Tektronix 2440 User manual

Service Manual
Tektronix
/
2440
Oscilloscope
Serial Number B014064 below
070-6603-00
Warning
The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to the Safety Summary prior to
performing service.
Please check for change information at the rear
of this manual.
First rinting: July 1988
Revised rinting: July 1993

Instrument Serial Numbers
Each instrument manufactured by Tektronix has a serial number on a panel insert or tag, or stamped on the
chassis. The first letter in the serial number designates the country of manufacture. The last fi e digits of the
serial number are assigned sequentially and are unique to each instrument. Those manufactured in the
United States ha e six unique digits. The country of manufacture is identified as follows:
BO10000
E200000
J300000
H700000
Tektronix, Inc., Bea erton, Oregon, USA
Tektronix United Kingdom, Ltd., London
Sony/Tektronix, Japan
Tektronix Holland, NV, Heeren een, The Netherlands
Instruments manufactured for Tektronix by external endors 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.).
Tektronix, Inc., P.O. Box 500, Bea erton, OR 97077
Printed in U.S.A.
Copyright © Tektronix, Inc., 1988. All rights reser ed. Tektronix products are co ered by U.S. and foreign
patents, issued and pending. The following are registered trademarks: TEKTRONIX, TEK, TEKPROBE, and
SCOPE-MOBILE.

WARRANTY
Tektronix warrants that this product will be free from defects in materials and workmanship for a period of three (3) years from
the date of shipment. If any such product pro es defecti e during this warranty period, Tektronix, at its option, either will repair
the defecti e product without charge for parts and labor, or will pro ide a replacement in exchange for the defecti e product.
In order to obtain ser ice under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty
period and make suitable arrangements for the performance of ser ice. Customer shall be responsible for packaging and
shipping the defecti e product to the ser ice center designated by Tektronix, with shipping charges prepaid. Tektronixshall
pay for the return of the product to Customer if the shipment is to a location within the country in which the Tektronixser ice
center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any other charges for
products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate maintenance
and care. Tektronix shall not be obligated to furnish ser ice under this warranty a) to repair damage resulting from attempts by
personnel other than Tektronix representati es to install, repair or ser ice the product; b) to repair damage resulting from
improper use or connection to incompatible equipment; or c) to ser ice a product that has been modified or integrated with
other products when the effect of such modification or integration increases the time or difficulty of ser icing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY OTHER
WARRANTIES, EXPRESSED OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIESOF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REPAIR OR
REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR
BREACH OF THIS WARRANTY TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS
ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

2440 Ser ice
TABLE OF CONTENTS
Page
LIST OF ILLUSTRATIONS................................................ iii
LIST OF TABLES................................................................
OPERATORS SAFETY SUMMARY ................................ i
SERVICING SAFETY SUMMARY ................................... ii
Section 1 SPECIFICATION
INTRODUCTION ....................................... 1-1
PERFORMANCE CONDITIONS .......... 1-4
Section 2 PREPARATION FOR USE
SAFETY...................................................... 2-1
LINE VOLTAGE SELECTION ............... 2-1
LINE FUSE . ................................................ 2-1
POWER CORD ......................................... 2-3
INSTRUMENT COOLING ....................... 2-3
START-UP ................................................. 2-3
POWER-DOWN ........................................ 2-4
REPACKAGING FOR SHIPMENT ....... 2-4
Section 3 THEORY OF OPERATION
SECTION ORGANIZATION.................... 3-1
INTEGRATED CIRCUIT
DESCRIPTIONS ....................................... 3-1
SIMPLIFIED BLOCK DIAGRAM
DESCRIPTION............................................... 3-2
DETAILED BLOCK DIAGRAM
DESCRIPTION............................................... 3-8
INTRODUCTION ....................................... 3-8
INPUT SIGNAL CONDITIONING
AND ANALOG SAMPLING.................... 3-8
ACQUISITION PROCESS
AND CONTROL ........................................ 3-10
DATA CLOCKING TO
ACQUISITION MEMORY ....................... 3-10
ANALOG DATA CONDITIONING
AND A/D CONVERSION ........................ 3-11
ACQUISITION PROCESSING
AND DISPLAY .......................................... 3-12
DETAILED CIRCUIT
DESCRIPTION............................................... 3-15
SYSTEM PROCESSOR ......................... 3-15
WAVEFORM PROCESSOR
SYSTEM..................................................... 3-22
Page
FRONT PANEL PROCESSOR .............. 3-28
FRONT PANEL CONTROLS ................. 3-30
SYSTEM DAC AND ACQUISITION
CONTROL REGISTERS ......................... 3-31
SYSTEM DAC (cont) AND
AUXILIARY FRONT PANEL................... 3-33
SYSTEM CLOCKS................................... 3-35
TIME BASE CONTROLLER
AND ACQUISITION MEMORY ............. 3-39
ATTENUATORS AND
PREAMPLIFIERS..................................... 3-43
PEAK DETECTORS AND
CCD/CLOCK DRIVERS........................... 3-45
TRIGGERS AND PHASE CLOCKS ..... 3-51
JITTER CORRECTION RAMPS .......... 3-56
TRIGGER HOLDOFF, JITTER
COUNTERS, AND CALIBRATOR ....... 3-58
CCD OUTPUT .......................................... 3-61
A/D CONVERTER AND
ACQUISITION LATCHES ....................... 3-62
DISPLAY AND ATTRIBUTES
MEMORY ................................................... 3-63
DISPLAY CONTROL ............................... 3-66
DISPLAY OUTPUT .................................. 3-73
HIGH VOLTAGE POWER
SUPPLY AND C R T ................................. 3-75
SYSTEM I/O ............................................... 3-80
VIDEO OPTION ........................................ 3-84
LOW VOLTAGE POWER SUPPLY ..... 3-92
LOW VOLTAGE REGULATORS ......... 3-98
Section 4 PERFORMANCE CHECK AND
FUNCTIONAL VERIFICATION
PROCEDURE
INTRODUCTION.............................................. 4-1
PREPARATION........................................... 4-1
INITIAL SETUP ......................................... 4-4
VERTICAL SYSTEM..................................... 4-6
TRIGGERING SYSTEMS .............................. 4-18
HORIZONTAL SYSTEM ............................... 4-26
ADDITIONAL VERIFICATIONS
AND CHECKS ................................................. 4-29

