Trio CS-1560AII User manual

TRIGGEREDSWEEPOSCILLOSCOPE
HIGH STABILITY
CS-1560AII
DUAL TRACEOSCILLOSCOPE
INSTRUCTION MANUAL
TRIO

CONTENTS
Page
FEATURES 2
SPECIFICATIONS 2
CONTROLSONPANELS4
FrontPanel4
Rear Panel4
OPERATION7
Preliminary operation 7
Operating Procedures7
APPLICATIONS8
Dual-traceApplications8
Single-channelApplications17
FM Receiver Adjustments19
X-Y Applications20
AmplifierSquare Wave Test 21
SCHEMATIC DIAGRAM 29

FEATURES
* Vertical axis oflow inputcapacitance (22 ±3pF) for2-
channeloperationprovideshighsensitivity and wide
band-width(10mV/div,15MHz).
* Highsensitivity CRT withexcellentbeampermeability
has sufficientbrightness for measurements of fastspeed
pulses of highfrequencies.
* Thehighvoltagepower for CRTaswellasthepower for
othercircuitsisfullystabilizedbecause of theuse ofDC-
DCconverter,thus the sensitivity and brightness are
completelyfreefromeffects of voltagevariations.
*X-Y operation is possiblewith CH2 amplifierused asX
axis.
The horizontal axis sensitivity isas high as 10mV/div,
permittingaccuratecalibrations.
* TimebaseswitchallowschangeoverbetweenCHOPand
ALT andbetweenV(vertical)andH(horizontal) of TVsync
separatorcircuit,automatically and electronically.
*CH1andCH2 can be individuallysynchronized(internal
syncronization).
*At AUTOposition of TRIG LEVEL, itis possible to check
thebrightness at no-signaltime andto adjusttriggering
level of inputwaveforms.
* Mode selectorswitch is provided for measurements of
sum and differencebetween 2 channels.
*Low powerconsumption (23W)for cooloperation.
*All componentparts are cleverly mounted on circuit
boards for improvedreliability.
* Tracerotationsystem for easyadjustment of horisontal
trace.
*The adoption ofIC's throughout circuitryassureshigh
performance and improvedreliability.
SPECIFICATIONS
2
CathodeRayTube
Type: 130BXB31orC535P31B
Accelerating voltage: 2kV
Scale: 8 div x 10div(1 div= 1 cm)
Vertical Amplifiers (CH1 andCH2)
DeflectionFactor:10 mV/div~20V/div,
1-2-5sequence (1 div=1 cm)
Precisely adjustablebetween
all ranges.
Sensitivity errorbetween
rangesis±5%.
Input Impedance: 1 MO±5%
Input Capacitance: 22pF ±3pF
FrequencyResponse:DCDC- 15MHz (less than
-3dB)
AC2Hz - 15MHz (less than
-3dB)
Rising Time: Less than 23 nsec.
Over-shoot: Less than3%
(at 100kHzsquarewave)
Cross-talk: Betterthan70dB at 1 kHz
OperatingModes:CH1 Channel 1 only
CH2Channel 2 only
DUALDualtrace(CHOPand
ALT areautomatically
selected by SWEEP
TIME/DIV)0.5Ms/div
~0.5ms/div
ALT (alternatesweep)
1 ms/div~0.5s/div.
CHOP(200kHz
switching)
ADDAlgebraicsum of CH1
andCH2.
SUB Algebraicdifference
ofCH 1 andCH2.
CHOPFrequency: 200kHz ±20%
Maximum Input
Voltage:600Vp-p or 300V (DC+ AC
peak)
SweepCircuit(CommontoCH1andCH2)
SweepSystem: Triggered and automatic. In
automatic mode, sweep isob-
tainedwithoutinputsignal.
SweepTime: 0.5/zs/div ~ 0.5s/div ±5%and
"X-Y", 1-2-5 sequenceFine
adjustmentbetweenall19ranges
SweepMagnification: Obtained by enlargingtheabove
sweep 5 times (±5%) from
center.
Linearity: Less than 3% (2yus/div ~
0.5s/div)
Less than 5%
(0.5(us/div ~ 1/us/div)
Triggering
Source: CH 1. CH2andEXT
Slope: NORM - positive and negative
TV- positive and negative
(TVH and TVV are automatically
switched by SWEEPTIME/DIV)
TVH (TV- Line):
0.5jus/div ~ 50Ms/div
TVV (TV- Field):
0.1ms/div ~ 0.5s/div
TriggeringVoltage: CH 1 andCH2 Amplitude on
CRT screen,morethan0.5div
EXT More than 1Vp-p
TriggeringRange: 20Hz ~ 1 5MHz

3
HorizontalAmplifier(Horizontalinput thru CH2
input)
X-Y Operation: With SWEEPTIME/DIV switch
in X-Yposition,theCH 1 input
becomesthe Y input (vertical)
andtheCH2inputbecomesthe
X input(horizontal).TheCH2
positioncontrolbecomesthe
horizontalpositioncontrol.
DefiectionFactor:SameasCH2
(10mV/div~20V/div±5%)
Frequency Response: DCDC- 1 MHz (less than
-3dB)
AC2Hz-1MHz (less than
-3dB)
Input Impedance: SameasCH2(1 Mfi ±5%)
Input Capacitance: SameasCH2(22pF ±3pF)
CalibratingVoltage: WP-p ±5%
(1kHzsquarewave)
Intensity Modulation
Input Voltage: More than20Vp-p
Input impedance: 470kfi±20%
Trace Rotation: More than20Vp-p
Input Impedance: 470kfl±20%
Trace Rotation: Trace angleisadjustable by pan-
el surface adjustor.
PowerRequirements
PowerSupplyVoltage:AC 100/117/220/240V ± 10%,
50/60Hz
PowerConsumption:23W
Dimensionsand Weight
Width: 260mm(277mm)
Height: 190mm(204mm)
Depth: 384mm(449mm)
Figures in ( ) showmaximum
sizes.
Weight: 9.3 kg
Accessory
Probe: PC-27 2
Damping 1/10
Inputimpedance 10Mfi
Input capacitance less
than18pF
Pin-plug: Shortingtype 1
Non-shortingtype 1
Replacement Fuse: 0.3A2
0.7A 2
InstructionManual: 1 copy

