Text preview for : 1471 Instruction Manual.pdf part of B&K 1471 Instruction Manual . Rare and Ancient Equipment B&K 1471 Instruction Manual.pdf
Back to : 1471 Instruction Manual.p | Home
!471
10 MHz,TRIGGERED
SWEEP
Dual-T aceOscIIosco
r I p
v
\
v
A Productof DYNASCAN 1801West Belle Plaine. Chicago,
CORP0RATI0N lllinois 60613
PRTCE
$2.00
l v
INSTRUCTION
MANUAL
FOR
B & K.PRECISION
MODELL47T
b TRIGGERED
10 MHz, SWEEP
DUAL.TRACE
OSCILLOSCOPE
DIVISION DYNASCAN
OF CORPORATION
| 801 W. Belle PloineAvenue
C h i c o g o ,l l l i n o i s 6 0 6 I 3
v
TABLE OF CONTENTS \t
Page
INTRODUCTION
FEATURES
SPECIFICATIONS
OPERATOR'S CONTROLS, INDICATORS AND FACILITIES
OPERATING INSTRUCTIONS
Initial Starting Procedure 9
Single-Trace WaveformObservation 9
CalibratedVoltage Measurement 10
CalibratedTime Measurement ll
External Horizontal Input (X-Y Operation) . . . l2
Z-Axis lnput t2
Dual-Trace WaveformObservation t2
DUAL-TRACE APPLICATIONS
Introduction . . 14
F re q u e n c y D i v i d e rWa v e fo rms
... 14
Dvide-by-8CircuitWaveforms... 14
Digital Circuit Time Relationships 14
Gated Ringing Circuit 14
DelayUneTests ......16 v
StereoAmplifier Servicing l6
TelevisionServicing t7
SINGLE-TRACE APPLICATIONS
Introduction . . 18
TelevisionServicing 18
SignalTracing and Peak-to-Peak Voltage Readings t9
CompositeVideo WaveformAnalysis t9
Sync PulseAnalysis r9
VITS (Vertical Interval Test Signal) . . . 2l
Vectorscope Operation 23
TELEVISION ALIGNMENT
Introduction . . 26
Importance Sweep
of Alignment 26
SweepAlignment Methods 27
Tuner Alignment 28
IF Alignment 29
ChromaAlignment... 29
v
v TABLE OF CONTENTS
Page
FM RECEIVER ALIGNMENT , . . . 3 1
PHASEMEASUREMENT 3l
FREQUENCY
MEASUREMENT
SQUARE WAVE TESTING OF AMPLIFIERS
Introduction . 33
TestingProcedure 34
34
CIRCUITDESCRIPTION
General 38
Vertical Preamplifiers 38
Mode Iogc 38
Vertical Amplifier 38
Trigger
Circuit 38
SyncAmplifierandInverter 38
40
40
40
40
b 40
50
CALIBRATION ADJUSTMENTS
CH I and CH2 DC Balance . . . 40
l12 and l/5 Attenuator Balance 40
Vertical Gain Adjustment 40
Horizontal Position Adjustment . . . 40
WARRANTYINSTRUCTIONS 42
WARRANTY 43
v
INTRODUCTION
The B & K-Precision Model l47I Dual-Trace Oscil- The dual-tracefeature,togetherwith the 10 MHz band-
loscopeis a laboratory-quality,
observingand measuring
professional instrument for
waveformsin electronic circuits.
width, wide range of sweep speeds,and high sensitivity
provided,-make this the ideal oscilloscope a broadrange
for
v
Dual vertical inputs are provided for simultaneous viewing of applications,including troubleshootingand repairing
of two waveforms. Low-frequency, low repetition rate electionic equipment, research and development,and
waveformsare chopped at a 200 kHz rate to provide for laboratorvinstruction.
simultaneous viewing. Alternate sweepof the two inputs
permitssimultaneous viewingof high-speed, high repetition-
rate waveforms.
FEATURES
DUAL TRACE Two input waveforms can be WIDERANGEOF Sweepspeedrangeof I ptSEC/cm
viewed either singly or simul- SWEEPSPEEDS to 0.5 SEC/cm provides every
taneously, desired.
as speednecessary viewingwave-
for
forms from DC to 10 MHz.
