

one of

six

frequency

1 MHz.

the

test

oscillator

Zero

Adjust: Allows output

mechanically

Varies

settingisthe

ranges,

range.

Monitors

output.

zeroed,

output

Dial

from10Hz

when

0 0

frequency

reading

output

Selects

the

amplitude

instru-

fre-

•

to

moni-

0)

AMPLITUDE COARSE and FINE

Controls PUT

eD

FREQUENCY VERNIER:

frequency

o LINE

applies

lamp power.

amplitudeofsignal

ATTENUATOR.

adjustment

ON

Switch (S3) and

primary

glowstoindicate

powertoinstrument;

for

applicationofprimary

® 115/230 V Slide Switch (S4):

to

operate

either

fromaprimary

115 Vacor230 Vac.

Controls:

appliedtoOUT-

Providesafine

FREQUENCY

Pilot

Lamp:

Sets

power

Switch

instrument

source

dial.

pilot

of

3-0

OUTPUT ATTENUATOR: cillator

Output output 600(20

output in nine

Connectors

signal,atimpedance

(75n

and

stepsot10 dB

(J2

and

600n

on Opt. 02).

Attenuates

J3):

levelsof50n

Figure

test

os-

each.

Provides

3-1.

the

and

LocationofControls

@ FUSE

from

@

Primary

primary

and

(F1):.

0.4

overloads.

Power

powertotest

Indicators

amp

fuse

Connector

oscillator.

protects

(J1):

instrument

Connects

01810-1

Model 651B Section m

3-1.

INTRODUCTION.

3-2.

The

Model 651B stable pedance quency of and

the

sine

levels

output

wave

of 600

the

outputisvariable

power microvoltsto3.16 The

amplitudeofthe

output

3-4. of and

3-5.

3-6. the 651Bisin erating the output accuracy

monitor,

3-3.

CONTROLS

Figure

all

the

front

indicatorsonthe

ADJUSTMENT

The

output

meter

temperature,

monitorasfollows to obtain

and

a.

Turn

M1.

3-1

and

pointer

normal

mechanical

651B on and allowitto

output

identifies

Test

thatisavailableatoutput

ohms

level

volts

into 600

output

AND

INDICATORS.

rear

panel

Model 651B.

OF

monitorisproperly

rests

over

operating

andisturned

stability

least20minutes,tolet reach

normal

b.

Turn

651B off, and allow30seconds

operating

capacitorstodischarge.

c.

3-7.

3-8. as

follows:

a.

Insert point

and

over

OPERATION.

To

Connect

pen) into

rotate

zero.

operate

pointed

wheel

the

primary

object

recess

until

651B

(115/230V,50to1000 switchS4to

b.

Turn cator of

LINE

lamp

primary

proper

ON

switchtoON

will

glow,

power.

c. Set FREQUENCY RANGE

QUENCY

Dialtodesired

d. Set OUTPUT ATTENUATOR

voltage

range.

OPERATING

Oscillator and50ohms.

from10Hzto10

can

be

varied

or

50

willbeindicated

and

describes

controls,

MECHANICAL

zero-set

the

zero

mark,

positionatnormal

off.

operate

the

meter

temperature.

(suchastip

on

adjustment

meter

pointerisexactly

Test

Oscillator,

ac

power

position.

to

HZ),

and

position.

verifying

switch

output

switchtodesired

SECTION

generates

The

from

ohm

loads.

on

the

function

connectors,

ZERO.

when

and

Zero-set

maximum

for

movement

for

of

ball-

wheel,

proceed

651B

set

slide

Indi-

application

and

FRE-

frequency.

III

INSTRUCTIONS

e. Connect loadtooutput

a

imfreMHz,

10

the

op-

at

all

f.

g.

connector

impedance

Adjust put

voltage,

The

valueofthe

level The

output

plying

itor

which

AMPLITUDE

as

output

monitor,

in dBm

voltage

the

monitor

scale

multiplier

matches

indicated

impedance

controls

on output

Ml,

for

indicates

output voltage, and

for

resistive

loadsof50 levelisobtained by scale

readingsbythe

which

appears

desired

OUTPUT ATTENUATOR switch. following tion

651B output

other

equation

graphofFigure

power

than

those

markedonthe

and

3-2

level

the

impedance

to obtain

in dBm,

output

tors.