4
CONTROLS ON PANELS
FRONT PANEL
REAR PANEL

1. J POSITION
This controladjustsverticalpositionduring CH1
operation andY positionduring X-Y operation.
Waveformscan be set to anydesiredverticalposition.
Arightturn of thecontrol will shiftwaveformupward,
andviceversa.
2. DCBAL
Vertical DC balanceadjustment for CH1(or Y).
Adjustment is made so thatwaveformposition isnot
shifted when the gaincontrolVARIABLES) forthe
vertical amplifier is rotated.
3.INPUT
Vertical inputterminal for CH1, orY inputterminal
duringX-Yoperation.
4. AC-GND-DC
Vertical inputselector for CH1, orforY inputselector
during X-Y operation.
AC: The DC component of inputsignalisblocked
bycapacitor.
GND: Theinputterminalopensandtheinput of in-
ternal amplifier is grounded.
DC: The inputterminal is directlyconnected to
theamplifier andall components of input
signal are amplified.
5.VOLTS/DIV
Vertical attenuator for CH1 orforY duringX-Yopera-
tion. The scale is graduated in voltage per "div"( =
cm) ofCRT screenarea.Calibratedvoltage isin-
dicated whenVARIABLE (6) isturnedfullyclockwise.
Set thiscontrol for properwaveformaccording to the
inputvoltageused.Selectable in11 rangesfrom
10mV/div to 20V/div.
6.VARIABLE
Vertical attenuator for thecontrol of vertical sensitivity
of CH1orY during X-Y operation. It continuously
controlsbetween 11 ranges of VOLT/DIV(5). Inthe
extreme clockwise (CAL) position, the vertical
attenuator is calibrated.
7.MODEICH1,CH2,DUAL,ADD,SUB)
CH1: Only the inputsignal to CH1 is displayed asa
single trace.
CH2:Only the inputsignal toCH2is displayed asa
single trace.
DUAL:Inthe range of 0.5s/div to 1 ms/div, the input
signals to both channelsareswitched by about
200 kHz signal(CHOPoperation).
In therange of 0.5ms/div to 0.5^s/div,theinput
signals to both channelsarealternately switch-
ed for eachsweep(ALToperation).
ADD:The waveformsfrom both channelinputs are
algebraically added and thesumisdisplayed as
a singletrace.
SUB:Theinput of reversepolarity toCH2is added to
theinput toCH1andthe algebraicdifference
obtainedbetweenCH1 andCH2is displayed as
a singletrace.
If CH1hasno input oritis grounded, the
waveform of reversepolarityfrom CH2 input is
displayed.
8.VOLTS/DIV
Vertical attenuator for CH2. It hasthesamefunction
as V0LT/DIV(5), butis alsousedas X attenuator du-
ring X-Y operation.
9.VARIABLE
Vertical attenuatoradjustmentprovidesfinecontrol of
vertical sensitivity of CH2. It hastthesamefunction
as VARIABLE(6), butis alsousedas X fineadjuster.
10.AC-GND-DC
Vertical inputselector for CH2. It hasthesamefunc-
tion as AC-GND-DC(4), butis alsoused asX input
selector.
11. INPUT
Vertical inputterminal for CH2 orX inputterminal dur-
ing X-Y operation.
12.* POSITION,X-Y«*
Vertical positionadjuster forCH2.It functions the
same as* POSITIONO), butis alsousedas X posi-
tionadjusterduring X-Y operation.
13.DCBAL
Vertical DC balanceadjustment for CH2(orX). It has
thesamefunction asDC BAL(2).
14.LEDPilotLamp
This lamplights asthe powerswitchILLUM(15) is
turned on.
15.POWER/SCALEILLUM
Poweristurned off attheextremeleftturnposition.
Arightturn will set the power toONand illuminate
thedial scale.
16.INTENSITY
Adjusts the brightness of spots and waveforms for
easy viewing. A leftturn will allow the waveform to
disappear.
17. TRACE ROTATION
This isused to eliminateinclination of horizontaltrace.
18.ASTIG
Astigmatismadjustmentprovides optimum spot
roundness and brightnesswhenusedwith
FOCUS09).Once itis adjusted, no further ad-
justments are required.
5