FULLY Only the cathoderay tube usesa
SOLIDSTATE filament. All other stages use EXPANDED A five time magnification(5X) of
transistors,diodes, FET's (field SCALE the horizontal sweepallowsclose-
e f fe ct transistors) and IC's. up examination of a portion of
Among the advantages solid
of the waveform.In addition,the 5X
stateconstruction are: magnification provides a maxi-
o No stabilization mum sweep speed of 0.2
warm-up
pSEC/cm.
time required.
o Low powerdrain. Permitsthe low-capacitance, high-
HIGH
o Dependability - impedance, l0:1 attenuation
SENSITIVITY
reliability probesto be used for virtually all
o Ruggedness. measurements, thus assuringless
o Light weight. circuit loading.
o Compactness.
TV SYNC A built-in sync separatorcircuit is
included specifically for viewing
v
TRIGGERED The 147|'s stabilityof waveform
televisionsignals.When using TV
SWEEP presentations beyond comPari-
is
SYNC, television vertical sync
son with non-triggered sweeP
The sweepsremain pulses are automatically selected
oscilloscopes.
at sweeptimes of 0.5 SEC/cmto
at rest until triggered the signal
by
0.1 mSEC/cm for viewing tele-
being observed, to assure that horizon-
vision frames.Television
they are always synchronized.
tal sync pulsesare automaticallY
Fully adjustabletrigger threshold
selected at sweep times of 50
allows the desiredportion of the pSEC/cm to I pSEC/cm for view-
waveformsto be used for trigger- lines.
ing television
ing. Waveforms can also be
synchronizedto an external sync
trigger. VECTORSCOPE The unit may be usedasa vector-
scope to provide a color displaY
exactly as specifiedby color tele-
LARGESCREEN T h e 1 3 0 m m (a p p ro x .5 . 1 i nches) vision manufacturers.
diameter cathode ray tube gives
easy-to-readpresentation on an CALIBRATION A builtin calibrated I volt peak-
8 x 10 cm rectangular viewing SOURCE t o-peak square wave Permits
area. checking and recalibrationof the
vertical amplifiers without addi-
CALIBRATED Accurate measurement the in-
of tional equipment.
VOLTAGESCALES stantaneousvoltageson l1 dif-
ferent attenuator rangesfor both Z-AXIS Intensity modulation caPabilitY
ChannelA and ChannelB. INPUT included for time or frequencY
markers. Compatible with TTL
CALIBRATED on
Accurate time measurements increases logic
logic; brightness in
SWEEPSPEED 18 different ranges. low state, decreases logic high
in
state.
WIDEBANDWIDTH DC to l0MHz bandwidthand 35
nSEC rise time assuredistortion- \,
free, high resolution presentation
at high frequencies.
SPECIFICATIONS
(CH
v VERTICALAMPLIFIERS A aNd B)
Deflection Factor
CH
0.01 V/cm to 2O Y lcm in I 1
TV Sync Vertical and horizontal sync
separatorcircuit providedso that
any portion of complexTV wave-
c a l i b r a t ed r a n g es i n l - 2 - 5
form can be synchronized and
sequence.
expanded for viewing. TVH (line)
CalibrationAccuracy ! 5% on all ranges. and TW (frame) sync switched
automatically by SWEEPTIME/
FrequencyResponse DC: DC to 10 MHz (- 3 dB)
CM switch.
AC : 1 0 H z to l 0 M H z e3 dB ). = 0.5 SEC/cm to 0.1
TW
Risetime 35 nanoseconds. mSEC/cm.
TVH = 50 pSEC/cm to I
Overshoot 3% or lessat 100 kHz squarewave pSEC/cm.
display.
Ringing 3% or less at 100 kHz squarewave
HORIZONTAL AMPLIFIER (Horizontal Input through
display.
CH B Input)
Input Resistance +
I megohm, 5%.
DeflectionFactor .01 V/cm to 20 V/cm.
Input Capacity 22 pF (t 3 pF).
FrequencyResponse DC to 800 kHz e3 dB).
Max. Input Voltage 300 V (DC + AC peak) or 600 V
Input Resistance I megohm(nominal).
p-p.
Input Capacity 22 pF (t 3 pF).
OperatingModes ChannelA only.
Madmum Input 300 V (ttC + AC peak) or 600 V
ChannelB only.
Voltage p-p.
