Tektronix 475 User manual

COMMITTEDTO EXCElLENCE
PLEASE CHECK FOR CHANGE
INFORMATION
AT THE REAR
OF THIS MANUAL.
Tektroni x, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-2039-00
475
OSC ILLOSCOPE
AND
DM44 DIGITAL
MULTIMETER
OPERATORS
I NST R U C T IO N M A N U A L
First PrintingJUL 1976
Seria l N umber Revised OCT 1981
Copy right s 1976 Tektronix, Inc. All rights
reserved. Cont ents of this publicatio n may not be
reproduced in any
fo rm without the wri tten
permission of Tektronix, Inc.
Produc ts of T ektr onix, Inc, and its sub sidia ries
are
cove red by U.S. and fore ign pa ten ts and /o r
pending patents.
T
EKTR ONIX, TEK , SCO PE·MO BILE. and ~
are registered tradem arks of Tekt ron ix, Inc.
TE
LEO U IPMENT is a registered trade mark of
Tektr onix U.K. lim ited.
Pr
in ted in U.S.A. Specifi ca tion and price c hange
privileges are reserved.

TA BLE OF CON T ENTS
Page Page
LIST OF ILLUS TRATIONS
;,
BASIC OSCILLOSCOPE DISPLAYS "
LIST OF TABLES ,
NORMAL SWEEP DISPLAY
'.
MAGNIFI ED SWEEP DISPLAY
17
BEFORE OP ERATING
1DELAYED SWEEP DISPLAY 17
INTRODUCTIO N1MIXED SWEEP DISPLAY
,.
SA FETY INFO RMATION
,X-V DISPLAY
,.
OP ERATING vO LTAGE
2SI
NGLE SWEEP DISPLAY
"
Line VOllage Selection
2
Regulating Range serecnco
2
OM44 DISPLAYS AND MEASU REMENTS 2.
OPT IONS
3RESISTANCE
2.
CONT ROL S,CO N NEC TORS,AND
VOL TS 22
IN DICA TORS
4TEMPERATURE 24
VER TICAL
4Accuracy
Check
24
DIS PLAY
7TIM E AND l fT lME 27
DM44 7
TRIG GER •A
PPLICATIONS AND MEASUREMENTS 2.
HQRIZQN TA_, CALIBRATOR , AND POWER
'2
REAR PA NEL
14 PRELIMINARY 2.
LEFT SIDE PANEL 14 SIgnal Ground 2.
RIGH T SID E PANEL 14 Input Coupling Capacito r Pr echa rg ing 2.
REV A JAN 1981 475/DM44 Operalors
TABLE OF CONTENTS (cont)
APPLICATIONS AND MEASUREMENTS (coni) Page APPLI
CATIONS AND MEASUREMENTS (cont) Page
OPERATOR'S ADJUSTMENTS AND CHECKS
2. PHASE Di ffEREN CE MEASUREMENTS 42
Trace Rotation 2. HIGH RESOL
UTIO N PHASE DIFFERENCE
Probe Compensation
2.
MEASUREMENTS 43
Vertical Gain Check 3. PULSE JITTER MEASUREMENTS 44
Basic 475 Timing Chec k 3. DELAYED OR MIXED SWEEP
DM44 Timing Check 3.
MAGNIF ICATION 45
Extemat Honzontat Gain Check 31 Magn ified Sweep Starts A ll er Delay 45
PEAK-TO-PEAK VOLTAGE Triggered Delay Sweep Magnification
4.
MEASUREMENTS- AC 31
INSTANTANEOUS VOLTAGE
MEASUREMENTS
-D C32 Baslc 475 Delayed or Mb ed Sweep TIme
ALGEBRAIC ADDITION 34 Measurements
4.
COMMON MOD E REJECTION 35 TIME Dif FERENCE BETWEEN REPETITIVE
AMPLITUDE COMPARISON PULSES (BASIC 475) 4.
MEASUREMENTS 36 TIME DURATION MEASUREMENTS
TIME-DURATION MEASUREMENTS 37 (BASIC 475) 4'
FREQUENCY MEASUREMENTS 38 FREQUENCY MEASUREMENTS (B
.&.S IC 475) 50
RISETIME MEASUREMENTS
3.
TIME Dif FERENCE BETWEEN TWO PULSES
TIME DIFFERENCE BETWEEN TWO FROM DIFFERENT SOURCES IBASIC 475) 5'
PULSES FROM DIFFERENT SOURCES 4. RISETIME (BASIC 475) 52
TIME COMPARISON MEASUREMENTS41 MIX (BASIC 475) 53
"475/DM44 Operators REVA JAN 1981

TABLE OF CONTENTS (cont)
OM44 Delayed or Mi xed Swe ep Time Page OPER
ATO R'S SPECIFICATIONS (c oni) Page
Mea sure ment s54
TIME OIFFEFIENCE BETWEEN REPETITIVEZ AXIS I
NPU T65
PULSES (DM44) 56
OUT PUTS 65
TI ME DU RAT ION ME ASURE MEN TS (DM 44) 57 AC POWER SOURCE 65
FREQUENCY MEASUREME NTS (DM44) 58
ENVIRO NME NT AL 65
TIME DIFFE Fl ENCE BETWEE N TWO PULSES OM44 DIG
ITAL MUL T1 METER 66
FROM DIFFERENT SOURCES (DM44) 58 RES
ISTANCE 66
RISET IM E (DM44) 60
TIME
66
MIX (DM 44) 61 l /T IME 66
TEMPERATURE 66
OPERATOR'S SPECIFI CATI ONS 62
DC VOLTAGE 66
475 OSCILLOSCOPE 62
VER TICAL
62 ACCESSORIES68
T RIGGERING
63
DIF FERENT IAL TIME MEASUREMENT 51 ANDARO ACCESSORIES 68
(BAStC 475) 63 OPT IONA L ACCESSORIES 68
DIFFERE NTIAL TIME MEASUREMENT
iD M44) 64
OPTIONS 6.
HORIZONTA L64 OPTION 16'
x-v 64 OPTION 4
6'
CALI B RAT OR 64
OPTION 769
REV A JAN 1961 475 /DM44 0p erst or siii
LIST
OF
ILLUSTRATIONS
Page Page
Fig 1.
Regulating range selec t or and line Fig . 17. Com m
on -m ode reject ion. 36
fuse. 3Fig. 18 Time d
urat ion. 38
Fig 2. Vertica l con
trol s. connect ors,
00'
Fig , "Risetime.
3.
motcatcrs. 4Fig , 20. Time di
fference betw een two pu lses
Fig. 3.
Disp lay and DM44 con tro ls, from d
iffer e nt so urces, 40
con n ecto rs, and in dic a tor s6Fig, 21 . Phase difference. 43
Fig. 4. Tr
igge r co nt r ols . conn ecto rs, and Fig 22 High
-re solution phase di ffer enc e. 43
tn otca tors. 8Fig 23 Pulse jitter. 44
Fig. 5. T
ng ger con t rols . connec to rs. and Fig 24
Delay ed s weep magnification. 46
in dica tors, 10 Fig 25 T ime di ffe
renc e between repetitiv e
Fig 6Hor izo nta l, c alibr ato r, and po wer
pulses ,
4'
co r arors. con necto rs, and in dic ato rs. 12 Fig. 26 Time
dur a tion .50
Fig 7. Rear panel and l eft sid e panel con trols,
Fig 27 . Time difference bet
ween tw o pu lses
co nnectors, and in dic ato rs. 15
from di ffe rent sources .51
F, .8. Resistance 21 Fig . 28 Risenm e. 53
Fig •• Volts. 23 Fig
2.
Time di ffer ence be tween repe tit ive
Fig 10. Te
mp era ture
25
pulses.
56
Fig 11. Pr ob ecor-ipensatton
2.
Fig . 30 Time
du ra tion and fre quency
Fig 12. Basic 475 timing check .30 measu re
ments ,57
Fig
13 DM44 timing check .31 Fig. 31
Tim e di f ference between two pulses
Fig 14. Peak-to-peak
voltage of a wave form ,32 from
diff erent sou rces,
5.
Fig 15. Insta
nt aneous voltage measuremen ts. 33 Fig . 32 Rtsetime.60
Fig 16. Algebraic addition. 35
I,
475 /DM44 Operator s@