19.FOCUS
Spotfocuscontrol to obtain optimum waveform
according to brightness.
20.EXTTRIG
External triggeringterminal. For externaltriggering,
external triggeringvoltage(morethan 1Vp-p) should
beapplied,withSOURCEswitch (21)settoEXT.
21. SOURCE
Three-positionswitch to selecttriggeringvoltages for
CH1, CH2and EXT.
CH1: Sweep is triggered byCH1 vertical input
waveform.
Bothsweeps are triggered bythe samesource
in dual(2-channel)traceoperation.
CH2:Sweep is triggered byCH2 vertical input
waveform.
Bothsweeps are triggered bythe samesource
in dual(2-channel)traceoperation.
EXT: Sweep is triggered byan externalsignalapplied
toEXTTRIG (20) terminal.
22. SYNC
Sync separator switch. It picks up syncsignal
component inTV videosignal and applied to trigger
circuit for completesynchronization of videosignal be-
ingviewed.
NORM ±: Used for viewinggeneralwaveforms. In
this position, TV syncseparatorcircuit isnot
connected.
At "-)-" polarity,sweepiseffected by "-)-" slope
and, at" —" polarity, by" —" slope.
TV ±: Used for viewingwaveformswith TV video
signal synchronizedwithsyncsignal. TVVand
TVH are automaticallyselected for sweeptimes
of0.5sto0.1msand 50MS to 0.5MS ofSWEEP
TIME/DIVrotary switch, respectively, andare
synchronizedwithvertical and horizontalsync
signals.
Polarity should besetto matchthat of video
signal as shown inthe illustration.
SYNC SWITQH
TV (+)
SYNCSWITCH
TV (-)
23. LEVEL
Triggeringlevelcontroladjustssyncphase to deter-
mine the starting point of sweep onthe slope of
triggersignalwaveform.
PULL AUTO:
By pulling LEVEL VR toward you, auto-sweep is
effected; the sweep issetin free-runningstateeven
when no trigger input signal is applied,withfly-back
line displayed onCRT.
With triggersignal,trigger-sweep is effectedwhere
sync level is adjustable. When the synclevelexceeds
thelimit, the sweep issetin free-runningstate.
24.<>POSITION,PULLX5MAG
Horizontalpositionadjuster to shiftwaveform toany
desiredhorizontalposition. A rightturn of theadjuster
will shift the waveform to right, and viceversa,
pull X 5 MAG.
Sweep magnifier switch. By pulling the knob toward
you,waveform is magnified to5 times in left and right
directions. Brightness is slightlydecreased.
25.SWEEP TIME/DIV
Horizontalsweeptimeselector. It selects sweep
times of 0.5MS to0.5sin19 steps. X-Y operation is
possible by turning the knob fullyclockwise.
ChangeoverbetweenCHOP, ALT,TVVandTVHis
also accomplishedautomatically by thisselector.
When VARIABLE (26)is turnedfullyclockwise,
calibrated reading is obtainedwhichisthesweeptime
per"div".
26.VARIABLE
Used for fineadjustment of sweeptime.Continuous
adjustmentbetween 19 steps of SWEEPTIME/DIV
(25) is possible.Sweeptime is calibrated attheex-
tremeclockwiseposition(CAL).
27.CAL
Calibrationvoltageterminal.Calibrationvoltage is
1Vp-p of about 1kHz squarewave.
28.ACVOLTAGESELECTOR
The CS-1560A IImaybe operated from 100V,120V,
220V,240V,putting theAC VOLTAGESELECTOR in
theplaceofanother.
29.FUSEHOLDER
For 100<~ 120Voperation a 0.7 amperefuseshould
beused.
For 220~ 240Voperation a 0.3 amperefuseshould
beused.
30.POWERCONNECTOR
For connection of thesupplied AC powercord.
31. Z AXIS INPUT
Intensity (brightness) modulation terminal.Intensity is
modulated at voltages of 20Vp-p or higher. When
modulation isnot needed, the suppliedshorting pin
must be plugged in.
32.CORD REEL
Wind powercordwhen the oscilloscope istobe
carried or stored.Theyalsoserveas a standwhen the
oscilloscope is used in upright position.
Fig.1
6

OPERATION
PRELIMINARY OPERATION
When operatingthisoscilloscope,refertopanelcontrolsand
OPERATING PROCEDURES
(1) Insertthesuppliedpowercordtothepowerconnec-
tor.Then, select thepositionofthepowervoltagese-
lector plug asindicatedbythearrowmarks.
(2) TurnPOWER(15) clockwise. Thepoweristurnedto
ONandLEDpilotlamp(14)lights.
(3) Horizontal axis will bedisplayed. When fly-backline
doesnotappearatthecenterofthescreen,adjust
POSITION(1)andPOSITIONPULLx5MAG(24).
AdjustbrightnesswithINTENSITY(16).Iffly-back
line isunclear,adjustFOCUS(19).
(4) Theoscilloscopeisnowreadyformeasurement.For
measurement,proceedasfollows:
ApplysignalvoltagestotheInputterminals(3),(11).
ThenturnVOLT/DIV(5)clockwiseuntilthewaveform
is correctlydisplayedonthescope.Bysetting MODE
(7) andSOURCE(21)toCH1,theCH1inputsignalto
theInputterminal(3) will appear.Similarly,bysetting
MODE andSOURCEtoCH2,thentheinputsignalto
theCH2terminal(11) will appear. When MODE (7)is
set toDUAL,twowaveforms(CH1andCH2) will ap-
pearonthescope. With SOURCE(21)settoCH 1, the
CH 1 inputsignalfromtheInputterminal(3)isfedto
thesynchrocircuitwheretheCH1signalissynchro-
nized.Similarly,whenSOURCEissettoCH2,the
CH2signalissynchronized.Useeither method for
easier observation.
When MODE issettoADD,theCH 1 signalisalge-
braicly addedtotheCH2signal;andwhenitissetto
SUB, theCH2signalinreversepolarityisaddedtothe
CH 1 signalandtheabgebraicdifferencebetweenCH1
andCH2isdisplayed.
(5) When thesignalvoltageismorethan10mVand
waveform fails toappearonthescreen,theos-
cilloscope maybecheckedbyfeedinginputfrom
CAL 1 Vp-p(27).Sincecalibrationvoltageis 1 Vp-p,the
waveformbecomes5divhighatthe0.2V/divposition,
tion.
(6)Bypushing LEVEL (23),thefree-runningautofunction
is released.Thewaveformdisappearswhentheknob
is turned clockwise, andappearsagainattheap-
proximatemidpositionofit.Syncphaseisalsoad-
justable inthis case. Thewaveform will againdis-
appearwhentheknobisturnedcounterclockwise
fromthemidposition.
(7) When DCcomponentismeasured,set AC-GND-DC to
DCposition.If,inthis case, theDCcomponentcon-
7
their functions(seepage4).
When startingthisoscilloscopesetinitially,settheoperating
controlsasfollowsandthesetmaybeturnedonsafely.