Output Voltage = RL+ R

X2V

S

Where,

R

= Load

L

R

=

S

V =Model 651B OutllutMonitorReading

m

Problem: 50

ohm output output volts, on actual of

monitor

with

the

1. 0 volt output

the

Model 651B.

Solution:

Resistance

(Terminating

sistance)

Source

Resistance

(Output

anceofOscillator

A 600 ohm loadisplaced

connector.

indicates

the

OUTPUT ATTENUATOR (+10,

dBm)

voltage

The

actual

The Model 651B

an

output of

range.

and

power

level

output voltageiscalcu-

latedasfollows:

Output Voltage = 600 +

600

50

X 2 (0.

1.66volts

The

indicated

dBm

for

the

3.0

volt

power

levelisthe

indicated factor of

obtained

Figure rectionof-10.8 ohm load. dBm [17.3 dBm +

an

output

power

3-2.

The

power

level

voltage

(+20

dBm)

range.

algebraic

level

and

from

the

For

this

dBmisobtained

actual

power

(-10.8

would

of 1. 66

The

sum

the

correction

impedance

exampleacor-

levelis+6. 5

dBm)] .

having

of load.

monitor.

the

power ohms.

multi-

mon-

on

Use

the

correc-

the

Model

for

loads

connec-

m

Imped-

on

0.9

Find

(indBm)

9)

=

be

17. 3

volts

actual

of

the

graph

for

a 600

an

out-

rms

the

Re-

the

set

the

on

01810-1

3-1

Section

~

m

Cl

Z

o

~

u

w

c::: c:::

o

u

c:::

w

~

w

~

ill

+25

+20

+15

"

Model 651B

"

+10

I

"

+5

"

-5

o

"

/

"

3-2

-10

-15

-20

-25

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I

)

"

-y

1

-

0783

10

Figure

100

IMPEDANCE

3-2.

Impedance

IK

OHMS

Correction

10K

Graph

lOOK

01810-1

Model 651B

Section

IV

4-1.

GENERAL

4-2.

The Model 651B oscillator, tor,

and

monitor

strumentisshown in

circuit

erateastable,

is detector voltagetothe appliedtothe

circuitisusedtoincrease at

improve with providesameansofattenuating put

itor the provides

4-3.

4-4.

ing 4-5. 4-6.

signaiatthe and FREQUENCY Dial RC consistingofan a

in conventional resistive the ance

4-7. possiblebythe back. quency lifier to

sitivetofrequency. will voltagetosustain

4-8. of SlC1

sitive the main

The RC tionshipofthe

uses

appliedtothe

circuit

the50ohm

the

changing output

connectors

circuit

inputtothe

all

CIRCUIT

Refer

discussion.

OSCILLATOR CIRCUIT. The

oscillator

bridge

resistive

the

Model 651B

voltage

conventional

Zl,

which

Oscillationatthe

Positive

sensitive

A2Q2 and A2Q3;

the

differential

the

positive

The RANGE switch,

resistors

through

RC

networks

instrument.

frequency

components

DESCRIPTION.

Test

power

amplifier,

circuit.

Figure

a modified

distortionless

power

providesadegenerative oscillator power

amplifier.

and

600 ohm output

frequency

loads.

in nine

continuously

attenuator.

voltages

to

frequency

networkisa modified

voltage

Wein

and

SlC13) to

positive

requiredbythe

DESCRIPTION.

Figures

circuit

RC

frequency

divider Test bridge

divider

Wein

bridgeisreplaced

consists

use

of both feedbackisprovided RC

networktothe

negative

amplifier

Onlyatthe

feedback

oscillation.

capacitors

for

The

FREQUENCY

tuning

elements

maintain

Oscillator

peak

A

block

6-1.

Wein

bridge

amplifier

circuittostabilize

the

stabilityofthe

The

stepsof10

monitors

The

6-2

thru

generatesasinusoidal

selectedbythe

locatedonthe

network. The W

Oscillator

circuitinthe

network. The

of A2CR6

selected

positive

throughanetwork

exceed

Sl,

(SlR1

establish

the

six

feedback

SECTION

THEORY

includes

detector,

diagramofthe

The

networktogen-

sine

wave

circuit.