LIST OF TABLES
P age
Page
TABLE 1 Regulating Ranges
TABLE 2Resistance Ranges
TABLE 3 Valls flanges
2
20
22
TABLE 4 Centigrade 10 Fahrenheit Conve rsion
TABLE 5 OM44 Delayed Sweep Displays
2.
54
@47S
/DM44 Operators ,
1039·15
20J!H2
475/DM44 O ~ ralo rs
@

BEFORE OPERATING
INTRO OU CTI ON
The Tek tro nix 475 Oscilloscope is a dual-ch annel
po
rtable Instrurr en t. The dual-channel oc- to-zan MHz
vertical system provides calib rated de flect ion factor s from
2 millivol ts to 5 vorts rofvrsron. Th e s weep trigger ci rcui ts
are capable of s
table triggering over the full ban dwidth
capabil ities 01the vertical deflec tion sys tem .The horizo n-
tal deflection system provides calibrated sweep ratesfrom
0.5 second to J.01 m icro second /divis ion a long wit h
delayed sweep feat ures for accu rate relative -l ime
measureme nts. A Xl 0 m agnifier exten ds the calib rated
sweep rate to 1nanosecond/division. The instrument
operates over a wide varia tion of line vo l tages and
f
reque ncies . Ma xim um power consumption is a bou t
100
watts
The Te ktronix DM 44 Digi tal Mufnmeter measures 0
ohm to 20 rneqobrns.0oc volt to 1200 dc volts ( ~or I,or
(using th e te
mp erature p rob e) - 55 °C to f150° C The
measurem ent is display ed on a 3-112 digi tal display whil e
the oscilloscope operates normally.
The digital mu tnrneter and oscilloscope comb ine to
prov ide a dig ital readout of the time bet ween any two
points on the oscilloscope dis play . Both time measure-
ment po ints are d isplayed on the crt at the same time . The
1 /TIM E function can p rovide direct mea surement of
frequency.
SAFETY INFORMATION
The ins trume nt is designed to oper ate from a single-
phase pow er source with one ot the cu rren t-car rying
conducto rs (the Ne ut ral Conduc tcr) at grou nd (earth)
pote ntial. Ope ra tion from pow er sourc es where both
cur r ent-ca r rying conduct ors are live with res pect to
ground (such as phase-to- phase on a thre e-wire sy stem)
is not r ecommended , since only Ihe line Conduc tor has
over-curren t (fuse) protec tion wi thh the instrument
The ins trument has a mree-wue po we r cord wit ha
m roo -te rmtne! polarized plug f or connec t ion to the po wer
source and safety-earth. The ground (e art h) terminal of
the plug is dire ctly connec ted to the Inst rum ent frame For
erectrtc-sbock pro tec tion ,lnsert thfs plug only in a mat ing
out let wit hasafe ly-earth contact.
@ 475/DM 44 Operat ors 1
OPERAT ING VOL TAGE
Ii'" or...- ... ...- ...- ...... ...
~ C A U TI ON ~
\ .. '1' r ... ' ... ' ",-'
This ins trum enl may be damaged if operated with
me lin e vol lage selec tor SWi tch or the reg u latin g
range selector set
'or Ihe wrong appl ied lin e v oltage
or if tne wrong line fuse is used.
lin e Voltage Selection
This instrument operates from either a 115-v ott or a
za c -vort nominal line voltage sou rce . 48 to 440 hertz . To
convert from one nominal line voltage range to the other ,
m
ove the line Voltage Select or switch (loca ted on side
pane l) to indicate the correct nom inal vo lt age . A 115 -to -
230 vo lt
adapte r may be requ ired tortne nne -cere plug. Be
sure to use the correct line fuse for the line voltage
selected (see Table 1).
R eg ulating Ran ge Selection
The Regu lating Range Selector assembly (located on
the rear
panel ) is set for one of the line voltag e ranges
shown in
Table 1. Italso conta ins the line fuse tor overtoao
prote ction
To ch ange the reg ulating range :
t . Disco nne ct the instrument from the p ower so ur ce.
2. Lo
ose n the two ca ptive sc rews that ho ld the cover
on
the selecto r assembly: the n pu ll to remove the cover.
3. P
ull out the ra nge select or switch bar (see Fig 1)
Select a
range from Table 1 wh ich is centered ab o ut the
aver
age line voltage . Slide the bar to the des ired position
and plug it in.
Push the cover on and tighte n the screws
TABLE 1
Regulating Ranges
Regulatin g Range
Range Selector
tts -vcns 230 -Vo ll s
Swllch Positi on Nom i nal N om inal
LO (Switch
bar in
lower holes ) 99 to 121 v olts 198 to 242 volts
M (Switch bar in
m idd le ho les) 104 to 126 vo lts 207 10 253 v olts
HI (Switch bar in
uppe r ho les) 108 to 132 volts
216 to 264 volts
Fuse Size 1.5 A 3AG 0.75 A 3AG
Fas t-b low Fast-blow
24
75/D M44 Ope rators
@

OPTIONS
Options are available to a lter osci lloscope performan ce
to
meet parti cu lar applications. A number in either MOD
slot (see Item 53. C ontro ls, Connecto rs, and Ind ic ato rs)
indicates a mod ified osci llo scope.
@
LINE F USE
Fig. 1. Regulaling range selector and line Iuee.
475/DM44 Opera
tors
CONTROLS , CONNECTORS AND INDICATORS
3
~
(2
cp
I ii
0 0 0 0 0 1 10 00 0
fu
~
~ -
~
~
1
dJR
1
( 6
@~ O l 'I I
.. (;' o0B8
><
:'- ~ B
~
4
2 Y --
•J:
~
:-
@~
[ \@
@@ O O
W
7 ~
10
2oj9-3
Fig. 2. VertIcal conlrols. connectors, and IndIcators.
VERTICAL
1. CH 1 and CH 2 VOLTS /DIV - Selecl s the verti cal
de
flection facto r in a 1-2-5 sequence (VAA control must be
in
the ca l ibrated detent for the indi cated defle ction factor).
2. VOLTS/
OIV Readou t- Consists of two small lamps
for each ch a nnel . located beneath the skirt of each
VOL TS /D IV knob . One or the othe r lamp will light up to
indicate the correct deflection factor when a probe with a
scale-switch ing connector is used. A probe without this
connector tights the xt lamp.
3. VAR- Provides
contin uo usly var iable u nceueratec
deflec tion fact ors between the ca l ibrated sett ings of the
VOL TS/DIV switch , and extends the maxtrnurn vertical
de flection to at least 12.5 v olts per d ivision (5 vol t
pos
ition) .
4.
UN CAL La mp - Ind ic ates 110 hen the VAA
VOL TS /DIV control is out ottne calibrat ed detent and the
vertical deflec tion factor is uncatib rated .
4475 /DM44 Ope ra tors
@