tains plus "+" potential,thewaveformmovesupward
and if it containsminus "—" potential,thewaveform
movesdownward.
The referencepoint of "0" potential is checked at
GNDposition.
APPLICATIONS
DUAL-TRACEAPPLICATIONS
Introduction:
The mostobvious andyetthe mostusefulfeature of the
dual-trace oscilloscope is that it has the capability for
simultaneouslyviewingtwowaveformsthatarefrequency-
orphase-related, or that a common synchronizingvoltage,
such as in digitalcircuitry.Simultaneousviewing of input
andits output isaninvaluableaid to thecircuitdesigner or
therepairman.Severalpossibleapplications ofthe
dual-trace oscilloscope will be reviewed in detail to
familiarize theuserfurther in thebasicoperation of thisos-
cilloscope.
Frequency DividerWaveformsViewing:
Fig. 3 illustrates the waveforminvolved ina basic
divide-by-two circuit. Fig. A indicatesthereference or clock
pulsetrain.Fig. B andFig. C indicatethepossibleoutputs of
thedivide-by-twocircuitry.Fig. 3 alsoindicatesthesettings
ofspecificoscilloscopecontrols for viewingthese
waveforms. In addition to thesebasiccontrolsettings, the
TRIGGERING LEVEL control,aswellastheCH1andCH2
vertical positioncontrolsshould besetas required to
producesuitabledisplays. In the drawing of Fig. 3, the
waveformlevels of2 cm are indicated. If exact voltage
measurements of CH1 and CH2aredesired,theCH1 and
CH2VARIABLEcontrolsmust be placed intheCAL
position.TheCH2waveformmaybeeitherthatindicated in
Fig. 3Bor Fig. 3C. In Fig. 3C,the divide-by-two output
waveformisshownwhichoccursduringthefallingtime of
pulses. In this case, the putput waveform is shiftedwith
respect totheleadingedgeofthereferencefrequencypulse
by a timeintervalcorresponding to the pulsewidth.
Divide-by-8Circuit Waveforms:
Fig. 2 indicateswaveformrelationships fora basic
divide-by-eight circuit. The oscilloscopesettings are
identical tothoseused in Fig. 4. Thereferencefrequency of
Fig. 3A issuppliedtotheCH1input,andthedivide-by-eight
output isappliedtotheCH2input.Fig. 2 indicatesthetime
relationshipbetween the inputpulsesand output pulses.
In anapplicationwherethelogiccircuitryisoperating at
ornearitsmaximumdesignfrequency,theaccumulated rise
timeeffects of the consecutivestagesproduce a built-in
timepropagationdelaywhichmust be compensated for.
Fig. 2C indicatesthepossibletimedelaywhichmay bein-
troducedinto a frequencydivider circuit. Useofthe
dualtrace oscilloscope,theinputand output waveformscan
besuperimposed (ADD or SUB) to measure the exact
amount of propagationdelaythatoccurs.
CH-1
WAVEFORM
CH-2
WAVEFORM
CH 1
A.REFERENCEFREQUENCYPULSETRAIN
(1000 PULSESPER SECOND)
CH 2
B. DIVIDE-BY-TWOOUTPUTSYNCHRONIZED TO
LEADINGEDGE OF REFERENCEPULSE
CH 2
C.DIVIDE-BY-TWOOUTPUTSYNCHRONIZED TO
TRAILINGEDGE OF REFERENCEPULSE
WAVEFORM
2
WAVEFORM
1
Fig.3. Waveformsindivide-by-twocircuit
Fig. 2. Waveformsindivide-by-eightcircuit
LEADINGEDGES MAYNOTBE
VISIBLE AT FASTSWEEPRATES
WAVEFORM
1
HEIGHT
WAVEFORM
2
HEIGHT
8

PropagationDelayTimeMeasurement:
Anexample of propagation delay ina divide-by-eight
circuit wasgiven in the previousparagraph.Significant
propagation delay may occur inany circuit. This os-
cilloscope has featureswhichsimplifymeasurement of
propagation delay. Fig. 5 shows the resultantwaveforms
whenthedual-tracepresentationiscombinedinto a single-
trace presentation by selectingthe ADDor SUBposition of
the MODE switch. In the ADD positionthetwoinputsare
algebraically added ina single-tracedisplay.Similarly,inthe
SUB position thetwo inputs are algebraicallysubtracted.
Either positionprovides a precisedisplay of the propagation
time(Tp).Usingthecalibratedtimebase(CAL), Tp can be
measured. A more precisemeasurementcan be obtained if
the Tp portion of thewaveform is expandedhorizontally by
pullingthe 5XMAG control.Italsomaybepossibletoview
thedesired portion of thewaveformata fastersweepspeed.
CH 1
CH 2
EXPANDTHISPORTION
FOR MORE PRECISE
TIMEMEASUREMENT
Fig.4. UsingADD or SUB modesforpropagationtimemeasurement
Digital Circuit TimeDelayMeasurement:
Since a dual-traceoscilloscope hasthe capability of
comparing the timing of one waveformwithanother, itis
necessary in designing,manufacturingandservicingdigital
equipment. In digital equipment, many of the circuits are
frequencydividers as previouslydescribed, but waveforms
are oftentime-related in manyothercombinations.Fig. 5
shows a typicaldigitalcircuit and identifiesseveral of the
points at whichwaveformmeasurementsareappropriate.
Under the operatingcondition,waveforms will varyaccor-
ding to the input or operating mode. Fig. 6 shows the
relationshipbetweenthenormalwaveforms tobe expected
at each of thesepointsandtheirtiming. If thecorrecttime
relationshipwithrespect to otherwaveform is unknown,
measurement of individualwaveformsmeansnothing. The
dual-trace oscilloscopeallowsthiscomparison tobe made.
In an application,waveform No. 3 would be displayed on
CH1andwaveform No. 4 thru No. 8 and No.10 would be
displayed on CH2. Waveforms No.11 through No.13
would probably be displayed on CH2 in relationship to
waveform No. 8 orNo. 4 on CH 1. No. 8 or No. 10 isanex-
cellent syncsource for viewing all of thewaveforms.
With No. 8 orNo.10 usedasexternalsyncsource,any
ofthewaveformsmay be displayedwithoutreadjustment of
theTRIG LEVEL control.Waveforms No. 4 through No. 7
should notbe usedasthesyncsourcebecausethey donot
contain a triggeringpulseatthestart of theframe.Itwould
not be necessary to viewtheentirewaveformsasshown in
Fig. 6 in all cases. In fact, there are manytimeswhen a
closer examination ofa portion of thewaveformswould be
appropriate. In such cases, it isrecommendedthatthesync
remainunchangedwhilethesweepspeed be increased or
X5 MAG controlused to expand the waveformdisplay.
ADD
SUB
9

Fig.5. Typical digital circuit using several time-relatedwaveforms
10

ANY INDIVIDUAL ADDRESS OR FUNCTION
DATA BITMAY BEPOSITIVE OR NEGATIVE
DEPENDINGUPONTHECODED INPUT
Fig. 6. Family of time-related waveformsfromtypicaldigitalcircuitin Fig. 5
DistortionMeasurement:
Distortion of anamplifiermaybemeasuredwiththisos-
cilloscope. Thismeasurement is especiallyvariablewhen
the slope ofa waveformmust be faithfullyreproduced byan
amplifier. Fig. 7 shows the testing ofa circuitusing a
triangular wave,such asis found inthe limitercircuit of a
transmitter modulator.Themeasurementmay be madeus-
ing any type of signal;merely usethe type of signal for
testing that is normallyapplied tothe amplifierduring nor-
mal operation. The procedure for distortiontesting isas
follows:
ADJUST POSITIONCONTROLS
TOSUPERIMPOSEWAVEFORMS
DIRECTLY OVEREACHOTHER
SUB=DISTORTION
Fig. 7.Distortion measurement
11
ADJUST SO BOTH
WAVEFORMS ARE
SAMEAMPLITUDE
AMPL
No.1 AMPL
No. 2

