Keithley 3933A User manual

e
eratof mual
perating nformation
Publication Date: March 1991
Document Number: 3933A-900-01 Rev. A

WARRANTY
Keithley Instruments, Inc. warrants this product to befree from defects in material and workmanship for a
period of 1year from date of shipment.
Keithley Instruments, Inc. warrants the following items for 90days from the date ofshipment: probes, cables,
rechargeable batteries, diskettes, and documentation.
During the warranty period, we will, at our option, either repair or replace any product that proves to bede-
fective.
To exercisethis warranty, write or call your local Keithley representative, or contact Keithley headquarters in
Cleveland, Ohio. You will begiven prompt assistanceand return instructions. Sendthe product, transporta-
tion prepaid, to the indicated service facility. Repairs will bemade and the product returned, transportation
prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at
least 90 days.
LIMITATION OF WARRANTY
This warranty doesnot apply to defectsresulting from product modification without Keithley’s expresswrit-
ten consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-re-
chargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow
instructions.
THIS WARRANTY ISIN LIEU OF ALL OTHER WARRANTIE S,EXPRESSEDOR IMPLIED, INCLUDING
ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE
REMEDIES PROVIDED HEREIN ARE BUYERS SOLE AND EXCLUSIVE REMEDIES.
NEITHER KEITHLEY INSTRUMENT S,INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR
ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQ
UENTIAL DAMAGES ARISING OUT
OF THE USEOF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS
BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAM-
AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTSOF REMOVAL AND INSTALLATION,
LOSSESSUSTAINED AS THE RESULT OF INJURY TO ANY PERSON,OR DAMAGE TO PROPERTY.
INSTRUMENTS
InstrumentsDivision, Keithley Instruments, Inc. l 28775 Aurora Road l Cleveland, Ohio 44139 l [phone] l Fax: [phone]
WEST GERMANY: KeithIey Instruments GmbH l Heiglhofsk. 5 l Munchen 70 l 089-71002-0 l Telex 52-12160 l Fax: [phone]
GREAT BRITAIN: KeitbIey Instruments, Ltd.
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ITALY: KeitbIey Instruments SRL l Vi&S. G~gnano 4/A l u)146 Milano l 02-4120360 or M-4156540 l Fax: [phone]

Operator’s Manual
Model 3933A
Phase Shifter
01991, Keithley Instruments, Inc.
All Rights Reserved
Instruments Division
Cleveland, Ohio, U. S. A.
Document Number: 3933A-900-01

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product names are trademarks or registered trademarks of their respective holders.

Safety Precautions
The following safety precautions should be observed before using the Model 3933A PhaseShifter and any associated
instruments.
This instrument isintended for useby qualified personnel who recognize shock hazards and arefamiliar with the safety
precautions required to avoid possible injury. Read over this manual carefully before using the instrument.
Exercise extreme caution when ashock hazard is present at the test circuit. The American National Standards Institute
(ANSI) states that a shock hazard exists when voltage levels greater than 30V rms or 42.4V peak are present. A good
safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring.
Inspect the connecting cablesand test leads for possible wear, cracks, or breaks before eachuse.
For maximum safety, do not touch the test cables or any instruments while power is applied to the circuit under test.
Turn off the power and discharge any capacitors before connecting or disconnecting cablesfrom the instrument.
Do not touch any object which could provide acurrent path to the common side of the circuit under test or power line
(earth) ground. Always make measurements with dry hands while standing on adry, insulated surface capable ofwith-
standing the voltage being measured.
Do not apply more than 42V peak between the outer shell of any BNC connector and chassisground.
Instrumentation and accessoriesshould not be connected to humans.