5. POSITION - POSitions the disp lay ver tically, In the
X-V mode. the CH 1 POSITION con trol pos i tions on the X
a
xis (ho rizon tal'y] and the CH 2 POSITION control
positions on the v-aos (ve rtically).
6. CH 1 OR X and CH 2 OR V- Inp ut connectors for
applica tion of exte rnal signals to the inputs of the vertical
ampli fier, In the X-V mode of operation, the signal
connected to t heCH 1OR X connector provides horizon-
tal de flec tion and the signal connected to the CH 2 OR Y
connector provtces vertical deflection ,
7,
AC -GND -OC - Selects the method used to couple a
signal to the inpu t of the ver tical amplifier, In the AC
position, sig nals are capacitively coupled to the ver tical
ampli fier, The cc cornpcnen t of the inpu t signal is blocked
In the GND position, the Input of 'he vertical am plifier is
disconnec ted f rom the input connector and grounded to
allow the inp ut coupling capaci tor to precnaeqe. In the DC
posi tion , all components 01 the input signa l are passed to
the input ampli fier.
8, VERT MODE - Selects mode of ope ra tion for ver-
tic al am pli fier system
CH 1
Chan nell only is displayed.
ALT: Provides dual-t race displ ay of tne siq nats ct both
ch
annels . Dis play isSWitched b etwe en ch annels at the end
of
each sweep , Useful at s weep rates faster than about 50
microseconds/divisi on .
ADD
Signals applied to the CH 1 and CH 2 input
connectors are alge braically added. and the atqeb rarc
sum is displayed on the cr t. The INVE =1T swi tch in Channel
2 allows the display to be CH 1 plus CH 2 or CH 1 minus
CH 2. Usefu l for common-mode rejec tion to remove an
undesired Signal or for oc offse t.
CHOP: Provides dual- trace dis play of the s ignals of
both channels . Disp lay is SWitched betw een channels at a
repetition rate of appro ximatel y 250 kHZ. Useful at s weep
rates slower than abou t 50 microseconds /division. or
when a dual-trace, single-sweep display is required
CH 2: Ch
annel 2 only is displaye d It mu st be selected
In X-V operation
9. 100 OR 20 MHz BW /TRIG VIEW - Three-purpose
SWi tch tha t l imits the band width of the v ert ical a mpl ifier
system to app ro xima tely 100 MH z (first detent) o r20 MH z
(second deten t) when pulle d. or when pressed. caus es the
s
ignal applied to A Trigger Generator to be d isplayed on
the crt.
10, INVERT- Channel 2 dlspl a)' is i nvert ed in the
INVERT (bu tton In)
position
6
@
18 19
ON SIDE
PAN EL
475/DM44 Ope rato rs
21 ~
•
-uo
@~
:@~
@ 11
Du• @
• 0
~ Bii
@:
0
@O
••
@)
@
Fig. 3. Disp lay and DM44 co ntrols, con nec tors , and indlcal on .
475 /DM 44 Oper ato rs @
5

DISPLAY
11. Inlern al Gr aticul e-cE timin ates parallax. atsetr-ne.
amp litude and n-eesuremeot points are indicated at the
le
ft-hand qra ticule edge .
12.
BEAM FI NDER ~ C o m p r e s s e s the display to wi thin
the gra ticule area independently of display position or
applied s ignals and p rovides a visible viewing level.
13.
INTEN SITY- Controls b righ tness of the crt dis-
play .
14. FO CU S - Adjusts for optimum display de fini tion .
15. SC
AL E ILL UM - Controls gralicule illumination
16. ASTIG- Used in conjunction with the FOCUS
contro lto obtain a well-defined display . II coes oot require
read jus tmen t in normal use .
17. TRACE RO
TA TION - Adjusts trace 10 align with
the ho rizontal q raticule lines .
DM44
18. Input Connectors- Two banana jac ks provide +
(red) and COM (otack] inputs for voltage and resis tance
only ,
19. Probe
Co nnec tor - Input connector f or the
temper atur e probe .
20. Rea dout - Negat ive
po la rity indication is
automatic for negativedcvoltage anc temperatu re with no
po lari ty indication for posi tive measurem ent. A blin king
display indica tes overrang e. The decimal point is pos it ion-
ed by the FUN CTI ON and RAN GE controls tor mutttme ter
operat ion and by the oscilloscope A TIM E /D IV swi tch in
the TI ME or l
/TI ME modes .
21.
RAN GE - Selects trom .2 V to 1,2 kV dc in 5 ranges
(1200 volts is the ma ximum sale Input in the 1,2 kV de
mode) : trom 200 ohms to 20 rneqoh-ns in 6ranges.
22. FU
NC TIO N- Selects VOLTS, OH MS, TEMP (QC).
l/TIME .or TIME functions of the DM44
23. Scale Factor Lamps- Two lamps.
In
the TIME function, the Readout and Sca le Fac tor
Lamps indicate the lime difference be tween the two
intens ified zones on the crt display , One lamp or the other
will light 10 indicate ms or ps , No lamp lit indicates
seconds .
In the l
/TIME function the Re adout and Sca le Factor
Lamps indicate the number ot m easured intervals per un it
of
time . One larnpor tne o ther will light to indicate i ntervals
per ms (Vms lamp) or I nt ervals pel ps (l ips lamp ). No
0 0 29
26
27
475 /DM44 O perators
la mp tit in dic ates intervals per second, It the du ration of
one eve nt is being measured. the Readou t and Scale
Fac tor Lamps indicate frequency, The 1/ms l amp in-
dicates kHz . the l /lJs lamp indicates MHz, and no lamp lit
indica tes Hz.
24.
lJ. TIME - Used in con junction with the DELAY
TIME
POSITION COn tro l in the TIME and l /TI ME tun c-
ttons. The lJ. TIME con trol mov es only the time-
me asu rement point. The DELAY TI ME POSITIO N con trol
mov es both the reference point and the t ime -
measu remen t point With the time-m easurement po int to
the lell of the re ferenc e point the Re adout indicates a
n
egative time dil1erence .
NOTE
You can modi fy your ins trumenf 10 make the DELA Y
TIME
POSITION control mo ve only Ihe reference
point. The procedure for making tllis modification is
located in Ihe Maintenance section of the DM44
Service manual,
TRIGGER
25. TR IG MODE - Determines the mode of trigger
operation tor A Swe ep
7
2039-5
Fig. 4. Trl9ger controls, conn ectors, and indicators.
AUTO. Sweep is initiated by the app lied t rigge r signal.
In the absence of an adequ ate trigger sig nal , or if the
trig ger rep etitio n rate is l ess than about 20 hertz , the
s
weep free runs and provides a brig ht reference t race .
B475 /DM44 Op erato n@