1. Apply the type of signalnormallyencountered inthe
amplifierundertest.
2. ConnectCH1 probe tothe input of theamplifier and
CH2 probe tothe output ofthe amplifier. Itis
preferable ifthetwo signals arenot inverted in
with respect to eachother,butinvertedsignalscan be
used.
3. Set CH1 andCH2 DC-GND-AC switches toAC.
4. Setthe MODE switch to DUAL.
5. Set SYNCSLOPEswitch to CH1 and adjustcontrols
as described inthe procedure for synchronizing
waveforms.
6.AdjustCH1 andCH2 POSITIONcontrols to superim-
pose the waveformsdirectlyovereachother.
7.Adjust CH1andCH2 verticalsensitivitycontrols
(VOLTS/DIV and VARIABLE) so that the waveforms
are aslargeaspossiblewithoutexceedingthelimits of
the scale, and so that both waveformsareexactlythe
same height.
8. Now.setthe MODE switch to SUBposition (ifone
waveform is invertedwithrespecttotheother,usethe
ADDposition).
Adjust the fineverticalsensitivitycontrol (CH2
VARIABLE) forthe minimum remainingwaveform; if
the two waveforms are exactly the sameamplitude
andsamewaveform and there isno distortion, the
waveforms will cancelandthere will be only a straight
horizontalline will remain onthe screen.
GatedRingingCircuit(burstcircuit):
Fig. 8 shows a burstcircuit.Thebasicsettings of con-
trolknobsarethesameasthose in Fig. 4. Thewaveform A
is the referencewaveform andis applied to CH1input. All
otherwaveformsaresampled at CH2 and compared tothe
reference waveform of CH1. The burstsignal canbeex-
amined more closelyeither by increasingthesweeptime or
bypulling the< • POSITIONcontrol to obtain 5 times
magnification.
Delay LineTest:
The dual-tracefeature ofthe oscilloscopecanalso be
used to determinethedelaytimes of transmissiontypedelay
lines as well as ultrasonictypedelaylines.The output of
delaylines is observed onCH2 while being synchronized
with the input pulse of CH1. The intervalbetweenpulses
should be largecompared to thedelaytime tobe observed.
In addition, to determiningdelaytime, the pulsedistortion
inherent in thedelaylinecan be determined by examination
of the delaypulseobserved onCH2 waveformdisplay.
Fig. 9 shows the typicaloscilloscopesettings as well
as thebasictestcircuit.Typical input and output waveforms
are shown onthe oscilloscopedisplay.Thisdelayline
checking method may also be used for color TV receivers.
Fig. 10 shows the oscilloscopesettings and typicalcircuit
connections to check the"Y" delayline employed inthe
videoamplifiersection. The input waveform and output
Fig. 8. Gatedringingcircuitandwaveforms
PULSE
GEN
ACDUAL AC
INPUT
ULTRA SONIC
DELAY LINE
(5/jSec)
5000PPS
lfiSec PULSE WIDTH
Fig. 9. Delaylinemeasurements
12
OUTPUT

waveformarecompared for delaytime,usingthehorizontal
sync pulse of thecompositevideosignal for reference. The
indicateddelay is approximately one microsecond. In addi-
tion to determining the delaycharacteristics of theline, the
output waveformreveals any distortionthat maybein-
troducedfrom an impedancemismatch.
TOHORIZONTALAMPLIFIER.
NOTE: NO ELECTRICAL CON-
NECTION; PLACE CLIP ON
NSULATION OF PLATE CAP
LEAD ORIN CLOSEPROX-
IMITY OF HORIZONTALAMP-
LIFIER TUBE.
VIDEO
AMPLIFIER
SET BOTHPROBES FOR
10:1 ATTENUATION
DELAY LINE
'NOTE: SETTING OF VERTICAL
ATTENUATORS SHOULD BE THE
SAME,BUT MAY VARYWIDELY,
DEPENDING ON CIRCUIT TYPE.
Fig. 10.Checking "Y" delaylineincolortelevisionreceivers
Stereo Amplifier Servicing:
Anotherconvenientusefora dual-traceoscilloscopeisin
troubleshootingstereoamplifiers. If identicalamplifiersare
used andthe output of oneis weak,distorted or otherwise
abnormal,thedual-traceoscilloscopecan be efficientlyused
tolocalizethedefect. With an identicalsignalapplied to the
inputs of both amplifiers, a side-by-sidecomparison of both
unitscan be made by progressivelysamplingidenticalsignal
points in both amplifiers. When the defective or malfunc-
tioningstage has beenlocated, itcanbe immediately
observed and analyzed.
Improving the Ratio of Desired to Undesired
Signals:
In someapplications, the desiredsignal may be riding
on a largeundesiredsignalcomponentsuch as 60Hz. Itis
possible to minimize orfor practicalpurposeeliminate the
undesiredcomponent.Fig. 11 shows the oscilloscope set-
tings for such an application. The waveformdisplay of
CH1indicates the desiredsignal andthe dottedline in-
dicates theaverageamplitudevariationcorresponding to the
undesired 60Hz component. TheCH2 displayindicates a
waveform of equalamplitude and identicalphase tothe
average of theCH1wavejorm. With the MODE switchset
toSUB, and by adjusting theCH2 verticalattenuatorcon-
trol, the 60 Hz component of theCH 1 signalcan be cancell-
ed bytheCH2 input andthe desiredwaveform can be
observed.
ADJUST FORONE
COMPLETE CYCLE
AT 60Hz
Fig. 11.Improving desired-to-undesired signal ratio
13
TOVIDEO
OUTPUT
AMPLIFIER
START WITH
DUAL
CHANGE TO
SUB

