Fairchild 74-13A User manual

rup 74.134 aALTEf,ATED DE
lnrlruclion
CALBNATED DETAYING
Monuol
Serlol No.
G
Ihir Plug-in llodulc ir dodgncd for urc with lhc Foirchild Typc 766H
Srriot Orcillorcopc. lnrcrt lhir lrtonuol into thr Undcr you rocrivcd
wllh tho Typc 766H Sorior lnrtnrdion Mqnuol.
fl.rl-t N.. aroa t,lra
FAIFIEHILE'
INSTRUMENTATION
,0 torlt,ar ttaca. clttTox, x. r. 07ota
@) liii {tir.lllu rccr.ro .rld hir.rr.nt Ccrp,
f_.-,--

scc'ion Tillc
t. IECHMCAT 'UNMATY
In troduction
i..ftni."t Summary (Specifrcations) ""'
Introduction
Trigger Circuit Description "- '.- --.- '
Triccer Clrcurt D€scrlPuon
Ciri[it Description of Normal s]'*P --
Clr.oii pet.tiirtion of Triggered'
rcuit LrescrrPu
Strobe Mode
Circuit DescriPtion
r'iocared i{ode
Triggered tion of DelaYcd-
Circuii DescriPtion
Strobe Modc ........ of Armed-
Circuit Description of DclaYed' rcult lrescnP
Anned Mode
Horizontal Deflection Circuit
Description
.. PERFOI'IIANCE A'IUIANCE IESI
4-l Maintenance Check to Assure
Performance
Sccaion Ti lc
5. IITAINTENANCE AND IECAIITIAIION
Figurc Titlc
Electrical Parts List
Soare Parts List ..... ................
ilist of Recommended Vendors """ "" "
CHARI
Sweep Check Calibration Chart .""""" 4-2
IlLUSTRAIIONS
Pagc
l-l
t-2 r.t
r4
2. OPEiATNo |NSTIUCIIONS
2-l Fint Time OPeration " ""' ""' 2-l
i.i s*ap-rriesding - ,--- tl
z-i itic&t-s"ir'.ce $lectiot' ?-l
;-i i;r"&; C;piing selection ?1
i: +iffii*mrk":l n^
i-i s*l6bp.*tional Modes ?-!9
z.i s*reeb Eipander """2-lI
i-6 s;;;'p c"Iiur"tion Adiwtment "" " "" 2-l I
I-io x-v bisptavs : 2-12
i-ii 6"t o,itp,it ..... '. ---- . """ z'tz
i-ii s-"*tJtt 'o"tPut ' . """ " """' ?'l?
I-ii fi-i-lt."t"rimet'ts .""""" "'' ?'l-Z
i-ii ;i"i'sillii Measunments 2-15
i is P"t* wia,n$;3suremena ulT ,-,,
2-16 Pulse Width Measurements Using
the DelaY Vernier Control --" "" ""' z'lt
2-l? P;il llii.-i u...,rrt-tnts - - "" "" ' """ 2'14
3. CIICUTT DESCTIPTION 6-l
6.1
&9
6A
6B
2-3
2-5
2S
E-r
3-l
3-:'
E6
4-l
4-l
+l
4-2
4-2
4-2
+2
4-3
4-3
3-l
3-2
&t
34
5-5
36
E4
3-8
4-2
4.'
+4
4-5
4.6
+7
4a
4-9
4.10
l-l TyPe 74-l3A Delaying Sweep Time
2-la TyF ?4-13fi. Function of Controls and
Connectors
Base PluEln
me 74-l3A Ft
z-lb TyPc ?4'l3A Function of Controls and
Connectorc
2-2 TvDe 74-l3A Normal Display ' """ ' "
2-5a Tft 74-l3A Triggered Strobe Display "
Checlins SweeP Calibration
Ct..rin! Trig5ier source and Polarity -
D€laY Calibration che
NDT Gare Out Ch€ct . ... ............ . . .4-2
Pagc
r-2
2-2
Cnecrini Nofral, Triggered and
Armed Swecp Displavr ........ .........
i-3b liire 7$l3A DeliYed Triggered
DisPlaY .... . ........ """r 'r-' " '." " '-':'-
Armeil Sweep Displayr
:lav calibration Cheak
2:7
2-8
2-9
2.12
2-1,
2-r5
NDT Saw Out Chect
bual Trace Switch Trigering Chect " "'
Beam Positioning IndiCitor Checl """""
Auto Triggering-and HF SYnc Check "
2-42 Tvrr-'7+lr{ Armed Strobe Display "" ""
i-lu f'vix Z+-ts,t Armed Delayed Display " "
2-5 Elibs€d Time Measurement . " '
2{ Finhing the FrequencY
2-7 Phase - Shift Measurements
TABLE OF CONTENTS
Page
34
t-10
3-10
5-l lntroduction '.""""" "" 5-l
i-i r{L.o"rl and RePlacemenl oI Parts "" 5-l
s-5 s.i"iii"s Hints .1. . ....... - - " " """" "" ' 5-t
i+ c.i"ind,t.."s to Chasis .. .. .......-. "" """" ' ' 5-2
6.i iiii iiuip*.nt Required for Service
Adiuitniena .... "" """"""""""" ........ "' " 5-2
56 Ni?E-DA irig Sens Adiustment ' "" "' 5-2
l] i'l'-*l'llaut;i;;;ru;;;,;.;; i'!
5-9 NDT Swcep Length Adiustment """ """ t'r
i-io 3i.'* si'iii'c.iXdiust 1'Front Panel) 5-5
5-lt DA Swecp Length Adjustment """ """,'' 5-5
s-ii 5*Lp n'ia Bai Adluitment 5-5
6-ii iio 'n.gi."ation -1 5'4
5-t4 X AmPliEer High'Frequencv
Adiustment 5'!
5-I5 x' iil;i- DC Balance Adjustment ' ' "" 54
5-16 Fast Sweep Calibration Adjustment """ '-5
5-17 Strobe IniensitY and Pattern
" " "-C;;.;ii;; A'djustment q-9
r-re o.;v- Z.io Adlrisrment " ' "" "" " ' """"""' 5'5
;-i, D;i;i,c,i aaj"i.*.", 5'5
6. PAiTS USI3 AND SCHEIVIATICS

