Tektronix 11A34 Owner's manual

TE K User Reference Part No. 070-5921-01
Supplement Product Group 47
11A34
Four Channel
Amplifier
Serial Number
Please
check
for
CHANGE
INFORMATION
at
the
rear
of
this
manual.
Second Edition SEP 1988
Revised
NOV
1988
Tektronix
COMMITTED TO EXCELLENCE

INSTRUMENT SERIAL NUMBERS
Each instrument has a serial number on a panel insert, tag, or stamped on the chassis. The first number or
letter designates the country of manufacture. The last five digits of the serial number are assigned sequen-
tially and are unique to each instrument. Those manufactured in the United States have six unique digits.
The country of manufacture is identified as follows:
B000000 Tektronix, Inc., Beaverton, Oregon, USA
100000 Tektronix Guernsey, Ltd., Channel Islands
200000 Tektronix United Kingdom, Ltd., London
300000 Sony/Tektronix, Japan
700000 Tektronix Holland, NV, Heerenveen, The Netherlands
Copyright© Tektronix, Inc., 1987-1988. All rights reserved. Tektronix products are covered by U.S. and
foreign patents, issued and pending. TEKTRONIX, INC. SCOPEMOBILE and Kar are registered
trademarks. Printed in U.S.A.

11A34 Features and Functions
Features .
Dual trace
Up to 300 MHz bandwidth (in 11402)
Calibrated sensitivities from 1 mV to 10 V/ division —
50 Q or 1 MQ input impedance
High-resolution, calibrated DC offset (0.25 division/increment, coarse; 0.025
division/increment, fine)
Fast overdrive recovery
Functions Signals applied to the CH 1 and CH 2 input connectors can be displayed or
removed from the display by pressing the display on/off buttons adjacent to the
input connectors.
All other 11A34 functions are controlled through the host mainframe. Such
mainframe-controlled functions are:
Sensitivity, Coarse and Fine, over a range of 1 mV to 10 V/division.
Vertical Offset.
Coupling: AC, DC, or Off.
Impedance (input termination): 50 Q or 1 MQ.
Bandwidth Limit: 100 MHz or 20 MHz.
Display Polarity: normal or inverted.
Trigger Polarity: normal or inverted.
Combination of Display Channels: See Operating Information section of
mainframe User Reference manual.
Combination of Trigger Channels: same as Display Channels; see Operating
Information section of mainframe User Reference manual.
11A34 User Reference Supplement i

ii 11A34 User Reference Supplement

Contents
Section 1—General Information
Contents of this Supplement sense hante
11A34 Service Manual sssisescesisissocessssesansssasessvuatedsnstdovaceaas dass Le
Plug-in to Mainframe a seu induites D A “bris 1-2
Initial Inspection ......sssrssseossserssncossesescscessseecsencesonacees PE EN Te 1-2
‘Operating Temperature aries ahi a iasi dt entente binnen 1-3
Installing and Removing the 11A34 .......... iten neen Hein 1-3
Instrument Options... EN EE |
Packaging for Shipment … Naam teaser see 1-5
Section 2—Operating the 11A34 in 11300-series Mainframes
Display On Once ENE oh 2-1
Selecting Coupling, HF Limit, and Impedance ............ eee valenta ded
Other Functions „iu darna enne buen tante dennen Doe
Position and Offset sions A EI PE ne
EER Lat SRE PR Et dafou E AR hase 2-3
DC Circuit LOA ed ER)
Adding Waveforms … A SE Re TN 24
Overdrive RECOVERY sisi wenskaart nnie ZaD
50 Q Overload essuie arane i iai PR nd
Active Probes since S a E EA anin POR 2-8
Probe En nr St isi online sive 28
Front-Panel Error Messages... TE ede EURE sit O
GPIB and RS-232-C Commands and Syntax …..sensenseneanen eee Sins 2-10
Section 3—Operating the 11A34 in 11400-series Mainframes
Display On/Off … nnn. nait Danoise mere De :
Other Fant Hons nes amenant
Vertical Offset uunissa irisean dereiran ainan PR Oks
BW
Limit
ci
sans
EG,
DC CHOCO LOA Ging raand anton sekste eedt eeen nge ded
Adding and Subtracting Waveforms ............ PR RE 3-4
Overdrive Recovery rennes EE Giles ba 3-5
50 Q Overload ss nn cnrs de nanas hasta Or
Active Probes ssadsescscocussaseacissse dst ares niet Te 3-8
Prope D ess Ras hs RE 3-8
Front-Panel Error Messages es.. node TS RTE ut À à
GPIB and RS-232-C Commands and Syntax … … ne RCE a N
Section 4—Specification
Performance Conditions … … EAA EEATT, REE EA adel
Electrical Characteristics … … … …… ledit PR PRES 4-1
Environmental Characteristics nr 4-7
Physical Characteristics ene desslveusdhsiatecesesstans if 4-8
Recommended
Probes
…
ann
saas
enso
oss
eneerosve
verccoreeenn
hendeken:
…4-8
11A34
User
Reference
Supplement
HI