Dual-trace automatically chopped
X-Y Operation With SWEEPTIME/CM switch in
at all sweeptimes of I mS/cm and
CH B position, the CH A input
slower; alternate trace automati-
becomes Y input (vertical)and
the
cally selectedfor all faster sweep
the CH B input becomesthe X
times.
input (horizontal).The CH B posi-
Chop Frequency 2OOkHz (x 2Wo). tion control becomes horizon-
the
tal position control.
ChannelSeparation Better than 60 dB @ I kHz.
b
(Common CH A andCH B) CALIBRATION VOLTAGE
SWEEP
CIRCUITS to
I V p-p squarewave(+ 5%) atline
SweepSystem Triggeredand automatic.In auto-
matic mode, sweep is obtained frequency.
without input signal.
SweepTime I pSEC/cm to 0.5 SEC/cmin 18 INTENSITY MODULATION
calibrated ranges, in l-2-5 se-
quence. Voltage TTL logic-compatible.Low logic -
increasesbrightness;high logic
SweepTime Accuracy ! 5%. decreasesbrightness.
SweepMagnification Obtained by enlarging the above lnput Resistance 470 kCl (nominal).
sweep 5 times from center.Maxi
mum sweep speed becomes O.2
pSEC/cm. POWERREQUIREMENTS
Horizontal Linearity 3Vo lessdistortion.
or Input ll7 or 230 VAC, I lVo,5016O
Ifz, 20 watts. (3-wire line cord,
CSA-approved oscilloscopes.)
for
TRIGGERING
S e eF i g .5 1 .
Source INT and EXT (lV p-p
PROBES(Not Included)
sensitivity).MODE switch selects
sourceof internal trigger;the CH A Model No. PR-208 or PR-24B.
signal is the triggering source in
Attenuation Combinationl0: I and direct.
the CH A and DUAL modes,and
the CH B signal is the triggering lnput Impedances l0:1 = l0 megohms8 pF.
l,
sourcein the CH B mode. Direct = I megohm,120 pF.
Slope Positiveand negative,continuous- Connector BNC
ly variablelevel control; pull for Tip SpringJoaded,
hook-on tip.
AUTO.
v TriggeringRange 20 Hz to l0 MHz (rrrih. I cm
deflectionasmeasured cathode
on
ray tube).
6
7
8
10
19 18 17 15
Fig. 1. Front panelcontrolsand indicators.
\'
OPERATOR'S INDICATORSAND FACILITIES
CONTROLS.
v l . CathodeRay Tube (CRT). This is the screen which
the waveforms viewed.
are
on I l. ChannelB POSITIONControl. Vertical position adjust-
horizontalposition
ment for ChannelB trace.Becomes
adjustmentwhen SWEEPTIME/CM switch 4 is in the
1 Scale. The 8 x l0 cm graticule provides calibration CH B position.
marks for voltage (vertical) and time (horizontal)
measurements. 12. Channel B DC BAL Adjustment. Vertical DC Balance
adjustmentfor ChannelB trace.
3 . Pilot Lamp. Lights when oscilloscope turned on.
is
13. ChannelB INPUT Jack. Vertical input jack of Channel
4. SWEEP TIME/CM Switch. Horizontal sweep time B. Jack becomes external horizontal input when
selector.Selectscalibratedsweeptimes of 1 pSECicm SWEEP TIME/CM switch 4 is in the CH B position.
(microsecondper centimeter)to 0.5 SEC/cm in l8
steps. In the CH B position, this switch disablesthe 14. ChannelB DC-GND-ACSwitch.
internalsweepgenerator and permitsthe CH B input to
providehorizontalsweep. DC Direct input of AC and DC componentof input
signal.
5 . CAL I V P-P Jack. ProvidescalibratedI volt peak-to-
peak square wave input signal at the line frequency. GND Openssignalpath and groundsinput to vertical
This is used for calibration of the vertical amplifier amplifier. This providesa zero-signalbaseline,
attenuators. the position of which can be usedas a reference
when performingDC measurements.
6 . < > POSITION Control. Rotation adjusts horizontal
position of traces(both traceswhen operatedin the AC BlocksDC componentof input signal.
dual trace mode). Push-pullswitch selects magnifi-
5X 15. ChannelB. VOLTS/CM Switch.Vertical attenuatorfor
cation when pulled out (PULL 5X MAG): normal ChannelB. Vertical sensitivityis calibratedin 1l steps
when pushedin. from .01 to 20 volts per cm. This control adjusts
7 . TRIGGERING LEVEL Control. Sync leveladjustment horizontal sensitivity when the SWEEP TIME/CM
determinespoints on waveform slope where sweep switch 4 is in the CH B position.
starts;(-) equalsmost negativepoint of triggeringand 16. MODE Switch. Three-position lever switch; selects
the
(+) equals most positive point of triggering.