Table of Contents
SECTION 1 - General Information
1.1 SUMMARY .................................................................. l-1
1.2 FEATURES.......................................~ ........................... l-l
1.3 WARRANTYINFORMATION .................................................... 1-2
1.4 ~ALADDENDA .......................................................... 1-2
1.5 SAFETYTERMSANDSMLlBOLS .................................................. 1-2
1.6 TJNPACKINGANDREPACKING ................................................. 1-2
1.6.1 Unpacking ................................................................. 1-2
1.6.2 ShipmentContents.. ......................................................... 1-2
1.6.3 InstructionManual ........................................................... 1-2
1.6.4 Repacking For Shipment ....................................................... l-2
1.7 OPTIONALACCESSORIES ...................................................... l-2
1.8 SPECIFICATIONS ............................................................. 1-3
SECTION 2 - Getting Started
2.1 INTRODUCTION....‘. ......................................................... 2-l
2.2 INSTALLATION .............................................................. 2-l
2.2.1 InstallationLocation.. ........................................................ 2-l
2.2.2 Fan.. ..................................................................... 2-l
2.3 LINE POWER SUPPLY AND GROUNDING .......................................... 2-2
2.3.1 LinePowerSupply
........................................................... 2-2
2.3.2 Grounding ................................................................. 2-3
2.4 HANDLINGPRECAUTIONS ..................................................... 2-3
2.5 BASICOPERATION ............................................................ 2-3
2.5.1 Front Panel Summary ......................................................... 2-3
2.5.2 TypicalTestConnections ...................................................... 2-3
2.5.3 OperatingExamples .......................................................... 2-3
SECTION 3 - Operation
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.3
3.4
3.4.1
LNTRODUCTION ..............................................................
FRONT PANEL AND REAR PANEL DESCRIPTION ...................................
Input and Output Connections ..................................................
InputConnections ...........................................................
Output Connections ..........................................................
GPIB Bus (Input/output Connector) ..............................................
FrontPanelDescription ........................................................
RearPanelDescription ........................................................
STARTUP ....................................................................
OPERATINGPROCEDURES .....................................................
Setting Parameters Using Numeric Keys ......................................... ; .
3-1
3-l
3-l
3-1
3-3
3-4
3-4
3-11
3-14
3-15
3-15

3.4.2 Setting Parameters with the MODIFY Controls ...................................... 3-16
3.4.3 ErrorCodes ............................................. . .................. 3-17
3.4.4 Amplitude Units Conversion ................................................... 3-22
3.4.5 Amplitude Programming ...................................................... 3-25
3.4.6 DC Offset Programming ....................................................... 3-25
3.4.7 AC Amplitude and DC Offset Relational Restrictions ................................. 3-25
3.4.8 Waveform Selection, Square-Wave Duty Cycle, and Synchronous Output .................. 3-28
3.4.9 Mark, Span, and PhaseParameter Programming ..................................... 330
3.5 SWEEPOPERATIONS.. ........................................................ 3-30
3.5.1 Sweep Phaseand Sweep Output Relationships ...................................... 3-32
3.5.2 OutputRangeMode.. ....................................................... 3-33

List of Illustrations
SECTION 2 - Getting Started
Figure 2-l LineFilter ............................................................... 2-3
Figure 2-2 FrontPanelSummary ...................................................... 2-4
Figure 2-3 TypicalConnections ....................................................... 2-5
SECTION 3 - Operation
Figure 3-1 LogicInputCircuit ........................................................ 3-1
Figure 3-2 AnalogInputCircuits ...................................................... 3-2
Figure 3-3 Typical Digital I/O Interconnections ........................................... 3-2
Figure 3-4 SweepMarker and Sweep Synchronous Outputs .................................. 3-3
Figure 3-5 Waveform Synchronous Outputs ............................................. 3-3
Figure 3-6 Model3933AFrontPanel ................................................... 3-5
Figure 3-7 Model3933ARearPanel .................................................... 3-12
Figure 3-8 Waveforms and Their PhaseDefinitions ........................................ 3-24
Figure 3-9 Relational Range for Allowed AC Amplitude Voltage and DC Offset Voltage ............ 3-26
Figure 3-10 PhaseRelationship Between Waveform and Output ............................... 3-29

List of Tables
SECTION 2 - Getting Started
Table 2-l Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
SECTION 3 - Operation
Table 3-l Main Synthesizer Amplitude Range When DC Offset is 0 Volts ....................... 3-18
Table 3-2 DC-only Voltage Setting Range, Resolution, and Accuracy (open load, 18to 28°C) ......... 3-18
Table 3-3 AC + DC Minimum Amplitude, Resolution, and Accuracy (open load) ................. 3-19