N ORM : Sweep is ini tiated by the appl ied tr igger signal.
In
the absence of an adequ ate tr igger signal, there is no
trace. When
the tr igger rate is too row lor A UTO use
NORM .
SINGL SWP: When this p ush butt on is pushed . the A
Sweep operates in the single sweep m ode . After a single
sweep is dtsptavec. further sweeps c annot be presented
until the SINGLE SWP butt on is aga in pushed II is usef ul
w
hen the signa l to be dis played is not repetitive or varies in
amp litude . shape or time causing an uns table conve n-
tional display . It can also be used to pho tog raph a
nonrepennve signal.
26.
READ Y Lamp - Indicates A Sweep is " arme d" and ,
upon
receip t of an adequate t rigger signa l, will present a
single -sweep disp lay ,
21. TR IG
Lamp - Indicates that A Sweep is triggered
and will produce a stable d isplay. It is usefu l for selling up
the tr
igg er circ uits when a trigger s ignal is avai lable
without a display on the crt (for example , whe n using
ex
ternal triggerS'I.
28. A
TRIG H O L D OFF ~ P ro v i d e s continuous con trol
of time between sw eeps . Allows tr iggering on aper i odic
signals (such as complex dig ital wo rds }. In th e fully
clockwise pos tncn (8 ENDS A),A sweep is rese t at the end
0 18 sweep to prov ide the fastest ooss.ote eweeo repeutton
rate for delayed-swe ep pre se ntat ions and l ow-repet iti on
rate signals, Use the A trigg er
cont rols f or the best
poss ible display befor e using the A
TRIG HO LDOF F
contr ol.
29. CO U
PLING - Determines meth od used to coup le
signals to the trigger generator circuit .
AC : Sign als are capaci tivety coupfed to the inp ut of the
trigger generator . Dc is rejected and s igna ls below abo ut
60 Hz are attenu ated
LF HEJ : S
ignals are capacttively coupled to the input
of
the trigge r circ uit. Dc is re jected and signals below
abo ut 50 kH Z are attenuated .It is useful for providing a
stab le d isplay 0 1 the h igh -freq uency components of a
comple x waveform .
HF REJ :
Signals are cececmverv coupled to the inpu t
01 the trigger circ uil. Dc is rejected and signals below
about 60 Hz and above about 50 kHz are attenua ted . It is
usetut
for p rovidi ng a stable display 01 the low-frequency
components of a comple x waveform .
DC : All
componen ts of a trigger signal are co up led to
the in
put of the trigger circuit. It is useful for pr oviding a
stabl e d isplay of l ow -f requency or low -repeti t ion rate
signa ls. except the combination of the ALT (dual trace )
mo de w ith the trigger SOURCE swi tch in NORM.
@
32
415/D M44 Opera tors
30. SLOPE- Selects the slope of the trigge r s ign al that
starts the sweep .
9
~@
~ B 0 1:1 -
~ BB=
O O O c=- @
33
fi g. 5. TrIgger (o nlrols. connec tors , and tndrce tore.
+: Sweep can be triggere d from the pos i tive-g oing
portion of a trigger signal.
Sweep c
an be triggered from the negati ve-going
porti on of a trigger sig nal ,
Co rrect SLOPE se tting is importan t in Ob taining a
disp lay when only a por tion of a cycle is bei ng disp layed .
31.
LEVEL - Selects the amplitude poinl on the trigger
s
ignal at wh ich the sw eep is triggered. It is usually
adjusted for the desired d ispla y after trigger SOURCE,
COUPLI NG and SLOPE have been sele cted .
10 415
/DM4 4 Oper ators @

32. SOUR CE- Determines the source of the t rigger
signa l coup led to the inpu t of the trigger ci rcuit
NORM : Trigger source is displa yed signal(s). It does
not indica te time relationship between CH 1 and CH 2
signa ls. However, stable triggering of non-time-relate d
signals usually can be obta ined by s ell ing VERT MODE to
AL T,
SOURC E to NORM and COU PLI NG to LF REJ.
Carefull y adjust LEVEL for a stable display
EXT:
Sign als connec ted to the EKt ern al Tri gge r Input
connec tors are used for trigge ring . External si gnals must
be time-related to the d isplaye d signal for a s tab led isplay .
It is useful wh en the
intern al signal istoo small or con tains
un desired s ignals that could cause unst ab le triggering It
is
use ful whe n opera ting in C HO P mode .
EXT -7- 10 (A
Trigge r circuit only) : Ext ernal trigge r
signal is atte nua ted by a factor of 10
CH 1: A
samp le of the signal ava ilable in Cha nnel l is
used as a trigger signal. CH 2 signal is unstab le if it is not
time-related.
CH 2: A
sample of the signal available in C hannel 2 is
used as a trigger sign al CH 1 signal is unstable if it is not
time-rela ted.
STARTS AFTER DELAY (8
T ri ~ ger ci rcui t onl y): 8
S
weep runs immediately after the delay li me selected by
the DE LAY· TIME POSITION con trol. When making
diff erential time measurements you must use this mode to
ob tain
valid measurements . On instruments e qui pped
with a DM44 you must use this mode to ob tain valid
measu rements when using the TIME or 1/T IME tuncuons.
LINE (A T rigger circuit only} : A sample of the power-
line frequency is used as a trigger signal. It is useful when
the input signal istime-related (mu ltipleo r submul tiple} to
the
line frequency or when it is desirable to p rovide a
stable display ot a li ne-frequency com po nent in a comple x
wavefo rm. 33.
Ede maI Trigger I npu ts- Input connectors for ex-
ternal trigger signals
@475/DM44
Op erators 11
Fig. 6. Horizontal. c, lIb. 't or , a nd power cn ntrota, co nnectors.
' nd in
dic, lo.s .
HORIZONTAL , CALIBRATOR , AND
POWER
34a. A AND B TI ME/ DIV AND DE LAY TIME- A
TIME /DIV switch (clear plastic skirt) selects the sweep
rate of the A Sweep circuit for A sweeocmvcce rauon and
selects the
basic delay time (to be used by the DEL AY-
TIME POS
ITION control ) for delayed sweep opera tion B
T1MEl DIV
swttcn ( pull out and e ota te to un tock }sel ects the
sweep rate lor the B Sweep circuit for delayed sweep
operation only. A VAR control must be in the calibrated
detent for calib rated A Sweep rates. When both TIME /DIV
swi tches are fully counterclockwise to the X-Y position ,
the
horizontal (X-axis) display is the CH 1 input.
35. FINE/P OS IT ION - Positions the display horizontal-
ly for A sweep and 8 Sweep
34b. DM44 A AND B T IME /D IV AND D ELA Y TIM E-
The
con trols operate in the same manner as 37a above.
The A TIME/DIV
switc h also contro ls the TIME lamps and
dec imal po int locat ion when the DM44 is in the TIM E
or 1
/TIME MODE .
36.
Xl0 MAG- Increases displayed s weep rate by a
fac
tor of 10. It extends fastest sweep rate to 1
nanosecond /division, The magni fied s weep is the center
division of the u nmagnified displ ay (0.5 division either side
of the center gr aticule line}.
42
34
0 0
39
-;;0
38 @
•
® l ~
•
0IiQ
0
0
0@@
12 475/DM44
Op erat ors @