Push-pull basicoperatingmodesof the oscilloscope.
switch selects automatic triggering when pulled out
(PULL AUTO). When automatic triggering,a sweepis CH A Only the input signal to Channel A is dis-
generated evenwithout an input signal. playedas a singletrace.
v 8 . EXT TRIG Jack. Input terminalsfor external trigger
signal.
CH B Only the input signal to Channel B is dis-
playedas a singletrace.
DUAL Dual-traceoperation;both the ChannelA and
9 . SYNC Switch. Four-position lever switch with the Channel B input signalsare displayedon two
following positions. separatetraces.
SLOPE. The SLOPE positionsare usedfor viewing all 17. ChannelA VOLTS/CM Switch. Vertical attenuatorfor
waveformsexcept televisioncompositevideo signals. ChannelA. Verticalsensitivity calibrated 1l steps,
is in
(+) Sweep is triggered on positive-going slope of from .01 to 20 voltsper cm.
waveform. 18. ChannelA DC-GND-ACSwitch.
(-) Sweep is triggered on negative-going
slope of DC Direct input of AC and DC componentof input
waveform. signal.
TV. In the TV positions, the sync pulses of a GND Openssignalpath and groundsinput to vertical
television composite video signal are used to trigger amplifier. This providesa zero-signalbaseline,
the sweep; the vertical sync pulses (frame) are the position of which can be usedas a reference
automaticallyselected sweeptimesof 0.5 SEC/cm
for when performingDC measurements.
to 0.1 mSEC/cm,and horizontalsync pulses (line) are AC BlocksDC componentof input signal.
automatically selected for sweep times of 50
pSEC/cmto I pSEC/cm. 19. ChannelA INPUT Jack.Vertical input jack of Channel
A.
(+) Sweepis triggeredon positive-going
sync pulse.
20. ChannelA DC BAL Adjustment. Vertical DC balance
(-) Sweepis triggeredon negative-going
sync pulse. adjustmentfor ChannelA trace.
10. SOURCE Switch. Selects triggering source for the 21. Channel A POSITION Control. Vertical position ad-
sweep. justmentfor Channel trace.
A
INT Sweepis triggeredby CH A signalwhen MODE 22. FOCUSControl.
switch is in CH A or DUAL position.
23. POWER/INTENSITYControl. Fully counterclockwise
Sweep is triggered by Channel B signalwhen
rotation of this control (OFF position) turns off
v MODE switch is in CH B position
EXT Sweepis triggeredby an external signalapplied
oscilloscope.
Clockwiserotation turns on oscilloscope.
Further clockwiserotation increases
brightness the
of
at the EXT TRIG jack 8. trace.
24. INT MOD Jack.Intensity modulation(Z-axis)input. probe designed for use with an oscilloscope
hav
nominal input impedance of I megohm shunte
25. AC Line Cord (See Fig. 2). v e n - a r , P r v Y v u for oscil-
tu \s!w "6' 2 ' ' CSA-approvedr v r
J5 pF and capable of operation up to 10MHz, c
loscopes.
26' Pro.bi]*9-Fie'3-)' B & K-Precision Pl':jt
The Model (Not shown).
" ir::l"r overray
-" rnterchanges
with
and PR-24Bcombination l0:1/Direct probeshavebeen io, vectorscope
operation.
designedfor use with this oscilloscope.
However, any
C R T R OTA TIONA D JU S TME N T
D C B A LA N C EC ON TR OL
(Oneon eachside)
Fig.2. Rearand sidepanelfacilities.
v
-r> 1.PULL APART
1O:1
ATTENUATION
P R O B E C O M P E N S A T I O NA D J U S T M E N T
( P R -2 4 8 O N L . Y )
2 . R O T A T E1 8 0 '
F R O B E O M P E N S A T I OA D J U S T M E N T
C N
( P R - 2 OO N L Y )
B
3. PUSHBACK TOGETHER
r>-
Fig.3. hobe details.
v
OPERATINGINSTRUCTIONS
INITIAL STARTING PROCEDURE
the l0:l position and I megohmwith l20pF shunt
v l. Set POWER/INTENSITYcontrol 23 to OFF position capacitancein the DIRect position. The higher input
(fully counterclockwise). impedance (low-capacity position) should be used
2. Connect power cord 25 to a I l7-vo1t,50/60 Hz outlet. when possible, decrease
to circuit loading.