Contents
Appendix A—Glossary
Appendix B—Instrument Documentation
Illustrations
1-1
2-1
2-2
2-3
3-4
4-1
Tables
2-1
2-2
3-1
3-2
4-1
4-2
4-3
Installing a plug-in unit in a mainframe oscilloscope….…..... soeren 1-4
Location of AC coupling capacitors in plug-in amplifiers … cesses 2-3
Overdrive recovery using long (top) and short (bottom) cables
terminated in 50 Q. Traces are offset two divisions and the
photograph is a double exposure... inner 2-6
Overdrive recovery using long (top) and short (bottom) cables
unterminated. Traces are offset two divisions and the
photograph is a double Exposure siscciscsssdassccscsasesssovsessaenciseassascaviogvssskissedenvaan 2-7
Location of AC coupling capacitors in plug-in amplifiers … nn. 3-3
‘Overdrive recovery using short (top) and long (bottom) cables.
terminated in 50 Q. Traces are offset two divisions and the
illustration is a composite of two waveforms ss 3-6
Overdrive recovery using short (top) and long (bottom) cables
unterminated. Traces are offset two divisions and the
illustration is a composite of two waveforms … “is ad
Sequence of decisions used to select i a new waveform ir in 1 response
to probe ID DUON isinisi RE Ramadan 3-9
Dimensions of ASE vooreen aas annde arten eenen ets 4-9
Functions and Where They are Described ren 2-2
Channel Parameter Commands (for 11300-series oscilloscopes) ............ 2-10
Functions and Where They are Described nee 3-1
Channel Parameter Commands (for 11400-series oscilloscopes) … … … 3-11
Electrical Characteristics assente edenis 4-1
Environmental Characteristics sss csisvacisasscossstenespeccsesubecdunsasiyiecsibasenandsaalanedliaoes 4-7
Physical Character deden natiestaten 4-8
11A34 User Reference Supplement

Section 1
General Information
This Supplement to the mainframe User Reference manual and the Incoming
Inspection Procedure manual are standard accessories to the 11A34. For a list of
related manuals, see Appendix B.
Contents of this Supplement
This Supplement contains the following four sections:
Section 1—GENERAL INFORMATION, describes mainframe to plug-in unit
compatibility, explains how to install and remove the 11A34 from a mainframe,
outlines any options available for the 11A34, and gives details about packaging
for shipment.
Most 11A34 functions, and their use, are described in the Operating Information
section of the mainframe User Reference manuals. These functions are those
common to all amplifier plug-in units. Examples of common functions are offset,
sensitivity, input impedance (where selectable), coupling, and bandwidth limit.
Only functions unique to the 11A34-11300-series or 11A34-11400-series
combinations are explained in the following sections.
Section 2—OPERATING THE 11A34 IN 11300-SERIES MAINFRAMES, explains
how to operate those 11A34 functions not covered in the 11301 and 11302 User
Reference Manual, or the 11301A and 11302A User Reference Manual.
Section 3—OPERATING THE 11A34 IN 11400-SERIES MAINFRAMES, explains
how to operate those 11A34 functions not covered in the 11401 and 11402 User
Reference Manual.
Section 4—SPECIFICATION, gives detailed specifications of all 11A34-
mainframe oscilloscope combinations.
ee
tet
gees
at
ot
ee
11A34
User
Reference
Supplement
1-1