lt[USf iAIIONS (Contlnucdl
Pagc
2-r3
2-14
2-t4
3-2
Figurc
5-7
3.E
3-9
3- 10
3-l I
Pagc
3-9
3-r0
3-l l
3-r2
Titlc
Sinrplifred Tinring Diagranr for
Delayed-Triggered Display
Arured'Strobe" tod., frir.tion"t ttio.L
Diagraur ...... .. ........ ..
Simpli6ed Tinring Diagraru tbr
Delayed-Armed Strobe Display ............
Delayed-Arrrred Mode, Functional Block
Diagranr
Simplified
3-2
3-4
rrplified Tiuring
Delayed-Arnred Diagraur for
Display ............
Figurc
2-8 Pulse Width
2-9 Pulse Width
Tialc
Measuremenb
Measurenrents Using
Circuit, Functional Block
3- 13
3-12
54
5-7
5-E
5-r
5-2
5-3
6-l
3- 12 Horizontal Deflection Anrplifier,
_ -Func,tional -Block Diagram ---. -- - -
Right Side View Showing 'I'ransisrors
and,A.djustrrrens
Left Side View Showing Transistors,
Nuvistors and Adjrrstrrrenrs .. ........
Top View Showing Transistors and
Adjustments
Front Panel Replaceable Parts ..... ............. .. 6-0

section I - technicol summory
.,,.-
*"-***\f.-
i,t{ jil
DEI.AYID colrPt e
cufrot f,t
l-2
Figutc l-1. fype 74-l3A Calibtoled Deloyiag Sweep Plug-la

SECTION I
TECHNICAT SUiAXTARY
I.I. INTRODUCTION
PTEASE NOTE
IMPORTANT INITIAL ADJUSTMENTS
MUST BE MADE BEtr'ORE OPERATING
THIS PLUG-IN MODULE' See Paragraph 2-l
entitled "First Time Operation" in Section 2 for
instructions.
The Type ?4-ltA Dual Time Base Calibrated De-
laying Sweep is designed for use with the Fairchild
Type 765/765IJ Series of Transistorized Oscilloscopes'
To simpli{y circuit description, the following ab-
breviations are employed to describe the dual tine
base delaying sweeps.
Dercription
The NDT sweep rettrs to Normal
Sweep operation and Delaying Trig'
gered operation (i.e., the delaYed
sweep starts immediately after the
delay pick-ofi trigger is generated).
'l'he DA sweep refers to Delayed
Arrrred operation (i.e., the delaying
sweep (NDT) generates a delay pick'
oft trigger which anns the DA sweep).
An input trigger signal is then re-
quire<l to fire the DA sweep.
I.2. IECHNICAI 5UIAf,IARY
The perfortrtatrce specificatiorr of this plug-in
rurodule is given in the technical strrnnlary which
[ollows.
Abbrevictlon
NDT
DA
t-3

section I -technicol summory
TIiAE BAsE sYsTEM
Cqlibruted Sweep f,onge (NDT & DA)
Colibroted lineqr iweep rqtes from 0.1 ;lsec/div to
2 sec/div in 23 steps of l, 2, ond 5 requencc
Uncolibrqted Sweep Ronge
The Sweep Vernier conlrol providcs o coniinuous
uncqlibrotcd ronge of sweep rolcs between ronget
ond exf€nds thc 2 sec/div ronge to 5 sec/div (50
:econds full scqlel. The UNCAI lomp leryc! oi qn
indicotor of uncolibrqted or yernier operotion
Swecp Accuroty
t3% meorured over the centered 8 div poriion of
lhc CRT screen
Sweep Ronge lndiaoto.
Push-pull clutch knob permits simultoncous or inde-
pendenl control of the NDT ond DA sweap rotes
Swcep Exponder
A cqlibrqted Xl0 swecp cxponder in the X outpui
omplifier will expond lhc rweep obout screcn
center; extends ,ortesl sweep role lo l0 nono-
seconds/div, Exponder occurocy is t5"L lor
rpeed3 fosier ihon 200 nonoseconds/div ond +3 %
for slower tweeps. Neglect the firlt 50 nqnosecondt
Sweep Colibrotion
A front-ponel screwdrivcr SWP CAt control i6 pro-
vided to pcrmit normolizotion of thc plug.in unit to
lhe Moin Frome qnd stondordizinq thc rweeps to on
externol timc atondord
Goie Out (NDT A DA)
Two fronl-ponel bonono iocks eoch provide o posi-
tive-going pulse of 2.5 yolts nominql. Outpui im-
pedonce is 500 ohms. For oplimum performonce,
lood impcdqnce should be greotcr thon lOOK ohms
ond shunted by less thon l5 pf. Gote is rcfcrcnced
direcily lo ground ond i5 time-coincident with the
swecp
5ow
Ponel bonono iock provides o posifive .ow outpul
of opproximolely 25 volts ond is coincident with
ihe NDT Sweep. Output impedonce is nominolly
l0K ohmr, ond lood impedonce should be greqte,
thon l00K ohms shunied by less thon l5 pl
Other Conlrols
lnlernol controls optimize setiings of outomoli€
strobe inteniity ond strobe ironsiiion. This normol-
izes the plug-in to the CRT of the Moin Frome qnd
ovoid: hoving to reset ihe iniensity conirol when
obrerving strobed disploy modes
l-4
SWEEP MODES
Normol Sweep Operotion
Conveniionql rweep disploy. lnlernolly or exiernolly
opplied trigger signols drive the NDT lime bose
circuil
Deloyed-friggered Strobe
Deloying rweep disploy showing lhe deloyed swcep
or o brightened reclor. The deloyed sweep stqrtr
immediotely ofier the deloy pick-off trigger is gen-
eroied
Deloyed-Armed 5trobe
Deloying sweep disploy showing ihe deloyed sweep
os o brightened rector, but dclqyed sweep (bright-
ened sector) i: ormed by the deloyed trigger ond
initioted by o sync lrigger
The deloyed sweep outomqticolly shuts ofl when
rhe deloying sweep is terminqted. Thie prevent3
brightening of the sweep retrqce in either STROBE
position
Deloyed Triggered or Deloyed Armed
The brightened scctor of the sirobe sweep disploys
ore exponded to full scole in either of the DE-
LAYED modei. Automotic proyision is mqdc for shut-
off of the deloying sweep (NDT) when the deloyed
sweep (DA) is lerminqied. Thir permits moximum
dury cycle performonce in the DEIAYED mode
Single Sweep
The sinEle iweep mode permits but one driven
sweep of the time bose lo oppeor oi the icreen
until ihe deloyed sweep {DAl is rescl or.eormed
The single rweep moy be reormed with q single
externql irigger pelse, by iurning the NDT Trigger
Level control or by switching the NDT trigger polority
swiich
The SWP READY indicotor is lit whenever the de-
loyed sweep goie multivibrqior i: ormed ond reody
to be irigge.ed
X Amplilier (for X-Y Disploys)
When the D|SPIAY LOGIC swirch ir 5et to X AA,IP,
X lnput signols moy be opplied to X Amplifier vio
EXT setiing of thc Trigger SOURCE switch ond pre-
lerobly " - Slope"
CAIIBRATED DEIAY IIME SYSIEM
Deloy Vernier Control
A len-turn precilion poteniiometer determinei the
on-icreen distonce lrom the deloying sweep (NDTI
itort o, which the deloyed sweep is either triggered
or ormed