SECTION
General Information
1.l SUMMARY
The Model 3933APhaseShifter isdesigned for usein con-
junction with aModel 3930A Multifunction Synthesizer.
Together, Mode13933A and Model 3930Aform avariable
phase, multi-phase oscillator with a phase setting range
from -360 to 360”.Phaseresolution is 0.1”.The frequency
range is the sameasthe Model 3930A.
Five output waveforms, $,2/,-rL,n,and\jare
available. Eachwaveform hasamaximum output of 30V
p-p (no-load) and 15V p-p into 5OQ.Waveform and am-
plitude may be setindependently of the Model 3930A or
another Model 3933A.Waveform output is isolated from
the Model 393OA,or another Model 3933A, allowing a
wide range of applications. Multiple 3933A units may be
combined with asingle 3930A to createamulti-phase os-
cillator system.
Phaseoutput isdirectly synthesized by acustom LSI digi-
tal IC, resulting in high accuracy and stability, and short
phase switching time.
In addition to phase sweep and amplitude modulation
(AM), variable square-wave duty cycle is also provided.
Parameter settings are easily made using either the front
panel keys and/or the modify knob.
The Model 3933A is equipped with a standard GPIB
(IEEE-488) interface, and can be programmed over the
bus to produce the same operating modes and parame-
ters that can be controlled from the front panel.
The Model 3933A uses a two-line, 40-character liquid
crystal display to indicate selectedfunctions, parameters,
and pertinent messages.
1.2 FEATURES
Wide phase setting range: -360” to 360”, with resolu-
tion of 0.1”.
High output and high AC voltage accuracy: 30V p-p
(no load), 15Vp-p into 5OQti.5% (-5OkHz, sinewave,
above 3V p-p).
A total of 5 units of Model 3933A may be combined
with aModel 3930A to provide up to a6-phase oscilla-
tor system.
Two-line, 40-character liquid crystal display.
Five output waveforms: %,2/,l,n,and\l.
Variable square wave duty cycle (5% to 95%, below
100kHz).
Multiple phasesweep functions. Eachsetting digitally
synthesized according to input from the front panel
numeric keypad or the modify dial.
Low distortion ratio (<O.l%, 1OHzto lOOkI&, above
30.0mV p-p, AUTO output range mode).
Isolated waveform output.
Battery backed-up memory can retain up to 10groups
of parameters. At power-on, it will automatically set
l-l

SECTION 1
GeneralInformation
itself according to those parameters which were in ef-
fect immediately prior to the last power shut-off.
GPIB interface included asstandard equipment.
Output mode switchable from automatic (AUTO) to
fixed (FXD).
A wide range of front and rear panel I/O interconnec-
tions to control or modify signal operations and pa-
rameters.
,.3 WARRANTY INFORMATION
Warranty information is located on the inside front cover
of this instruction manual. Should your Model 3933A re-
quire warranty service, contact the Keithley representa-
tive or authorized repair facility in your area for further
information. When returning the instrument for repair,
besure tofill out, and include, the service form atthe back
of this manual in order to provide the repair facility with
the necessary information.
1.4 MANUAL ADDENDA
Any improvements or changes concerning the instru-
ment or manual, will be explained in an addendum in-
cluded with the unit. Besure to note these changes and
incorporate them into the manual before using or servic-
ing the unit.
1.5 SAFETY TERMS AND SYMBOLS
The following safety terms and symbols arefound on the
instrument, or used in this manual.
The A 1 symbol on the instrument indicates that the
user should refer to the operating instructions.
The WARNING heading used in this manual explains
dangers that might result in personal injury or death. Al-
ways read the associated information carefully before
performing the indicated procedure.
The CAUTION heading used in this manual explains
hazards that could damage the instrument card. Such
damage may invalidate the warranty.
1.6 UNPACKING AND REPACKING
1.6.1 Unpacking
After carefully unpacking the instrument from its ship-
ping carton, inspect it for obvious signs of physical dam-
age.Report any such damage to the shipping agent im-
mediately. Savethe original packing carton for storage or
possible reshipment.
1.6.2 Shipment Contents
The following items are included with every Model
3933A order:
l Model 3933A PhaseShifter
l Model 3933A Instruction Manual
l Power Cord
l Fuse 0.5A, WOV,5.2x 20mm (FU-96-2)
l Digital I/O interconnection cable (CA-941
l BNC toBNC signal cable(Keithley Model 7051-2,-5,or
-10)
l Additional accessoriesasordered
1.6.3 Instruction Manual
If an additional instruction manual is required, order the
manual package, Keithley part number 3933A-901-00.
The manual package includes an instruction manual and
any pertinent addenda.
1.6.4 Repacking For Shipment
Should it become necessary to return the Model 3933A
for repair, carefully pack the unit in its original packing
carton or the equivalent. Besure to useacardboard box of
sufficient strength.
Include the following information:
l Advise asto the warranty status of the instrument.
l Write ATTENTION REPAIR DEPARTMENT on the
shipping label.
o Fill out and include the service form located attheback
of the manual.
1.7 OPTIONAL ACCESSORIES
The following accessoriesare available for use with the
Model 3933A.
l-2

