Tektronix PG 509 User manual

Tektronix, Inc.
P.O. Box 500
Beaverton. Oregon
IbktfDnix-
COMMITTEDTO EXCELLENCE
PG 509
Pulse
Generator
INSTRUCTION MANUAL
97077 Serial Number
070-77K^
Product Group 75 First Printing OCT 19B9

Copyright •1909 Tektronix, Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix, ir>c.
Products of Tektrorux, Inc. and its subsidiaries are covered
by U.S. and foreign patents andjor pending patents.
TEKTRONIX. TEK, SCOPE-MOBILE, and &are
registered trademarks of Tektronix, Inc. TELEQUIPMENT
is aregistered trademark of Tektrorrix U.K. Limited.
Printed in U.S.A. Specification and price change privileges
are reserved.
INSTRUMENT SERIAL NUMBERS
Each instrument manufactured by Tektronix has aserial
number on apanel Insert, tag, or stamped on ttre chassis. The
letter at the begmning of the serial number designates the
courrtry of manufactire. The last five digits of the serial nurrk)er
are assigned sequentially and are unique to each instrument.
Those manufactured in the United States have six urtique
digits. The country of manufacture Is identified as follows:
B010000 —Tektronix. Inc. Beaverton, Oregon. USA
G100000 —Tektronix Guernsey. Ltd., Chartnel Islands
E200000 —Tektronix Urrited Kingdom, Ltd., London
J300000 —Sony/Tektronix, Japan
H700000 —Tektronix Holland. NV. Heerenveen,
The Netheriartds
Instruments manufactured for Tektronix by external vendors
outside the United States are assigned a two digit alpha code
to identify the country of manufacture (e.g., JP for Japan, HK
for Hong Kong, IL for Israel, etc.).

CONTENTS
ILLUSTRATIONS il{
TABLES iv
OPERATORS SAFETY SUMMARY v
SERVIONG SAFETY SUMMARY vli
tSpectflcatlon
SPECIRCATION 1-1
IMTROOUCnON 1-1
PB1FORMANCE CONOmONS 1-2
2System Installation
SYSTEM INSTALIATION 2-1
PREPARATION FOR USE 2-1
FRONTPANELCONTROLSANDCONNECTOTS 2-3
REPACKAGING INFORMATION 2-3
3Applications
APPUCATIONS 3-1
SYSTEM FUNDAMENTAIS 3-1
TYPICAL APPUCATION 3-3
wAnaiMQ
Tht intomMen In Vmnmsining Motions of lor qualified aBniotpfsonni only. fMfto th*
•Service Safety Summary' lOGsaea later minis menuet.
4Theory of Operation
THEORY OF OPERATION
INTRODUCTION
CLOCK AND PRETRIQGER
PULSE DELAY ORCUfT .
.
STROBE GENERATOR . .
.
OUTPUT 4-2
CHARGE UNE 4-2
POWER SUPPUES 4-2
PG 503 PulM Gcrwrctor Instnictlgn Manual

Content*
5Performance Check Procedures
PERFORMANCE CHECK PROCEDURES 5-1
INTRODUCTION 5-1
PERFORMANCE CHECK INTERVAL 5-1
PREWtfWnON 5-1
CHARACTERIZATION OF TWE 11801 OSOLLOSCOPE 5-2
TRANSIENT RESPONSE AND AMPUTUDEVERinCATION 5-2
6Adjustment Procedures
ADJUSTMENT PROCEDURES 6-1
INTRODUCTION 6-1
PERFORMANCE CHECK INTERVAL 6-1
PREPARATION 6-1
POWR SUPPLY VERinCATlON/AOJUSTMENT 6-2
CHARACTERIZATION OF THE 11801 OSOLLDSCOPE 6-3
TRANSIENT RESPONSE AND AMPLITUDE VERIRCAT10N/ADJUSTMENT ...6-4
7Maintenance and Diagnostics
MAINTENANCE AND OWGNOSTICS 7-1
GENERAL MAINTENANCE 7-1
CIRCUrr BOARD REMOVAL AND INSTALLATION 7-4
SIDE COVERS 7-4
MAIN BOARD 7-4
TROUBLKHOOTING 7-4
SOptions
9Replaceable Electrical Parts
10 Diagrams
1 1 Replaceable Mechanical Parts
II PG 500 PulM Genarater Instruction Manual