3. Set CH A POSITION control 21, CH B POSITION 3. SetCH A DC-GND-ACswitch 18 to AC for measuring
only the AC component (this is the normal position for
control I I and<>POSITIONcontrol 6 to the centersof
their ranges. most measurements and must be used if the point
being measured includesa large DC component).Use
4. Pull TRIGGERING LEVEL control 7 to the AUTO the DC position for measuringboth the AC component
Position. and the . DC reference, and any time a very low
5. Set CH A DC-GND-AC switch 18 and CH B frequency waveform (below 5 Hz) is to be observed.
DC-GND-AC switch 14Io the GND positions. The GND position is required only when a zero-signal
ground referenceis required, such as for DC voltage
6. Set MODE switch 16 to the CH A position for readings.
single-traceoperation or the DUAL position for dual-
4. Connect ground clip of probe to chassisgroundof the
traceoperation.
equipment under test. Connect the tip of the probe to
7. Turn on oscilloscopeby rotating POWER/INTENSITY the point in the circuit where the waveform is to be
control 23 clockwise.It will "click" on and pilot lamp measured.
3 will light.
8. Wait a few secondsfor the cathode ray tube (CRT) to WARNING
warm up. A trace (two tracesif operatingin the DUAL
a. If the equipmentunder test is a transformer-
mode) should appearon the face of the CRT.
less AC powereditem, use an isolation trans-
9. If no trace appears, (clockwise)the setting of
increase former to prevent dangerous electricalshock.
I\TENSITY control 23 until the trace is easily
b. The peak-to-peakvoltage at the point of
observed.
measurementshould not exceed 600 volts
10. Adjust FOCUS control 22and INTENSITY control 23 when using the DIRect position of the probe.
for the thinnest, sharpest
trace.
11. Readjust positioncontrols6,21 and 11 if necessary,
to 5. Set CH A VOLTS/CM switch 17 to a position that
centerthe traces. gives 2 to 6 cm (two to six large squares the scale)
on
v 12. Check for proper adjustmentof DC BAL controls 12
vertical deflection. The display on the screen will
probably be unsynchronized. The remainingstepsare
and 20 as described in the MAINTENANCE AND
CALIBRATION portion of this manual. Theseadjust- concerned with adjusting synchronization and sweep
ments require checkingonly periodically. speed, which presents a stable display showing the
desired number of waveforms. Any signal that pro-
The oscilloscopeis now ready for making waveform duces at least I cm vertical deJlectton develops suf-
measurements. ficient tigger signal to synchronize the sweep.
CAUTION 6. Set SOURCE switch l0 to the INT position. This
Never allow a small spot of high brilliance to provides internal sync so that the waveform being
remain stationary on the screen for more than a observed is also used to trigger the sweep. Most
few seconds. The screenmay becomepermanently waveformsshould be viewed using internal sync. When
bumed. Reduce intensity or keep the spot in an external sync source is required, the SOURCE
motion by causingit to sweep. switch should be placed in the EXT position and a
cable should be connectedfrom the EXT TRIG jack 8
to the externalsync source.
SINGLE.TRACE WAVEFORM OBSERVATION 7. Set SYNC switch 9 to the TV (+) or TV (-) positions
for observingtelevision compositevideo waveformsor
Either Channel A or Channel B can be used for
to the SLOPE(+) or SLOPE(-) positions for observing
single-trace operation. For simplicity, Channel A is usedin
all other types of waveforms.Use the (+) position if
the following instructions.
the sweepis to be triggered a positive-going
by wave,or
"Initial StartingProcedure
1 . Perform the steps of the the (-) position if the sweepis to be triggeredby a
with the MODE switch 16 in the CH A position. Then negative-going wave. If the type of waveform is
connect the probe cable to the CH A INPUT jack 19. unknown, the SLOPE(+) position may be used.