General Information
11A34 Service Manual
The 11A34 Service manual is for use by qualified service personnel
only. To avoid personal injury, do not perform any service other than
that contained in the Operator's manual unless you are qualified to do
so. Refer to the Operators Safety Summary and Service Safety
Summary before performing any service.
The 11434 Service Manual contains the following information:
Section 1—GENERAL INFORMATION.
Section 2——THEORY OF OPERATION.
Section 3—MAINTENANCE AND DIAGNOSTICS.
Section 4—PERFORMANCE VERIFICATION AND ADJUSTMENT.
Section 5—INSTRUMENT OPTIONS.
Section 6—REPLACEABLE ELECTRICAL PARTS.
Section 7—SCHEMATIC DIAGRAMS & CIRCUIT BOARD ILLUSTRATIONS.
Section 8--REPLACEABLE MECHANICAL PARTS.
Plug-in
to
Mainframe
Compatibility
The
11A34
is
designed
for
use
in
the
11301,
11301A,
11302,
11302A,
11401,
11402
and
future
11000-series
plug-in
mainframes.
11A34
bandwidth
varies
depending
on
the
host
mainframe.
Details
about
bandwidth
are
included
in
Section
4,
.
Specification,
of
this
Supplement,
and
in
the
Tektronix
Corporate
Catalog.
Refer.
to
the
Tektronix
Corporate
Catalog
for
complete
compatibility
information.
Initial Inspection
This
instrument
was
inspected
mechanically
and
electrically
before
shipment,
and
should
meet
all
electrical
specifications.
First,
inspect
the
11A34
for
physical
damage
incurred
in
transit.
Secondly,
to
verify
that
the
instrument
is
functioning
properly,
perform
the
Functional
Test
Procedure,
shipped
with
the
instrument.
This
brief
procedure
verifies
most
instrument
functions
and
checks
the
internal
auto-calibration
references.
If
you
find
instrument
damage
or
deficiency,
contact
your
local
Tektronix
Field
Office
or
representative.
eeeh
ede
S
1-2
REV
NOV
1988
11A34
User
Reference
Supplement

General Information
$
Operating
Temperature
The 11A34 can be operated where the ambient air temperature is between 0° and
+50° C and can be stored in ambient temperatures from —40° to +75° C. After
storage at temperatures outside the operating limits, allow the chassis to reach
operating temperature limits before applying power.
Installing and Removing the 11A34
To avoid instrument damage set the mainframe ON/STANDBY switch
to STANDBY before installing or removing the 11A34.
If the green indicator light remains ON, when the STANDBY position
is selected, the switch has been internally disabled.
To remove or reinstall plug-in units, use the mainframe PRINCIPAL
POWER SWITCH (rear panel) to shut OFF the power. This will
prevent damage to either the plug-in or the mainframe.
To once again enable the ON/STANDBY switch, refer the instrument
to qualified service personnel.
When installed in any 11401 or 11402 plug-in compartment, or in the 11301,
11301A, 11302 or 11302A left or center plug-in compartment, the 11A34 will
provide a conventional display.
When installed in the center or right plug-in compartment of the 11301, 11301A,
11302 or 11302A, the 11A34 will also provide the X (horizontal) part of an X-Y
display, or provide a trigger signal for the mainframe time base.
To install the 11A34 in any 11000-series oscilloscope mainframe, set the
mainframe ON/STANDBY switch to STANDBY. Align the grooves in the top
and bottom of the 11A34 with the guides in the mainframe plug-in
compartment, then insert the 11A34 into the mainframe until its front panel is
flush with the front panel of the mainframe.
To remove the 11A34 from a mainframe, set the mainframe ON-STANDBY
switch to STANDBY. Then pull the release latch (see Figure 1-1) to disengage the
unit from the mainframe, and pull the 11A34 straight out of the plug-in
compartment.
11A34 User Reference Supplement 1-3

General Information
-TOP GROOVE
MAINFRAME
RELEASE
LATCH
Figure 1-1. Installing a plug-in unit in a mainframe oscilloscope.
Instrument Options
Option 23 includes four P6134 probes.
1-4 11A34 User Reference Supplement

