Tue 4OOl
UnaavARrABLE
PutsE aENERATIR
Operation Manual
99 Washington Street
Melrose, MA 02176
Phone 781-665-1400
Toll Free 1-800-517-8431
1486Highland
Avenue,Unit2
Cheshire,
CT 06410
(203)272-3285 FAX:(203)272-4330
Visit us at www.TestEquipmentDepot.com
WARRANTY
Global Specialties@
warrants this device to
be free from defective material or workmanship for a period of one full year from the date
of original purchase.
under this warranty is
- Global Specialties@
limited to repairing the defective device when
returned to the factory, shipping chargesprepaid, within one year from date of original
purchase.
Units returned to Global Specialties@
that
have beensubjectto abuse,misuse,damageor
accident,or have been connected,installed or
adjustedcontrary to the instructionsfurnished
by Global Specialties@,
or that have been repaired by unauthorized persons will not be
coveredbv this warrantv.
Global Specialties@
reservesthe right to discontinue models, changespecifications,price
or design of this device at any time without
notice and without incurring any obligation
whatsoever.
The purchaseragreesto assumeall liabili
tiesfor any damagesand / or bodily inj ury which
mayresultfromthe useormisuse of this device
by the purchaser,his employees,or agents.
This warranty is in lieu of ali representations or warranties expressedor implied and
no agent or representativeof Global Specialties@
is authorized to assumeany other oUtigationinconnectionwiththesaleand purchaseof
this device.
FACTORY SERVICEAND
Global Specialties@
will serviceand repair this instrument free of chargefor a period of one full
year,subjectto the warranty conditions above.
To obtain a return merchandiseauthorization (RMA) required for all returns, phone our
CustomerServiceDepartmentfor an RMA and all shipping instructions:
Tel. 1-800-572-1.028
or write:
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GLOBALSPECIALTIES
1486Highland
Avenue,
Unit2
Cheshire,
CT 06410
(203)272-3285FAX:(203)272-4330
ATTN: CUSTOMERSERVICEDEPARTMENT
BREADBOARDING SOCKETSLIFETIME GUARANTEE
All Global Specialties@
breadboardingsocketsare guaranteedfor life. If a socketever fails to
meet your requirements, return it and we will replace it,
NO QUESTIONSASKED.
Specificationssubject to changewithout notice.
@ and TM trademarks are the property of INTERPLEX ELECTRONICS, INC., New Haven, CT.
TABLEOF CONTENTS
SPECIFICATIONS..
..PAGE2
INTRODUCTION.....
.PAGE4
DESCRIPTION.......
..PAGE
4
LOCATION
AND DESCRIPTION
OF OPERATING
CONTROLS............PAGE
5
CHECKING
OUTTHE4OO1
.....PAGE
9
APPLICATIONS.....
...PAGE
14
CIRCUIT
D E S C RPIT I O N . . . . . . .
REcALIBRATIoN
PRocEDURE
AND;usEnepLACEMENi............
B1BE
??
CIRCUIT
SCHEMATIC..........
...PAG2
E7
SERV|CE
A N DW A R R A N TtYN F O R M A T | O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . .e. . z. .e. . . . . . . . . p n e
LISTOF ILLUSTRATIONS
FIGURE1. Location
of Operating
Contro1s.............
PAGE5
FIGURE2. RunlModeandcom[lemented
waveforms.............. pAGE5
l99l!
q TrigMode
Waveforms..............
............PAGE
6
FIGURE
4 . G a t eM o d eW a v e f o r m s . . . . . . . . . . . . . .
......,...PAG
E
6
FIGURE5. One-Shot
ModeWaveforms..............
...PAGE
6
FIGURE6. RunModeand Squared
Waveforms..
..PAGE7
FIGURE
Z . C h e c k o uCt o n f i g u r a t i o n . . . . . . . . . .
. . . . . . . . . . . . . . P A9G E
FIGURE
8. Waveforms..............
. . . . . . . . . . . . . P A1G0E
FIGURE9. Checking
TriggerandGateModes.....
.PAGE14
F I G U R E1 0 . M i s s i n p
g u l s eD e t e c t oArp p t i c a t i o n . . . . . . . . . . . . . . . . . . . . . p A G1E5
Frequency
Response
Test.........
..........pAGE
II9yl_E 11 Amptifier
17
FIGURE12. Transmission
LineTest...
...PAGE1g
FIGURE13. ScopeWaveformPatterns-Transmission
LineTesting.......pAGE
20
FIGURE14. CaseDisassembly
andAssembty
.......PAGE
25
F I G U R E1 s . C i r c u iSt c h e m a t i c . . . . . . . .
. . . . . . . . . . . . . . . . . . . ...p. .A. .G
. .E
:2. 7
LISTOF TABLES
patterns
square-wave
andInterpretation...................pAGE
IlPf_E1.Typical
16
T A B L E2 . P o w e r / O u t pRuet t a t i o n s h i p s . . . . . . . . . . . . . . . . . . . . : . . ...... . . . . . . . p A G E
17
4OO1SPECIFICATIONS
FrequencyRange:
PulseWidthand
SpacingControls:
DutyCycle:
Accuracy:
(PulseWidthand Spacing)
0.5 Hz to 5 MHz
1O0nsec.-1sec
in 7 overlapping
ranges.