Contents
ILLUSTRATIONS
Figure Page
1-
1PG 509 typical system instaUstion 1-1
2-
1Installation and Removal 2-2
2-
2PG 509 front panel controls and connectofs 2-3
3-
1Terms used In describing pulse charactertstics 3-1
3-2 Rise time dKference tor two cascaded devtcsB 3-2
3-
3Typical N(F>-frequency distortion effect 3—3
4-
1PG 509 bloctc diagram 4-3
6-
1PG 509 adjustment locatiors 6-2
7-
1Orientation and (Ssassembly of multipin connactorB 7-3
7-2 Troubleshooting Ftowcnart 7-5
PG 509 Pulse Generator Instruction lisnual

Contents
TABLES
Table Pag«
1-1 Etecdlcal Characteristics 1-2
1-2 EnvironmentalCharacteristicsa 1-3
1-3 Mechanical Characteristics 1-3
5-
1Test Eqiipment Requlrad 5-1
6-
1Test ^ipment Requtrad 6-1
6-
2Power Supply vertflcallon 6-2
7-
1Relative Susceptibility to Static Oischarpe Damage 7-1
Iv PC SOe Pulse Generator instruction Manual

OPERATORS SAFETY SUMMARY
The generel safety mtormatton In this part of the summary Is for
both operating arKl servicing personrtel. Specific wramfngs and
cautions will be fouid throughout the manual where they apply
and do not appear in this surrwnary.
TERMS
In 'Dtls Manual
CAUTION statsmeras Identify conditions or practices that could
result In damage to the equipment or other property.
WARNING statements Identify conditionsorpracticeethat could
result In personal injury or loss of life.
TERMS
Power Sourea
TNs product is mtended to operate from apower source that will
not apply more than 2S0 volts rme betwaan the supply
conductors or between either supply conductor and grtxax). A
protectivegretndccmsctlanbywayofthegroindtngcorKluc-
tor in the power oord Is essential for sate oparation.
GrouncBno the Product
TYtis pro^jd Is grounded through the grounding conductor of
the power cord. To avoid electrical shock, plug the power cord
Into aproperty wired receptacle before making any connections
to the product Input or output terminals. Aprotactivs grocnd
corviacbon bywayofthe grounding conductor In the power cord
is essential for safe operation.
Danger Arising from Lose of Ground
As Marked on Equipment
CAUTION irxiicates apersonal ir^ury hazard not Immediately
accessible as one reads the markin(^ aahazard to property,
including the equipment Itself.
DANGER indicaies apersonal ir^uy hazard Immediataly
accessible as one reads the martdnq.
SYMBOLS
L^on loss of the protective-ground connection, all accessibla
conductive parts Ohduding knobs and controls that mayappear
to be irguiaed) can render an otoctric shock.
Uee the Proper Power Cord
Use ot^ the power cord and comecior^Mctfied for your
product
Use only apower cord that is in good corxlKion.
Um the Proper Fuse
In Thle Manual
TMt tymtMl McMs where appioible oauSanary
or oewr MomuSon eto be lowid.
To avoid fire hazard, uae only afuse Of the correct type, voltage
rating and ajrws rating as specified in the parts list for your
product
Do Not Operate In Explosive Atmoapherea
At Mwkad on Equipment
DANGER-votuge.
Toaveid K^locion. donot operatathls mainjment in anexpioelve
atmosphere iniees it has bean specifically certtfiad for such
opwatiorv
Do Not Remove Covert or Panels
ProlKlIw ground (eerei) tMmfcwl.
ATTENTION -Refr to irenuN.
To avoid personal Injury, do not remove the product covers or
pwrels. Do not operate the Inetrumera without the covers and
panels praparty mstailad.
PG 60S Plies Generator Instruction Manual V