The

power

output

selective

selects

the

power

connectors

output

the

signalatthe

dB each. The

the

regulated

651B

6-4

front

Wein

differs

and

frequencyismade

and

differential

feedbackisprovided

selected the

negative

through

the

frequency

Dial

C1A, C1B, and C1C.

proper

voltage. At

attenua-

oscillator

signal

The feedback

the

signal

amplifier

available

and

ou,tput

signal

for

bridge

combinations

signal

attenuator

level

power

circuits.

the

follow-

RANGE

panel. The

circuit,

network

ein

from

designofthe

resistor with

imped-

A2CR7.

negative

throughafre-

insen-

frequency

feedback

SlR24,

ranges

varies

phase

frequen-

OF

an

in-

which

peak

to

out-

mon-

at

supply

switch

and

bridge

the

in

feed-

amp-

and

sen-

of

the

rela-

IV

OPERATION

cies

where

phase

Figure

At

frequencies feedback sufficient

4-9.Afield

impedance input

provides

impedanceofthe

four

frequency pedance being ential quency on

the

valuesinthe 4-10.

from amplifier plementary emitter from cuitisapplied the

collector quency ageatthis tanceofthe

impedanceofthe

collector

The

increaseinthe

in

the back quency A2R9 followeratthe

Xc =R,

with

the

4-1)and

voltageisneitherofthe

amplitudetomaintain

effect

converter

impedance

a high

added

loadedbythe

amplifier.

ranges.

X100K

the

loop

voltageisremovedonthe

exceeding

F

p

F

and

RC

The

difference bridge A2Q2 and A2Q3, andisappliedtothe

symmetry

follower

output of

circuit

ranges.

pointisusedtomake

collector

current

gainofthe

ranges

0.5

0.4

0.3

0.2

~//

0.1

,./

Fp =

POSITIVE TO

AMPLIFIER

F =

FEEDBACKTORC

Figure

4-1.

the

positive

oscillator

exceeds

other

and low

impedanceinseries

differential

ranges

prevents

A2Q2 The

X1M

bridge.

circuitisamplifiedbydifferential

A2Q4. A

between

The

emitter

duetothe

the

higher

the

than

transistor,

becauseofits

noise

(X10 - XlOK). The high

theRCbridge

low input

and

impedance

ranges

between

circuit

the

complementary

resistors

of A2Q2, on

applicationofthe

load

follower

into

the

base

current

oscillator

valueofresistors

input

frequencies.

FREQUENCY

f

/

--

FEEDBACK

NETWORK

RC Network

feedback

output

where

baseofthe

voltage

negative

amplifier

impedanceofthe

A2Q3, on

A2Q5

positive

higher

impedanceofthe

feedback

Xc=

R,

right

oscillations.

A2Q1,isusedasthe

extremely

characteristics.

with

on

circuit

the

converterisbypassed

duetolower

the

feedback

and feedback

symmetry A2R8 and A2R9. in the

first

feedback

the

effective

than

A2Q4.

emitter

resultsinan

circuit.

X100K and X1M

\

\//////

////

\

--

"'-

~

RATIO--

PHASE

6ScIA-S-IOA

Characteristics

voltageisin

(refer

the phase

the

lower

A2Q6,

the

forcing

The

A2R8

/

-----

voltage.

positive

nor

high

input

lower

from

differ-

resistor

voltages

com-

through

voltage

four

resis-

input

follower.

increase

feed-

fre-

emitter

LAG

PHASE

LEAD

'to

of

It

im-

fre-

cir-

fre-

volt-

the

and

01810-1

4-1

Section

IV

Model 651B

4-11. to voltage impedanceofthe prevents ed by the RC circuit

A2CR2, A2CR3,

plied, distortioninthe

4-12. The output of power

AMPLITUDE COARSE

The voltage held

4-13. 4-14.

of 4-15.

bias

output, to

A2CR6

only on

nal. When

exceed a ing down

of ward and diodes tance,

The

complementary

provide

power

rangeofthe

the

oscillator

bridge.

transistors

are

conducting

amplifier

level

constantbythe

PEAK DETECTOR.