SECTION 1
GeneralInformation
Models 3900-l and 3900-2 Rack Mounting Kits: The
Model 3900-l mounts one Model 3933A in astandard 19
inch rack. The Model 3900-2mounts two Model 3933A’s,
side by side, or one Model 3933A and one Model 3940A
side by side. Both kits include all necessaryhardware for
proper rack mounting of the instruments.
Model 7007 Shielded IEEE-488 Cables: The Model
7007-l (lm, 3.3ft.) and Model 7007-2(2m, 6.6 ft.) can be
used to interface the Model 3940to the IEEE-488bus.
Model 7051-2 BNC-to-BNC Cable: The Model 7051-2isa
50 Ohm BNC-to-BNC cable (RG-58C), 2 feet (0.6m) in
length. The Model 7951-2is terminated with male BNC
connectors at both ends.
Model 7051-5BNC-to-BNC Cable: The Model 7051-5is a
50 Ohm BNC-to-BNC cable (RG-58C), 5 feet (1.2m) in
length. The Model 7951-5is terminated with male BNC
connectors at both ends.
Model 7051-10 BNC-to-BNC Cable: The Model 7051-10
is a 50Ohm BNC-to-BNC cable (RG-58C), 10feet (2.4m)
in length. The Model 7951-10 is terminated with male
BNC connectors at both ends.
1.8 SPECIFICATIONS
Detailed Model 3933A specifications may be found in
Appendix A.
l-3

SECTION2
Getting Started
2.1 INTRODUCTION
ment must be free of dust and vibration, and the Model
393314must not be exposed to direct sunlight.
This section contains basic information on installation
and power line connections. It also provides typical sim-
ple operating examples. The Model 3933Ausesanin-line electrical noise filter, but
pulse noise or strong magnetic or electric fields may
cause incorrect operation of the unit. Do not install the
2.2 INSTALLATION
unit near a source of pulse noise or strong magnetic or
electric fields.
The following paragraphs discuss Model 3933A installa-
tion. Improper installation will adversely affect the life,
reliability, and safety of the unit.
The Model 3933A weighs about 10 pounds. Be careful
when carrying the unit or mounting it in arack.
WARNING
The guards on the rear panel of the unit are
designed to protect rear panel connectors
and should not be used as legs for installa-
tion. Do not stand the unit vertically on the
rear guards, because it may fall over, causing
instrument damage or personal injury.
2.2.1 Installation Location
The allowable ambient temperature and humidity
2.2‘2 Fan
ranges for the Model 3933A are:
Operating: 0” to 4O”C,10to 9O%RH The Model 3933A is air-cooled by a fan. Insufficient air
flow may causeacomponent in the unit to fail. Follow the
instructions given below.
Storage:-10” to 5O”C,10to 8O%RH.
CAUTION
Besure to install the unit in alocation that satisfies these Observe the following precautions to pre-
temperature and humidity conditions. Also, the environ- vent damage to the unit:
2-l