Strvie* Safety Summary
SERVICING SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Aa/ar a/so to th§ procodIng Oponton Stfoty Summary.
Do Not Sarvlea Alona Disconnect power beforBramovtnoproMcUvepan8is. 60iOerino.
or replacing componanis.
Do not perform Internal servloe or a^ustmerv of this product
unless another person r»<tpAhtfl of rendering first aid and
resuscitation is present Power Source
This product Is Intended to operate from apower source that
Use Care Whan Servicing With Power On does not apply more than 2S0 vote rms between the supply
eonductors or between either supply conductor artd ground. A
DangerouB voitagas ascist at several points In this pnxjud To protective ground connection by way of the {pounding cortouo-
avold personal Injury, do not touch exposed comectlors or tor In the power cord Is eesersial for safe operation,
components while power is on.
vl PG 509 Pulse Generster Instruction Manual

Section 1
SPECIFICATION
INTRODUCTION
The PG 500 Pulae Ganantor is afast-rtaatlma pulsa aoifca
producing narrow ractangUar pulses at arapamion rata of 50
KHz.The PQ 509 can deliver acontinuous pulse train at an
anplituds of 25 votts noan output load of 50 ohms.
The PG 509 Pulae Ganarator Is aTM 500 Series piug-ln
mstnimantAII functional aiactronlcsaraincludad.butltraQuns
Insertion In aTM 500 or TM 5000 Sarias Power liAoduia
htainframa for nartscing to basic power suppliea.
The PG 509 Pulse Garwator was primarily dasignad to be an
negrai part of ataat systam. Flgua 1-1 rtiows primary
components and cormactions immedlataly related to the Pulse
Generator metypical system. Other than the System Coraroller.
Device Under Test, and PG 509, thaea are:
•Aprogranwnabla attenuator {TEKTRONIX AT 5010, or
equivalent); used to provtda system salaction tor the
daTse of attenuation required.
•Ahigh frequency multiplaxar/switcher
(TEKTRONIX SI 5010, or equivalent); used to route inputs
and outputs between Inatrumeres and taat devloas while
irder system control.
Note that wNia the PG 509 Is not uider diract (^Bcorarol, It Is
typically directed by instruments that are.m amostly Tektronix
insitumerB configLration, this would typically mean that the
PQ509 be installed In aTM 5000 (programmable piug-ln
compatible) Power litodule, as is requited for the other
twodevtcas.
Standard Aceeatory
1meauction manual
Rgura 1-1. PO 500 typical system InstaBatioro
PG 509 Puisa Gertsrstor Instrueflon Manual 1-1

SpecHIcatlon
PERFORMANCE CONOmONS
The limits stated in the Pertormance Requirements column of
Table 1-1 are valid only If the PG 509 Is operated In an ambient
temperature t3etweenO*Cand -»-90*C.urtie6sotherwlse8tatad.
The PG 509 must be In an anvlronmern whose limits are
described under Erwironmerttl Characteristics (Table 1-2).
Allow at least 15 minutes warm-19 time for oparatloo to specified
accuacy. 60 mlnutas aftersfotage In high hurnidityerwlrortmertt.
Ihble1-1
Electrics) Characteristics
Chsrseterlstlcs Performance Requirements
Output Amplitude 2SVimo50n.
variable Arrplltijde Range
Front Panel Adjustmers Range ±S%.
Amplitude Control Input Maximum safe input voRage ^10 V.
Input Currertt Output Voltage
<-0.15 mA Output Is corvolted by the front
panel VARIABLE AMPLITUDE
adfustmers.
-0.5mA 2625 V±2%.
-1.0 mA 2520V±2%.
-IJmA 23.TOV±2%.
Piise Output Fraquertcy SOfotz ±.10%.
PifoeWldtfi 44 ns ±2 ns (measired at 50% poin^.
Pulse DIaabte TTL logic low to disabie; maximum safe Input voRage ^10V.
Rise Time 350 ps ±fiO ps (meastfsd at System output eonneciorl.
PRETRIQGER Out 220 mV ±.20% (Mo SO 0).
PRETRIGQER signal before PULSE OUTPUT signal 115na ±25% (delay (acioq.
1-2 PG 509 Pulse GetMrster Instruction liamial