Independent
variablewidthand spaiing
controls.Two concentric,
single-turn
verniers
providecontinuous
adjustmentbetween
ranges.
107-to-1range,cont.adjustable
(Amplitude)
+5%typical,tlso/o
@ max
verniersetting.
+5o/o
of controlsetting.
Jitter:
Lessthan0.1%+S0psec.
OperatingModes
(pushbu
tton selectable)
Run:
0.5 Hz to 5 MHz,frequencysettable
throughpulsewidth/spacing
controls.
Trig:
DC to approximately
10 MHzfrom
externalsource.
Gate:
Generatorstartssynchronously
with
leadingedgeof gatesignal-"One
Shot"
pushbutton
can manuallyactivategate in this
mode.
One Shot:
Enablesmanual"One
Shot"pushbutton.
SquareWave:
Squarewavemay be obtainedat the
outputsby depressing
"SquareWave"
pushbutton.
Complement:
the
Q{guts may be invertedby depressing
"COMPL"pushbutton,
withoutlosingsync
time reference.
NOTE:pulsespacingcontrolsnot active
during"Trigger"and "One-Shot"
modes.
Trig/Gate
Input:
TTL compatible
input,DC coupledlogicinput:
pulses>2.4V
peak>4Onsec
wide.Sinewave
input:>1.7V
RMS<1OMHz.
Inputimpedance:
400Q max.input:r10V.
Output:
Var Out
Amplitude,
0.S-10V,
adjustable
via singleturn
vernier;rise/falltime3Onsec;impedande,
50CI
TTL Out:
Fan out,40TTL loads;sink,64mAat O.gV
maximum;
rise/fall
time:lessthan2Onsec.
SyncOut:
Amplitude
2.4Vminimum;
fan out, 1OTTL
loads;sink,16mAat O.8Vmaximum;riseifall
time,lessthan2Onsec;
syncpulseleadtime,
greaterthan2Onsec.
Power:
105-125VAC,
50/60Hz
220-240VAC,
50i60Hz (Optionat)
OperatingTemperature:
0"Cto50"C
(calibrated
at 25" C t55" C).
32" F to 122" F
'(calibrate
d al 72" F*9" F).
Size (WxHxD):
10"x 3" x7" (254x 76 x 178mm).
Weight:
2.2tbs.(1 kg)
INTRODUCTION
The GlobalSpecialties
4001Ultravariable
PulseGenerator
is a reliablelowcostpulse
Generator.
lts uncomplicated
rugged.design
and highqualitycomponents
ensurelong
and dependable
service.The 4oo1offersthesefeaiures:
SeparateTTL Output
A VariableOutputfromO.5Vto 10V
5Q Outputlmpedance
PulseWidthRangefrom lOOnsec
to lsec
DESCRIPTION:
The Model4001,primarily
designedas a pulseor clocksource,is compatible
with lC
and discretecomponent
circuits.lt alsofindsapplication
as a syste. sieppet(OneShotMode),gatedoscillator(GateMode),or prir" stretcher(TiiggerMode).With
a
minimumof adjustments,
the 4oo1can alsoserveas a missirigillse detectoror a
frequency
discriminator.
The outputcan be complemented
or converted
to a square
wavewith a pushof the button.
The Model4001offerstwo Simultaneous
Independent
Outputs(TTLand Variable)
with riseand fall timeslessthan30nsec;2OnsecTTL compatibleleading-edge
Sync
pulseoutput'Thereare independent
pulsewidthand pulsespacingcontrols(both
selectable
form lOonsecto lsec) eliminating
incompaiible
frequenJy
ano pulsewidth
settings.Also on the panelare four pushbutton
selectable
operatindmooeswitches
marked(Run,Trigger,Gateand One-Shot).
LOCATION
AND DESCRIPTION
OF OPERATING
CONTROLS
Referto Figure1 for the locationof all operatingcontrols.
Thesenumbers
willbe
referredto throughout
the text.
NOTE
All pushbutton
switchesare push-to-activate
switches.
1
2
*rrrorx
3
-.-
l-E'|.-
-',
;Ai.ffi:/n
|
aoor eulse
[(
o^rt[.rc
'13
12
*
5, 1.f.
tY* ar
11
5
-,
19,
GENERAToer
l]--
\lZ
4
1
rr! out
0
/
,\-/..
va. ovr
9
8
FIGURE1. Locationof Operating
Controls
POWERSwitchand LED Indicator:
(1)
MODESwitch(2)
NOTE
The four ModeSwitches(2)
aremechanically
interlocked
allowingonlyone switchto
be activated
at a time.Theyare designated
RUN,TRIGano ofr-sHor.
RUN:
In the Runmode,the 4OO1is self-oscillating.
All externalinputsare disconnected,
and
all timingcontrolsare functional.