SECTION 2
Getting Started
2.3
An air intake port is provided on the rear
panel of the unit. Allow a space of at least
four inches between the rear panel and a
wall or other obstruction.
An exhaust port is provided on the bottom
panel of the unit. Install the unit on a rigid,
flat surface, and avoid installing it on soft
material, such as a cushion. Be careful not to
insert foreign material between the bottom
of the unit and the surface underneath. An-
other exhaust port is located on the top panel
of the unit. Be careful not to block the top
port by placing an object on top of the unit.
Avoid mounting two or more units vertically
(for example, when using two or more units
synchronously). Placing one unit on top of
another will obstruct the exhaust port.
Dust collecting in the fan filter will prevent
sufficient air flow. In a clean operating envi-
ronment, wash the filter with a mild deter-
gent every three months. When operating
the unit in adusty environment, wash the fil-
ter with a mild detergent at least once a
month.
Immediately turn off the power to the unit if
the fan ceases to operate. Operating the in-
strument with an inoperative fan may result
in damage to the instrument.
LINE POWER SUPPLY AND
GROUNDING
2.3.1 Line Power Supply
The Model 3933A operates with lOOV, 12OV,22OV,or
24OV,&lo%, 48 to 62Hz, single-phase AC power supply.
The power consumption is about 38VA.
Line Voltage Selector Switch
The Line Voltage Selectorswitch on the rear panel allows
you to change the operating voltage of the power supply.
The standard setting of the switch is the sameasthe volt-
agein the country to which the unit is shipped.
To change the power supply voltage, first disconnect the
line cord, and setthe supply voltage switch in the correct
2-2
position. Wait at least five seconds before turning the
power back on after turning it off.
WARNING
Disconnect the power cord from the instru-
ment before changing the supply voltage
setting.
CAUTION
Be sure to set the line voltage switch to the
correct position for the line power voltage to
be used. Operating the instrument on an in-
correct voltage may cause damage to the unit.
LINE Receptacle Connection
Connect the supplied power cord to the rear panel LINE
receptacle and to a grounded AC power receptacle sup-
plying the correct voltage.
WARNING
The Model 3933A is equipped with a 3-wire
power cord that contains a separate ground
wire and is designed to be used with
grounded outlets. When proper connections
are made, instrument chassis is connected to
the power line ground. If the AC outlet is not
grounded, the rear panel ground terminal
must be connected to safety earth ground us-
ing #lSAWG (or larger) wire before use.
LineFuse
The line fuse protects the instrument from over-current
situations. To replace the fuse, first disconnect the line
cord, then unscrew the center cap with a small screw-
driver. Replacethe blown fuseonly with the type listed in
Table 2-1, then replace the fuse cap.
WARNING
Disconnect the line cord from the instru-
ment before replacing the fuse.
CAUTION
*Use only a fuse of the rating listed in Table
2-1, or instrument damage may occur.

SECTION2
Getting Starfed
Table 2-l. Fuse Replacement
220,240V 1 0.5A 1 FU-96-1
NOTE: Fuses are 5 x 20mm and have 25OV, normal blow ratings.
2.3.2 Grounding
To prevent the possibility of electrical interference,
the Model 3933A using the grounding terminal
WARNING
If the Model 3933A is not connected to a
grounded AC outlet, be sure to connect the
grounding terminal on the rear panel to
safety earth ground using minimum
#18AWG wire before use.
The Model 3933A usesthe line filter circuit shown in Fig-
ure 2-l. The maximum leakage current at 250V/60Hz is
1mA rms. Touching the metallic part of the chassisof the
unit may, therefore, causean electric shock if the Model
3933A is not properly grounded.
I- II 1 -I-l*
transformer
-1 I
Power
inpur
Figure 2-1. Line Filter
2.4 HANDLING PRECAUTIONS
A flat keyboard, coated with a polyester film, forms the
control panel surface of the Model 3933A. Becareful not
to damage the keyboard surfaceby cutting it with asharp
instrument or touching it with ahot object.
When the panel or casebecomesdirty, clean it with asoft
cloth. If the panel or caseis too dirty for cleaning with a
dry cloth, lightly dampen the cloth in mild detergent so-
lution, and wipe the panel or casewith the damp cloth.
Never use solvents such asthinner or benzene, or chemi-
cal dust cloths, as these may damage the caseor front
panel surfaces.
2.5 BASIC OPERATION
The following paragraphs summarize front panel operat-
ing controls, give typical test connections, and discuss
typical operating examples for the Model 3933A.
2.5.1 Front Panel Summary
Figure 2-2 summarizes each front panel feature. For de-
tailed information on eachoperating feature, refer to Sec-
tion 3.
2.5.2 Typical Test Connections
Figure 2-3 shows typical tests connections between the
Model 3933A PhaseShifter and adevice under test.Note
that 50 ohm characteristic impedance cables,such asthe
Model 7051,should be used for all signal connections.
2.5.3 Operating Examples
The following examples give step-by-step instructions
for setting basic Model 3933A operating parameters,
Example 1: Selecting the Waveform Type (Function)
The waveform type canbe selectedusing the FCTN key,
of the ENTRY group, asfollows:
1. Press FCTN and note that the instrument displays
the existing function and the available functions
(sine, triangular, square, sawtooth, DC).
2. Pressthe number key corresponding to the desired
function (O-5),or rotate the MODIFY knob until the
desired function number is displayed. For example,
press 3 to select the square wave function. The
waveform will immediately change to the selected
function.
3. PressDSPL to return to the normal display mode.
2-3