Sp«enc«tlon
Tabl«l-2
EnvlronmintAl Chwaetcrtstles*
Chvoetorlsttcd Daaerlption
TampvatuTB Matoa MIL'T'28800B. Class 5.
OpetaUng 0*C»+50*C.
Non-opofBting -S5*Cto+75»C.
Humidity Masts MIL-T-28800B. Class 5.
95% RH.0*CtO -f30*C
75% RH.to40*C
45% RH, to SO'C.
AWtudo Maas MlL-T-288006. class S.
Opanting 4.6 km (15.00 ft).
Non-oporating 15 km (50X100 ft).
Vibration^ Moats MIL-T-28800B, class 5. whan installad In quallflad powar moduiaa”.
10.38 mm (04)15 in) paak to paak. 5Hz to 55 Hz, 75 mlnulsa.
Shock Masts MIL-T-28800B, class 5. whan Installad In quallflad powar modulaa*.
20g‘s (1/2sina).11 msdUBtlon.3shockslnsachdiractlanatong3major
axas, 18 total shocks.
Banch Handling^ Meats M1L-T-28800B. ctsas 5. whan Installad In quallflad powar moduias*.
12 drops fiom 45*. 4in or a^llbrkim, whichaiter oocus first
Transponatlon
1
QuaRfiad isidar Nsttonal Sato Transit Association ftashipmant Tast
ProoadLsas lA-B-1 and lA-B-2.
EMC Within limitt of FCC Regulations. Pwt 15. Sitopart J. Class A; VDE0B71; and
MIL-461A taels RB01, RE02. CB)1, CE03. RS01. RS03, CS01, and CS02.
EtecOlcal DIscharga 20 kV maximum charge applied to instrument casa.
po«Mr BMdiM.
*ft«qidrM ratilMr dip.
•Rater to TV 6000 Pmmt Moduto ipaeaMdom.
*WKhcut Itewr Modute.
'bblo1*9
Moehanleol CharoctorMle*
Charaetarlstics Description
Nominal Overall OlmanslonB
Haight 4.961 In (126.0nm).
Widlh
Length I11.493 in (291.9 mm).
NstWeIgN 2to (0.907 kg).
Finitfi (front penal) PlastiCitokjmirun Isndnate.
PG SOfl PidM Gonontor Inatruetlon klanua] 1-3

S«ction 2
SYSTEM INSTALLATION
PREPARATION FOR USE
Opsrttlng Envtronmant
The PG 509 should be operated in adean, controllod
envlrorvnent that doee not exceedtheerwironmentai limitations
listtd mSection 1. Table 1-2.
NOTE
Befon Installtton, mfw (o the Operators Sa/My
Summary tn the front of OUs manual and to the
Change bdormation section at the rear of this
manual. Also refer to the power module Instni&lon
manual for tine voAage requirements and power
module operatlen.
The instument operates in any compartment o( aTM 500 or
TM 5000 Series Powrer Module. Refer to the TM 500/5000 Sehes
Power IModule Inetructlon Manuals tar module connector Irtfor-
matlon, as well as details on line vottages and general pcM«r
module operatioa
The PQ 509 must becalibrated in the system it will be used with.
The spectflcations llstad In the previous section are for file
PG 509 at the system output, not at the PG 509 front panel.
Installation and Removal
SCAUTION <
•WVNrv\r>Ai<«
To preventdantagetothePGSOB, turn offthe pcerer
module before Installation or removal. Donotuse
excessive force when Installing or removing the
PG 600. Refer to the Operator Safety Summary at
the from of this rrranuaJ and check the change
Mbrmafion at the PecA of th/s menua/tar addArona/
safety notes.
Figure 2- 1showsthe Installation andremoval procedixa. Check
to see If the plastic barrier on the Intarconnacttng Jack of the
eelected power module compartments matchss the cut-out In
the ckcuit board edge connectors at the rear Interface.
Align the chassis of the phjg-ln uiit with the upper and lower
guide rails ofthe selectad compartmerfis. ^£hinward andpress
firmly to seat the circuit board edge cormectors in the
bfiereonnectlng lacks.
PG 509 Pulae Generator Instructien Manual 2-1