(SeefigureZ)
aOpr3^.20nsec
1 l*
n
n
n
SyncOut n
TTLor
VarOut
TTLor --l
Var our
t-t
t-l
l-'l
f-l
f-]
f-l
l-]
{ z.aV Min.
n
:n
I
l-l
l-l
f-l
l-l
Run
Mode
Complemented
l-
FIGURE2. Run ModeandComplemented
TRIG:
In the Trig mode,the 4001outputsproducea synchronous
positivegoingoutputpulse
for eachpositiveinputtrigger.The outputpulsewidthis adjustedbyihe pulse
Width
and WidthVerniercontrols.The outputpuiseis initiatedby the posltiu"-.dge
of the
inputtrigger.Whenthe modeswitch.isin the Triggermode,
rrrv 'pulse
v'vv Spacingand
ve' i"v-Y' the
Spacing Vernier are inactive. (See Figure B)
l0 V Max
Trig
f,,,n
tvtode
TTL or
VarOul
I
FIGURE3. TrigModeWaveforms.
GATE:
In the Gatemode,the 4991outputsproducetrainsof pulsesfor the
durationof the
appliedgallngsignal.The leadingedgeof the gatingsignalstartsthe outputpulse
teioingedgeof the gatingsignat.
!ai1 The firstpulsein the trainii synchronized'witti
Boththe PulseSpacingand Pulsewiotn controlsthe programpulse
trainparameters.
lf the gatingpulseendswhilean outputis present,
the lait pulsewill be
complemented.
(SeeFigure4).
I 2.4V Min
.Irloi
Var Oul
lcate
l;il'"
With LeadEdge
of GateSignai
)
FIGURE4. GateModeWaveforms.
ONE-SHOT:
In the One-Shotmode,the modeswitchis latchedand the One-Shotpushbutton
pressed,.
(-s)'when
initiates
an'outputpulse.Pulseparameters
are set by the pulse
Width(11)and WidthVerniercontrols.,Pulse
Spacingand SpacingVerniercontrols
are not active.(SeeFigure5)
one Shot---r,/
Pushbutton
oepressed
lone-snot
.Irlol
Varout
-l
Figure5. One-ShotWaveforms.
6
SQUAREWAVE:(3)
when this buttonis depressedthe outputis convertedto a squarewave.The
output
now changesstatewith everypositiveedgeof the original"piogrammed"
waveform.
This dividesthe frequencyof the signalOytwo.All inputsand controls
are still
functional.
(SeeFigure6)-
Run
Mode
TTL or
Varout
i-t_i-i_ro*r"o
FIGURE6. RunModeand SquaredWaveforms
COMPLEMENT:
(a)
Whenthis buttonis depressed
the TTL and Variableoutputsare automatically
complemented.
All inputsand controlsare stillfunctionat.
1net.Figure2)
ONE-SHOTMODESWTTCH:
(5)
See MODEswitches(2)for details.
AMPLITUDE
CONTROL:
(6)
The AMPLITUDE
controladjuststhe amplitude
of the vottageat the VAR OUT BNC
connector
from0.5 Voltsto 10 Volts.
VAR OUT:(7)
The VAR OUT BNc connector
providesa convenient
meansfor interconnecting
the
generator
outputto its destination.
The VAR OUTsignalhas a riseandfalltimeof
3Onsecand outputimpedance
of 50 ohms.
TTL OUT:(8)
The TTL OutputBNC connectoris fed by four TTL gatesin parallel,providing
fanoutof 40. Riseandfall timesare lessthan20ns6c.Both'TTLand'vAR a TTL
ouT pulses
are derivedfrom the sameinternalsourceand are svnchronous.
SYNCOUT:(9)
The SYNCOUT BNCconnector
producesan outputpulse2onsecwideand 2onsecin
advanceof the mainoutputpulses.The Syncpulseamplitude
is a minimum ol 2.4
Voltsand can drive10 TTL loads.
GATE\TRIG
INPUT:(10)
The GATE\TRIGinputterminalsare DC coupledto the 4001internalcircuitry.The
inputsignalcan be a sinewavegreaterthan 1.7VRMSor a positivepulsegreater
than2.4V
NOTEAmplitude
mustnot exceedtlOV.
W I D T HV E R N T E R
( 1: 1 )
The WIDTHVERNIERis usedfor continuous
adjustment
of pulsewidthbetweenthe
limits9f.the rangeset on the PULSEwIDTH sWtrcH. A stightovertapat both
ends
of the Vernierrangeinsurescontinuous
adjustment
overthe entiresevendecadesof
pulsewidthadjustment.
PULSEWIDTHSWTTCH:
(12)
The PULSEWIDTHswitchis usedto selectoutputpulsewidthsfrom 1oonsec
to lsec
in.sevenranges'Whenusedin conjunction
withthe WidthVernier,continuous
adjustment
overthe instrument
rangeis achieved.
SPACING
VERNTER
( 1: 3 )
The SPACEVERNIERis usedfor continuous
adjustment
of pulsespacingbetween
the limitsof the rangeset on the pulsespacingsr,vitch.
n stightou"ri"p at bothendsof
the vernierrangeinsurescontinuous
adjustment
ouerthe entiresevendecadesof
pulsespacingadjustment.