RefertoFigure

the

peak

detector

Feedback

voltage,

proportional

control

and

A2CR7. The

the

positive the

positive

set

level,

the

reference

the

reference

biasonthe

A2CR7. The

to conduct

and

thus

symmetry

gain

andtoincrease

oscillator;

complementary

output

circuitfrom

The

complementary

are

forward-biased

and

A2CR4, and

slightlytoreduce

output

signal.

the

oscillator

withaconstant

and

FINE

applied

action

to the

ofthe

peak

4-2

forasimplified

circuit.

from

the

peak

detector

to the

the dynamic

resistance

peak

detectorA2Q7,

peaksofthe

the

peak

detector

diode A2CR5. The

diode

causesareductioninthe

RC

bridge

voltage decreaseinforward less,

increasing

the

impedance

increaseinimpedanceZ1increases

negative

A2Q2 and A2Q3,

oscillator compensates

feedback

output

for

voltagetothe

which

results signal. the

The

initial

differential

in a

reductioninsignal

increaseinthe

output. 4-16.

differencesinthe

A2CR6 and A2CR7,

negative feedback, oscillator

A2R17

output.

WEIN BRIDGE

A

may

be

adjustedtocompensate

operating

characteristics

minimizing

thus

minimizing

Diodes

\

A2CR8

+FEEDBACK

circuitisused

the

also,

the

low output

symmetry

being

symmetry

by

withnosignal

cross-()ver

circuit

voltage

controls,

power

drives set

R2

amplifier

detector

provides

oscillator

circuit

of

oscillator

output

oscillator

conducts,

breakdown

divider,

bias

causes

the

dynamic

Z1. The

the

amount

reductionofthe

oscillator

distortion

in

distortion

and

A2CR9

dynamic

circuit

load-

diodes

ap-

the

by

the

andR3.

is

circuit.

schematic

a

diodes

conducts

sig-

output

break-

for-

A2CR6

the

resis-

of

amplifier,

level

for

ofdiOdes

the

in

the

compen-

+30V

sate

for

reverse

current

increasesintemperature. 4-17. 4-18.

power circuit.

A2Q8 and A2Q9,

plementary similartothe circuit. put of the to bilize

amplifier itor attenuator

4-19. 4-20.

applied a

the The

converter amplifier provide put from

monitor,

a

resistors

amplifier ageatthis

sistanceofthe

amplifierA1Q9 sourcetothe small A1CR8 non-linear

at

ment, circuit

frequency

or, ment

4-21. 4-22.

tenuating 600 ohm output UA resistor signal

POWER

The

gainofthe

AMPLIFIER.

power

amplifier

signal

The

operationofthe

emitter

symmetry

corresponding

The

negative

complementary

the

differential

the

power

amplifierata fixed

amplifier

outputiscontinuously

circuit

before

the

circuit.

MONITOR

The

monitor

CmCUIT.

circuit

to the output

signaltothe

amplitude

amplifier

full-scale

impedance

being

positive

output

of the output in RMS

A1Q9 between output

the

circuit,

monitor

of A1Q9

loaded

M1.

feedback

The

with

emitter voltage

A1R18 and A1R19, in the

A1Q8. The

pointisusedtoincrease

collector

appearingasa high

monitor.

amountofforward·

and

one-tenth

A1C15,

A1CR9, region,

full-scale

which

thus

compensates

capacitancesothe

response.

A1R23,

providesanadditional

whichismadeat400 Hz.

OUTPUT ATTENUATOR. The

output

attenuator

the

signal

level

connectors.

TOR

switch,

S2,

selectsacombination

networkstoproduce

attenuation.

Each

received

follower

circuit

feedback

symmetry

output

signalisappliedtothe

attenuator

monitor

serves

monitor

andasa

prevents

the

applicationofthe

circuit,

Diode A1CRlO

biastorectifier

keeps

increasing

readings.

monitor

The

monitor

applied

step of10dB. The AMPLITUDE vary

the

levelofattenuationinincrements each10dB UA

TOR switch.

step

selected

by

leakage

in A2Q7, due to

circuit

from

increases

the

differential

A2Q10,

A2Qll

and A2Q12

stagesinthe

voltage

from

oscillator

amplifier

and

oscillator

the

circuitisapplied

level

to

signal.