AmplifierPhaseShiftMeasurements:
In the squarewavetestingsection of thismanual,
squarewavedistortionisexplained in terms of phaseshift of
thesignalcomponentswhichcomprise the squarewave.
These phaseshifts can be verifieddirectly by providing a
s\newave
input signal to the amplifier and observing the
phase of output signalwithrespect to the input signal.
In allamplifiers, a phaseshift is alwaysassociatedwith
a change in amplituderesponse.Forexample, at the—3dB
response point, a phaseshift of45° occurs.Fig. 11 il-
lustrates a method of determiningamplifierphaseshift
directly. In this case, the measurements are being made at
approximately5000Hz. The input signal is used asa
reference and is applied to theCH1 input jack.
The VARIABLEcontrol is adjusted as required to
provide a complete cycle of the input waveformdisplayed on
8 div horizontally,whilethewaveformheightisset to 2 div.
The 8 div displayrepresents 360° at thedisplayedfrequen-
cy andare centimeterrepresents 45°of the waveform.
The verticalattenuatorcontrols of CH2areadjustedas
required to produce a peak-to-peakwaveform of2 div. The
CH2POSITIONcontrol is thenadjusted so that the CH2
waveform is displayed on the samehorizontal axis asthe
CH1waveform. The distancebetween thetwo waveforms
thenrepresents the phaseshiftbetween thetwo
waveforms. In this case, the zerocrossoverpoints of the
twowaveforms are compared. The illustrationshows a
phasedifference of 1 div whichmeans a phaseshift of45°.
ADJUST AS REQUIRED
FORCOMPLETECYCLE
IN8cm
AF
SIGNAL
GENERATOR 4r INPUT
AUDIO
AMPLI FIER
OUTPUT
LOAD
Fig. 12.Measuringamplifier phase shift
Television Servicing:
Many televisionservicingprocedurescan be performed
usingsingle-traceoperation.Theseareoutlinedlater inthe
applicationsectioncoveringsingle-traceoperation. One of
these procedures,viewing the multi-burstsignal in theVITS
(vertical intervaltestsignal), canbe accomplished more
effectively using a dual-traceoscilloscope.TheVITSsignal
is specificallyused for characteristic checks of thetransmis-
sionsystem ofa broadcaststation ora networkincluding
repeaterstations or for changeover of transmissionsystem.
In many cases, thissignaldoes not appear in the normal
videosignal.Evenwhen itis included inthe signal, the
method of insertingtheinformationdiffers depending on the
broadcaststation.Also,theVITSinformation in Field 1 (1st
interlaced scanning) and Field 2 (2nd interlacedscanning)
are different in many cases. Examples of VITSsignals are
shown in Fig. 13.
Because the oscilloscopesweep is synchronized to the
vertical blankingsignal, the waveform of Field 1 cannot be
distinguished from that of Field 2. Thiscauses the VITS
signals to be superimposed onto eachother,resulting in dif-
ficulty in viewing. With dual-traceoperationusingthesame
input, the waveform canbe viewedseparatelywithout
overlappingbecause ofthe effects ofthe oscilloscope's
alternate sweepoperation and interlacedscanning ofTV
signal.
The possibility of viewingVITSsignalprovides anim-
portantrole in servicing TV sets. ThisVITSsignals can
localize trouble in the antenna,tuner, IFor videosections
andshowswhenrealignmentmay be required.Thefollow-
ingproceduresshow howto analyze and interprete os-
cilloscope displays of the VITS.
The VITS is transmitted during the verticalblanking in-
terval. On thetelevisionset, it can be seenas a bright white
line above thetop of the picture,when the verticallinearity
orheightisadjusted to viewtheverticalblankinginterval (on
TV sets withinternalretraceblanking circuits, the blanking
circuits must be disabled to seethe VITS).
14

ThetransmittedVITS has a specificfrequency,
amplitude and waveform as shown in Fig. 14. Television
networksusepreciesignals for adjustment and checking of
networktransmission equipment, butthe multi-burstsignal
inVITS can also be used for checking the operating
condition of TV sets. The firstframe of VITS atthe "B"
section (line 18) in Fig. 14 beginswith a whitereference sig-
nal, followed by sinewavefrequencies of 0.5MHz, 1 .OMHz,
2MHz,3MHz, 4.0MHz and 3.58MHz. Thissequence of
frequencies is called a "multi-burst"which is veryuseful.
FIELD 1
(MULTI-BURST)
FIELD 2
FIELD 1&2
Fig. 13. VITS signal,Fields 1 and2
TheVITSotherthan the multi-burstsignal is different
depending on broadcaststation.VITSstaircasewaveform
containing a 3.58MHz burstsignal is valuable to the
network, but has less value tothe servicetechnician. As
Field 1 is interlacedwithField 2, line 17 is followed by line
279 and line 18 is followed by line 280.The entireVITS
appears at the bottom of theverticalblankingpulseandjust
before the firstline of the video signal.
Each of the multi-burstfrequencies is transmitted at
equalstrength. By observing the comparativestrengths of
these frequenciesafter the signal is processed through the
televisionreceiver,thefrequencyresponse of thesetcan be
checked.
All multi-burstfrequencies are transmitted atthe
samelevel, but will appear as shown in Fig. 14 even on a
good colortelevisionset, dueto itsresponsecurve;showing
theallowable amount of attenuation for eachmulti-burst
frequency.Rememberthat — 6dBequalshalfthereference
voltage (the 2.0MHz modulation should be used for
reference).
15
NO.18
-HORIZ.SYNC.PULSE
VERTICAL BLANKINGINTERVAL
(NO 1 ~ N021)
LINE NO.17
3,58MHZ
NO 279
NO 280
•VERTICAL BLANKINGINTERVAL
(NO263 ~ NO 282)
(MULTI-BURST)
0,5 1 2 3 3,58 4,2
MHZ
NO 17
NO 279
N018
NO 280
RESPONSE-dB
FREQUENCY—MHz
Fig. 14. ColorTVIFamplifier response curve