PULSESPACING
SWTTCH:
(1a)
The PULSEWIDTHswitchis usedto selectoutputpulsespacingfrom 1ggnsec
to
lsec in sevenranges.when usedin conjunction
wiin the SpACI-ruG
vrnrutrn,
continuous
adjustment
overthe entireinstrument
rangeis achieved.
FLIP-UP
LEGrM: (15)
Easilyraisedor folded.Elevatesthe frontof the generator1 i/2 inches.
FUSEHOLDER:
(REARPANEL)
Thefuse postis mountedto the rearpanel.(see Figure14).
CHECKING
OUTTHE4OO1
To checkout the Model4001PulseGenerator
the following
equipment
is required.
(SeeFigure7).
1. A dual-trace
oscilloscope,
100MHzbandwidth
minimum.(HewlettpackardModel
1740or equivalent)
2. A TTl-levelfrequencysource.(GlobalSpecialties
Model2001or equivalent)
3' ThreeBNC-toBNCcables(GlobalSpecialties
ModelPSA-2or equivalent)
4. A 50 ohm terminator.
Procedure
Plugthe 4001intoa powersourceof the propervoltageandfrequency.
(105to
11SVAC,
60Hzor 210to 230VAC,50 to 6OHz)Pressin the pOWrn ON switch.The
LEDadjacentto the switchwill illuminate.
o@
o
o
o o
oB'3oo o
Y Fauln
l
o
n
S
o
FIGURE7. Checkout
Configuration.
StepA:
Set the controlson the 4001as follows:
CONTROL
PowerSW
PulseWidthSW
PulseSpacingSW
WidthVernier
SpacingVernier
RunModeSW
SquareWaveSW
ComplSW
Amplitude
Cntrl
POSITION
ON
100ns
100ns
Xl (fullyclockwise)
X1 (fullyclockwise)
IN
NormalOut Position
NormalOut Position
10V (fullyclockwise)
StepB:
Connect
oneBNC-Io-BNC
cablefromthe4001TTLOUTBNCto theoscilloscope
channel"A"input.
connectthesecondBNC-Io-BNC
cabtefromthe4001syNc our
BNCto the oscilloscope
channel"B',input.
StepC:
Set the oscilloscope
in the ALT modeto triggeron the risingedgesof the ,,61,,
input,
with a sweepspeedof 50nsper divisionor faster.
observethatthe""syNc
purseriseandfat timesare ressthan2ons.
Pulsewidthis approximately
2Ons.
Amplitude
is 2.4Vminimum.
Risingedgeof the syNc pulseleadsthe risingedgeof the TTL
pulseby approximately
20ns.
StepD:
Pressin the COMPswitchon the 4001.
observethat the""
Rising.
edgeof the syNc pulseleadsthe fallingedgeof the TTL
pulseby approximately
20ns.(SeeFigureg).
Width- 1 gsec
_:l-l*_i
l<-
-:l
l.<-
(
n
sPbcine
r sec -->f
widthl sec ---->l
Spacing
1 zsec
FIGURE8. Waveforms.
10
Step E:
Returnthe COMPswitchto it,snormalposition.
Observethatthe.....
Riseandfalltimesof the TTL outputare lessthan20ns.
NOTE:
some overshootor ringingmay havebeenobservedon the TTL signal.This is
a
resultof the undampened
transmission
lineeffectsof the BNC cabl6and is not
inherentto the waveform.The sameform of distortionmay also be in
evidenceduring
the followingstepswherethe VAR OUTsignalis used.Thesereflections
will ceaseto
existonceproperimpedance
matchingis obtained.
StepF:
Disconnect
the BNCcablefromthe TTL our and connectto VAR our.
Rotatethe AMPLITUDE
pot fromits fullyclockwise
positionto its fuliy
counterclockwise
position.
Observethatthe.....
waveformamplitudedecreasesfrom its initial1oVvalueto a o.5V
level.
StepG:
Set outputamplitude
to 5V.
Connectthe 50fJ terminator
at the oscilloscope
"A" channelinputin-linewiththe BNC
cable.
NOTE
Manyoscilloscopes
havea 5OOterminator
that may be usedin placeof the external
terminator.
Observethatthe....
output amplitudeis now 2.5Vand that ringingpreviouslypresent
dueto impedance
mismatching
no longerlpfears.
NOTE
VAR OUT riseand fall timesare lessthan30ns.
observethatthe""
ursewidthand pursespacingare each100nsxso/o.
1t_
StepH:
Rotatethe WIDTHVERNIERto its uX10"position.Notethat the pulsewidthis
now
lpsec *15o/o
andthatthe pulsespacingis unchanged.
Pressin the coMp switchand notethe waveforminversion.
Pressin the SQUAREWAVEswitch.Notethatthe resultingwaveformhas a pulse
widthof.1.1psecand a pulsespacing
of 1.1psec,(the.r*if the wIDTHandrf".ing
settings)for a totalof 2.2p"s.
Returnthe SQUAREWAVEand COMPswitchesto theirnormat(OUT)positions.
STEPI:
Rotatethe SPACINGVERNIERto its "X10"position.
Notethatthe pulsespacingis
now lusec t15%.
ChangePULSESPACING
and pULSEWTDTH
to 1ps.
Observe....