2440 Ser ice
TABLE OF CONTENTS (cont)
Page
Section 5 ADJUSTMENT PROCEDURE
INTRODUCTION.............................................. 5-1
CALIBRATION SEQUENCE AND
PARTIAL PROCEDURES ........................ 5-1
WARM-UP TIME REQUIREMENT ...... 5-1
PRESERVATION OF
INSTRUMENT
CALIBRATION............................................. 5-2
INTERNAL ADJUSTMENTS.......................... 5-3
SELF CALIBRATION..................................... 5-19
EXTERNAL CALIBRATION ......................... 5-20
Section 6 MAINTENANCE
INSTRUMENT CALIBRATION .............. 6-1
NATIONAL BUREAU OF
STANDARDS TRACEABILITY ............. 6-2
VOIDING CALIBRATION........................... 6-2
STATIC-SENSITIVE COMPONENTS ....... 6-3
PREVENTIVE MAINTENANCE ..................... 6-4
INTRODUCTION ......................................... 6-4
GENERAL CARE ........................................ 6-4
INSPECTION AND CLEANING ............. 6-4
LUBRICATION............................................. 6-6
SEMICONDUCTOR CHECKS.................. 6-6
PERIODIC READJUSTMENT.................. 6-6
TROUBLESHOOTING ..................................... 6-7
INTRODUCTION.......................................... 6-7
TROUBLESHOOTING AIDS .................... 6-7
TROUBLESHOOTING
EQUIPMENT ................................................ 6-9
TROUBLESHOOTING
TECHNIQUES............................................ 6-9
CORRECTIVE MAINTENANCE ................... 6-11
INTRODUCTION ........................................ 6-11
MAINTENANCE PRECAUTIONS ......... 6-11
OBTAINING REPLACEMENT
PARTS ......................................................... 6-11
MAINTENANCE AIDS .............................. 6-12
INTERCONNECTIONS ............................. 6-12
TRANSISTORS AND
INTEGRATED CIRCUITS ........................ 6-12
SOLDERING TECHNIQUES ................... 6-14
REMOVAL AND REPLACEMENT
PROCEDURE ........................................... 6-15
Page
DIAGNOSTICS AND
INTERNAL CALIBRATION
ROUTINES...................................................... 6-25
INTRODUCTION ....................................... 6-25
OVERVIEW ................................................ 6-25
CALIBRATION ROUTINES.................... 6-25
DIAGNOSTIC ROUTINES ...................... 6-27
DIAGNOSTICS OPERATION
VIA THE GPIB INTERFACE .................. 6-34
DIAGNOSTIC PROCEDURES .............. 6-35
Section 7 OPTIONS AND ACCESSORIES
OPTIONS DESCRIPTION ...................... 7-1
OPTIONS A1-A5— INTERNATIONAL
POWER CORDS ...................................... 7-1
OPTION 1R— RACKMOUNTED
2440............................................................. 7-1
OPTION 03— WORD
RECOGNIZER PROBE........................... 7-2
OPTION 05— VIDEO OPTION .............. 7-2
OPTION 11 — PROBE POWER ............. 7-2
STANDARD ACCESSORIES ................ 7-2
RAtKMOUNTING ACCESSORIES ..... 7-2
OPTIONAL ACCESSORIES................... 7-2
Section 8 REPLACEABLE ELECTRICAL PARTS
Section 9 DIAGRAMS
Section 10 REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION
Diagnostic and Troubleshooting Information:
Diagnostics ......................................................... 6-25
Diagnostic Operation ........................................ 6-30
Diagnostic Procedures...................................... 6-32
2440 Troubleshooting Procedures Table...... 6-35
Video Option Troubleshooting Table ............ 6-99
Troubleshooting Charts .................................... Section 9
ii