The following instructions assume the use of the
8. ReadjustTNGGERING LEVEL control 7 to obtain a
B & K-hecision Model PR-20B combination probes.
synchronized displaywithout jitter. As a startingpoint,
2 . For all except low-amplitude waveforms, the probes the control may be pushedin and rotated to any point
are set for l0:l attenuation.For low-amplitudewave- that will produce a sweep,which is usually somewhere
forms (below 0.5 volt peak-to-peak), the probe for
set in the center portion of its range. The trace will
v DIRect. See Fig. 3 for changingthe probesfrom l0:l
to DIRect, or vice versa.The probe has a l0 megohm
disappear if there is inadequate signal to trigger the
sweep, such as when measuringDC or extremely low
input impedance with only l8 pF shunt capacitance
in amplitude waveforms.If no sweep can be obtained,
pull the control out (PULL AUTO) fof'automatic waveform at which sweep triggering will occur. The
triggering. control may be adjusted to start the sweep on any
desiredportion of the waveform.
9. Set SWEEPTIME/CM switch 4 for the desirednumber
of waveforms.This control may be set for viewing only l1'. For a close-up view of a portion of the waveform,pull \
a portion of a waveform, but the trace becomes outward on I^he<>POSITION control 6. This e*puhds V
progressively dimmer as a smaller portion is displayed. the sweep by a factor of five (5X magnification) and
This is because sweepspeedincreases the sweep
the but displaysonly the center portion of the sweep.To view
repetition rate doesnot change. a portion to the left of center,turn the <>POSITION
control clockwise, and to view portion to the right of
NOTE center, turn the control counterclockwise. Pushinward
on the control to return the sweep to the normal,
When usingvery fast sweepspeedat low repetition non-magnifie condition.
d
rates, the operator may wish to operate with the
intensity control toward maximum. Under these CALIBRATED VOLTAGE MEASLJREMENT(SeeFig. 4)
"pip" may appear at the
conditions, a retrace
extreme left of the trace.This doesnot in any way Peak voltages, peak-to-peakvoltages, DC voltagesand
affect the oscilloscope operation and may be voltagesof a specific portion of a complex waveform are
disregarded. easily and accurately measuredon the Model 1471 Dual-
Trace TriggeredSweepOscilloscope.
10. Alter obtainingthe desired number of waveforms, in
as
l . Adjust controls as previously instructed to display the
step 9, it is sometimes desirable to make a final waveform to be measured.
adjustment of the TRIGGERING LEVEL control 7.
The (-) direction selectsthe most negativepoint on the 2 . Set CH A VOLTS/CM switch l7 for the maximum
waveform at which sweeptriggering will occur and the vertical deflection possible without exceeding the
(+) direction selects the most positive point on the limits of the vertical scale.
.} P O S I T I O N O N T R O L D J U S T E D OT H A T
C A S
T O PO F W A V E F O R M R O S S EC E N T E R F
C S O
V E R T I C A L C A L EM A R K E RF O RA C C U R A C Y
S
ANDEASE FREADING
O
o- Y
@..t
o Irlo
oLz-JB
qfr@H@'
P O S I T IO N C O N T R O L A D J U S T E D
SO THAT BOTTOM OF WAVE-
FORM ALIGNS EXACTLY W]TH
A H O R I Z O N T A L R E F E R E N C EL I N E
VOLTS/cm
S E TT O
.o2v
EXAMPLE:
VERTICAL DEFLECTION = 4.2cm 1O:1
VOLTAGE/CM = .O2 P R O B EA T T E N U A T I O N .
.084V
PROBE TTENUATION
A = 10
=
P E A K - T O . P E AW A V E F O R M 04v
K
v
Fig. 4. Typiqal voltagemeasurement.
l0
3 . Read the amount of vertical deflection (in cm) from CALIBRATED TIME MEASUREMENT (SeeFig. 5)
the scale.The CH A POSITION control 2l may be
readjustedto shift the referencepoint for easierscale Pulse width, waveform periods, circuit delays and all
Whenmeasuring DC voltage,
readingif desired. a adjust other waveform time durations are easily and accurately
measuredon this oscilloscope. Calibrated time measure-
v the CH A POSITION control 2l to a convenient
referencewith the CH A DC-GND-ACswitch l8 in the ments from .5 second down to 0.1 microsecond are
GND position, then note the amount the trace is possible.At low sweepspeeds, entire waveformis not
the
deflectedwhen the switchis placedin the DC position. visible at one time. However, the bright spot can be seen
The trace deflectsupward for a positivevoltageinput moving from left to right acrossthe screen,which makes
the beginningand ending points of the measurement easy
and downward for a negativevoltageinput.
to spot.