A pulsewidthand pulsespacingof lOpsec+11o/o.
STEPJ:
Observe....
A pulsewidthand pulsespacingof 1ps xlo/o.
ChangePULSEWTDTH
and pULSESPAC|NG
to 1Ops.
Observe....
A pulsewidthand pulsespacingof 10ps r5%.
STEPK:
Rotatethe WIDTHVERNIER
andSPACING
VERNIER
to ..X10...
Observe....
A pulsewidthand pulsespacingof l0Oprsec
t15%.
changethe PULSEwtDTHand pULSEspActNGto 1oops.
Observe....
A pulsewidthand pulsespacingof lmsec +1|o/o.
L2
STEPL:
Observe....
A pulsewidthand pulsespacingof 100ps xilo/o.
changethe PULSEwtDTHand pULSEspActNGto 1ms+\-5%.
STEPM:
Rotatethe WIDTHVERNIERand SPAOING
VERNIERto ,'X1O'..
Observe....
A pulsewidthand pulsespacingof lOmsec+15"/o.
changePULSEwrDTHand pULSEspAcrNGto 10ms.
Observe....
A pulsewidthand pulsespacingof 100mse
c x15o/o.
STEPN:
Rotatethe WIDTHVERNIER
and SPAOING
VERNIER
to ,,X1,,.
Observe....
A pulsewidthand pulsespacingof lOms+So/o.
changethe PULSEwtDTHand pULSEspActNGto 100ms.
Observe....
A pulsewidthand a pulsespacingof 100msxlyo.
STEPO:
Rotatethe WIDTHVERNIERand SPAOING
VERNIERto ,,X10,'.
Observe....
A pulsewidthand pulsespacingof lsec xl}o/o.
changethe PULSEwrDTHand pULSEspAcrNGto 1ms.
Pressin the ONE-SHOT
modeswitch.
Momentarily
pushin the whiteoNE-sHor pushbutton.
Observe....
One single1Omspulseis generatedfor eachactuationof the pushbutton.
1_3
STEPP:
Pressin the TRIGmodeswitch.
connecta TTL-level, signalfroma TTL-levelfrequencysourceto
the GATE\TRIG
l\z
lN connectoron the 4001
pulsegeneratorusinga BNCcabte.
Observe..
A 10mspulseoccurringat the 2Hz rate.
STEPQ:
Pressin the GATEModeswitch.
Observe....
Pulseburstsoccurringat a 2Hz rale.
STEPR:
Turnoff the powerand disconnect
all cables.Thisconcludes
the 4oO1pulsegenerator
checkout.
Gate/TriggerPulseSource
L-
i-.-
(a)
oo
o
t")
Al
t)
(J
s'so
E E .
V
o o
o o
4001UnderTest
Figureg. CheckingTriggerand GateModes.
APPLICATIONS
The 4001 PulseGeneratorwith its manyfeaturesand easeof operationmake
it a
welcomeadditionto any lab.
The followingis just a samplingof the variedusesof the 4001.
L4
Missing-Pulse
Detector
Programthe 4001pulsewidthfor 1Opsec.Set the inputtriggerpulserepetitionperiod
(.pnplto Sprsec.Eachtimethe triggerpulsegoespositive,-the
ioot i. resetand must
timeoutto itsfull 10psec.
The outputsof the 4001remainin the HighState.lf one of the triggerputsesis not
present(missing)the 4001outputwill tim-eout to 1Opsecand then return
to its low
stateuntilthe nexttriggerpulseoccurs.(see Figure10).
t'199::
----l t /sec
f*
Input
I
4oor
I
I
I
I
_>1logsec
FIGURE10.MissingpulseDetector
Application.
TRACINGDIGITALLOGICFLOW
The 4001and a digitallogicprobesuchas the GlobalSpecialties
Lp-Bmakean
excellent
troubleshooting
system.Justusethe 4001as a signalinjectorto injecteither
a pulsetrain,a singleone-shot,
or the complement
of eitherlThentracethroughthe
circuitswiththe LP-3and quicklyfindthe defective
component.
ANALYZING
A MICROPROCESSOR
PROGRAM
By substituting
your4001for the microprocessor
systemclockyou can giveyour
microprocessor
th_ecapabilityof steppingthroughiis microprogiam
eithera stepat a
time (in the One-Shotmode)or at much-reducddspeed,oy uiing tongtimingperiods
in the "RUN"mode.
Note,however,that somemicroprocessors
havea minimumclockspeed,belowwhich
correctoperationis not assured.lf in doubt,checkthe datasheettoi tfre
microprocessor
thatyou are using.
TESTINGRADIOCONTROL
RECEIVERS
Proportional
radiocontrolis usuallyimplemented
by sendinga variablemark-space
ratiolow frequencymodulation
on a radiofrequencysignal.-your
4001may be usedto
simulatethe radiotransmitter
whentestingthe low-irequency
stagesof your receiver.
The 4001is alsoidealfor simulating
thejoystickinputto the transmitter.
15
AUDIOTESTING
The4001 againshowsits versatilityin testingaudioamplifiers.
Squarewavesare
usedin audiotestingto.displaya wioerangjof frequencies
simulianeously.