SECTION 2
Getting Started
DISPLAY
,*I
I--
MODIFY
3
Changes
parameters,
selections
SYNC OUT
I s
AM IN: Enables or
;;k$Ies AM
RUB OUT: Deletes current
SHIFT
L
1
ENTRY 4 e STEP SIZE
L
I
Used with modify
keys to change
parameter values
Adds shifted function
to some other keys PHASE: Sets phase parameters
AMPTD: Sets output amplitude
OFFSET: Sets DC offset (main only)
FCTN: Sets waveform type
I
2 DUTY FXDBO I 1 DSPL 1
-1
t-i- DUTY: Allows setting squarewave -
duty cycle
FXDBO:Fixed 50% duty cycle
L
,
Returns display
1
to normal
Sets applicable units
definition value for
parameters set with
SWEEP
START. Programs start
STOP. Programs stop
CTR: Sets center
SPAN: Sets span
.S&marker
SWEEP FCTNI Sets function
SWEEP TIME: Sets time
J
SWEEP OPR
START: Starts sinole or
I caltinuoussweep
SWEEP OFF: Cancels sweet mode
Figure2-2. Front PanelSummary
2-4

SECTlON 2
Getting Started
Model 3933A Function
output
Figure 2-3. TypicaZConnections
Example 2: Setting the Output Amplitude.
Usethe AMPTD key, of the ENTRY group, to setthe out-
put voltage amplitude asfollows:
1. PressAMPTD, and note that the instrument displays
the existing amplitude and allowed amplitude
range.
2. To enter a completely new amplitude value in p-p
units, press the keys for the desired numeric value,
then pressV or mV, asrequired. For example, to en-
ter a30mV p-p amplitude, press the following three
keys: 3 0 mV.
3. To simply modify the existing amplitude value, use
the cursor keys and the MODIFY knob to set the
value asrequired.
4. PressDSPL to return to normal display.
Example 3: Programming the DC Offset
The OFFSETkey allows you to setthe DC or averagelevel
of the main synthesizer output waveform, as in the fol-
lowing example:
1. PressOFFSETand note that the instrument displays
the existing offset value and allowed range.
2. Either press the numeric keys for the desired offset
value, or use the MODIFY knob and/or cursor keys
to change the value.
3. PressDSPL to return to normal display.
Example 4: Setting Phase Shift
The PHASE key allows you to set the amount of phase
shift, in degrees, of the main synthesizer output wave-
form, asin the following example:
1. PressPHASE and note that the instrument displays
the existing phase value and the allowed range.
2. Enter the desired phase shift value, or usethe MOD-
IFY KNOB and/or cursor keys to change the existing
value.
3. PressDSPL to return to normal display.
2-5

CTION 3
Operatio
3.1 INTRODUCTION
This section contains detailed information on front panel
and rear panel operation of the Model 3933A. For de-
tailed GPIB (IEEE-488bus) operation, refer to Section 4,
GPIBOperation, in the manual for the Model 3930AMul-
tifunction Synthesizer.
3.2 FRONT PANEL AND REAR PANEL
DESCRIPTION
3.2.1 Input and Output Connections
CAUTION
Restrictions apply to input and output signal
levels and signal types. Adhere to signal
level and load characteristics as described
below. or the instrument may be seriously
damaged.
3.2.2 Input Connections
Two types of input signals may be applied through the
front and rear panel BNC input connectors of the Model
3933A: LOGIC and ANALOG. The specifications of the
input signals are given below.
BNC LOGIC INPUTS (Rear Panel)
Logic inputs include SWEEPSINGL START IN (single-
sweep start input), and SWEEPHOLD IN (sweep hold
input). Important specifications for theseinputs include:
Input voltage: TTL level
Allowable maximum input voltage: OVto +5V
Circuit: SeeFigure 3-1,Logic Input Circuits.
(SWEEP) SINGL START IN
(SWEEP) HOLD IN
1Fiaure 3-l. LoaicInvut Circuit