CAIIBIAIED OETAY lll E SYSIEM (Concludedl
The DEIAY VERNIER control is colibroied io reod
from zero to l0 divisions. This control functioni qs
o Deloy Multiplier when used in coniunction with ihe
Deloyed TIME/DlV coorrol
Accurocy
lncrementol occurocy of the len-turn cqlibrqled con-
trol is within i0.25 %
Deloy Zero Conlrol
Zero deloy i: odiustoble from the front ponel. For
extreme occurocy, cny or oll steps con be odiuslcd
to on exlernol slondord from the front pqnel
Deloy Ronge
from o minimum of ya microsecond to more lhon
20 seconds
IRIGGERING SYSTEM
(Scporole fqciliiior for cqch fimc losc orc proyid.dl
HF Recur
A unique high-frequency stobility switch moy bc
used to improve counl down qnd lock-in of signolt
hoying repetition rqte of 5 Mc or grcqlcr. lt provides
iloble synchronizqtion of signols of I cm dcflection
to beyond 50 Mc
lnternol Trigger
Signols will trigger from 0.5 div of Y signol up io
I Mc; from I div of Y signol up to | 0 Mc wiih
Type: 76-01A, 76-02A,76-03 qnd 76-08 Modules
in Y covity. With the HF STAB control set to RECUR,
qdiurtment of the Trigger IEVEL qnd HF STAB con-
trols will produce o stoble disploy with 0.2 diviiion
o{ Y signol ol I Mc qnd 2 divisions o{ Y signol ot
30 Mc
Extcrnol frigger (Xl)
0.5 volt peok-to-peok lrom dc to I Mc will trigger
the sweep; I volt peok-to-peok will trigger the sweep
to l0 Mc. Trigger leveling, slope ieleciion qnd qc
or dc coupling ore included. Wirh the HF STAB con-
,rol sei io RECUR, odiusiment of the Trigger LEVEI
control will produce o stoble disploy with 0.2V to
lOV input ot I Mc
Externol Trigger (XlOl
Some frequency limits os exiernql trigger Xl; o
'10,1 qttenuqtor is provided to extend the dc level.
ing copobility to :t100 volts dc
Trigger Level
A ronge of i'l 0 volis (nominol) with respeci io
ground on exiernol lriggering
technicol summory - section I
Trigger Slope
Selection of positive or negotive slopes on lnternol,
Line, or Externol triggering is ovoilqble
[ine Trigger
Line frequency triggering con be selected in either
poloriiy ond the iriggering poinl mqy be :hifted
with the Trig LEVEL conlrol
Ext frig lnput lmpedonce
I megohm shunted by 40 pf (nominol)
AC Coupling
High-poss filter with low-frequency cutoff ol 80
cycles
DC Coupling
Direcf coupling is provided to optimize trigger 3ensi-
tivity when very slow woveforms ore opplied; to
mointoin lhe iniliol reference porition of lhe lroce
wiih respect to the CRT scole oi o given trigger level
setting; ond lo ovoid trigger point voriolions du€ lo
rondom repelilion role lrigger signqls
ACF
Differentiqled trigger input; high-poss {ilter is pro-
vided to reiect hum ond low-frequency omplitudc
modulotion; low-frequency cutoff nominolly l0 Kc.
Signols should rise or foll in lesr thon 100 prsec to
pois the LF reject filter
Automolic Triggering
Visible bose line on oll sweep ronges when there is
no iignql inpui, The rweep free runs uniil o lrigger
signol of l0 cps to l0 Mc is opplied. Applicorion of
q trigger signol switches the sweep to the triggcrcd .
mode immediotely
HORIZONTAI. DEFTECTION sYsTEM
Bondwidth
Direct Coupled: DC to 2 Mc; down 3 db ot 2 Mc
Copqcitively Coupled: Low-frequency cutoff is 80
cycles
Sensitivity (XI0 Exponsionl
EXT/XI Ronge: 0.1 voli/div
EXT/XI0 Rongc: I volt/div
X Vernier, A tert-io-one ottenuotor is pro-
vided in the horizontol deflec-
tion chonnel io exiend the inpul
signol ronge to l0 volts/div
Seniitivity (Xl Exponsion)
Reduces oll obove sensitivities by l0:l (Restricied
scon) I -5

rection I -technicol rummoty
\--. HOIIZO TAf DEfLECIION SYStEil (Concludodl X Poritlonins \
lnPut lmP'don" A fronr-ponal control p.rmitr coqrrc ond finc poai-
I mcAohm rhuntod by 40 pf (nominqll tioning of th. X lnput rignol or ony ponion oI th.
rwcap to withio iwo divirion! of rcrqGn caniar
lnFul Connaclot
x A lp froni-ponal conna€ror i! providcd ro parmil Boom Porillon lndltoloru
usc ol lhc horizonlql dcfloclion omplifior for X'Y Two indicqlor lonpr orc locotrd on th. tront pqnrl
dirployr. (DA EXT TRIG connccto. tGrvc, thit duql to qlad th. op.roior or lo the dircciion of tho Lcom
purporel whan ii ir poritioncd off lhc rcrccn
I
I
t-6
I