Square
wavesconsistof a fundamental
frequency,and a seriesof odd harmonicsto square
off the waveshape.
WaveformLF Gain LF Gain l-{FGain HF Gain Damping
qra
oK
l
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OK
O
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oK
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OK
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o
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K
K
H
L
H
l:l"
OK
L
OK
H
H
'az'
H
H
L
L
H
qJ-
H
L
L
H
H
4
.
'"u
'-'Ll-
L
H
H
L
H
'Sharp
oK
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OK
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L
t-
O
r
i
r
o
K
O
K
K
o
H
K
O
*
K
o
L
K
L
L
Cutoffor
Peaked
L =Low
LL = VeryLow
H = High
OK= Suitable
Proper
TABLE1. TypicalSquarewave Patternsand an Interpretation
of TheseShapes.
For an amplifierto reproducea squarewave it musthavea flat frequency
response
from0.1Fto 10Fwhere"F" is the fundamental
frequency
of the squarewave.
The traditional
testfrequencies
are SOHzfor the lowfrequency
testand 1gKHzfor the
highfrequency
end.(SeeTable1)
connectthe 4001to the amplifierundertest as shownin Figure12 and observe
the
outputon the scope.Table2 showsthe tableof powerand voltagerelationships
for
40 and SOspeakers.
lt alsoliststheoutputvoltagelevelfor lOdBbelowthe maximum
outputof amplifierswith differentpowerratings.bhoosethe ratingclosestto
the
amplifierundertest.Testingat 1OdBbelowmaximumoutputensuresthatthe
amplifier
will not be in saturation.
This levelis approximately
2lS of the full poweroutput.
16
o
o
o o
o o
Amp UnderTest
FIGURE11.AmplifierFrequency
Response
Test.
PowerRatings(RMS)
8(l
4J)
1 W 2W
5 W 10w
1 0 w 20w
20w 4 0 w
5 0 w 100w
100w 200w
E2
8V
, 4 0v
80v
Output(RMS)
Full
Output
l0 dB Below
Max Output
2.8V
6.3 V
2.3V
5.2V
7.3V
10.3V
16.3V
23.1V
160V
8.9 V
12.6V
400v
800v
20.0v
28.0V
TABLE2. Power/Output
Relationships
L7
TESTING
TRANSMISSION
LINES
lf a transmission
line is not terminated
at the far end by its characteristic
impedance,
reflections
will occur.This phenomenon
can be usedto find faultson transmission
lines'Usingyour 4001you can find out if the cableundertest is open,
or short
circuited,and with somesimplecalculations,
you can find the lengihof tn" cable.
Equipment
1-4001PulseGenerator
1-50Qcoaxialcableto be tested(=1Om
long)
1-oscilloscope
1-passive
probe10:1
1-50Qtermination
1-adaptor
bananafemale-BNC
male
1-BNCT connector
oo
o
o
o a
o o
BananaFemale
10:l PassiveProbe
FIGURE12.Transmission
LineTest
Set up the equipment
as shownin Figure12.
Set the 4001to:
Amplitude-6.5V
Pulsewidthtime-Sprsec
Pulsespacetime-Sl-rsec
SquareWave-engaged
(useVAR.outputconnector)
l
Set the scopeto:
VerticalDisplay-1V/cm
InputCoupling-DC
TrigSource-lnt
Trig Mode-Audio
Trig Level-Adjusted
SweepTime-2psec/cm
1_8
Withthe far end open,the scopeshoulddisplaya signalas shownin Figure13.
The
finalamplitudeis reachedin two steps.At the momentthe 4001meetsthe 50e
of the
cableitself,the outputis at nominalvalue(midscale
dotsB on Figure13)and a
reflectiontakesplaceat the openend.Whenthis reflection
feedsbackto the pulse
generatoroutput,it tellsthe 4001thatthe far end is open,and the open
circuiivoltage
of the 4001appears.
Now-change
the Time/Divof the scopeto 0.1psecand observethe signalin Figure
13.The time betweenpoints"A" and "B" is the time it takesfor the miisingsigriat
to
reachthe openend and return.For example,assumethat (as in Figuretsny
lne
reflectiontakes12Onsec.
lt is knownthatihe velocityof a signatin I coaxialcableis
about0.7c (c=3x108 m/sec).lf the cablehasthe length"L'iit willtake2uo.7c
before
the signalreturnsas a reflection.
Usingthe timeobservedon the scopethe cable
lengthis calculated
as shown:
2l
,=ffC
where"T,,is TIMEfor Reflection
Solvingfor "L" we get:
-t __ 0- .27 c T
2= (0. 7) x(3x/08/ ms?c)x( 120xf2'sec)
2
Remember
thatthe accuracyof thisresultis determined
by the Time-Base
accuracy.
clrcuiting
the
end
of
the
cable
results
in
the
waveform
shownin Figure138 and
9!fn
13C'After12Onsec
the 4001"knows"thatits outputis shortcircuited
and the voltage
dropsto zero.The cableloadinfluences
this idealbehaviorand zero means
"almost"zero.
The cableloadinfluences
this idealbehaviorand zeromeans"almost,,
zero,whichcan be noticedfromthe offsetlevelwith respectto the start.