2440 Ser ice
LIST OF ILLUSTRATIONS
Figure Page
The 2440 Digital Oscilloscope.................................................................................................................. iii
1- 1 Dimensional drawing................................................................................................................................... 1-24
2- 1 LINE VOLTAGE SELECTOR, line fuse, and power cord receptacle ............................................... 2-1
3- 1 2440 simplified block diagram.................................................................................................................... 3-3
3-2 Simplified Memory Map of the 2440........................................................................................................ 3-18
3-3 System Clock wa eforms............................................................................................................................3-37
3-4 Simplified Peak Detector block diagram................................................................................................. 3-47
3-5 Simplified CCD architecture.........................................................................................................................3-49
3-6 Trigger Logic Array Control Data Byte.................................................................................................. 3-53
3-7 Jitter correction wa eforms........................................................................................................................ 3-57
3-8 Readout State Machine flow chart........................................................................................................... 3-71
3-9 Vertical Vector Generator............................................................................................................................3-73
3-10 DC Restorer.................................................................................................................................................... 3-78
3-11 GPIB data flow diagram................................................................................................................................3-81
3-12 GPIB three-wire handshake state diagram............................................................................................ 3-82
3-13 Video Option wa eforms...............................................................................................................................3-87
3-14 Video Option field-sync identification....................................................................................................... 3-88
3-15 PWM Regulator and In erter.......................................................................................................................3-94
3-16 PWM switching wa eforms.......................................................................................................................... 3-96
5-1 Adjustment locations for Displays 4 through 6 ..................................................................................... 5-4
5-2 Display 5— Vertical and Horizontal Gain, Offset, and Vector
Compensation adjustment pattern......................................................................................................... 5-5
5-3 Display 6— Integrator Time adjustment pattern.................................................................................... 5-6
5-4 (SN B010250 & Abo e) CH 1 and CH 2 CCD Clock Adjustments
(shown centered, as after doing part b)................................................................................................ 5-7
5-4 (SN B010249 & Below) CH 1 and CH 2 CCD Clock Adjustments
(shown centered, as after doing part b )................................................................................................ 5-8
5-5 CCD counts display and CM adjustment menu.................................................................................... 5-8
5-6 CCD sides 1 -4 for CH 1 before L-clock adjustment............................................................................. 5-12
5-7 Sides 1 and 3 before adjustment of LIS and after .............................................................................. 5-13
5-8 CH 1 with L-clocks correctly adjusted, but with stray samples ........................................................ 5-14
5-9 Display for adjusting CCD A and T clocks............................................................................................. 5-15
5-10 Typical CH 1 and CH 2 displays after clock adjustment.................................................................... 5-16
5-11 Checking sample dispersion...................................................................................................................... 5-17
5- 12 Input and output (after adjustment) wa eforms.................................................................................... 5-20
6- 1 Multipin connector........................................................................................................................................ 6-8
6-2 Circuit board Location.................................................................................................................................. 6-16
6-3 Installation sequence for installing the crt frame screws .................................................................... 6-23
6-4 Trigger LED binary coding for diagnostic tests..................................................................................... 6-29
6-5 Main EXT DIAG Menu.................................................................................................................................. 6-30
6-6 Initial troubleshooting chart......................................................................................................................... 6-36
6-7 Mux Test wa eforms................................................................................................................................... 6-41
REV SEP 1988 ®

2440 Ser ice
LIST OF ILLUSTRATIONS (cont)
Page
6-8
6-9
6-10
Typical Register test wa eforms.............................................................................................................6-55
Front Panel n P diagnostics test...............................................................................................................6-79
System ftP data bit D7 in the Bus Isolate mode.................................................................................6-102
9-1
9-2
9-3
9-4a
9-4b
9-5
9-6
9-7
9-8
9-9
9-10
9-11
9-12
Color codes for resistors and capacitors.
Semiconductor lead configurations.
Locating components on schematic diagrams and circuit board illustrations.
Detailed 2440 Block Diagram.
Detailed 2440 Block Diagram (cont).
A12— Processor Board.
A13— Side Board.
A14— Front Panel Board.
A10— Main Board.
A30, A31, A32 and A33-Gain Cell Boards.
A ll— Timebase/Display Board.
A17— High Voltage Board.
A16— Low Voltage Power Supply Board.
i