System InstellsUen
To remove the PG 509, turn off the powermodule and pull on the Power-Up and Front Panel Indications
release latch (front panel, lower left comer) until the
interccrvwcting jacksdlsengaoe. Pull strato^ forward toremove Apply power to the PG 509 by activating the POWER switch on
the plug-ln from the power module. the TM SOO/TM 5000-Senes power module.
There Is no Indication on the front panel that power Is applied.
Figure 2-1. inatanatlon and Removal.
2-2 PG 609 Pulae Generator instrucUon Manual

System Installation
VARIABLE AMPLITUDE Adjustment
FRONT PANEL CONTROLS AND
CONNECTORS ©
See Figure 2-2 for the PG S09 front pane! controls and
connectors.
Conrtactlone to the front panel PULSE OUTPUT SMA-type
cormectorshoutdbemadeusIngahlghquBlItysami-rlgld SO-H
coaxial cable, such as Tektronix pan number 01S- 1015-00. or
better.
77SS-12
Figure 2-2. PO 600 front panel controls and connectors.
^PRETRIGGER Connector
Outputs atfiggar pulaa In advance of tha output pulaa
(from the PULSE OUTPUT connactor) to propel trigger
related calibration egulpmenL
This adjustment varies the output level of the PULSE
OUTPUT connector sigrtal.
^PULSE OUTPUT Connector
SMA-type plug-ln output ^gnal connecbr.
^AMPLITUDE CONTROL INPUT Connector
This conrtecta providas ameans ofcomrolling the output
amplitude of the generatorvia an Input current source that
varies between 0mA and -2 mA. For currants less than
-0.15 mA, the generator output level is controlled by the
front panel VARIABLEAMPUTUDEadjustment. This Input
Is also at the rear module conrtactor.
PULSE CONTROL INPUT Connector
This Irputenablee Ofdtcablas the generator outputsignal.
When the signal to the connectofis aTTL LO, then
generator oiSput elgrtal is disabled; when aTT1. HI, the
generator OLSput signal Is enabled. This Input Is also at the
rear module corrector.
REPACKAGING INFORMATION
IfthektsinsTtent Is to beshipped toeTektronixStfviceCenterfor
ssnrice or repair, attach atag showing:
•Owner (with address) and the name of the Individual at
your firm that can be coniactad
•Complete Irwtrumera deecrtption and Its serial number
•Adescription of frte service required
Hthe origfrtal package Is not1H to uee or not available, repackage
fra inetaRtsm as foBows:
•Surovtd the IngeucnafS with polyethylsra sheeting, or
other suitable material, to protect fra exterior firtlsh.
•Obtain acarton of oonugatad cardboard of adequaa
stiangii tii iat hesInsIdedlrTanBkxanolaeBthanslxirches
more than the Instrurrant dlmeralone.
•Cuehian the tnstrumeni by tightly packing dunnage or
ixefrara foam between the carton and the InetrumenL on
all sides.
•Seal fra carton wkh shipping tape or an industrial stapler.
The carton test strength for yoir instnjment Is 2X pounds.
For best vswr (voltage-standing wave ratio] and maximum
power franefer conditions, the signei some output Impedance
should match the input load Impedance of the signal receiving
device. Unmatched source and load impedarxas degrade the
vswr specificatione. If tarmirtatora are ueed, they should be
placed at the signal some or load (or both), never at the frora
panel PULSE OUTPUT SMA-type connector.
PG 500 Pulae Generator Instruedon Manual 2-3