General Information
À
?
Packaging
for
Shipment
If this instrument is to be shipped by commercial transportation, we recommend
that it be packaged in the original manner. The original carton and packaging
material should be saved and reused for this purpose.
NOTE
Package and ship plug-in units and mainframes separately.
If the 11A34 is to be shipped to a Tektronix Service Center for service or repair,
attach a tag to the instrument. On the tag, include the following information:
e Name and address of the instrument owner;
« Name of a person at your firm who can be contacted about the instrument;
e Complete instrument type and serial number; and
+ A description of the service required.
If the original package is not available or is not fit for use, package the 11A34 as
follows:
1. Obtain a corrugated cardboard carton with inside dimensions at least six
inches greater than the instrument dimensions. Use a carton with a test
strength of at least 200 pounds.
2. Fully wrap the 11A34 with anti-static sheeting, or its equivalent, to protect
the finish.
3. Cushion the 11A34 on all sides by tightly packing dunnage or urethane
foam between the carton and the instrument. Allow three inches of packing
on each side.
4, Seal the carton with shipping tape or with industrial staples.
5. Mark the address of the Tektronix Service Center and your return address
on the carton in one or more prominent places.
11A34 User Reference Supplement : 1-5

General Information
1-6 11A34 User Reference Supplement

Section 2
Operating the 11A34 in
11300-series Mainframes
Display On/Off
The 11A34 has only four front-panel controls—the display on/off buttons.
Pressing a display on/off button will cause its channel, and signal, to be
displayed or removed from the display (the function toggles). When a channel is
displayed, its label (CH 1 or CH 2) will be lighted.
Selecting Coupling, HF Limit, and
Impedance
To select the desired setting for Coupling, HF Limit, or Impedance, proceed as
follows:
la. If no trace is displayed, press any plug-in display on/off button to create a
trace.
1b. If several traces are displayed, select a channel by touching the desired
trace description at the top of the CRT.
2. On the 11301 and 11302 oscilloscopes press any VERTICAL button once-
OFFSET, SIZE, or POS. On the 11301A and 11302A oscilloscopes press any
VERTICAL button twice. This will cause the Control Menu to be displayed.
3. Touch the desired function’s label. Successive touches will change its state.
11A34 User Reference Supplement 2-1

Operating the 11A34 in 11300-series mainframes
Other Functions
Other 11A34 functions are controlled within the 11300-series mainframe, and
their operation is described in detail in Section 2, Operating Information, of the
11301 and 11302 User Reference Manual, and the 11301A and 11302A User Reference
Manual. Table 2-1 shows where to find information about operating the 11A34.
TABLE 2-1
Functions and Where They are Described
Function Described Under Heading
Offset, Waveform Acquisition: Vertical Menu;
Size (V/div) or for X-Y Display: Horizontal Menu.
Display +Ch 1, +Ch 2 Waveform Acquisition: Vertical Menu.
Polarity Waveform Acquisition: Waveform Menu.
Trigger Selection Trigger Source Major Menu and Polarity
Position and Offset
2-2
All 11300-series oscilloscopes assign position control to the Left Control knob by
pressing the VERTICAL POSition button once. The Vertical Position control
moves the trace as a user convenience. For example, when displaying multiple
channels it may be desirable to set ground references for each trace on separate
graticule lines. Position is a screen-related function; its units are divisions.
The offset function, accessed by pressing the VERTICAL OFFSET button,
subtracts a precision voltage from the input signal. Changing offset moves the
trace just as does the position control. However, if the deflection factor is
‘subsequently changed, the effect is different.
Changing the sensitivity will increase or decrease the size of the display around
some screen level (e.g., two divisions above graticule center) set by the Position
control. When using a sensitivity that makes the displayed waveform larger than
the screen, the Offset control is used to bring the waveform area of interest to the
screen location established by the Position control.
The Position control has a range of plus and minus four divisions from graticule
center, but the Offset control has a range defined in volts. Offset can be as much
as 1000 divisions at 1 mV/division. The Offset control range is one volt for all
sensitivities from 1 mV to 99.5 mV/division, but increases to 10 volts for
sensitivities from 100 mV to 995 mV/division. For sensitivities from 1 volt to
10 volts/division, Offset control range increases to 100 volts.
11A34 User Reference Supplement