2440 Ser ice
LIST OF TABLES
Table Page
1-1 Electrical Characteristics......................................................................................................................... 1-5
1-2 En ironmental Characteristics................................................................................................................ 1-19
1-3 Mechanical Characteristics..................................................................................................................... 1-21
1- 4 Option 05 (TV Trigger) Electrical Characteristics............................................................................... 1-22
2- 1 Voltage, Fuse, and Power-Cord Data.................................................................................................. 2-2
3- 1 Host Memory-Mapped I/O....................................................................................................................... 3-20
3-2 Processor Control Register Functions................................................................................................. 3-21
3-3 Processor Miscellaneous Register (PMREG) Output Functions..................................................... 3-22
3-4 Wa eform ^P Address Decoding........................................................................................................... 3-27
3-5 Trigger Logic Array Addresses (6080h-6087h).................................................................................. 3-52
3-6 Phase Clock Array Control Lines (CC3 through CCO)...................................................................... 3-55
3-7 Holdoff Delay Range for Current Source s Charging Capacitor
Combinations............................................................................................................................................ 3-59
3- 8 Side Board Address Decoding............................................................................................................... 3-60
4- 1 Test Equipment Required........................................................................................................................ 4-2
4-2 Accuracy Limits CH 1 and CH 2 CURSOR VOLTS Readout and A and
B TRIGGER LEVEL Readouts.............................................................................................................. 4-10
4-3 Minimum Display Le el for CH 1 or CH 2 Triggering....................................................................... 4-19
4-4 Minimum Signal Le el for EXT1 or EXT2 Triggering ........................................................................ 4-21
6-1 Relati e Susceptibility to Static-Discharge Damage ......................................................................... 6-3
6-2 External Inspection Check List............................................................................................................... 6-5
6-3 Internal Inspection Check List................................................................................................................ 6-6
6-4 Power Supply Voltage and Ripple Limits............................................................................................. 6-10
6-5 Maintenance Aids...................................................................................................................................... 6-13
6-6 2440 Troubleshooting Procedures......................................................................................................... 6-37
6-7 Video Option Troubleshooting................................................................................................................ 6-104
6-8 INIT PANEL States.................................................................................................................................... 6-108
V

OPERATORS SAFETY SUMMARY
2440 Ser ice
The general safety information in this part of the summary is for both operating and servicing personnel.
Specific warnings and cautions will be found throughout the manual where they apply and do not appear in this
summary.
Terms in This Manual
CAUTION statements identify conditions or practices that
could result in damage to the equipment or other property.
WARNING statements identify conditions or practices that
could result in personal injury or loss of life.
Terms as Marked on Equipment
CAUTION indicates a personal injury hazard not immedi
ately accessible as one reads the markings, or a hazard to
property, including the equipment itself.
DANGER indicates a personal injury hazard immediately
accessible as one reads the marking.
Grounding the Product
This product is grounded through the grounding conductor
of the power cord. To a oid electrical shock, plug the
power cord into a properly wired receptacle before making
any connections to the product input or output terminals.
A protecti e ground connection by way of the grounding
conductor in the power cord is essential for safe operation.
Danger Arising from Loss of Ground
Upon loss of the protecti e-ground connection, all accessi
ble conducti e parts (including knobs and controls that
may appear to be insulated) can render an electric shock.
in This Manual
This symbol indicates where applicable cau
tionary or other information is to be found. For
maximum input oltage see Table 1-1.
as Marked on Equipment
DANGER — High oltage.
Protecti e gound (earth) terminal.
ATTENTION — Refer to manual.
Power Source
This product is intended to operate from a power source
that will not apply more than 250 olts rms between the
supply conductors or between either supply conductor and
ground. A protecti e ground connection by way of the
grounding conductor in the power cord is essential for safe
operation.
Symbols
A
Symbols
♦
©
A
Use the Proper Power Cord
Use only the power cord and connector specified for the
instrument.
Use the Proper Fuse
To a oid fire hazard, use only the fuse specified in the
instrument parts list. A replacement fuse must meet the
type, oltage rating, and current rating specifications for
the fuse that it replaces.
Do Not Operate in Explosi e Atmospheres
To a oid explosion, do not operate this instrument in an
atmosphere of explosi e gasses.
Do Not Remo e Co ers or Panels
To a oid personal injury, the instrument co ers or panels
should only be remo ed by qualified ser ice personnel. Do
not operate the instrument without co ers and panels
properly installed.
i

2440 Ser ice
SERVICING SAFETY SUMMARY
F R QUALIFIED SERVICE PERS NNEL NLY
Refer also to the preceding perators Safety Summary.
Do Not Ser ice Alone
Do not perform internal ser ice or adjustment of this pro
duct unless another person capable of rendering first aid
and resuscitation is present.
Use Care When Ser icing W ith Power On
Dangerous oltages exist at se eral points in this product.
To a oid personal injury, do not touch exposed connec
tions or components while power is on.
Disconnect power before remo ing protecti e panels, sol
dering, or replacing components.
Power Source
This product is intended to operate from a power source
that does not apply more than 250 olts rms bwetween
the supply conductors or between either supply conductor
and ground. A protecti e ground connection by way of the
grounding connector in the power cord is essential for safe
operation.