The

monitoredbythe

output

monitors

bothasan

indications. low

follower, A1Q8,

whichisapplied

the circuit M1, which

volts

circuit

and

current

the

power

impedance

collector

signal

and

provides indicates and dBm.

impedance

the

source

The

high

amplifier

of the output

provides

between

lead

feedback

the

effective

which

results

impedance

provides

diodes

the

diodes

monitor

out of the

accuracy

The10MHz

for

small

variations

will

have a calibration calibration

resist-

adjust-

providesameansofat-

to the50ohm and

The OUTPUT

ATTENof four

the

desired

level

providesanattenuation

controls,

R2 and R3,

between

the OUTPUT

ATTEN-

the

com-

is outsta-

power

mon-

level

power

to

in-

of

volt-

re-

in the

current

a

adjust-

in

flat

of

4-2

Figure

4-2.

Peak

Detector

Circuit

4-23. and 600 of

Output

resistor

impedances

ohms

can

S2R13. The

be obtained by changing

ing S2R13isaddedtothe

impedancetoobtain levelatthe

600

ohm

the

connector.

other

value

of the

50

ohm

new output

than

resistor

oscillator

the

standard

the

impedance

50

value

replac-

output

01810-1

Model 651B

Section IV

4-24. 4-25.

ages power supply and a referenced

4-26. tional A1Q2isusedtoincrease cuit, volt

REGULATED POWER SUPPLY. The

regulated

required

supply

-25

to the

The

+30

series

thus

adjustment,

regulator

improving

consists

by

volt

power

the

test

series

+30

volt

regulated

voltage

A1R4,

of a

type.

supply

oscillator

+30

volt

regulated

circuit.

supplyisofthe

The

the

loop gain of

regulation.

sets

the

provides

circuits.

series

supply

emitter

+30

volt

all

volt-

The

regulated

which

conven-

follower

the

cir-

The

+30

and

-25

volt supply output 4-27.

tional

the

is

addedtolimit the limiter

to

inganexcessive and A1CR7 against or

The

series

+30

volt supply. A

load

current

conducts,

reduce

short

circuitsinthe

the

-25

level.

volt

regulated

regulator

the

output voltage

protect

circuits

type and

current

load

current

exceeds

causing

currentisremoved.

the

between

output of

supplyisoftheconven-

limiter,

the

set

the

series

level

control

the

operates

toaset

two voltage the

the

A1Q7,

value. When

value, the

regulator

until

the load

Diodes A1CR6

transistor

-25

volt supply.

same

as

has

been

current

A1Q4

caus-

A1Q6,

supplies,

01810-1

4-3

Section

V

Table

5-1.

REQUIRED

TEST

EQUIPMENT

Model 651B

Instrument

Oscilloscope

Electronic

RMS

Voltmeter

Distortion DC Null

AC

Attenuator

Amplifier

Thermal

Voltmeter

Differential

Converter

Type

Counter

Analyzer

Voltmeter

Required

Passband: Sensitivity: Input

Range: Accuracy:

Frequency Voltage

Accuracy:±1%

Distortion Range:

Accuracy:

Range: 3 V to 4 V

Accuracy:

Attenuation

Frequency Gain: 40

Frequency

Input: 3 Output: 7 mV dc

Accuracy:

Frequency

10

Hz to10MHz

50

mV/cm

Impedance:1megohm

10

Hz to10MHz

± 5

counts

Range:

Range: 1 mVto6.32

Sensitivity:>42

10

J1.V

to30V

±2%offull

±0.1%

Range:90dB in10dB

Range:

dB

Range:

VRMS

±O.2%

Range:

Characteristics

10Hzto10MHz

dB

scale

10

Hz to10MHz

10

Hz to10MHz

10Hzto10MHz

V

steps

Recommended

-hp-

Model 175A

-hp-

Model 5244L

Electronic

-

hp-

Model 3400A RMS

Voltmeter

-hp-

Model 331A

-hp-

Model 419A

-hp-

Model 741A Differential Standard

-hp-

Model 355D VHF

Attenuator

-hp-

Model 461A

Amplifier

-hp-

Model 11049A Thermal

Converter

Model

Oscilloscope

Counter

(withknown

AC-DC

Voltmeter/DC

(withknown

error)

oto

10

mV

Terminating

Adapter

Reference

Resistance

Supply

See

Figure

a.