sEcTroN 2
OPERATING INSTRUCTIONS
2.I. FIRST IIME OPERATION
(Figurrt 2-l to 2-41
If this is the ftrst tinte these plug-ins have ever been
Used, then certain initial adjusttncnts rrrust be lnade.
For instructions, reler to Section 5, Maintenance and
Recalibration and to the paragraph indicated, and
nrake the tbllowing adiustnrents.
The following illusrations are designed to aid the
operator in beconring tamiliar with the Delaying
Sweep Plug-ins.
screen each time the sweep runs. This will either cause
the waveform to drift across the screen or to be unintel-
ligible. The sweep theretbre must be triggered by the
input signal, or by sonre signal which bears a fixed
tinre relationship to the input signal. For present Pur-
poses, the starting of each horizontal waveform across
the screen rnay be callerl "triggering the sweep." The
lollowing instructions tell yorr how to select and use
the proper triggering signal for various applications.
2.3. TRIGGEI SOURCE SELECTION
o. lnlernol
For rrrost applications, the sweep may be triggered
by the Y input signal. The only requirement is that
the signal amplitude be sufficient to triSSer the sweeP'
To obtain riggering of the sweep from the input
signal, set the TriSger SOURCE switch to INT. In-
ternal triggering is convenient since no external trig-
gering connections are required. Satisfactory results
are obtained in rnost applications.
b. Extemql
Sornetirrres it is advantageous to rigger the sweeP
with an external signal. Exrcrnal triggering is es-
pecialty useful where signals are going to be sampled
lrom several difierent places within an instrument.
With external riggering, the triggering signal usually
reurains constant in amplitude and shape. Thus, it is
possible to observe the shaping and amplification of a
signal in an external circuit without resetdng the
oscilloscope triggering controls for each observation.
AIso, time and phase relationships between the wave-
forms at difierent points in the circuit can be seen.
For example, if the external riggering signal is de-
rived from ihe waveform at the input to a circuit, the
tirrre relationship and phase of the waveforms at each
1>oint in the circuit are cornpared to the inPut signal
by the displayed waveform.
When a stable, external triggering signal is avail-
able, it is possible to observe and accurarcly measure
jitter of the displayed waveform with respect to the
trigger input signal. This is not possible when the
sweep is triggered internally. A trigger preceding the
signal nray b€ used to externally trigger the oscillo-
scope to display the entire signal.
External triggering should also be used with a dual-
trace amplifier module in the AlTernate mode to
show the proper time relationship between the two
displayed signals. To obtain a stable display, the ex-
ternal triggering signal must have an amplitude of at
Adiuctmcnt
NDT Swecp lcngth
Sweep Col
DA Swecp lcngth
Strobe lniensity qnd
Pqitcrn Correclion
Deloy Zero Adiurimcnt
Dcloy Col Adiurtncnt
Porogrcph
5-9
5-r0
5-l I
5-17
5-t I
5-19
Figures 2-l a
& 2-lb
Figure 2-2
Figure 2-3a
Figure 2-3b
Type 74-13.4, Function of Controls
and Connectors
Type 74-13A, Normal Display
Type 74.134, Triggered Strobe
Display
Type 74-13,{, Delayed Triggered
Display
Figure 2-4a Type 74-13A, Armed Strobe Display
Figure 2-4b Type 74-13A, Armed Delayed Display
Unless otherwise designated, it is presumed that a
Y Amplifler Plug-in module is inserted in the Y cavity
(left-hand side) and the Type 74-l3A Time Base
Plug-in unit is inserted in the X cavity (right-hand
side) of the Main Frame.
We know that you are anxious to get acquainted
with your new instrumenl To aid you in this en-
deavor, you may set up the insrument using the built'
in calibrator signal to demonstrate the effects of the
various conrols on the display.
2.2. SWEEP IRIGGEIING
Two trigger circuits are built into the Delaying
Sweep plug-ins. Each Time Base is provided with its
own separate triggering facility.
To obtain a stable display, the sweep must con-
sistently start at the same time relative to recurring
cycles of the input waveform. If the sweep is allowed
to occur at random or at a rate unrelated to the rate
of occurrence of the input waveform, the displayed
pattern will be traced out at a difterent point on the
2-l

section 2 - operoting instructions
\
DA FACITIII€S
DEI.AYIl{G SWEEP
Tdg!f,. Lr.l S.l.d.r,
FrI lrcb io .rt nd dc
l.tdini t +100V oll
.rr fig; ..w.. q! I
Y.rrb co.rrol Yh.o
OlSttAY IOCIC tril.n
T.i99.r L.v.l S.lGror:
pel t.ob to . .nd dG
le.ling io a l00Y on
*,'frfl' Yo ,Ih ''/'
H --o-- LDtuYEo nnuEo J
-O_ tl-l
l 5 2:
ltoflItt At{D DtuYilrG TimffitfiG
E*.rnol lrigs.r o. X
Ahpli6.r Input.on...-
Irifff, S.l.cl,o. .lidt
rit h.' 13) for lh.
[email protected] 5*..p
+ GAIE otpol <oi.-
.id.it *ilh rh. DA
Sw..9, 2.5V 500l)
SAW o{lput coin.id.nt
with rh. NDT 3w..p;
25V, l0(
I
+ GA'IE ouiFl,t .oin-
.id.nl wiih rh. NDT
Sw..p, 2.5V. 500()
Trigg.r S.l..tor did.
.wiiGh6 13, lor lhc
No.nql o.d D.loring
_l
IlI'
ul me
s0utct
I
.l cllt
r6flu t(I nttri0
rUIO
,S'
clnoi. i., u.st
Xt STAI .onhol im-
vs .&nld6vn dnd
il;tffhi'li*- s:I";,if:*# ::'.'i::,:J"ff:iJ?'
' rion .ot
I
NDT FACILITIES
Figvrc 2-lo. fype 74-l3A Funclion ol Controk ond Connecrort
s0ufltt
t
I
Ill
TRIG
uit
stP cll
C
#'t
2-2

operoting instructions-section 2
BEm mrilion
-l
DE[AYlliG SWEEP 11=
?#'ffiI" \-?J.h"..?-/ -t
-':-f\. ;lffu'*#"7*",*
SIVEEP CAL <onlrol
nornolir.! rh. Pl!9.ir
DELAY ZERO GontrcI
p.rmit! prci.. DEIAY
VERNIEI r..o odiurl- g#iitli
O-T;: LI
ffi uI nt6
s0uict
I
+ €llt
DISPiAY LOGIC aw ch
d.t.rhin.. 3w..p oF-
.,olionol modG, !..
Con..n[i. .onrol po-
{lionr normol o, .t-
pond.d dhplo, o.
!.ran; pull tnob 60r
Iox oos of dirploy
DELAY VERNIEI con-
l.ol d.t riin.. lh. on-
rc.... dirlonc. frcm
th. no'nol rwep ,orr
ot which rh. dcloy.d
,wcp ir .ilh.. l ig-
g.r.d 6r om.dr tun.-
lioh. dr on a..ordl.
d€loy Eultipli.r vh.n
!r.d eilh lh. DA
Dtut
TIORIIAL AITD DEI.AYII{G IRIGGTRII{O
PU(l
txT
'id Int!
J*:
NOr & OA Trl4E/DrV
S.l..ror !rit.h.s: lnobt
noy b. rctoi.d l,og.th.r
or th€ DA tw..p lnob
con b. di!.ngog.d ond
rot.l.d !.porot iy; con-
c.nric knob provid.r
Y.mi.r 3wccp opcrolion
IUNCAL lomp lightt)
ftrfru f,r
SWEEP READY lo'np
indi.ot.. DA Swnp ir
orF.d ond r.odI to
Figvte 2-lb. fype 74-l3A Fvnctioa o, Controls ond Cornecrort
sorJtct
2-3