Section 1— 2440 Ser ice
SPECIFICATION
INTRODUCTION
The TEKTRONIX 2440 Digital Oscilloscope is a
portable, dual-channel instrument with a maximum digitiz
ing rate of 500 Megasamples per second. The scope is
capable of simultaneous acquisition of Channel 1 and
Channel 2 input signals. It has a real-time useful storage
bandwidth of 200 MHz for single-e ent acquisitions, with
an equi alent-time bandwidth of 300 MHz when repetiti e
acquisitions are acquired. Since both channels are
acquired simultaneously, the XY display is a ailable to full
bandwidth. Options include a Word Recognition Probe,
Video signal triggering. Probe Power, and Rackmounting.
The instrument is microprocessor controlled and menu
dri en, displaying at the top of the screen alphanumeric
CRT readouts of the ertical and horizontal scale factors,
trigger le els, trigger source, and cursor measurements.
Menus, displayed at the bottom of the CRT display, are
used by the operator to select the operating mode.
A user makes decisions as to what operation and mode
setup the instrument must ha e to make the measurement
wanted and then selects the proper functions using a
combination of front-panel buttons and the
displayed menu.
Fi e menu buttons mounted on the CRT bezel are used
to make selections from the entry choices displayed. The
top line of the menu display usually contains the menu
title, and the bottom line labels the buttons with the
control functions they select. The selection is made
(indicated by an underscoring of the menu label in the
display) when the bezel button below the selected function
is pressed. The menus, system operating modes, and
auxiliary functions are described in Section 5, “Controls,
Connectors, and Indicators” of the Operators manual
included with this instrument, and the “Getting
Acquainted” procedure in Section 1 of that manual fami
liarizes the user with menu operation.
VERTICAL SYSTEM
The two ertical channels ha e calibrated deflection
factors from 2 mV to 5 V per di ision in a 1 -2-5 sequence
of 14 steps. Use of coded probes ha ing attenuation fac
tors of IX , 10X, 100X, and 1000X extends the minimum
sensiti ity to 5,000 V per di ision (with the 1000X probe)
and the maximum sensiti ity to 200 n V per di ision (using
a 1X probe in SAVE or AVERAGE expanded mode).
VOLTS/DIV readouts are automatically switched to
display a correct scale factor when properly coded probes
are attached. Each channel can be separately in erted.
ADD and MULT are display functions pro ided by the pro
cessor system.
In SAVE mode, the wa eforms may be both horizon
tally and ertically repositioned, expanded horizontally and
ertically, added to each other, or multiplied together for
either XY or YT displays.
HORIZONTAL SYSTEM
Horizontal display modes of A, A INTEN, and B
Delayed are a ailable. The time base has 29 calibrated
SEC/DIV settings in a 1-2-5 sequence from 2 ns per di i
sion to 5 s per di ision. An External Clock mode is
pro ided that accepts clocking signals from 1 MHz to
100 MHz.
The B Trace and the intensified zone on the A INTEN
Trace may be delayed by time with respect to the A
trigger, and a DELAY by EVENTS function permits the A
display to be delayed by a selected number of B Trigger
e ents. In the case of DELAY by EVENTS, the B Trigger
SOURCE, COUPLING, SLOPE, and LEVEL controls define
the nature of the signal needed to produce e ents
triggering. The number of e ents required to satisfy the
1-1