Resistor:

b.

Resistor:

c.

Resistor: Battery:

d.

a.

Feedth.r6ugh, Feedthrough,

b. BNCtoBinding

5-3

for fxd, var, var,

1.34V 500

6000

Post

schematic 65000±1%

5000

±5%

500

±5%

a.

-hp-

b. c.

-hp-

d.

Mallory

a.

-hp-

b.

-hp-

Model 10111A

Part

No. 0811-0392

Part

No. 2100-0324

Part

No. 2100-1481

RM-42R

Model 11048B Model 11047A

Adapter

5-0

01810-1

Model 651B

SECTION V

MAINTENANCE

Section

V

5-1.

INTRODUCTION.

5-2.

This

section

information

Included

Calibration

cedures.

5-3.

5-4. Model 651BislistedinTable type of quirements, available Table fies

the

5-5.

5-6. that

insure

operating

used

for

and

for performance ance

before

5-7.

a.

b. Set 651B

c.

for

are

Procedures,

REQUIRED

The

equipment

equipmenttobe

test

5-1isnot

given

PERFORMANCE

The

performance

that

within

incoming

specification

making

DIAL ACCURACY CHECK.

Connect 651B

put

terminalofelectronic

in

Figure

FREQUENCY

FREQUENCY OUTPUT ATTENUATOR. . .3.0 V

AMPLITUDE. . . . . . . . .

Set

electronic

counter

contains

the

-hp-

Model 651B

Performance

and

TEST

EQUIPMENT.

needed to

used,

and the

equipment. If

specifications

specifications.

checks

recommended

available,

CHECKS.

checks

the

Model 651B

inspection,

checks

to

verify

internal

50n

5-1.

controlsasfollows:

RANGE.. Dial.

monitor

countertoread

should

indicate

maintenance

Checks,

Troubleshooting

properly

5-1.

the

equipment

any

instrument

maybeused.

are

Test

These

periodic

afterarepair.

instrument

adjustmentsorrepairs.

output

terminal

. . . . . 1

indicationof3.0

100±3ms.

and

service

Test

Oscillator.

Alignment

maintain

The

table

lists

specification

commercially

listed

that

in-cabinet

checks

counterasshown

X10

Adjust

period

checks

Oscillator

may

maintenance,

Use

perform-

to de

for

V

average;

and

Pro-

the

re-

satis-

be

the

in-

in

is

d. Set 651B FREQUENCY

counter

e. Set 651B FREQUENCY

counter

f. Set 651B FREQUENCY RANGEtoX100 and

set er

g.

Set counter

h.

Set 651B FREQUENCY counter

i.

Set Set 651Btoeach

If

frequencyisnot

perform

Paragraph

Table

Frequency

10K 50K 50K

lOOK lOOK

500K 500K ±10K

1M

5M

10M

should

FREQUENCY

should

651B FREQUENCY

should

electronic

5-2.

(Hz)

1K 1000 ±20 5K

indicate20±O.6ms.

indicate10±O.3ms.

indicate

indicate1±O.02ms.

countertoread

frequency

counter

within

the

frequency

5-21.

Dial

Accuracy

dialto5;

dialto10;

dialto1;

10

±D.

dialto5;

2

dialto10;

indication

the

Electronic

Indication

5000 ±100

10K

1M

5M

10M ±300K

electronic

2

ms.

electronic

±D.

04

ms.

electronic

frequency.

listedinTable

dial

for

listed

calibration,

Check

Counter

(Hz)

±D.

2K

±lK

±2K

±30K

±150K

tolerance,

count-

5-2.

each

01810-1

8-0851-RO

TEST OSCILLATOR

hp

6518

Figure

FEED THRU

5-1.

50

OHM

hPII048B

:::J~------""

01:[

Dial

Accuracy

ELECTRONIC COUNTER

hP5244L

(-----ntl@1

'-

\

"

I

/

Check

•

0

©

@

0

~

5-1