Operating the 11A34 in 11300-series mainframes
The 11A34 attempts to maintain the user-selected offset voltage even though the
offset range changes due to a change in sensitivity. An offset voltage of less than
one volt will be maintained as the sensitivity is changed over the entire range of
1 mV/division to 10 V/division. A selected offset of greater than one volt is
beyond the offset range for the most sensitive settings and will be reset to one
volt when the sensitivity is increased to any value between 99.5 mV and
1 mV/division.
HF Limit
Two four-pole (24 dB/octave) bandwidth limit (low-pass) filters are available for
each 11A34 channel. The purpose of these filters is to reduce the amplitude of
unwanted noise or interference occurring at frequencies above the frequency of
the signal of interest. The user has a choice of cut-off (-3 dB) frequencies, either
20 MHz or 100 MHz, independently for each channel. The trigger, auxiliary
trigger, and display signal bandwidths for a channel are always the same. The
auxiliary trigger is the signal sent to the right plug-in compartment.
o DC Circuit Loading
AC coupling capacitors are connected differently in the 11A52 and 11A71 than in
the 11A32 and 11A34. Figure 2-1 shows this difference.
500
41452, 11471
500
11432, 11434
Figure 2-1. Location of AC coupling capacitors in plug-in amplifiers.
C5922-203
11A34 User Reference Supplement 2-3

In the 11A52 and 11A71, the coupling capacitor isolates both the input
termination and the amplifier from external DC voltages. However, the coupling
capacitor in the 11A32 and 11A34 does not.
Always use caution when working with voltages in excess of 25 volts.
When 50 Q Impedance mode is selected and input coupling is set to
AC or DC, a 50 Q termination resistance is connected directly from
the 11A34 input connector to ground. Take care that the circuit
connected to the 11A34 input will not be damaged by the 50 Q load.
Switching from 1 MQ to 50 Q Impedance mode when more than
25 VDC is present at the 11A34 input will exceed the peak input
voltage specification and may damage the 11A34 input relay.
A damaged relay could cause an error in calibration.
Adding Waveforms
NOTE
Before adding waveforms, check that each channel's display is
independently on screen. |
The 11300-series oscilloscopes allow the addition of any two channels. That is,
one channel may be added to a channel from another plug-in unit. A simple
restriction applies. Each channel must be in its linear operating range. This is
assured if each channel separately is within the screen area before addition.
Those portions of a trace which are off screen will not be valid when brought
back on screen using another channels input signal or Offset control. This
general restriction applies to any dual-channel oscilloscope.
24
11A34
User
Reference
Supplement

Operating the 11A34 in 11300-series mainframes
~ Overdrive Recovery
Overdrive occurs when any 11A34 channel is driven out of its linear range of
approximately +15 divisions.
The 11A34 has extraordinarily good overdrive recovery, and this feature may be
used to greatly extend measurement resolution. For example, suppose a signal
changes from -1.7 V to +0.8 V in 1 ns. The 11A34 could be used to determine if
the signal stabilized immediately at +0.8 V or if perhaps had some small
aberration following the transition. By setting the 11A34 offset to +0.8 V and the
sensitivity to 1 mV/division, aberrations of just 0.1% of the original transition
will be 2.5 divisions in amplitude (0.1% of 2.5 V is 2.5 mV or 2.5 divisions at
1 mV/division).
Any amplifier will ultimately reach an equilibrium value after an input step
{although its accuracy will determine how far that equilibrium value is from
the correct value). The 11A34’s ability to settle quickly to within a very small
fraction of its equilibrium value is exceptional. The time it takes the 11A34 to
settle to within a stated fraction of the equilibrium value is its overdrive
recovery time.
Measuring the overdrive recovery time of an 11A34 takes some care and can
lead to some surprising results, An interesting experiment is to use a very flat
pulse generator, such as the Tektronix PG 506, to pulse the 11A34. Connect the
generators fast-rise output to the 11A34 input through a short (one foot or less)
coaxial cable and select 50 Q input impedance. Adjust the pulse amplitude to
1 volt. Set the 11A34 sensitivity to 1 mV/division. Each division now represents
0.1% of the input signal. Trigger the oscilloscope and observe the recovery of the
11A34 using 50 ns/division sweep rate. Now increase the cable length by about
three feet (for example, use a 42-inch length of RG-58 cable, Tektronix part-
012-0057-01) and observe the new waveform. See Figure 2-2.
11A34 User Reference Supplement 2-5