Specification— 2440 Ser ice
delay may be set from 1 to 65,536, with a resolution of
one e ent. The DELTA DELAY feature produces two
independently settable delayed B Traces in DELAY
by TIME.
TRIGGER SYSTEM
The trigger system of the scope pro ides many features
for selecting and processing a signal used in triggering the
acquisition system. The con entional features of SOURCE
selection, Trigger LEVEL control, Trigger SLOPE, Trigger
MODE, and CPLG (coupling) include enhancements not
normally found in a con entional oscilloscope.
The choices of VERT, CHI or CH2, EXT1 or EXT2,
LINE, and A'B or WORD (16-bit data word recognition) are
a ailable as SOURCE selections for triggering A Horizontal
Mode acquisitions. These sources for trigger signals
pro ide a wide range of applications in ol ing specialized
triggering requirements. Except for A*B (A AND B) and
LINE (power-source frequency), the same Trigger
SOURCE selections are a ailable for triggering B acquisi
tions. The selected trigger signal is conditioned by the
choice of input CPLG (coupling). These coupling selections
are AC, DC, HF REF, LF REJ, and NOISE REJ. LEVEL
control pro ides a settable amplitude (with CRT readout)
at which triggering will occur, and SLOPE control deter
mines on which slope of the triggering signal (plus or
minus) the acquisition is triggered.
Trigger MODE choices are AUTO LEVEL, AUTO,
NORM, and SINGLE SEQ (single sequence), for the A and
A INTENSIFIED Modes, and Triggerable After Delay and
Runs After Delay, for the B Mode. AUTO LEVEL pro ides
for automatic le eling on the applied trigger signal. AUTO
MODE produces an auto trigger in the e ent a trigger
signal is either not recei ed or not within the limits needed
to produce a triggering e ent. When triggering conditions
are met, a normal triggered display results. At SEC/DIV
settings of 100 ms per di ision and longer, the AUTO
MODE switches to ROLL. In ROLL MODE, the display is
continually updated and trigger signals are disregarded.
NORM (normal) trigger MODE requires that all
triggering requirements are met before an acquisition will
take place. SINGLE SEQ (single sequence) MODE is a
ariation of the con entional single-shot displays found on
many pre ious oscilloscopes. In SINGLE SEQ, a single
complete acquisition is done on all called-up VERTICAL
MODES. Since an acquisition depends on the acquisition
mode in effect, many of the scope operating features are
altered in SINGLE SEQ. A complete description of this
mode is discussed in ‘Controls, Connectors, and
Indicators” in Section 5 of the Operators manual.
The user has a choice of trigger points within the
acquired wa eform record by selecting the amount of pre
trigger data displayed. The trigger location in the record is
selectable from a choice of fi e pretrigger lengths
beginning at one-eighth of the record length and increasing
to se en-eighths of the record length. A record trigger
position is independently selectable for both A and B
acquisitions. Additional trigger positions in the record are
selectable ia the GPIB interface commands.
CURSOR MEASUREMENTS
Time and Voltage cursors are pro ided for making
parametric measurements on the displayed wa eforms.
Time may be measured either between the cursor
positions (DELTA TIME) or between a selected cursor and
the trigger point of an acquired wa eform (ABSOLUTE).
Time cursor readouts are scaled in seconds, degrees, or
percentage alues. The 1/TIME cursors may be scaled in
hertz (Hz), degrees, or percentage.
Voltage cursor measurements on a wa eform display
can be selected to read either the oltage difference
between the cursor positions or the absolute oltage posi
tion of a selected cursor with respect to ground. The olts
measurement readouts may be scaled in units of olts,
decibels (dB), or percent. The Voltage cursors and Time
cursors may also be coupled to track together (V@T and
SLOPE) and assigned to a particular wa eform for ease in
making peak-to-peak and slope wa eform measurements.
The units for V@ T may be olts, percent, or dB; SLOPE
may ha e units of slope (VOLTS/SEC), percent
(VOLTS/VOLT), or dB.
WAVEFORM ACQUISITION
Wa eforms may be acquired in NORMAL, ENVELOPE,
or AVG (A erage) acquisition modes; the mode chosen
depends on the measurement requirements. NORMAL
mode continuously acquires and displays successi e
acquisitions producing a “li e” wa eform display similar to
that seen with an analog oscilloscope. AVG (a eraging)
mode a erages successi e acquisitions of a wa eform
resulting in an impro ed signal-to-noise ratio of the
displayed wa eform. Low-amplitude signals masked by
noise become easily isible for making measurements and
analysis by a eraging from 2 to 256 acquisitions for
remo ing uncorrelated noise. ENVELOPE mode sa es the
1-2

Specification— 2440 Ser ice
maximum and minimum data-point alues o er a selected
number of acquisitions from 1 to 256 plus CONT (continu
ous). The display presents a isual image of the amount of
change (en elope) that occurs to a wa eshape during the
accumulated acquisitions. Frequency, phase, amplitude,
and position changes are easily identified when acquiring
in ENVELOPE mode. The glitch-catching capability of
ENVELOPE mode can capture single-e ent pulses as nar
row as 2 ns at the slowest SEC/DIV setting of 5 seconds
per di ision.
For all three acquisition modes, equi alent-time sam
pling extends the Useful Storage Bandwidth to 300 MHz if
the signal is repetiti e and REPET mode is turned on. At
50 ns/DIV and faster, randomly-acquired data points (or
samples) taken from successi e acquisitions of a periodic
signal are used to fill the complete record (1024 data
points) of the signal wa eform display. Depending on the
SEC/DIV setting, as few as 10 data points (at 2 ns/DIV) or
as many as 512 data points (at 50 ns/DIV) may be
obtained on each triggered acquisition. Sampling of suc
cessi e acquisitions continues until a predetermined
number of data points are acquired and any remaining
points in the record are determined by interpolating
between the acquired points. (The predetermined number
includes at least enough data point to meet the Useful
Storage Bandwidth of 300 MHz specified for REPET
mode.) These interpolated points are replaced by
randomly-acquired data points as they become a ailable
from successi e acquisitions.
Horizontally, the record length of acquired wa eforms is
1024 data points (512 max/min pairs in ENVELOPE mode),
of which 500 make up a one-screen display (50 data
points per di ision for 10 di isions). The entire record may
be iewed by using the Horizontal POSITION control to
position any portion of the record within the iewing area.
STORAGE AND I/O
Acquired wa eforms may be sa ed in any of four REF
wa eform non olatile memories. Any or all of the sa ed
reference wa eforms may be displayed for comparison
with the wa eforms being currently acquired. The source
and destination of wa eforms to be sa ed may be user
designated. Assignment can be made to sa e either chan
nel 1 or channel 2 (or the results of an addition or multipli
cation of the two channels) to any REF memory or to
mo e a stored reference from one REF memory to
another. Reference wa eforms may also be written into a
REF memory location ia the GPIB interface.
The scope is fully controllable and capable of sending
and recei ing wa eforms ia the standard equipped GPIB
interface. This feature makes the instrument ideal for
making automated measurements in a production or
research and de elopment en ironment that calls for
repetiti e data taking. Self- calibration and self-diagnostic
features built into the scope to aid in fault detection and
ser icing are also accessible ia commands sent from the
GPIB controller.
Another standard feature is the “DEVICES" setting for
GPIB Interface control. This feature allows the user to out
put wa eforms (and other on-screen information) from the
front panel to many printers and plotters that use HP®
Graphics Language. In this way, hard copies of acquired
wa eforms can be obtained without putting the scope into
a system controller en ironment
EXTENDED FEATURES
There are se eral other features incorporated into this
instrument designed to make it more usable, namely, the
HELP, Auto Setup, MEASURE, and AutoStep
Sequencer features.
HELP: The HELP function can be used to display
operational information about any front-panel control.
When HELP mode is in effect, manipulating almost any
front-panel control causes the scope to display information
about that control. When HELP is first in oked, an
introduction to HELP is displayed on screen.
Auto Setup: The Auto Setup function is used to
automatically setup the scope for a iewable display based
on the input signal. The user can specify the wa eform
characteristic the display is optimized for (front-edge,
period, etc.) from a menu displayed upon executing Auto
Setup.
MEASURE: MEASURE automatically extracts
parameters from signal input to the scope. In the
“SNAPSHOT” mode, 20 different wa eform parameters
are extracted and displayed for a single acquisition. In the
continuous extraction mode, up to four parameters are
extracted continuously as the instrument continues
to acquire.
1-3