section 2-operoting instructions
least 0.5 volt, peak-to-yeak (l mc) and bear a 6xed
time relationship to the disptayed signal. To use an
external signal lbr triggering the sweep, connect the
signal to the EXT TRIG connector and set the Trig-
ger SOURCE switch to EXT.
c. Line
lf the pattern on display bears a frxed time relation-
ship to the power-line frequency, the sweep may be
triggered by this signal. To accoruplish this, set the
Trigger SOURCE switch to LINE. Always use dc
coupling mode with LINE Trigger Source.
2-4. IRIGGER COUPTING SEIECIION
o. AC Coupling
Selection of the AC triggering rnode is accomplished
by setting the COUPLING switch to AC. This rlode
is provided with a high-pass filter that has a low-fre-
quency cutoff noruinally at 80 cycles, This feature
prevents erratic triggering when positioning the pat-
tern vertically and using internal triggering. In the
AC ruode, triggering is unaftected by the rlc com-
ponents o[ the triggering signal or by the vertical posi-
tioning of the race. The triggering level can be
selected to provirle the desired tlisplay via use of the
Tlig LEVEL control.
When using the AC rrrode, the Trigger COUPLING
switch is set to AC. The trace always starts at the sarne
point on the Wovef ol n for a given Trig LEVEL
control setting regardless o[ the vertical positioning.
Note: AC coupling triggering on the line-frequency
calibrator signal or lquare wave signals less than l(X)
cycles, rnay be erratic since the 80-cycle cutoft 6lter
severely integrates the trigger. DC coupling is reconr-
rnended lbr these signals.
b. DC Coupling
The DC ruode is especially useful for viewing wave-
fornrs which change very slowly and which are there-
lbre discrinrinated against by the low-frequency cutoft
ot the AC position (80 cps). llecause of the coupling
network tinre constant in the AC rnode, signals having
randonr repetition rates are solnetirnes viewed ruore
stably in the DC rnode, This urocle pennits excellent
triggerirrg on all tyJrs of waveforrns and is rnost useful
in the lbllowing applications:
l. For optinrizing trigger sensitivity or operation
when low-[re<lrrency signals are applie<t:
2. For maintaining the initial reference position of
the uace with respect to the CRT scale at a given
TRIG LEVEL control setting when on Internal
source: anrl
3. For avoirling rigger point variatiorrs rlue to ran-
dorrr repetition rate triggering signals.
2-4
When using the DC mode, the Trigger COUPLING
switch is set to DC. When using internal source, the
trace always starts at the sarne point on the Scale for
a given setting of the Trig LEVEL control regardless
of the vertical positioning.
c. ACF Coupling
The ACF rnode is a special high-frequency lbrrn of
the AC urode and is used to reject low-freqr.rency
components in the triggering signal. Use AC trigger-
ing unless low-trequency rejection is required. Trigger-
ing signals with fre<luency corrrponents below l0 Kc,
lbr exarrrple the calibrator signal, rnay not initiate the
sweep circrrits when the ACF ruode is use<l. Also, the
ACF mode uill asmre stable ttiggeting lxnn the d.ual-
hace plug-in when it is set up fo| alte|nate sueep
mod,e, ond, using internol tt igger source. Thus the
ACF ruo<le prevents the difterence in positioning level
of the two channels froru interfering with stable trig-
gering.
Signals nrust have rise or fall times faster than
l0 g,sec when using the ACt' mode. If slower dual
tirne signals are to be <tisplayed, use external trigger-
ing. Note that the Type 76-08 and other multi-trace
plug-ins are provided with a selector switch which
pernrits triggering from one channel only. Therefore
the ACF electronic switch mode no longer applies.
Occasionally it is required to obtain stable trigger-
ing fronr a corrrplex high-frequency wave[ornr that
contains unclesirable low-trequency noise or line-fre-
querrcy cornponents. In such cases, the additional noise
and line pickup rnay rnake it difficult to obtain a
stable display. Il this occurs, select the ACF triggering
rlo(le, thereby elinrinating the efiects of these un.
<lesirecl corrrponents. The low-frequency corrponents
are blocked fronr the riggering circuit while the high-
frequency triggering waveforu is passed to produce
the stable triggering that is required. In all other
respects, the ACF [iggering rnode is identical to the
,A.C rnode.
2-5. IRIGGEI SLOPE SEIECIION
When the Trigger SLOPE switch is set to +, the
sweep is riggered on the rising or positive slope of
the excitation signal. When the Trigger SLOPE
switch is set to -, the sweep is triggered on the falling
or negative slope o[ the excitation signal.
2.6. IRIGGER IEVET SEIECTION
The Trig LEVEL control perurits selection o[ a
specific voltage which the triggering signal must ex-
ceed betore the sweep fires. When the Trigger SLOPE
switch is set to rhe + position, adjustment of the
Trig LEVEL conrol urakes it possible to trigger the
sweep consistently on the positive slope of the ex-

t
I
I
?
,60fl
e
o
lvoLTs/Dtv, to
CAL O{& IME
ta al iT
NAnlASLEl tully
tDrsPraYroclcl
l,o NORli L
",, .
R.odiu, IPOSIIIONI
co.lrcl on th. Y An-
plific. io c..t . di3-
R.adiu3, INIENSITY,
FOCUS A ASIIG
operqt:ng instructions-section 2
Mltflal swEEP DrSPtaY ot cat stclt t
Io obl,oin th. .qlib.otor dirploy u!i.g NOR^IAL
.r&p. t.l th. conlrok .ro.rt o. rhorr ond
p.rforn ih. nu6b.r.d tt.p. in r€qu.nc..
Ul. lhc ro,n. proc.dur. 'h.n difii.ulry L .r-
p.i.n<.d in obtoining o ditpl6y. Thir will .lini-
not. ".o.lp,r" l6!b1.. ds. l,o nhoiignm.nl ol
6'i;t'
"I
ffi*a
$fa
a- o
S.t rully
{NORM}
S.t ASIIG, TOCUS,
& NIINSIIY con-
kolt ro ccnl.r of
to 5 nSEC
S.r vElNlEl tully
+ actUNE
'Ihc IIME/O|V "clukh.d
knoba or. .nsos.d
wh.. th. .ot.h o. th.
pl6ri< rlirt ir qlig..d
with lh. yhir. point.r on
Figvre 2-2. fype 74-l3A Normol Dirploy
2-5