APPLICATIONS
Sections
SYSTEM FUNDAMENTALS
Some fundamental factors to consider when preparing the
PG 509 Pulse Generatorfor use Inasystemwill oecovered intrus
section. These systems provide abasis for the development of
other specialtzBd systems as required by speciflc applications.
Pulse Definitions
The following terms are commonly used in descrSaingpulse
characteristics and are defined here for cortvertienoe. Theterms
are Illustrated and appliod In Figure 3-t. The other waveforms
reprecem typical output waveforms In order to show the
relationshipe. The terms and the^ definitions are:
•RisetimeVThetimelniervatduringwhichthearrpiltudeof
the ou9ut voltage changes from 10% to 90% of the rising
portian of the pulse.
•Falttimetf: The time Intwai during which the amplitude of
the output voNage changesfrom 90% to 10% of thefall^
portian of the waveform.
•Pulse Widih (or Duration) VThetime duration of the pulse
measured betvveen the 50% amplitude levels of the rising
and tailing portions of the waveform.
•Tilt Ameasure of the tilt of the full am^itude. fiat-top
portlonof puise.Thetilt maasurement Is usuallyexpressed
as a percentage of the amplitude of the rising portion of
the pulse.
•OverahootAmoBSUBof theovershoot occuring generally
above the 100% amplliude level. This measurement Is
also expressed as apercentage of the pulse rise.
Bear In mind that thesedefinitions are for guide purposes only.
When the pidses are very Irregular <such as excessive tiit,
overshoot, etc.) the deflnitlonB may becomeambiguous. In such
cases, amore complele description of the pulse will probably
beneceesary.
Figure 3-1. Tenns used In describing pulse eharactertstles.
PQ 509 Pulse Generator Instruction llanual 3-1

AppUcatlens
Rise Time
The rise time of any particular assembly of the PG 509, an
osciiioecope (conventional or aampiino), artd accessory pieces
such as coax cables, is avariabie depending upon the c^M
characteristics as well as individual rtsetimes. The ‘root of the
sum of the square’ method can generally be applied as an
approximation methodonly, as ekin effect loeceo ofthe cables do
not add preperty using this method. (The rooi-sum-squares
method applies accurately to Gaussian syctems only.}
Asageneral rule. Htheequipmentorsigrtal being measured has
arise time 10 times slower than the PG 509 arxl other related
measuring equipmera. the error is 1%. This amoure Is small and
can be coneidared to be rtegliglble. Hthe equipment being
measued has arise time three times slower than the related
measuring equipment, the error Is slightly less than 6%. By
keeping these relailonships in mind, the results can be
interpreted inteiligenily.
Waveforms
The lliuBtration shown In Figure 3-2 can be used as aojideime
for the following general consideraiione:
•Oscllloecopas should have avsrtical system rise time
about cne-eevenih at the tastast signal appiiad to keep
system emxB to amlnirrajm. Conversely. If the signal rise
time is at least seven times faster than the rise brrra of the
oGcillascope vertical systerrv the disptayed (observed)
warnform will have artse time that Is very doseto the rise
time of the vertical system.
•The dteplayed rlsa tima Is related to total system
bandwidffi Asystem with Hmitad high-frequency
responee will produce adisplayed rise time that Is slower
than expected. If atost-step signal preduoes aor display
with little or not overshoot or rirrging, the product of
aecHlceooperteetlmeandoecuioecopebandividtti should
result Inateclorwhose value ilssbsiwesn0.329 andO.350. devteee.
3>2 PG 509 PuiM Generator InstrucUort Manual