37. VAR -P rcvtoe e con tinuously variable s weep rates
b etween the cali bra led se ttings of the A TIM E/D IV swi tch
It extends the slowest A Sweep rate to at least 1.25
seconcs/dwrsron. The A Sweep rate is calibr ated when the
control ISset fully clockwise to tne canbratec ce tent Must
be in Ihe deten t ccee.cntc maee eccurete c.tterenuat time
measurements On Instruments equipped with a OM4 4the
VAR control must be in tne detent position to make
accura te measu rements in the TIM E and 1 !TI ME tunc-
tiona
38. UN CAL l a mp - Indicates tne A S weep rate is
unc
ali brated (VAR con trol out 01 th e cali bra ted dAten t)
39. X10 MAG Lamp - Indicates that the X10 mag ni lie r
IS on,
40a.
DEL AY TIME POSIT ION - Provides variable
s weep delay to more than to times the delay time indicated
by me A T IME /DIV SWItch.
40b . DM44 DELAY TIME POSI TION -Opera tes In the
same manner as ~ ta Also. when ttle DM44 ISIn the TIME
or 1 T IME funct.cn. mrs control operates in conjunction
with rne lJ. TIME cont rol. The DELAY TI ME POSIT ION
conuot moves both the relerence pom t and tne nme-
measu rement oc nt The lJ. TIME contro l moves only the
time-me asurem ent pom t. With the lim e -m e asurement
point to the lett 01 the r efer enc e p oin t th e Readout
i
ndica tes a negal ive ti me ou rere nce.
NO TE
You can modify your Instrument to make t heD ELA Y
TIME POSITION control move only me reference
po.nt The procedure for ma iling m,s modification IS
located In ttle Operatmg tntorrnenon section of the
DM44 Servrce manual,
41. CALIBRATO R- A commn artcn cu rrent
lo op /squ ar e-w ave vol t age cu tout tnat per mits the
op erator to compensa te vol lage probes and ch eck ver tical
gain, curren t pro bes and OSCilloscope operation It is no t
inte
nde d to verily ti me-ba se cal ibrat io n.
42. POWER - Turns in
str um ent cowe r on and ou.
43. LOW
LINE Lamp - Indicates th at the applied hne
voltage is below Ihe lo wer limit 01 Ihe regulating range
selec ted by the Regul ating Range Selector
44. HORtZ D ISPLAY - Determines the mode 01 opera-
lion for tne horizontal deflection system.
A" Honeo nta ! deflec tion provi ded by A Swee p at a
sweep rate
de te rrmned by the se tting o f th e A T IME/ DIV
switch, B sweep is Inoperative.
@475
iDM44 Op eralor s13
M IX: Th e flTst part 01 tne ho rizontal s weep is displayed
al a rate set by th e A TIME/ DIY SWitch and thelatter part 01
the s weep al a rate set by the B TIME/DIY swit ch . Re lat ive
am
ounts of me disp lay all oca ted to e ecn of tne t wo s weep
rates are determined by tne setting of the D ELAY -T IME
POS ITIO N con trol.
A INTEN The swe ep rate is de te rmin ed by the A
TIME/DI V SWitch, An inlen Sllred
portion appe ars on the
di s
play durin g th e B Sweep time , wh ich is ab out 10 times
the B TI ME
/D IV s wit ch setting. Th is swi tch pos iti on
provides a c hec k of the durat ion and positio n 01 the B
Sweep
(de l ayed s weep) With respect to the A S weep
( del ayi ng sw eep) ,
B DLYO: The s
weep rat e is ceterrmnec by the B
TIM E/DI V SW itch wrlh the delay time deter mined by the
setting 01 tne D ELAY TIM E (A TIME/D IY) swi tch and the
DEL AY· TIME POS ITION ccntror .
REAR PANEL
45. A + GATE -Provid es a pos ltlve..going rect angu lar
pulse coinci dent wilh tne A S weep ume . wtlich can be
used 10 tr igger tne sgn al sou rce (With TRIG MODEsw itch
set to
AUT O )
46. B + GATE-
Pro vides a posi tive- goin g re cta ngular
pulse
co inci den t with the B S weep time , wh i ch can be
used to trigg er the signal sou rce alt er a s ele cte d delay
time. pro vi
din g that A Sweep is tr igg ered int ern ally.
47.
CH 2 VERT SIGNAL OUT - Provides a sa mp le of
the sign al applied 10 the CH 2 mpu l connec tor.
48. EXT Z
-A XI$ - Permits intensity -nodcrauon of the
crt disptay , Does not affect d isplay wevesnepe. Signals
w il h f asl rise and tau pr ov ide the mos t ab rupt intensily
change . Signals must be ti me -related to the display for a
stable display . Use ful lor adding time mar k ers in un-
calib rated modes 01 o per ation .
49.
Un e Fuse Ho ld er - Contams the line fuse and the
regulating range
selec tor.See Table 1lor ch ange info rma -
tio n,
50. Regulating Range Select
or - Shown in Medium
regula
ting range , See Table 1 l or chen qe in forma tion .
51. PR
OBE POW ER- Power source for act ive p robe
systems .
52.
Lin e Cord - Makes the connec uc n be twee n tne
oscilloscope and the po we r sou rce , The co rd may be
conven iently stored by w rapping u ar ound th e teet on tne
rear p ane l.
53.
MOO SLO TS - A number in ermer sial ind icates
tne i nstrumen l c onta ins an op tion or other mod ific at ions ,
LEFT SIDE PANEL
Acce ss Ior extern auy a vailable a dius t-nents (see Fig 7).
RIGHT SIDE PANEL
L INE VOLTAGE SEL ECTOR SWIT CH ( loc ated on tee
righ t s ide) -Se lec ts eithe r t 15 V or 230 V nomina l line
vortace.
14 475
/0M44 O pera t or s@

51
50
CH 1 GAIN
53 CH 1 GAIN S mV
__ 2 mV _
:-----; - ~ . "'l:' I
QIi ' ;:: - ~ ~ " ' - ~
~ O';;: ~ ~. :'':J
..1 - ~ ~ -- . , ~
C "'~ <, ~ --- '\
<, 47 ---...j \/ CH2 GAlN
~ _ ' mV
4 8 ~ C H2GA lN
I .. 2m V
20398
Fig. 7. Rea' p.~ 1 and !ell . kI, p ane l con lrol•. conneclors. lind indic atoll .
@475,OM44 O
pe- ralors 15
BASIC OSCILLOSCOPE DISPLAYS
The se instructions pe rmu the operato r to obtain the mosl commonly used b asic displays
NORMAL SWEEP DISPLAY
1. Set the controls as tcuow s: INTENSITY Display
Full y cou nterclo ck wise
2_ Pull the PO WER SWi tch (on) . Connect the signal to
the CH 1 Input connec tor .
T
rigger
(Both A and B II a ppli cable)
+
o
NOAM
AC
AUTO
N ORM
SLOPE
LEVEL
SOU RCE
COUPLI NG
TRIG MODE (A on ly)
A TRIG HOL DO FF
ver neet
CH 1
Pe
s.non det erm i ned by
amplitude 01 signal 10
be app lie d
Cali
brated de ten t
AC
Midrange
Not hrmted (yello w band
not
visible)
But ton ou l
VERT MODE
VOL TS/ DIV
VOLTS /DI V VAR
A C-GND -DC
Vertical PO SITI ON
100 MH z-20 MHz B .......
INV ERT
Horizontal
T
IME / DIV Swi tc hes Locke d together at 1 ms
A
TlM E/D IV VAR C alibr ated de tent
HOR IZ DISP LAY A
X
l0 MAG 011 (button out)
POS I TIO N M idra nge
3
Adjust the I NT E NSITY cont rol lor the desired
display brlght ness_ If the display is not visible with the
INTE
NSITY con t rol at midrange . press t .., e BEAM FIN DER
pushbutton and adjust the CH 1 VOLTS /D IV SWItch to
reduce the ve rtic al d ispl ay size Cen ter the comp ressed
disp lay with the ver tical and ho rizo ntal POSITI ON con-
tr ols; release the BEAM FINDER cus n eutton .
16 475 /0 M44 O pera tor s@