section 2 - operoting instructions
IR]GGIRID STTO3E AND DEI.AYED
Thi! ii d conll.lorion of lh. iniliol r.tup oI
figu..2-2. S.t lh. .ont.ok .ro.fy o.
thorn ond p..fon th. .u6b.r!d n.Ps in
S.r DETAY VtRNlEl
diol ,o 0 ond odiu.t
th. OELAY ZEIO .on-
trol uDtil th. 3i.ob.
iu.i di.opp.or on
rh. l.fr hond rid. ot
th. i.o... Thir op.r-
otion colibroLr ih.
DEIAY YEtNlEl diol
Sd rh. DIS?taY
IOGIC ayiich ro
Tdgg.r.d 5TnO3E
S.i 08 Y vEtNlEl
diol to a. Ih. ponion
ot th. dirploy b.rw..n
4 o.d 6 dlviion. ol
ih. .tqd ot rh. NoF
nol Sw..p .hould b.
b,ighl.r ihon ift. r..t
,ighr ll 6SEC!. Ih.
inr ro 5 nstlc
m6inm -
fir
NOIE
Th. on@nr o, d.l.y o.c!ri.t lrci rh. oFplicorion of rh.
rrigg.rins rienal cnnl th. D.iot.d lr..p ri.rt, i! indi<ot d
di..c{y by ,h. ,.nine ol rh. NDI IIME/D|V .rikh lplorti.
rkiri ond DEL Y VElNlEt.diol. h rhit inrronc., rh. NOT
,v..p rcr. ot 5 nse/Div i. mulripli.d by ri. OEL Y vEt-
NlEl diol ..ting oa a div ri.ldins . .olib.or.d d.loy rim. ol
20 millit..ondi. Th. oba. opplio onlt rlDn ,h. d.lor.d-
lrigg.r.d op.r.rio..l nod. i. u,.d.
2-6
Figure 2-3o. fype 74-l3A friggered Strobe Disploy

DISPTAY O' CAL SIGNAL
operoting instructions - section 2
{ol
(b)
Lo.. i.i..rifi.d by 6.
Erpand.d pr.i.6iction
ot rh. iii.tuifi.d Doti.n
Th. O.loy.d Sr..p r.pr...nb a r.ction ot lii. lstrob.l *ithin
|ft. nom.t r*.., dirploy cnd thit l*lio. moy b. .xp.nd.d to
fu[ ..o1.. ll,!c. rh. d.loy.d p..p not b. co.rid.r.d or o
colibrot d, no!.ifi.d r.dio. of ih. NDT 3y..p. Ih. nordifi-
<otion .ado my 5. .'pr6r.d.
NDT Sw..p lot
DA Sw.Gp [ot
5 nSEC/D|V
r. thr rnr6n<. w. h@.: ---------------
-
-- 5
r dEc/Dtv
Figwe 2-3b. fypc 71-l3A Deloyed tfiggered Disploy
2-7

section 2 -operoting instructions
s.r rh. DlsPtlY
IOGIC twiich to
Ann.d SIXO3E
thi. ir o conti.l)otion of lh. iniliol r.t!P oI
tigur. 2-3b. S.l rlt. <onlrcl..6dlY or
,han ond p.rforn lh. nunb.r.d tt.tr In
n.odili INIENSITY
tSTlOlO i' r..dily
figvte 2-1a, fypc 74-l3A Armed Slrcbe Disploy
atntD $to!t I DI]AYED
+ ac t LlNl
,isht ll SECI. n'.
ing io 5 mSEC
Adiurt OeAY VEI-
Nl€t .6ntrol l,o ob.
2-8

operoting instructions - section 2
DIgPI.AY Oi CAI SIGNAL
@u
S.r OISPLAY LOGIC
DELAY. th. bighn
I
;
t:;
(a)
ln rh. d.loy-orn.d mod., th. O.loy.d Sy..p do., noi
.tort pr..ir.ly ot iic d.ldy riD. indi.at d by th.
opdqtor, but inn.6d i. inifior.d by th. n.rt ruilqbl.
ki99d lollo*iig th. d.lny int.Ml. Sin(. lh. rw..p i!
trigg.r.d by ih. inpul lignol, iirt r i. .liminot d froi
iha di5ploy !v.n iholgh it i. inhlr.nl in th. inpui
Figvre 2-4b. lype 74-l3A Armed Deloyed Dizploy
2-9