4 . Calculate the voltage reading as follows: Multiply the
vertical deflection (in cm) by the VOLTS/CM control 1. Adjust controls as previously describedfor a stable
displayof the desiredwaveform.
17 setting(seeexamplein Fig. a) Don't forget that the
voltage reading displayed on the oscilloscopeis only 2. Set the SWEEPTIME/CM contrcI 4 for the largest
1/l0th the actual voltage being measuredwhen the possible display of the waveform segment to be
probe is set for l0:l attenuation.The actualvoltageis measured, usuallyone cycle.
displayedwhen the probe is set for DIRect measure-
ment. 3. If necessary, readjustthe TRIGGERING LEVEL con-
trol 7 for the most stabledisPlaY.
5. Calibration accuracy of this oscilloscopemay be
occasionallychecked by observingthe I volt peak-to- 4. Read the amount of horizontal deflection (in cm)
peak square wave signal availableat the CAL lV P-P betweenthe points of measurement. oPOSITION
The
jack 5. This calibrated source should read exactly I control 6 may be readjusted to align one of the
volt peak-to-peak.If a need for recalibrationis in- measurement points with a vertical scale marker for
dicated, see the "MAINTENANCE AND CALIBRA- easierreading.
TION" section of the manualfor completeprocedures. 5. Calculate the time duration as follows: Multiply the
HORIZONTAL
D E FL E C T I O N
6.35
cm
<> S W E E PT I M E / C M
P O S I T I O N C O N T R O L A D J U S T E DS O 'l
set to 0p sec
THAT LEADING EDGEOF WAVE-
v FORM ALIGNS WITH A VERTICAL
R E F E R E N C EL I N E . E D G E
MAY NOT BE VISIBLE ON VERY
F A S T P U L S E S ;l N T H I S C A S E
A L I G N W H E R E V E RW A V E F O R M @ . S L O P Es e t t o Q
( t o s t a r t s w e e po n
BEGINS. negatlve-going dge) e
o
INT
3@fr@f@'
P O S I T I O NC O N T R O L A D J U S T E D S O
THAT TRAILING EDGEOF WAVEFORM
CROSSES ORIZONTAL SCALE MARKER
H
FOR ACCURACYAND EASEOF READING
EXAMPLE:
HORIZONTAL DEFLECTION= 6.35cm
S W E E PT I M E / C M = 1 0 p S E C
TIME DURATION = 63.5pSEC
( o r P E R I O D )O F W A V E F O R M
FREOUENCY= 1
TrME .0000635 SEC DISPLAYSHOW YPICAL ELEV!SION
T T
R E C E I V E W A V E F O R M T G R I DO F
R A
= 15,750 z
H HORIZONTAOUTPUT UBE
L T
v Fig. 5. Typical time measurement.
ll
horizontal deflection(in cm) by the SWEEP TIME/CM
switch 4 setting (see example in Fig. 5). Remember,
when the 5X magnificationis used,the result must be
dividedby 5 to obtain the actualtime duration.
6. Time measurements often requireexternalsync.This is
especiallytrue when measuringdelays.The sweepis
v
started by a sync signal from one circuit and the
waveformmeasured a subsequent
in circuit. This allows
measurement the display between the sync pulse
of f a \ t \
\ t
and the subsequent waveform.To perform suchmeas- l I I , t
urementsusing external sync, usethe following steps:
a. Set the SOURCEswitch l0 to the EXT position.
a
b. Connect a cable from the EXT TRIG jack 8 to the t I \ t
sourceof sync signal.Usea short shieldedcable.
c. Set the SYNC switch 9 to the SLOPE(+) or (-)
position for the proper polarity for the sync signal.
d. Readjust the TRIGGERING LEVEL control 7 if
necessary a stablewaveform.
for
e. If measuringa delay, measurethe time from the
Fig. 6. trace with Z-axisinput.
Oscilloscope
start of the sweepto the start of the waveform.