Operating the 11A34 in 11300-series mainframes
C5922-201
Figure 2-2. Overdrive recovery using long (top) and short (bottom) cables
terminated in 50 Q. Traces are offset two divisions and the photograph is adouble
exposure. |
The waveform change is due to skin effect loss in the longer cable. What is
Surprising is that the skin effect loss persists for over 200 ns even though the
total cable delay is only 5 ns. At 400 ns the loss is still 0.02%.
This experiment shows the importance of using a short cable to test overdrive
recovery.
À second surprise is that skin effect loss disappears almost completely (after two
cable delays) when one end is unterminated.
To observe this, use the short cable again, and select 1 MQ input impedance on
the 11A34. Insert a 2X attenuator between the cable and the pulse generator to
improve the reverse termination and to provide the same amplitude signal as
before. Observe the response and change cables again. Even at 0.1% per division
the skin effect loss is hard to detect without the forward termination. The reason
for this is that the skin effect loss is an increase in the effective series resistance
of the cable. Without current, the cable develops no series voltage drop. See
Figure 2-3.
11A34 User Reference Supplement

C5922-202
Figure 2-3. Overdrive recovery using long (top) and short (bottom) cables
unterminated. Traces are offset two divisions and the photograph is a double
exposure.
50 Q Overload
When the input impedance is set to 50 Q and the input voltage substantially
exceeds 5 Vrms, the 11A34 will sense the overload, disconnect the 50 Q input
termination, and connect the 1 MQ termination. The Impedance menu will show
1 MQ, and the mainframe will display the message:
Input channel N overload on LEFT/CENTER/RIGHT plug-in
where N = 1 or 2.
To reset the input impedance to 50 Q, first correct the overload condition, then
select 50 Q from the Impedance menu.
11A34 User Reference Supplement 2-7

Operating the 11A34 in 11300-series mainframes
Active Probes
Probe ID
Using an active probe, such as the P6231, eliminates two options: AC Coupling
and 1 MQ input impedance. Coupling options available when using such a
probe are Off and DC; the only Impedance available is 50 Q.
The Probe ID section of the Utility Menu is the means of selecting how any
11300-series oscilloscope responds to an ID button-push of recommended
probes. All, or some combination of the following operations may be set to start
in response to probe ID buttons. To display the Utility Menu, press the front-
panel UTILITY button (once on 11301 or 11302 oscilloscopes, twice on 11301A or
11302A oscilloscopes). For details, see the Probe ID section of the Waveform
Acquisition subsection in the mainframe User Reference manual.
Pressing the probe ID button can initiate one or more of the following
operations:
1. Present a new display, or if that channel is already displayed, select the
existing trace. Pressing the ID button of a probe connected to an
undisplayed left or center compartment channel will cause that channel to
be displayed, unless doing so would exceed the maximum number or
traces. Unlike the 11A34 display on/off button, pressing the probe ID
button a second time will not remove the display. Probe ID button-presses
for displayed channels will do two things: a) select the trace(s) using this
channel, and b) momentarily brighten all traces using this channel.
2. Stored settings can be sequentially recalled. Pressing the probe ID button
can cause a sequential recall of stored settings. The stored settings feature
must be enabled using the Probe ID Utility menu. Settings must be stored
as explained under STORE/RECALL Major Menu in the 11301 and 11302
User Reference manual, or the 11301A and 11302A User Reference Manual.
3. The mainframe can Autoset to accommodate the input signal introduced
by the probe. The Autoset feature can be enabled or disabled using the
Probe ID Utility menu. Autoset is the automatic setup of vertical deflection
factor, triggering, and sweep speed to produce a meaningful display, e.g.,
two to five divisions of vertical deflection and two to five repetitions of the
input signal. For more information, refer to Autoset in the 11301 and 11302
User Reference manual, or the 11301A and 11302A User Reference Manual.
11A34 User Reference Supplement