section 2 - operoting instructions
citation signal. Conversely, with the Trigger SLOPE
switch set to the - position, adjustruent of the Trig
LEVEL control makes it possible to rigger the sweep
consistently on the negative slope ol the excitation
signal. Normal trigger level range is tl0 volts. This
ntay be extendecl to :t I00 volts on external source by
pulling the Trigger LEVEL knob into EXT/10 posi-
tion.
2.7. SWEEP OPEIATIONAT MODES
o. lntroduction
When using the Delaying Sweep Tirne Base Plug-in,
the start of thg horizontal sweep can be delayed {or a
period of from I rnicrosecoud to 20 seconds after
application of the triggering waveform. This is accom-
plished through simultaneous use of the NDT Time
Base and the DA Tirne Base. In this application, the
NDT Time Base is used to provide the accurate time
delay while the DA Tiure Base provides a normal
horizontal sweep at the end of the delay period. The
duratiou o[ the sweep delay is controlled by the NDT
TIME/DIV and the DELAY VERNIER control set-
tings.
The delayed sweep ltature of this instrument rnay
be employed in a nuruber o[ special applications to
increase its versatility. Such applicatiorrs include high
magnification of a selected portion of an undelayed
sweep, accurate tirne rueasurerrrents, and accurate
neasureDlens of wavefornr jitrer. Also, it is possible
to pick off and display any desired line of a television
scan or to check pulse-time rnodulation.
b. Sweep Rongc lndirotor:
The NDT TIME/DIV switch is provided with an
indicator window nrounted on a plastic skirt; the DA
TIME/DIV switch is urounted on top of this skirt and
is identified as the Delayed Sweep knob. Turning the
knob of the latter will also perurit control of the
Delayed Sweep tiure duration. A push-pull clutch
permits the outer'knob to engage the skirted knob
to adjust both sweep ranges sirrrultaneously, or the
Delayed Su'eep range knob nray be declutched and
rotated indepe[dently to sweep rates faster than the
NDT sweep rate.
c. No.mql Swo.p Dirploy
lvhen the DISPLAY LOGIC switch is set to NOR-
NIAL, only the NDT Tirne Base is displayed. Trigger-
ing is derived fronr the displayed signal internalty or
line. External signals uray be applied to the lower
EXT TRIG connector. Reter to Figure 2-2.
d. Triggered Strobe Dirpldy
\Vhen the DISPLAY LOGIC switch is set to Trig-
gered STROBE, and the Delayed TINIETDIV switch
2-to
is set for a higher sweep rate than the NDT TINIE/
DIV switch, a portion o[ the sweep tnay be brightened.
(See Figures 2-3a and 2-4a.) The start of the
brightene<t portion (Strobe) irrclicates the start of the
Delayed Sweep ancl the length of the strobe inclicates
the Delayed Sweep cluration. The start of the stroh
uray be positioued left or right with the DELAY
VERNIER control. The length ol the strobe nray be
adjusted with thc Delaye(l TINIE/DIV corrtrol. Note
that the start o[ the stobe is not afiected by the setting
ol the latter control. Using these two controls, it is pos-
sible to inch,rde any portion of the display waveform
in the brightened or strobed area.
The arnount of delay occurring fronr the applica-
tion of the triggering wavefomr unril the Delayed
Sweep is pemritted to run, is determine<l by the
setting of the NDI' TINIE/DIV switch ancl the
DELAY VERNIER control. The Detayed Sweep will
occrrt iurrrre<liatcly at the en<[ of the preset delay
1;rliod. This rrrocle frortr uow on will lrc referre<l to as
tlre Delaye<l-Triggerecl su'eep rrrotle. It is thc ruo<le
of operatiotr that pernlits the operator to select con-
tinuously variable delay tirrres for uraking accurate
tirne arrd waveform jitter tneasurements.
The Delayett Sweep autouratically shtrts off when
the Normal Su'ec1t is ternrinated. This prevents
brighteuing of the sweep retrace in either of the
STROBE positions.
e. Deloyed Triggered Dirploy
When the DISPLAY LOGIC switch is set to Trig-
gered DELAYED, the brighterred section of the dis-
play in the STROBE position is now expancled to full
scale. See Figures 2-3b ancl 2-4b.
The amourrt of nragnification is the ratio of the
NDT sweep rate to rhe Delayed Sweep rate. The
magnification ratio ulay be expresse<l:
, Norrnal Sweep Rate (Tirne/Div)
IIaEnifrcation rittio -
-
)elayed Sweep Rate (TirrreTDiv)
For exarnple, if the NDT TINIE/DIV switch is set
to I mSEC, and the Delayed TINIE/DIV switch is set
to I pSEC, the brightened portion of the swcep is
uragnified horizontally 1000 tirnes when the DISPLAY
LOGIC switch is set to the Triggered DELAYED posi-
tion.
Autonratic provision is rnade for shutofi of the
Normal Sweep when the Delayed Sweep is terurinated.
This pernrits rnaximurn duty-cycle perforrrrance in the
DELAYED N'TODE.
f. Deloyed-Armed Operoiion
If the display is set for Delayecl-Arnred operation,
the delayed sweep does not start at the en([ of the
indicated delaved period until a triggering pulse is
applied to the DA trigger circuit. This triggering prrlse

nlay be either the input wavefon to the oscilloscope
ot an externally-derived niggering signal. The trigger-
irrg Source, Coupling, Slope, and Level nray be selected
in the sanre lnanner as for the conventional STROBE
antt DELAYED triggere<l operation. In the Dclayecl-
Arrrre<t mode of operation, the Delayed Sweep does
not start lxecisely at rhe delay rirne indicated by the
DELAY VERNIER and NDT TINIE/DIV control
setting, but instead is initiated by the next srritable
triggering following the indicated delay interval. 1'his
ruro<le frorl now on will be referrecl to as the Delayed-
.{rured urode of sweep operation. See Figrrres 2-4a ancl
2-4b.
The arrtted clelayed tirne <lisplay does not appear
to be conrirruously variable. The Arnred nrode shoul<l
lrc used whenever the signal to be displayed has ac-
cunrulatiye jittel between the start o[ the nornral
sweep and the delaye(l magnified section.
g. Automotic NDT Swrep
Auto triggering provides a visible base line on all
sweep ranges'when there is no signal input. The
sweep free runs undl a trigger signal with frequen-
cies between l0 cycles and approximately l0 6ega-
cycles is applied- The application of the trigger sig-
nal immediately switches the sweep to the tiiggered
mode. thus -providing stable sync. When the trigger-
lng srgnal ls removed, the sweep reverts ro the free-
running mode after a delay of about I second"
,The autornatic NDT sweep mode is very uselul
when doing equipment testing since a reference trace
will always be visible with or without a signal applied
to the -oscilloscope. To obtain automatic NDT sweep
operation, set the Sweep Mode toggle switch O
AUTO position.
h. HF lecurront Sweep
Stable synchronization of very high frequency sig-
nals can.be best accomplished when the NDT sweep
is operadng in the recurrent mode. Recurrent operi-
tion -is- selected by setting rhe Sweep Mode [%gle
switch in the HF RECUR position. Use of this switih
improves the count down and lock.in of signals hav-
ing repetition rates of 5 Mc or greater. Ii provides
stable synchronization of signals of I cm deflection
to beyond 50 Mc.
i. Single-Swcop Operotion
Sirrgle-sweep oyleration irrlers that the tirrre base
nloves but one sroke rrntil reset. Using a reptitive
sweep to view a varying wavelorrrr u'ould result in an
overlappd arrd rrnintelligible <lisplay caused by many
displays being suprinrposed on one another. How-
ever, r'hen it is rlesirecl to view a single <lisplay of an
input signal which continually varies in amplitude,
shape, or tinle, the instruurent rnay be set up for
operoting instructions - section 2
single-sweep presentation. Thus, by corlrnandilg but
one stroke of the sweep at a tirne, single sweep oper-
ation elinlinates the overlapping cause<l by the nrul-
tiple traces and enables the display to be vie\^'ed and/
or recorded clearly.
Single-sweep operation is obtained by using the
Delayecl Sweep in the Delayed Arrred rlo<te. Since
the Delaye(l SweeP is arnred by a trigger derived froru
the NDT Delayiug Sweep, the arnlirrg procctlure is
to trigger the NDT Delaying Sweel:. This is accom-
1:lishe<l nrantrally by rotating the NDT Delaying
Sweep LEVEL control to both extrernes or electrically
by a signal applietl to the ND-I- EXT TRIG input
connector. The Delayecl Sweep will renrain anrretl
uDtil a triBger signal arrives to fire the sweeP. One
sweep will occur after which further incorning triggers
are locked oua until the circuit is rearnre<l. In other
words, a single trace will sweel) across the screen each
tinre the sweeP is triggere<l and at the end of its
travel, the beam will rest ofi screen.
'l'o rearrrr the sweep, procee<l as instructed above.
The swecp will then retrace to the left hand si<[e oI
the screen arrd is arrne<l ready to fire rvhen the rrext
trigger signal arrives.
2-8. SWEEP EXPANDEN
When the POSITION control knob is pulled out,
thc sweel) nray be exl.rarrderl horizontally bv a factor
o[ l0 about thc screen center. Thus, to achieve an Xl0
exparrsiorr of a desire<l segrnent of the trace, set that
segrrcnt of inierest to rhe screen center with the POSI-
TION control and pull out this control. Any portion
o[ the exparr<led <lisplay nray It observecl by adjusting
tlte POSITION coutrol.
lVheu the irrstrurrrent is set up tbr Xl0 expansion
of the sweep, the sweep rate indicated by the setting
of the TINIE/DIV control rrrust be divided by l0 to
obtain the actual tinre required for the sl)ot to nove
one division. For exanrple, it the TIME/DIV control
is set to l0 nrSEC, the actual tirue per division is l0
rnilliseconds, <livkterl by 10, or I millisecond per divi-
slon.
2.9. SWEEP CATIBRATION ADJUSTTAENT
Whenever thc -I'irrre Base Plug-in is removed from
the Main Frarrre and inserted in another, rhe front-
panel screwdriver SWP CAL control lrrust be reset.
This procetlure is necessary to conrpensate for difier-
ence in dellection plate sensitivities. In addition, if the
'I'irne Base unit is switche<l from the X cavity to the
Y cavity of the sarne Main Frame, readjustment will
be necessary since the difierence in average deflection
plate voltages between modules affects the over-all
deflection sensitivity of the carhode-ray tube. To
proprly noruralize the gain between channels or be-
tweeD the plug-in unit aml the Main Frarrre, proceed
as lbllows: 2-tt