Terminating
the far endwith5OOresultsin the waveform(shown
in Figure1gD).
Matchingthe far end of the cablewith a resistorequalto itre characteiistic
impedance
completelyeliminatesreflections
from the far end,iesultingin a perfectsquarewave
at the generatorend of the cable.
L9
2rceclDiv <->
-1
\A
I
A
L
L
-
"u"YFIGURE13. scopewaveformpatterns-Transmission
LineTesting.
0.1psec/Div<--+
t
ft-B
I
0 'olts
- A
FIGURE13A.scopewaveformpatterns-Tnansmission
LineTesting.
20
2rcec/Div€
0 V cIts r
J\
tr
,E
J
FIGURE138.scopewaveformpatterns-Transmission
LineTesting.
0.'l6ec/Div €
0 V rt lts .
-:t
t
F
I.;;f.T
-
l
2nd Rerfleclion
?
t
\-
t
f
l
1r;t Reflectior
t
l
FIGURE13c.scopewaveformpatterns-Transmission
LineTesting.
2L
2 psec/Div <+
r
J
0 V (tts
I
't
FIGURE13D.ScopeWaveformPatterns-Transmission
LineTesting.
CIRCUITDESCRIPTION
Figure15 showsthe schematic
diagramof the 4001PulseGenerator.
The heartof the
pulsegenerator
is the integrated
circuitA-1 dualmonostable
multi-vib
rator
#74123.
The two monostable
multi-vibrators
are cross-coupled
from the "e,, outputof the first
to the "A" inputof the secondand vice_versa.
Anti-Latch
CircuitOperation
The cross-coupled
monostabled
multi-vibrator
circuitsas longas their,,8,,inputsare
high'However,
sincethe couplingbetweenthe two circuitsii purelyDc it is possible
for he oscillator
to latch-up.
The froblemis overcome
by a specialtriggering
cir:cuit
gated
is
on
if
a1
fails
to
osciilate.
Transistors
!9t
Q3 and e4 form a hookoscillator.
R30and R32 biasthe baseof Q3 to 1/2Vccwhilethe emitterof
e3 is controiledby
R28and R29.Theseresistors
are connected
to the e outputof the nt-t ano 41-8.
As longas 41 oscillates,
one of the Q outputswill be high.The averagevoltageat the
emitterof Q3 will be halfthe Q highvoltage.Thisholdsthe emitter
of e3 more
negativethan its base,and e3 istut off.
lf the oscillatorstops,b-o!hQs go high.Q3 emittervoltagerises
aboveits basevoltage
and startsto conduct.Q3 and Q4 turnon and latch,dis;harging
Cre. ns eB and e4
recoverfromthe latchcondition,
the "B" inputof At-n goeshigh,forcinge of 41_A
low,turningoff the hookcircuitand restarting
the oscillator.
22
TimingCircuitOperation
The timingof A1-Ais controlled
bythe selection
of capacitors
C1 throughcTand R1
throughR10.
The timingresistorR9 or R10and the trim potsR1 and R7 set the rangefor
Rg,the
SpacingVernier,Joreachof the pulsespacingswitchpositions.
41-B timingsystemis
the sameas A1-A.
ModeSwitchOperation
Run Position
ln the run mode,53 removesthe 5 voltsfrom the inputto A5-Bcausing
the outputto
go high,enablingthe oscillator.
Trig.Position:
In the trig'position,
54 applies5 voltsto R31,Q4 saturates
and shortsthe,,B',inputof
the.A1-Ato ground,disabling
41-A.Whena positivetriggerpulseappearsat J4, e5
emittergoeshighandA5-Alow,A5-Bgoeshigh,triggeiing
41-B on.'
GatePosition:
ln the gateposition,
55 tiesboththe baseof Q3 andthe "8" inputof A1-Ato the S
volt.linethrougha 1K resistor(R33)turningoff Q3 and insuring
that41-A is in the
oscillator
mode.
To gatethe oscillatoron, a positivevoltageis appliedto J4, whichvia
emitter{ollowed
Q5 causesA5-Ato go low,A5-Bto go high,and'theoscillator
to start.The oscillator
willcontinueto runwhilethe gatesignalis present.Whenthe gateis removed,
the
oscillator
completes
itsfinalcycle.
One-ShotPosition:
The pushbutton
fires? J-K FlipFlop(A2-A)whoseoutputturnsoff e5 throughCR2
and R44.Thismanuaily
simurates
the inpuiof a triggeipurse.
OutputCircuitOperation
TTL Out:
The TTL outputis derivedfromfourtwo-input
NANDgates.A 4.7?resistorlimitsthe
outputdriveto 40 TTL loads.
Var Out:
Q2 is the finaldriverfor the VARoutput.The collector
of Q2 is tiedto Vcc whilethe
baseis tiedto the collector
of Q1 througha 47Qresistor.
The collector
of e1 is tied
highthrougha 330Qresistorand is alsoshuntedto groundby a 2.SKa amptitude
pot.
Q1 and cR1 alsoprovideactivepulldown
for the outputwhenit is low.
The outputis fed via a 47o resistor,providingthe correctimpedance
and overload
protection.