SECTION 3
Operation
BNC ANALOG INPUT (Front Panel)
The AM IN BNC canbeused to apply an external analog
input signal which controls the amplitude of the
waveform.
Input voltage range: -3V to +lV
Allowable maximum input voltage: rtl5V.
Input phase range: DC to 1OOkHz.
Input impedance: Approximately 1OkQ.
Signal ground: insulated from ground.
Circuit: SeeFigure 3-2,Analog Input Circuit.
+6.3V
AM IN
Figure 3-2. Analog Input Circuits
DIGITAL INPUT CONNECTOR (Rear Panel)
A third type of input is the DIGITAL INPUT. One digital,
36-pin, D-type input connector transfers MAIN SYN-
THESIZER signals from amaster Model 3930to aModel
3933A slave unit, and between successiveModel 3933A’s
in a chain of phase shifters. A jumper cable, CA-94 is re-
quired to interconnect units.
The main synthesizer signal from aModel 3930A (master
unit) is applied to the DIGITAL IN connector on the rear
panel of a Model 3933A (slave unit). If an additional
phase shifter unit is chained to provide multiple phase
operation, a second cable (CA-941is connected from the
DIGITAL OTJTof the first slave, to the DIGITAL IN on
the rear panel of the second slave unit. This may be re-
peated until amaximum of5(five) slave units aretied to a
single master synthesizer. The DIGITAL IN and DIGI-
TAL OUT signals atthe rear panel of the slavesareidenti-
cal to the master main synthesizer output signal.
Interconnection details are shown below, in Figure 3-3.
CA-94 Cable
3930A
3933A
Next
, \ I
3933A
3933A
Figure 3-3. Typical Digital I/O Interconnections
3-2

SECTION 3
Operation
3.2.3 Output Connections
Five output signals are available from various BNC con-
nectors on the Model 3933A. The specifications for the
output signals are given below.
CAUTION
Be careful not to connect an input signal to
an output connector, or instrument damage
may occur.
BNC LOGIC OUTPUTS (Rear Panel)
Logic outputs include the SWEEPSYNC OUT (sweep
synchronous output) and SWEEP MKR OUT (sweep
marker output). Specifications for theseoutputs aresum-
marized below.
Output voltage: TTL level
SweepMKR OUT and Sweep SYNC OUT are connected
to ground.
Circuits: SeeFigure 3-4.
+5v
9 SWEEP MKR OUT
SWEEP SYNC OUT
Figure 3-4. SweepMarker and SweepSynchronous
outputs
BNC LOGIC OUTPUT (Front Panel)
Waveform SYNC OUT (front panel synchronous output)
Output voltage: TTL level
Waveform SYNC OUT is electrically isolated from chas- The interconnection between the Model 3930A Wave-
sis ground. form Synthesizer (master), and the Model 3933A Phase
Circuits: SeeFigure 3-5.
SYNC OUT
Figure 3-5. WaveformSynchronousOutputs
DIGITAL OUTPUT CONNECTOR (Rear Panel)
One digital, 36-pin, D-type input connector transfers sig-
nals among several Model 3933A’s (up to 5) in achain of
phaseshifters. A jumper cable,CA-94 isrequired to inter-
connect units.
BNC ANALOG OUTPUT (Rear Panel)
Sweep X Drive Out (Sweep X Axis Drive Output)
Output voltage: OVto +lOV/no load
Output impedance: 6OOQ
Recommended load impedance: lOkG!or more
BNC ANALOG OUTPUT (Front Panel)
Fctn Out (Waveform Output)
Maximum output voltage: &15V/no load, *7V/5OQ load
Output impedance: 50R
Recommended load impedance: 5OQor more
OUTPUT CONSIDERATIONS
All logic outputs are driven by a7400family IC. Becare-
ful not to connect aload that exceedsthe drive capability
of this TTL IC. Also, do not use excessively long connect-
ing cables;the resulting capacitance may have detrimen-
tal effectson the output signals.
3-3