Applications
Hgure 3-3 illustrates waveform distortion due to Incorrect
hlgh-frequertcy compertsaiions. Ringing Indicatas Incorect
peaking adjustments or undesired irvJuctive effects. Excessive
overshoot and rolioff indicatas Incorrect capacitive ac^ustmants.
UmHsd high-frequency response is also indicated by rise time
measurementsthat are much sloworthan expected. Impedance
mismatchbig will usually ehmv as excessive aberrations
somewhere along the fiat portion of the waveform.
Rgure 3-3. Typical Ngh-frequtney dtatortton affect
•Shield measuring equipment leads to prevent undesirad
coupling to other parts of ths circuit. Shielding Is especial-
ly required where radiation Is aproUam and where
Ngh-tmpedanca dividers or drcutts are involved.
•Cfriooeacomportents which frjnctlon properly at frequerv
des and rise times encountered.
•Keep In mind Inherent parameters In drcuit components
such as Inductance present in capacitors or resistors.
•Corsider the possibla nonlinear behavior of drcuit conv
ponares due to changes In voltage or temperature
coefficients.
•Consider the Input impedance of maasuing equipman
Ths impedance may be enoughto cause loading effects,
detunhg. or undesirable reflectiane.
TYPICAL APPUCATION
Measuring OUT Rise Tlnte
The PG 509 can be used in conjuncHon with an osdlloscope to
datarmirw the rtaa lima ofaDevlca UnderTest pi/T). Risa time Is
normalty maasired between the 10% and 90% amplitude levels
onthe ieacSng edge of awavefonn. The dse time of adsplayed
waveform is shown In Rgura 3-1.
Batore measuring the rise time of adevice under test, the
oombined rise time of the PG 509 output signal and the
oediioecope verricai ampuner system must be known. Refer to
Figure 3-1for the parcertage error to be expected whenmetwo
devices are For example, a2-rs oediioecope
monttoringalO-na signal (5:1 ratio) wouUpermltanobsarvation
error of 2%. Note that If the rise timaa are equal, me error is
41.4%.
Basic PrscttiUons
For fafthful reproduction ofthe pulae, osrtain precautions should
be fdlowsd. These are surrwnartzsd below;
•Uaeptopertypes of cabi«.terTTiinatiors. attenuators, and
impedance matching networks. Low-impadance coaxial
cabiee are used wimthe PG 509 as aignai conductors. It ia
Importars that theea cablas be tarminstad In their
characteristic Impedance (SO ohms) to prevsrs refiactione
and standing wavaa unlaaa you daltoetetafy wish to
Imprcparly tarmingia tha mMis Ona application for
Impmpsr Mrminatlon woiid be to booet the signal to an
ampitfiar Input by leaving tha and of afranamiaslon Una
untarmfriated.
•Keep irshieidad wlraa of uncertain impedanoe short ao
that reflection and/or croaa-ooupling eftacts are not
irvoducad. Keep Touid-ratun paths short and direct.
PG 509 Pulae Geitcrster Inatruelkin Manual 3-3

Sactlon 4
THEORY OF OPERATION
INTRODUCTION
TTiis section provides adiscussion ol ttw major elements
Incorporated In the schematic for the PQ 509 Pulse Qerwator.
Thecircuit cortsiats of six major elemenis: Clock and Pretripoer.
Pulse Delay. Strobe Generator. Output Pulse and Regulator.
Charge Line, artd Power Suppllas. An Illustration showing the
relationship of the circuR elements, as welt as major control and
output locations. Is provided In Figure 4-1.
The PQ 509 Pulse Generator produces narroM, fast rise,
rectangular pulses at arepetition rate of SO kHz. The rrtethod
used In this generator charges alength of coaxial cable which is
than swftchad to the SO-ohm load with atransistor switch
operating mavalanche modaThe charge line contained within
the unit develops apulse width equal to twice the electricai
length ofthe line. Forthe model, this width is equivalent to44 na.
The nomirtal output amplitude of the pulse is 25 Vmto SO ofvns.
Afoidout schematic Is located In the Diagrams seetlen near the
back of this manual. The following paragraphs describe the
hxttvidual elemerss.
CLOCK AND PRETRIGGER
Traneistora 030 and 035 form aSchmitt Osdtiator producing a
low-duty cycle, poeitive-going pulse atthe collectorof 030. The
repetitian rate Is set by 040, a0.9 mAcurant soifce, and C28. a
0.1^F capectter In 040's oollactor. Apaeitive-going ramp of
approximately 2voltsl6SiS3pliadtothebaa8ofQ3S,tumtngHaiT
when the bese goes more po6iti\ra than the base of 030. The
voltage step at the cotlecior of 030 una 045 on. dischartfng
C28.fseott i^the PretriggerSchmitt, andsuppiyingaputeefrom
the emitter of 045 to the Pratrigger Schmitt drculL
pulse to the anode of CR20. The purpose of this circuit is to
supply atrigger pulse in advance of the output pulse to property
trig^ calibration equipmeriL
PULSE DELAY CIRCUIT
The positive going Pratrigger pulse turns off 060 and 065. This
allows C2S to Stan cnatging in anegative diraction. When the
voltage becomes sufficiently negative to tun on CR16, the
current from current source Q7D Is switcned to 075.
Theresistorchain In the base Of07S determinas where 075turns
on, and therefore the time after the Pratrigger pulse. This
provktes anominal delay ofl 15 ns. Apulse is coupled from 075
to the base of 080 throi^ transformer T2. tuning on 080. The
negative portion of the Pretrigger putse at the anode of CR20 Is
zero votts. This allows 060 to conduct, tuning on 065 which
dlschargBSC25andresetsthedelay drcutt Diodes ^17.CR18
and CR19 prevent 065 from satuating. thereby ensuing a
fast tun-off.
STROBE GENERATOR
Transistors 083and090form aregulated powersupply fromthe
+150 Vunregulated kpuLThb bused to supply +110 vote to
the collecter of 080 which ta biased to operate In the
avalanche mode.
Transistor 080 will avalanche whan apulse from T2 fonvard
biaseo te basa-emliMr junction. Capacitor C20 bthen db-
chaiged through R64. R99, andthe primary ofTi.Thbproduces
avoltaga In the eecondary which bsuifficiertt to forward bias the
base-emitter Jurctlan of Q100. the oulpurt switching transbtor.
The Pretrigger Schmitt drcuR. 050 and 058. outpubapoeitlve
voltage pube of 220 mV at JSS Into aSO-ohm load and a 2 V
PG 509 Pulse Generator Instruction Manual 4-1