4. Set the CH 1 VOL TS/DIV swi tch and vertical
POSI TION con trol to loca te the display within the d isplay
area.
5.
Adjus t the A T rigger LEVEL control for a s table
d isplay .
6. Set
the A TIME iD IV switch and the horizontal
POSIT ION con trol to loc ate the display within the display
area . Then adjust the FOCUS control as needed
MAGNIFIED SWEEP DISPLAY
1. Obt ain a Normal Sweep Display.
2.
Adjust the horizon tal POSITIO N con t ralto move the
area to be ma
gnifie d to within tne cen ter qratrcute civiaion
(0 5 division on each side of the center vertical graticu le
line) . It may be necessary to change the TI M EIDIV switch
se tting.
3. Push the X1Q MAG switch (on ) and adjust the
ho rizon tal POSITIO N cont rol for p recise posi tioning of
the magnified d isplay . Divide the T IME /DI V selling by 10
to
dete rmine the m agnified sweep rate.
DELAYED SWEEP DISPLAY
NOTE
Differentia/ lime measurem ents and measurements
usmg the T/ME or 1f T/ME funcfio'1s of the DM 44 are
in valid when theB TriggerSOURCE switch is not set
to STARTS AFTER DEL AY.
1. Obtain a Normal Sweep Display.
2. Set the HORIZ
DISPL AY switch to A INTE N and the
B Trigger SOURCE swi tch to STARTS AFTER DEL AY.
3. Pull
out on the B T1ME/DIV knob and tur n cw u ntil
the intensified l one is the desired length Ad just the
I NTE NSITY control as needed to make the int ensif ied
lone dist inguishable from the rest of the d isplay . If your
ins trument ISe quipped with a DM44, set the FUN CT I ON
switch to a function o the r than TIM Eor l !T IME for a s ingle
delayed sweep . Dual delayed dis plays are discussed in
step 6.
@475/DM44 Operators 17
4. Ad just the DELAY TIME POS ITION co ntro l to move
the
inten sified l one to cover the port ion of the display to
be disp
layed in delay ed form.
5. Set
the HORIZ DIS P LAY switch to B DLY 'D The
in
tensif ied lone noted in steps 3 and 4 is now d isplayed in
delayed form . The del ayed sweep rate is indi cated by the
dot on the B TIME /ON k nob .
6. If y
our instrument is equipped with a DM44 de layed
displays of two signals can be obtained at the same t ime .
The DM44 will ind icate
the time differen ce b etwee n the
beg
inning 01the del ayed displays. To obtain two delayed
disp lays set the FUNCT ION switch to TIME and the VERT
MODE switch to ALT. The DELAY TIME POSITI ON
con
trol pos iti ons b oth d elayed displays . The ALT DELAY
c ontr ol positions on ly the CH 2 delayed displa y.
7. F
or adelayed display w ith less jitter , set the B
Tr i gger SOURCE switc h to the same position as the A
Tri
gger SOURCE swit ch and adjust the B LEVEL c ontrol
for a stable disp lay .
MIXED SWEEP DISPLAY
1. Obtain a no rmal sweep d isplay .
2. Pull
out on th e B TIME /D IV k nob and turn cw to the
desired sweep rate. If your instrum ent is equ ipped w ith a
DM44 set the FUN CT ION sw itch to a func tion ot her t han
TIME or l /T IME for a single mixed disp lay . Dual mixe d
disp lays are discu ssed in
step 4.
3 Set the
HQRIZ DISPLAY swi tch to MIX. The display
n
ow c onta ins two sweep rates. The first p ort ion of the
di
splay is at the A sweep rate while th eta tter p or tion ofthe
disp lay is at
the B sweep rate . The start of tne e sweep rate
por tion can be ch a nged by a dju sting the DE LAY T IME
POSITION con tro l.
4. If your
instr ument is eq u ipped w ith a DM44 , mixed
sweep
dis plays of two s igna ls can be obtained a tthe same
tim e The DM44 wilt indicate the t ime d tte rence betwee n
the
begin ning of the B sweep p ortio ns of the tw o displays .
To
obta in two m ixed sweep d ispla ys set the FUN CTI ON
switch to
TIME and the VERT MODE swi tch to ALT. The
DELAY TIME PO SITION contro l po s itio ns both mixed
displa ys. The t. TIME co nt rol pos ttfc-ts only the CH 2
mixed display.
X-Y DISPLAY
1. P reset the instr u ment con tro ls as give n in step 1 of
N
ormal Sweep Disp lay, then turn the instrument p ow er
on. All
ow several min ute s lor instr ument war m- up .
1B 475
/D M44 Operators @

2. Set the TIME /DIV switc hes to X-V and the VERT
MODE s
witch to CH 2. Apply the vertical signal 10 the
CH 2 OR Y input
connector and the horizon tal signal to
the CH 1 OR Xinpu t
connec tor .
3Advance the INTENSITY control until the display is
visible.If the display is not vis
ible with the INTE NSITY
control at rmdraeqe.press the BEAM FINDER pushbutton
and adjust tne C>-i 1 and CH 2 VOL TSIOIV switches until
the displ ay is reduced in size, both ve
rtically and horizon-
tally . Cen ter the comp ressed display with tne POSITION
controls (CH 2 POSITION v
ertically , CH 1 POSITIO N
horizon t ally ): release the BEAM FINDER pushbutton.
Adjust the FOCUS con trol lor a welt-defined display.
SINGLE SWEEP DISPLAY
1. Obtain a Nor mal Sweep Display . For random
signals, set the trigger ci
rcuit to trig ger on a signa lt t1 at is
appro xim ately the same ampli tude and frequency as the
random
signa l.
2. Push the SI
NGl SWP button on the A TRIG MODE
sw-tcn . Th e next trigger pulse starts the sweep and
displays a s
ingl e trace, If no triggers are present, the
READY
lamp lights, indicat ing the A Sweep Generator
circu it is set and waiting to be triggered.
3, Alter the sweep is complete . the circuit is "lock ed
out " and the READ Y lamp is out. Press the SI NGL SWP
button to prepare the circu it lor another single-sweep
dis play.
@475
/0M44 Operators
DM44 DISPLAYS AND MEASUREMENTS
19
Exc ept for the TIME and 1/TIME funct ions, the DM44 is independently usable anyt ime the osci llo scope is turned on.
The TIME
and l /TIME functi ons are discussed in the OSC illoscope App licati ons and Measurementss ection of this manua l
un
der Delayed or Mixed Sweep Measurement s,
RESISTANCE
( ~ ~ ~ ; ; ; ; ~<
\.. ." ,.,. , ,. ,,,,1
The meter may be dam aged by allempring /0
measure volta ge if rhe meter is in the resistance
mo de of co erenon (O HMS FUN CTI ON button push -
ed
in) and the a ppli ed voltage is in excess of 120 V
rms.
l . Push in the OHMS FUNCTION b utt on and the
20 MO
RANGE butt on. See Fig. e.
2. Co
nnect tne +and COM leads to the unknown
resistance.
3.
Reduce the range. using the followi ng table, until a
pro
per readout is obtained.
TABLE 2
ResistanceRanges
RANG E REAOOUT MEASUREMENT
20 MO 20.00 0
200 20 MG 2 MO
2 MO 2.000 0.200 2 MO 200 kG
200 kG 200,0 20.00 200 kG 20 kCl
20 kG 20,00 02.00 20 kG 2k0
2k0
2.000 -0 .200 2 kO -20 0 0
200 0 200,0 000.0 200 0 00
A blink ing readout on any range, when co nnected to
any unk nown res istanc e, indicates an o verr ange cond i-
tio n and a need to select a t1 igher range.
A blinking readout.
whe n meter leadsare disco nnected
is no rmal.
20 475/
0M4 4Operators @