23
Sync.Out:
The inputsof A4-Dare connectedto a timingchainconsistingof 3 TTL gates(AOA,A3-8,A4-A)
and R39,C19.The outputof n-s-ois normallyhigh.When it goes low,
therewill be a briefintervalbeforethe signalreacheste ortpi,t of A4-A
in which
neitherinputof A2-D.will
be high,and sJa syncwilrbe generated.Dependingon the
positionof the complement
switch,the firsttrinsitionof ine outputwitieitherbe
simultaneous
withthe fallingedgeof the syncpulseor lsnsec afterit.
PowerSupply:
A plug-intype powersupplysuppliesraw DC, plus(+) and (-) through power
the
switchdirecilyto the regulators.
RECALIB
RATIONPROCEDURES
FuseReplacement
The 4o01 is protectedby a type3AG slo blo 114amp(1/8amp for 230V)
25oVpower
fuse'The fuse is accessible
at the rearpanelof the'unit.lf replacement
of the fuse
shouldbecomenecessary,
followthisprocedure:
1. Disconnect
the AC powercord.
2' Use a screwdriver
to removethe fusecap holdingthefuseand removethe fuse.
3. lnsertfuse with correctrating.
NOTE:Newfusesseldomfailwithoutmalfunction
of the instrument.
Repeated
replacement
of the fusewithoutcorrecting
the problemmaycausefurtherdamage.
CaseDisassembly
andAssembly
To openthe case,turnthe unitupsidedownwiththe rubberfeetfacing
up (see Figure
14).Removethe four padsfromihe plasticfeet.Remou.tn" ;;;";;
i;"m the center
recessof eachof the four feet.
Note
The flip-uplegwillautomatically
comefreewiththe frontfeet.
Carefullyseparatethe two halvesof the caseand recalibrate
the unit.To closethe
case,lowerthe casebottomand guidethe frontand rearpanelsinto
theirslots.
Positionthe rubberfeet as illustraied
and screwthe two halvesof the casetogether.
Do not overtighten
screws.Instailthe four rubberpads.
24
Recalibration
Procedure
Bgforebeingshipped,your 4001PulseGeneratorwentthrougha very
thoroughseries
of testsand calibration.
lf recalibration
becomesnecessary,
f|llow the instructions
outlinedbelowcarefully.Do not attemptto recalibrate
this'unitunlessyouhave
e19ughexperiencein ihe use of an oscilloscope.
See warranty(backcover)for limits
of liability.
Duringthis recalibration
procedure,
referto Figure1, controlLocations:
1. Disconnect
all cabresfromthe 40-01.Removepowercordfrom wail prug.
2' Removethe top casehalf as outlinedin the CaseDisassemory
piocboure.(See
Figure14)
FuseHolder
And LlneCord
FIGURE14.CaseDisassembly
and Assembly
3' Reconnect
powerand connectthe oscilloscope
to the TTL ouT BNCon the 4001.
25
4. Set up 4001frontpanelas follows:
CONTROL
POSITION
Power(1)
Mode (2)
PulseWidthSw (12)
PulseSpacingSW (14)
SpaceVernier(10)
WidthVernier(11)
SquareWave(3)
Comptement(4)
ON
RUN
100ns
100ns
X1
X1
OUT
OUT
5. AdjustR17for a pulsewidthof 10Onsr5o/o.
6. AdjustR7 for a pulsespacingof 10Onsxlo/o.
7' SwitchPULSEWIDTHand PULSESPACINGcontrolsto their1ps positions.
B. AdjustR16for a pulsewidthof 1ps +So/o.
9. AdjustR6 for a pulsespacingof 1ps xlo/o.
10' SwitchPULSEWIDTHand-PULdE
SPACINGcontrolsto their1oprspositions.
11.AdjustR15for a pulsewidthof 10ps5%.
12.AdjustR5 for a pulsespacingof 16ps5%.
13' SwitchPULSEWIDTHanOpUtSE SPACINGcontrolsto their100pspositions.
14.AdjustR14for a pulsewidthof 100ps xlo/o.
15.AdjustR4 for a pulsespacingof lObps l:lo/o.
16' SwitchPULSEWIDTHano putsr SpnCtruGcontrolsto their1mspositions.
17.AdjustR13for a pulsewidthof 1ms xlo/o.
18.AdjustR3 for a pulsespacingof 1ms xlo/o.
19' SwitchPULSEWIDTHano pUtSE SPACINGcontrolsto their
1Omspositions.
20. AdjustR12for a pulsewidthof 1Omsxl"/o.
21. AdjustR2 for a pulsespacingof lOms+So/o.
22' SwitchPULSEWIDTHano putsE SPACINGcontrolsto their100mspositions
23. AdjustR11for a pulsewidthof lOOms+5o/o.
24. AdjustR1 for a pulsespacingof 100msxlo/o.
25'.Turnoff power,disconnect
ail cablesfromthe 4001,and reassemblethe
caseas
outlinedin the CaseReassembly
proceclure.
Thiscompletes
recalibration
of the 4001.
99 Washington Street
Melrose, MA 02176
Phone 781-665-1400
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
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