Tolocalizetrouble,start by observingtheVITS at the
videodetector.This will localizetrouble toa point either
before or afterthedetector. If thepicturequality of each
channel is different,thetrouble isin thetuner or antenna
system. Ifthepicturequalityisthesameforallchannelsbut
themulti-burstisabnormal,thenthetroublemaybe in the
IF stage.
As anotherexample,letusassumethatwehave a set
on the benchwith a very poor picture. Our oscilloscope
shows theVITSatthevideodetectortobe about normalex-
cept thattheburst at 2.0MHz is lowcompared to other
burstsignals.ThissuggeststheIFtrapisdetunedintothe
passband, chopping outfrequencies about 2MHz belowthe
picture carrierfrequency.Switchtoanotherchannel.Ifthe
amplifierrequiresrealignment. If thepicturequalityisthe
same, thenourreasoningisright,andifthepicturequalityof
anotherchannelisnormal,theFMtrapatthetuner input is
misadjusted. Fig.15showsthe method ofviewingtheVITS
waveforms.
VIDEO
START WITH
2mS
See text)
PICTURE
TUBE
Fig. 15. Set-up forviewingfields1 and2 of VITS information
1. Seta color TV receiver tothe stationtransmitting
colorsignalscontaining VITS.
2. The method shown in Fig.16isusedtoobtainField 2
vertical signal on CH1.
3. Settheoscilloscopeandthereceiver for operation.
ConnecttheCH 1 probe (setat10 : 1)tothetest point
ofvideodetector or otherdesiredtest point inthe
videosection of thetelevisionreceiver.
4. SettheSYNCswitchasfollows:
A. If thesyncandblankingpulses of theobserved
videosignal are positive,use theTV+ switch
position.
B. If thesyncandblankingpulsesarenegative,use
theTV—switchposition.
5. AdjustthesweeptimeVARIABLEcontrol so that 2
vertical fieldsaredisplayedontheoscilloscopescreen.
6.ConnecttheCH2 probe (setto10 : 1)tothesametest
point asdoestheCH1 probe.
7.Setthe MODE switch to DUALposition.
8.PlacethesweeptimeVARIABLEintheCALposition.
9. Setthe SWEEPTIME/DIVcontrol tothe 0.1ms
position to expandthedisplay.TheVITSinformation
will appeartowardtherighthand portion of theex-
panded waveformdisplays.Thewaveforminforma-
tion on eachtracemayappearasshown in Fig. 13.
Because thereisnoprovisionforsynchronizingtheos-
cilloscope display to either ofthe twofieldswhich
comprise a completeverticalframe, it cannot be
predictedwhichfielddisplay will appear on CH1 or
CH2.
10. Pull the <>POSITION controloutward to obtain an
additional X 5 magnification.Rotatethecontrol mov-
ingthetracetotheleftuntiltheexpandedVITSinfor-
mationappearsasshown in Fig. 13. Because of the
lowrepetitionrateand the high sweepspeedcom-
bination,thebrightnesslevelofthesignaldisplays will
bereduced.
11. OncetheCH1andCH2displayshavebeenidentified
16
VERTICAL
SYNC
PULSE
VERTICAL
BLANKING
l F
AMP VIDEO
DETECTOR
VI DEO
AMP VIDEO
AMP
SOUND
IF
COLOR'
I F
TELEVISION SET

as being eitherField 1 or Field 2 VITSinformation,the
probe corresponding tothe waveformdisplaycan be
used for signal-tracing and troubleshooting, andthe
remaining probe should be left atthe videodetector
test point to ensurethat the syncsignal isnotin-
terrupted. Ifthe syncsignal is interrupted, the
waveformdisplays maybe reversedbecause, as
previouslyexplained,there isno provision intheos-
cilloscope to identifyeither ofthetwo verticalfields
which comprise a completeframe.
SINGLE-CHANNEL APPLICATIONS
Introduction:
In addition to thedual-traceapplicationspreviouslyout-
lined, thereare, of course,manyservicing and laboratory
applicationswhereonlysingle-trace or single-channel
operation ofthe oscilloscope is required. By setting the
MODE switch toCH2and using theCH2 amplifier,many
flexible operations will be achieved;and, in addition, by plac-
ing the MODE switch to SUBposition(with the CH 1 DC-
GND-AC switch in the GND position),whateverwaveform is
obtained canbe inverted in polarity if desired bythe
operator.
TelevisionServicing:
Atriggeredsweeposcilloscope is advantageous in ser-
vicing and aligningtelevisionreceivers.Thisoscilloscope
also includesseveralfeaturesthatwereincorporated to
maketelevisionservicingeasierobservation and more com-
prehensive.
* With the SYNCswitch settoTV position, the SWEEP
TIME/DIVcontrolautomatically selects theTV vertical
sync at sweepspeedsappropriateforviewingframesand
TV horizontalsync at sweepspeedsappropriate for view-
inglines.
* Wide bandwidth for high resolutionvideoand high speed
pulsepresentation.
Single-traceOperationandPeak-to-Peak
VoltageReadings:
For generaltroubleshooting and isolation of troubles in
television receivers, the oscilloscope isan indispensable in-
strument. It provides a visualdisplay ofthe absence or
presence of normalsignals.This method (signal-tracing)
may be used to trace a signal by measuringseveralpoints in
thesignalpath. As measurementsproceedalongthesignal
path, a point maybe found where the signaldisappears.
When thishappens,thesource of troublehasbeenlocated.
However, the oscilloscopeshowsmuch more than the
merepresence or absence of signals . It provides a peak-to-
peakvoltagemeasurement of thesignalaswellaspresenta-
tion of waveforms. The schematicdiagram or accom-
panyingservicedata on the equipment being servicedusual-
ly includeswaveformdiagram.Thiswaveformdiagram
includes the requiredsweeptime andthe normal
peak-to-peakvoltage.Compare the peak-to-peakvoltage
readings onthe oscilloscopewiththoseshown onthe
waveformdiagram.
CompositeVideo Waveform Analysis:
Probablythemostimportantwaveformintelevisionser-
vicing isthe compositewaveformconsisting ofthe video
signal, theblankingpedestalsignalandthesyncpulses. Fig.
17 andFig.18 showtypicaloscilloscopetraceswhen
observingcompositevideosignalssynchronizedwith
horizontalsyncpulses and verticalblankingpulses.Com-
positevideosignalscan be observedatvariousstages of the
television receiver to determinewhethercircuitsareperfor-
ming normally.Knowledge of waveformmakeup, the
apperance ofa normalwaveform, and thecauses of various
abnormalwaveformshelp the technicianlocate and correct
manyproblems. The technicianshouldstudysuch
waveforms ina televisionreceiverknown tobein good
operatingcondition, noting the waveform at variouspoints
in the videoamplifier.
TELEVISION SET
Fig.16. Set-up for viewing horizontal fields of composite video signal
17
HORIZONTAL
SYNC PULSE
HORIZONTAL
BLANKING
PULSE
IF
AMP VIDEO
DETECTOR
VIDEO
AMP VIDEO
AMP
PICTURE
TUBE
SOUND
IF
COLOR
IF I