RESISTAN CE
INP
UT
RA NGE SELECTION 1
465 / OM'O· 2 1 20 39 ·9
Fig. 8. Resistance.
@
VOLTS
\ -~-~--~-- '
~ CAUTION ~
),,-" . .... -'"-'" . ..... .... -'" -"' ~
The ma ximum safe in put voltage is ± 1200 V (dc +
peak ec ) between the + and COM inputs or between
me + input and chassis.
The ma ximum CO M flo atin g volt age is ±500 V(dc +
peak ac ) 10 chaSSIS,
Tne meter may be damaged by a ttempting to
measure vol tage if the meter is in the resistance
mode of operation and the applied volta ge is in
excess
of 120 V rms.
If tne rea din g excee ds 1200 V or the readout blinks
(indicating ov err ange) disconnect the + lead at once
to pr even t possible meIer damage.
475 /0M44 Opera tors 21
3. Reduce the range. using Table 3. until a prope r
reado
ut is ob tain ed.
NO TE
When no voltage is appli ed in Ihe 20 V to 1.2 kV
ranges.the
readout is 0000 and individual readout
elements may blink. Also, noise picked up by the
meter leads may increase Ihe readout in the.2 Vand
2 V ranges .
A blin king rea doul on any range inaicetes an
o
verrange condition and a n eed to select a higher
range.
TABLE 3
Volt s Ranges
1. Push in the VOL1 5 FUN CTI ON button and the
1.2 kV RANGE b utt on. See Fig. 9.
2.
Con nect the CO M MO N lead to the reterence point
(usu all y a g roun d or test point) and the HIGH lead to the
un
kno wn vol tage to be mea s ur ed and observe the reading.
RANGE READOUT MEASUREMENT
1.2 kV 1.200- 0.200 1.2 kV
-200 V
200 V 200.0 020 ,0 200 V 20 V
20 V
2 0 ,OOO~0 2,OO
20 V 2V
2V
2,000 0.200 2 V ,2 V
200 mV 0.200 0.000 ,2 V OV
22
475 fOM44 Operators
@

VOLTAGE
INPUT
REF EREN CE
'ii f !ff,
ii.. :t
14 6 S : 0M- O-31 20 J 9- 1 0
Fig. 9, verts.
@
TEMPERATURE
,1'1' 1''J" ''.I'J' ' .I '.1
} CAUT ION ~
\.-,.,.,.,.,,.,.,.,..\
475/DM44 Ope rato rs
NOTE
Temperature accuracy is affected by several factors
such as the angle olcontact between the probe and
the device 10be measured , a th ermal gradien t, heat
remo ved from the device by the probe . etc.
These
items and Olher probe information are in the
probe manual . which should be reviewed.
23
The maximum sete voltage on the measur ement
sur face is ±400 V (dc + peak ec} abo ve chassis
ground _
The
sensor tip is fragile and may brea k i1droppedor
subj ected to excessive stress. Force exerted on the
sensor tip should no t e xceed 20 pounds .
If the
reading exceeds - 55° C or + 150°C, remove
the probe al once to prevent probe damage .
1. Push in the TEMP (Q C) FU NC TION bu tt on. See
Fig _
10_
2_ Apply the tempe ra ture p robe to the device to be
measured so the flat surface of theprobe tip mates against
the dev ice to be measured and observe the readi ng See
Table 4 to conv ert the r eading from cent igrale to
fahrenheit.
Accuracy Check
The DM44 is cali brated to its o rigina l p robe , giVing
accurat e r ead ings within 2°C f or examples that follow.
The DM44 shou ld be recaubrateo to any replacement
probe .
In the following
chec ks , use an accura te thermometer
to veri
fy water temperature. Anything in solution affec ts
the melting
tempera ture and the boilin g poin t is affected
by changes in alti tude and b aro me tric pressure .
low Temperature
Allow a container (preferably insulated) of c rushe d ice
to melt
unt i llhere are on ly a few pieces of ice remaining
24 475 /0 M44 Ope rators
@

PROBE
INPUT
NO' /1
THIS "'J
AP PLY S IL ICONE GREASE
TO THE SURFACE TO BE
M EASUR ED (WHEN POSSIBLE).
SENSOR TIP
-iii ·- ·~ i
SEA LE D PORT ION
T H1S ...d
1 4650M-0-412039-11
@
475 fDM44 O pe-r alors 25
-50
TAB LE 4
CENTIGRADE TO FAH R ENH EIT CONV ERSI ON
CENTIGRAD E
FAHREN HEIT
CENT IGRADE o-
50
-40
-40
10
-30
-30 -20
20
-20
-10 0
30
- 10
10
40
o
FAHREN HEIT
CENTIG RADE
FAHRENH EIT
CENTIGRADE
50 50
60 60
70
100 110
90
120
100
26
FAHRENHEIT
220 230 240 250 260 270 280 290 300
475/ DM44 Operator. @

\ "- '.1'.1 .r.r ....
, CAUTION ~
, <
................ " ....... ..- ... -.
To prevent possible probe damage ,be sure only the
sealed portionoflheprobeis Immersed (see Fig. 'O }.
Put
the probe tip int o the water , avoid ing the side or
bo ttom of Ihe co ntaine r, Wait lor the readout to stab ilize .
indicating tne probe has reached the
water te mperature .
The readout should be - 2 °C to 2 °C . There should be
Ice
remain ing after the test to verify that inserting the
probe did n ot raise the water temperature
High T emper atur e
Bring water to a sl ow b oil (to prevent spla lle ring ). Put
me pro be trp into the wa ter ,avoi ding the side or b ottom of
the container . w a.t tor the readout to s tab ilize, indicating
the probe has re ached the water tempe ra ture .
The readout sh ould be between 98°C and 102°C for
clean wa
ter at sea level.
TIME AND 1 /TIME
See DM44 DELAYED OR MIXED SWEEP TIM E
MEASUREMENTS in
this manual.
@475
/DM44 Operator s
APPLICATIONS AND MEASUREMENTS
Refer to Basic Oscill oscope Displays as needed to obta in correct d isplays
27
Si gnal Ground
PRELIMINARY
provides a measure of protec tion to the external circuitry
by reducing the c urreot revets that can be drawn from the
externa l circuitry d uring capacitor charging,
., .....-,,__ ' /, __ ,' -'J"J~.r
~ CAUTION ~
~ J _.r-.r ,-.r~
Av oid cross-grounding because instrument damage
may occur .
The most reliable me asurements are made when the
os
cilloscope ground is connect ed to the ground of the un it
under test by the ground strap on the signal probe . Also a
ground lead can be connec ted to the ground banana jack
on the oscilloscope chassis to estaortsh a comm on ground
with the un il unde r test
I
nput Coupling C apa citor Pr echarging
In the GND posi tion , the input signal is connected to
ground t hrough a one-megohm resistor to torm a
prech arg ing network . This ne twor k al lows the Input
Co upling c apacitor 10 charge 10 the average de vo ltage
level of the
signal applied to the p robe Thus, any large
voltage transients
accid entally generated will not be
a ppl ied to the ampli fier inpu t The precha rge networ k also
The 10 1J 0wing proce dure should be used whenever the
probe up is co nnec ted to a signal sou rce having a di fferent
de level than that prev iously appl ied, especially if the oc
level
cttterence is more than 10 times the VOL TS lOIV
setting .
1.
Befo re connecting the probe lip to a signal s ource ,
set
the Input Coupl ing switch to GND.
2.
Touch the probe tip to osc illoscope chassis ground
Wait several seconds for the Input Cou pling capacitor to
discharge .
3.
Connect the probe tip to the signal source,
4. Wait several seconds for the Inpu t Coupling
capacitor to charge ,
5. Set the
Input Coupling Switch 10AC The d isplay
will remain on the s creen so the ac component of the
signal can be measured in the normal -nanner-.
2.
475 /DM44 Operator s@