7. Another excellentmethod for measuringtime delaysis
with dual-traceoperation.The procedures given in
are
the "DUAL-TRACE APPLICATIONS" section of the DUALTRACE WAVEFORM OBSERVATION
manual. (Refer to Fig. 7)
In observing simultaneouswaveforms on channelsA
EXTERNAL HORTZONTAL rNPUT (X-y OPERATTON) and B, it is necessarythat the waveforms be related in
frequencyor that one of the waveforms synchronizedto
be
For some measurements. externalhorizontaldeflec-
an the other although the basic frequenciesmay be different.
tion signal is required. This is also referred to as an X-Y An example of this is in checking a frequency divider or
measurement, where the Y input providesvertical deflec- multiplier. The reference, "clock" frequencycan be used
or
tion and the X input provideshorizontal deflection. The on ChannelA, for example,and the multiple or submultiple
horizontal input may be a sinusoidalwave, such as for of this referencefrequency will be displayedon ChannelB.
phase measurement,or an external sweep voltage. This
input must be l0 mV per cm of deflection greater;thus
or
In this way, when the waveform display of Channel A is
eynchronized, the display on ChannelB will also be in sync
b
any voltage of 100 mV or greater is sufficient for with the Channel A display. If two waveforms having no
satisfactoryoperation.To use an externalhorizontalinput, phaseor frequencyrelationshipto eachother are displayed
usethe following procedure: simultaneously, will be difficult if not impossible lock
it to
1. Set the SWEEPTIME/CM switch 4 fully clockwiseto both waveformsin sync for any useful observation.
the CH B position. To display two waveformssimultaneouslyfor observa-
2. Use the Channel A probe for the vertical input and the tion, usethe following procedure:
ChannelB probe for the horizontalinput. l. Perform the steps of the "Initial StartingProcedure."
3. Adjust the amount of horizontal deflection with the probe cablesto both the CH A
2. Connect oscilloscope
CH B VOLTS/CMcontrol 15. and CH B INPUT jacks 19 and 13.
4. The CH B POSITION control I I now servesas the 3. If the recommended & K-Precision
B Model PR-20Bor
horizontal position control, and the <> POSITION PR-24B oscilloscope probesare used,l0:l attenuation
control is disabled. should be used except for waveforms of 0.5 volt
peak-to-peakor less. For the lower amplitude wave-
forms the DIRect position should be used.See Fig. 3
NOTE for changingthe probe from l0:l to DIR or vice versa.
Do NOT use the PULL 5X MAG control during Whenever possible, use the high impedance, low
X-Y operation.Use the CH B VOLTS/CM control capacityl0: I position to minimize circuit loading.
to adjust horizontal gain. 4. Set MODE switch 16 to the DUAL position. Two
tracesshouldappearon the screen.
5. All sync controls are disconnected
and have no effect.
5. Adjust CH A and CH B POSITIONcontrols2l and 1l
Z.AKS INPUT to place the Channel A trace above the Channel B
The trace displayed on the screen may be intensity trace,and adjust both tracesto a convenient
reference
modulated (Z-axis input) where frequency or time-scale mark on the scale.
marks are required.A TTL compatiblesignalappliedat the 6. Set both the CH A and CH B DC-GND-AC switchesl8
INT MOD (intensity modulation)jack 24 on the rear of the
oscilloscopewill provide alternate brightnessand blanking
and 14 to the AC position.This is the position usedfor
most measurements and must be used if the ooints
v
of the trace.SeeFie. 6. beingmeasured includea largeDC component.
r2
7. Connect the ground clips of the probesto the chassis Use the (+) positionsif the sweepis to be triggeredby
gound of the equipmentunder test. Connect the tips a positive-going wave, or to the (-) position if the
of the probes to points in the circuit where tle sweepis to be triggered a negative-going
by wave.
waveformsare to be measured. The signalto which the I l. Adjust TRIGGERING LEVE! control 7 to obtain a
v waveform will be synchronizedmust be applied to the
ChannelA input for internalsync operation.
stable, synchronizedsweep. As a starting point, the
control may be pushedin and rotated to any point that
will produce a sweep,which is usually somewhere in
WARNING the center portion of its range.The tracewill disappear
if there is inadequate signalto trigger the sweep,such
a. If the equipmentunder test is a transformer-
as when measuring extremelylow amplitudesignals. If
less AC unit, use an isolation transformerto
no sweepcan be obtained,pull out the control (PULL
preventdangerous electrical
shock. AUTO) for automatictriggering.
b. The peak-to-peakvoltage at the point of
12. Set SWEEPTIME/CM switch 4 for the desired number
measurement should not exceed600 volts, if