section 2 -operoting instructions
l. Set up the itrstrurnent for nonnal display of the
CAL signal. Allow a warmup tirne of l5 minr.rtes. (See
Figure 2-2.)
2. Set TINIE/DIV switch to l0 mSEC.
3. Adjust SWP C.{L front-parrel screwdriver con-
trol for precisely 6 cvcles o[ the calibrator display
(60-cycle line) iu l0 divisions.
NOTE: For 5O-cycle line, adjust SWP CAL conrol
for 5 cycles of the calibrator display. For 400-cycle line,
use 0.5 msec/div sweep and adjust SWP CAL control
for 2 cycles of the calibrator display.
2-r0. x-Y otsPt AYs
CAUIION
KEEP INTENSITY LOW
Screerr <larrrage carr rcsrrlt [rotl too irrterrse a
bearn resting at orre point on the screen.
When <lesiring to view one voltage plotted against
another (not the internal tinre base) apply the Y
signal to INPUT A connecror on the Y Plug-in and
the X signal to X AMP (green) BNC connector on
the Delayirrg Sweep module. X-Y displays nray be used
to shorv sweep signal generator plots, Lissajous phase
rneasurernents, curve trace itrforruation and other
sinrilar signal relationship.
Set the DISPL.{Y LOGIC swirch to X ALIP, the
DA Trigger SOURCE switch to EXT, and the DA
SLOPE switch ro +. Adjust the VOLTS/DIV and
X.4,\IP ATTEN con[ols to obtain an aPpropriate
display on the screen.
2.I I. GAIE OUIPUT
A positive gate coincident r.ith the sweep olrrpr,rt
is available on a front-panel BNC counectoi labeled
+ GATE. The gate amplitude is 2.5 volts nourinal
into an irupedance of 500 ohtrs and load irnpedance
shor.rld be gteater than l00K ohrns shunred by less
thau l5 pf. This positive pulse nray be usecl to trigger
other devices in order to achieve sufficient delav to
vierv the output of such <levices conrpletely displlyecl
on the oscilloscope.
Use of the gate ourput in conjuncrion with triggered
pulse generators will perrnit rhe instrutnenr to display
the leading edge of the pulse waveforrn even tholrgh
no signal clelay is incorporared in the Y Arnplifier.
1'he perio<l of the Posirivc gate n)ay of course, be
rneasured extrerrrely accurately with an electronic
counter. Since the pcl io(l of the gate outpnt is a direct
neasure of total sweep tinre, it is possible to use this
oscilloscope in conjrrncrion u'ith a corrnter to cligitize
the tiure duration of input signals. Use of rhe TIttE/
DIV anrl the V,\RI.\BLE controls rtill perruit the
. operator to rlisplav the rvavetbrn to lrc nreasurecl over
\- the entire srveep. Tirling accuLacies of I l)arr in lOi
ar-e thrrs readily obtailable.
2-12
2.I2. SAWIOOIH OUTPUT
A front-panel connector labeled SAW provides a
positive-going saw ol approxirrrately 25 volrs arnpli-
tude. The saw outpur is referenced within minui 3
volts oI ground and is time coincident with the NDT
sweeP.
The sawtooth voltage nlay be used for initiating
tlelayed activities, controlling an X-Y plotter, or actint
as a tirne base for associatecl analog equiprlent. The
sawtooth output should not be loaded by an irnped-
ance to ground of less than l00K oh[rs shunted by no
trrore than 15 pf. Voltage take-oft through an attenu-
ator probe is recorutrendecl.
2.I3. TI'IIE MEASUREMENIS
o. How to lvloke Elopred firne Meosuremenl:
UsinE the CRT Scqle
,{ny horizontal distance on the screen of the oscillo-
scope can be used to represent a precise interval of
tirrre when the tinre-base circuits are set up for cali-
brated sweep (TINIE/DMernier control set to
CAL). Use of this fearure 1>enrrits yott to accrrrately
nreasure rhe elapsetl tinre benveen the clesired point
of interest on the clisplay. To rrreasrrre the rinre inter-
val, proceecl as follorvs:
l. Using the calibrated scale, nreasure the hori-
zontal (listance in divisions between that portion of
the clisplay whose time interval you wish to find.
2. llultiply the horizorrtal dirnension obtained in
Step I by rhe I'IME/DIV conrrol setting to obtain
the tirne interval. See Figrrre 2-5,
b. How to find Repetition Rote of Frequency
Uring the CIT Scqle
The repetition rate or frequency tbr periodic signals
cau be expressed as the nultrber of cycles or pulses per
urrit of tinre (TINIE/DMernier control set to
CAL). To use the oscilloscope for rueasuring the
repetition rate or frequency of perioclic signals, pro-
ceed as follows:
ELAPSED TIME EOUALS:
T
I
x
E
s
Figwe 2-5. Elopsed fime ,Ueossrement