OPERATOR'S ADJU STMENTS AND
CHE
CKS
To verify measurement accuracy . perfo rm the follow-
ing ch ecks and adjustments before making a me asure-
ment See the C alib ration section of the Service manu al
ror calibra tion inf or mation.
Trace R ol atlon Adjustment
Normally not requi red.Obtain a Normal Sweep Display
using o nly steps 1 through 3. Set the CH 1 input Coupling
switc h to GND to display a tree- runmnq trace with no
vertic al d eflection . Adjust the TR ACE R OT ATION (screw-
driv er adjustment loca ted belo w the cr t qratrcule } to align
the trace with the center horizontal gra ticu le line.
Probe C ompe n sat ion
Miscompensa-ion is one of the grea test sources 01
opera
tor error. Most at tenuator probes are equ ipped With
adjus t ments to ensu re optimum measur emen t accu racy.
P
robe com p ensa tion is accomplished as follows'
Obtain a Normal Sweep Dis play presen ta tion of the
ca libra tor squar e -wave voltag e Set the app ropriate
VOL TS /D IV switch to .1 V position and the Input coupling
to DC . Check the wavefor m presen tation for ov ershoot or
rouou. and if necessary , readjus t comp ensation for flat
tops on the waveforms . See Fig . 11. Refer to probe manual
for method of com pensa ting the p rob e being used
1
CORREC T
k ··
FlAT
..
--
•
IIOVER COM·
PENS ATED
![
OVERSHooTl
..
,
'T
1 "-
rr
,...."
Ir0UNDER COM-
PENSATED
tI " '-'-
IROllOFF )
....... -......
46S /DM·O·S
Fig. 11. Probe comp ensation.
@47S
/0M44 Ope ralors
29
V erti cal Gain Ch e ck
Obtain a Normal Sweep Display presentation of the
calibrator square-wa ve Voltage. Set the appropria te
VOL TS /DIV switch to the 50 mV position and the Input
Coupling switch to DC. Make sure the VAR VOL TS /DIV
control is in the calib rated detent. Check that lhe vertical
deflection is 5.8 to 6.2 divisions .
B
TIME /DIV
HORIZ DISPLAY
B SOURCE
FUNCTION
t:. T IME
5 ",
AI NT
STARTS AFTER DELAY
TI ME
To move the
time-
m easurement point to the
right of the reference
po int.
Ba s ic 475 Tim ing Ch e ck (60 H ertz Lin e Only )
Obtain a Normal Disp lay . Set the A TIME /D IV sw itch to
5 ms
position , Set the A Trigger SOURCE switch to LINE.
Push
the TR IG VIEW swi tch and hold it in , Th is disp lays a
sample of the line vo ltage . Use the A Trigger LEVEL
control to vertically posi tion the top olthe displ ay to with in
the display area. Use the ho rizonta l position control to
position the lef t peak to the left gra ticule edge (see Fig.
12). Ve
rify the h or izontal distance be tween the lirst and
the fou rth peaks is 9.8 to 10.2 divisions . If the fou rth peak
is
not visible. verify the horizont al d istanc e between the
first and the third peaks is 653 to 679 div isio ns
DM44 Timing Ch e ck (60 H ertz Lin e Onl y)
Per
for m the Basic 475 Timing Chec k to ve rify the
accuracy 01 the horizon tal de flection syst em .
Leave
con trols set as for the Basic 475 Timi ng Check
except as follo ws'
9.8 TO 10.2
6.53 TO 6.79
,~
....
.. ..
'"
I
•.... .... ... ..
1738 -14
Fig. 12. B asi c475 liming check.
30 47SID M44 O
perat ors @

Push the TRIG VIEW b utton and hol d It in. Use the
DELAY TIME POSITION con trol to mov e the reference
po
int to the center horizontal qra tic ufe line (see Fig. 13.
Po int A). Use the ALT DELAY con tral to move the ti me-
measurement point to the cente r hor iz ont al qraticute nne
on the next cycle (see Fig 13, Poin tB). Verify th e readout
is 16.49 to 16.84 and the rns l amp is lit
I
, ~
J.
<a
•
~
~
1\
I
,
1
"I
0 ,
I1
73a-1 5
f ig. 13. OM44 timing cheCk.
E xt ern al H or iz ontal G ai n Ch eck
(It X-Y operation is to be used .) Use steps 1 through 3of
the Basic Osci llo
scop e Displays procedure for obtain ing a
No rma l Sweep Display of the ca
ibrat or sq uar e-wa ve
voltage wavef
orm ; then, set the TIME /DIV switch to X-Yo
With the ca librat or signal connected to the CH 1OR X
input conn ector and the CH 1VOLTS /DIV switch set to
50 mV, the cr t displ ay sho uld be two dot sseparated
h
or izo nta lly by 5.75 to 6.25 divisio ns.
PEAK-TO-PEAK VOLT AGE
MEASUREMENTS- AC
Obt ain a Normal Display , Make sure the VAR
VOL TS /DtV control is in the calibra ted d etent. V ertically
position the d isplay so the lowe r portion coincides w ith a
h
orizontal qratrcute line (see Fig, 14. Point A) Horizo nta lly
p osit ion the display so one ct the upper peaks co incides
with the cen ter verti cal g raticule l ine (see Fig ,14. Poin tB).
Measure the ve rtical deflec tion 'ro m peak- to-peak (Point
A to
Point B)
@475/D M44 Operato rs 31
Mult ipl y the vertical def lect ion just measured by the
VOL TS /DIV s witc h sett ing Also include the atte nuat ion
fact or of the pr obe if the pr obe doe s not have a scal e-
factor sw itch ing connector.
Substitut ing the given values'
Examp le: The peak-to-peak
meas ured is 4.6 divis ions (see Fig
sw
itc h sett ing of .5.
POSITION TO
CENTERLI NE
'. B
•
,.
l~-- ~
--I
1\
~ (A
II ,II
,
'I
VERTICA L
~ /
DEFLE CTION
..
J
,"
'J !L
0
MEASURE AMPLIT UOE
FRO
MATDB
(1 738 16 12 0 39 ·15
Fig. 14. Peak -l a-peak vol tage of a ..... avef orm .
Using the f orm ula:
Volts
Peak-to -peak
vertic al
deflection
(divisions)
vertical defle ctio n
14) with a VOL T SIDIV
X VOL TS /DIV
se tting
NOT E
If 'he ampJirude measurement IS cnucet or if the
trace is thi ck as a result of hum and 'or none on Ihe
Signa l, a
more accurate measurement can be ob ·
tetnea by measur,ng from the t op ot a peak 10 the top
of a 'rIal/ey. This Will socrrecr the trace thic kness from
the measurement .
Volts P eak-to-Pe ak = 46 X0,5 V= 2.3 valls .
INSTANTANEOUS VOLTAGE
MEASUREMENTS -DC
Ob tain a Norma l Display , Make s ure the VAR
Val TSi OIV con trol is in the ca librated detent.
32 475 /0M 44 Ope rat or s@