Specification— 2440 Ser ice
AutoStep Sequencer (PRGM): With AutoStep, the user
can sa e single front-panel setups or sequences of setups
and associated flow control and Input/Output actions for
later recall. If MEASURE and/or OUTPUT are sa ed as
part of these setups they can be used for automatic
parameter extraction and data printout. 100 to 800 front-
panel setups (depending on complexity) can be stored in
one or more sequences.
The complete descriptions of these four features are
found in Section 5 of the Operators manual included with
this instrument.
The following items are standard accessories shipped
with the scope instrument:
2 Probe packages
1 Snap-lock accessories pouch
1 Zip-lock accessories pouch
1 Operators manual
1 Programmer’s Reference Guide
2 Users Reference Guide
1 Fuse
1 Power cord (installed)
1 Blue plastic CRT filter (installed)
1 Clear plastic CRT filter
1 Front-panel co er
For part numbers and further information about
standard accessories and a list of the optional acces
sories, refer to “Options and Accessories” (Section 7) in
this manual. For additional information on accessories and
ordering assistance, contact your Tektronix representati e
or local Tektronix Field Office.
PERFORMANCE CONDITIONS
The following electrical characteristics (Table 1-1) apply
when the scope has been calibrated at an ambient tem
perature between +20°C and +30°C, has had a warmup
period of at least 20 minutes and is operating at an
ambient temperature between —15°C and + 5 5°C (unless
otherwise noted).
Items listed in the “Performance Requirements” column
are erifiable qualitati e or quantitati e limits that define
the measurement capabilities of the instrument.
En ironmental characteristics are gi en in Table 1-2.
The scope meets the en ironmental requirements of MIL
T-288000 for Type III, Class 3, Style D equipment, with
the humidity and temperature requirements defined in
paragraphs 3.9.2.2, 3.9.2.3, and 3.9.2.4. The rackmounted
scope meets the ibration and shock requirements of
MIL-T-28800C for Type III, Class 5, Style D equipment
when mounted using the rackmount rear-support kit sup
plied with both the 1R Option and the Rackmount
Con ersion kit.
Mechanical characteristics of the scope are listed in
Table 1-3.
Video Option characteristics are gi en in Table 1-4.
RECOMMENDED ADJUSTMENTS SCHEDULE
For optimum performance to specification, the internal
SELF CAL should be done:
1. If the operating temperature is changed by more
that 5°C since the last SELF CAL
was performed.
2. Immediately before making measurements
requiring the highest degree of accuracy.
1-4