Thtory of OporitJon
OUTPUT
Transistor O100 is biased to operate as an avalancfie transfer
switch which connects DL1X, acharoed 50-ohm coaxial catale
(Charge Line), Into a50-ohm load when conducting.
The output pulse is peak detected and applied to the gate of
Q160A. Kis compared with areieranoe voltage reoeived at the
gate of 01606 from the collector of Q210/TP1. This refarertce
voltage, nominally 23.4 V. can be varied by adjusting R18, the
voltage at pin 2of J25, or the dfrent at pin 2of J5.
The amplifier consisting of transistors O110, 0120, 0130, 0140,
0150, 0160, and U210A adjusts the voltage at the coiiecia of
OlOOurSII the output pulse is similarto the reference from 0210.
Varying the rKxninal -1 trtA of current mpia to J5 pin 2by
±.0.5 mA will vary the output voltage ±5%. Decreasing the
currenttoapprexIrTtately -O.ISmAorleeswIUcausetheoutpuiaf
U210Cto switch positive, turning off Q224B, disabling the Input
from 35-2/P1B-1S. and turning on Q224A, enabling the front
panel VAFUABLE AMPUTTIJOE oontrol through J2S.
Transistor 0200, CR203 arrd R44 limit the maximum currert that
01 10cansupply, to about 10 mA. Diode VR2lO,a^-voRZaner,
and CR1 1 limit the Q1X collector vottage to about 100 vote In
the abeerree of an output pulse. Note that without eorvoi, the
vottage on the Charge Line center conductor can go to the
irregutaied value of about •»-200V, deperrdng on the line
voltage. Pin 1of J5 providee anreans to cSsabie the output when
aTTL logical LO is supplied by the attenuator, AT 5010, aothat
switch contacts vrill not be damaged as various ranges are
selected.
CHARGE LINE
The Charge Lirte Is ahigh quality, teflon dlelecfrtc. 50-ohm
cable. Installed in acoil within the module. The line Is
oorviected to J100 at one end and left open terminated at the
ether. The line has atotal physical length of approximately
15-1/2 feet and an eiactricai ierigth of about 22 ns. The Output
Pulse width is equal to twice the eJectrical length ofthe line; thus
the pulse from Q100 resutis In apulse width of approximately
44 ns. Capacitore C101, C102. and C103 are In parallel with the
Charge Line and are used to adjust the flatness and aberrations
of the pulse.
POWER SUPPUES
Thsurvegulaied-f ISO-VsupplyisrTtadebyconrrectingsorTwof
the TM 5000 power module transformer windings In series and
then doubting the result
All other voltages used by the PG 509 Pulse Generator are
regulated on the dreuti board. Voltagesused, as well asprincipal
Integrated circuits a-s«rick»teri wnh each voltage regulation, are
provided below:
U2QA-«-9V
U206-9V
U10A+18V
U2QA-18V
4>2 PG 509 Pulse Generator Instruction Manual

Theory of Operation
Figure 4-1. PG 509 block diagram.
PG 509 Pulse Generator Instruction Manual 4>3