VIDEO
VIDEO
DETECTOR
TELEVISION SET
VIDEO
AMP
SOUND
IF
PICTURE
TUBE
COLOR
IF
Fig. 17.Set-upfor viewingvertical fields ofcompositevideo signal
13. Push in theTRIGGERING LEVEL controlandrotate to
a positionthatprovides a wellsynchronizeddisplay.
14. Adjust the INTENSITY and FOCUScontrols for the
desiredbrightnessandbestfocus.
15. To view a specific portion of thewaveform,such as
thecolorburst,pullthe ^ •POSITIONcontrol forX5
magnification.Rotatethesamecontrolleft or rightto
select thedesired portion of thewaveform to beview-
ed.
16. Thepolarity of theobservedwaveformmayberevers-
edwhen moving from one monitoring point to
another;therefore, it maybenecessary to reversethe
polarity of theSYNC switch.
Sync Pulse Analysis:
The IF response ofa televisionreceiver canbe
evaluated to someextent by carefulobservation of the
horizontalsyncpulsewaveform. The appearance Of the
sync pulsewaveformisaffectedbytheIFamplifierbandpass
characteristics. Sometypicalwaveformsymptomsandtheir
relation toIF amplifierresponse are indicated in Fig. 18.
Sync pulsewaveformdistortions produced by positive or
negativelimiting in IFoverloadconditionsareshown in Fig.
19.
18
VERTICAL
SYNC
PULSE
VERTICAL
BLANKING
IF
AMP VIDEO
AMP
Toset up theoscilloscope for viewingcompositevideo
waveforms,usethefollowingprocedures:
1. Tune the televisionset toa localchannel.
2. Setthe MODE switch to CH2position.
3. SettheSWEEPTIME/DIVswitchtothe10/usposition
forobservingTVhorizontallinesortothe2msposition
forobserving TV verticalframes.
4. SettheSYNCswitch to the TV+ position.
5. SettheSOURCEswitch to theCH2position.
6. Setthe TRIGGERING LEVEL control to the AUTO
position.
7.SettheCH2 AC-GND-DC switch to the AC position.
8.Connect a probe cable tothe CH2 INPUT jack.
Connectthe ground clip of the probe to thetelevision
set chassis.
With the probe set to10 : 1 attenuation,connectthe
tip of the probe to the videodetector output of the
television set.
9. SettheCH2VOLTS/DIVswitchforthelargestvertical
deflectionpossiblewithout going off-scale.
10. RotatetheTRIGGERING LEVEL control toa position
thatprovides a synchronizeddisplay.
11. AdjustthesweeptimeVARIABLEfortwohorizontal
lines ortwo vertical frames of compositevideodisplay.
12. If thesyncandblankingpulses of thedisplayedvideo
signals arepositive,settheSYNCswitch to theTV-f-
position; if thesyncandblankingpulsesarenegative,
use theTV—position.

Fig. 18. Analysis ofsyncpulsedistortion
FM RECEIVER ADJUSTMENTS
1. Connect a sweepgenerator to themixerinput of the
FMreceiver.Setthesweepgeneratorfor a 10.7MHz
center sweep.
2. Connect the sweepvoltageoutput ofthe sweep
generator to theCH2input jack of theoscilloscope
andsettheoscilloscopecontrolsforexternalhorizon-
tal sweep(SWEEPTIME/DIV to X-Y).
3. Connecttheverticalinputprobe to thedemodulator
input of the FM receiver.
4. Adjust the oscilloscopevertical and horizontalgain
controlsfordisplaysimilartothatshown in Fig.20A.
5. Setthemarkergeneratorprecisely to 10.7MHz. The
marker"pip"shouldbeinthecenter of thebandpass.
NORMAL
SYNC PULSE
SYNC PULSE
COMPRESS ION
CAUSED BY
L IMITING
"WHITE"
SATURAT ION
CAUSED BY
L IMITING
6.AligntheIFamplifiersaccordingtothemanufacturer's
specifications.
7. Move theprobe to thedemodulatoroutput.The"S"
curve should be displayed,and the 10.7MHz "pip"
shouldappear in thecenter(seeFig.20B).
Adjust the demodulatoraccording tothe manufac-
turer's instructionssothemarkermovesanequaldis-
tance from the center asthe markerfrequency is
amplifiedanequalamountfromthe 10.7MHz center
frequency.
Fig. 20. Typical FM receiveralignment set-up
19
Fig. 19. Sync pulsewaveforms
CIRCUIT
DEFECT
HORIZONTAL
PULSE
DISTORTION
OVERALL RECEIVER
FREQUENCY RESPONSE
EFFECT ON
PICTURE
NORMAL
CIRCUIT
PICTURE
NORMAL
LOSS OF HIGH
FREQUENCY
RESPONSE
LOSS OF PIC-
TURE DETAIL
EXCESSIVE HIGH
FREQUENCY RE-
SPONSE, NON-
LINEAR PHASE
SHIFT
FINE VERTICAL
BLACK t WHITE
STRIATIONS FOL-
LOWING A SHARP
CHANGE IN PIC-
TURE SHADING
LOSS OFLOW
FREQUENCY
RESPONSE
CHANGE IN SHA-
DING OF LARGE
PICTURE AREAS;
SMEARED PIC-
TURE
MARKER
GENERATOR
SWEEP
GENERATOR
MARKER
INPUT
RF
OUT
SWEEP
VOLTAGE
RF
MIXER
l-F
AMPS
DEMODULATOR
AUDIO
AMPS
OSC FM RECEIVER
DIRECT