Specification— 2440 Ser ice
Table 1-1
Electrical Characteristics
Characteristics Performance Requirements
ACQUISITION SYSTEM— CHANNEL 1 AND CHANNEL 2
Resolution 8 bits.®
Displayed ertically with 25 digitization le els (DL)b per di ision.
Dynamic Range®
SEC/DIV
100 or slower -1 2 8 to +127 DL’s.
50 to 500 ns -1 2 4 to +123 DL’s.
200 ns -121 to +120 DL’s.
100 ns -1 1 3 to +112 DL’s.
50 ns to 2 ns
Repet OFF -1 1 3 to +112 DL’s.
Repet ON 121 to 120 DL’s.
Record Length 1024 samples.®
Displayed horizontally with 50 samples per di ision, 20.48-di ision
trace length.®
Sample Rate 10 samples per second to 500 megasamples per second (5 s per
di ision to 100 ns per di ision).
Sensiti ity
Range 80 fiV per DL to 0.2 V per DL in a 1-2-5 sequence of 11 steps
(2 mV per di ision to 5 V per di ision).
Accuracy
Normal and A erage Modes Within ± (2% + 1 DL) at any VOLTS/DIV setting for a signal
1 kHz or less contained within ± 75 DL (± 3 di isions) of center
when a SELF CAL has been performed within ±15°C of the
operating temperature. Measured on a four- or fi e-di ision signal
with VOLTS or V@T cursors; UNITS set to delta olts.
En elope Mode Add 1 % to Normal Mode specifications.
Variable Range Continuously ariable between VOLTS/DIV settings. Extends
sensiti ity to 0.5 V per DL or greater, 12.5 V per di ision or
greater.
■Performance Requirement not checked in the manual.
b“DL” is the abbre iation for “digitization le el.” A DL is the smallest oltage le el change that can be resol ed by the internal 8-bit
A-D con erter, with the input scaled to the VOLTS/DIV setting of the channel used. Expressed as a oltage, a DL is equal to 1/25
of a di ision times the VOLTS/DIV setting.
REV NOV 1988 1-5

Specification—2440 Ser ice
Table 1-1 (cont)
Characteristics Performance Requirements
ACQUISITION SYSTEM--CHANNEL 1 AND CHANNEL 2 (cont)
Bandwidth Bandwidth is measured with a le eled, low distortion, 50-12 source,
sine-wa e generator, terminated in 50 12. The reference signal is
set to 6 di isions or to the maximum le eled amplitude obtainable
if the Volt/Di setting is too high to yield 6 di ’s on screen.
Bandwidth with probe is checked using a probe-tip-to-GR
termination adaptor (017-0520-00).
Bandwidth with external termination is checked using a BNC 50-12
feed-through terminator (011-0049-01).
—3 dB Bandwidth
Normal or A erage Modes. En elope Mode
at SEC/DIV settings of 0.2 ms or faster. Using standard accessory probe or internal termination (not
checked with probe in manual).
— 15°C to +30°C
+30°C to +55°C
Dc to 300 MHz.
Upper Bandwidth Limit reduced by 2.5 MHz for each °C abo e
30°C.a
En elope Mode at SEC/DIV settings of
0.5 fis or slower. Dc to 150 MHz using standard accessory probe, internal 50-12
termination, or external 50-12 termination on 1-M12 input.3
-4 .7 dB Bandwidth
Normal or A erage Mode. En elope Mode at
SEC/DIV settings of 0.2 ns or faster. Using 50-12 external termination on 1-M12 input.
+30°C to +55°C Upper Bandwidth Limit reduced by 2.5 MHz for each °C abo e
30°C.a
Single E ent Useful Storage Bandwidth
Normal or A erage Mode, SEC/DIV at
0.1 /ts or Faster; Repet OFF DC to 200 MHz (calculated).
USB F(samptetreqmax)c
2.5
AC Coupled Lower - 3 dB Point
IX Probe 10 Hz or less.®
10X Probe 1 Hz or less.®
Step Response, Repet and A erage On;
A erage Set to 16
Rise Time 1.17 ns or less (calculated).®
T, On ns) - 6 w jg°MHz>
■Performance Requirement not checked in the manual.
■Sample freq. max. is 500 MHz.

Specification— 2440 Ser ice
Table 1-1 (cont)
Characteristics Performance Requirements
ACQUISITION SYSTEM--CHANNEL 1 AND CHANNEL 2 (cont)
En elope Mode Pulse Response
Minimum Single Pulse Width for 50% or Greater
Amplitude Capture at 85% or Greater Confidence 2 ns.a
Minimum Single Pulse Width for Guaranteed 50%
or Greater Amplitude Capture 8 ns.a
Channel Isolation Measured with a 10-di ision, sine-wa e input and equal VOLT/DIV
settings on both channels. 100:1 or greater at 100 MHz for
VOLT/DIV settings from 2 mV/DIV and 500 mV/DIV; 50:1 or
greater at 300 MHz for VOLT/DIV settings from 20 mV/DIV to
500 mV/DIV. 25:1 or greater at 300 MHz for VOLT/DIV settings
of 5 mV/DIV and 10 mV/DIV.
Acquired Channel 2 Signal Delay with Respect to
Channel 1 Signal at Full Bandwidth ±250 ps.a
Input R and C (1 Mfi)
Resistance 1 Mfl ±0.5% .a
In each attenuator, the input resistance of all VOLTS/DIV
positions is matched to within 0.5%.a
Capacitance 15 pF ± 2 pF.a
In each attenuator, the input capacitance of all VOLTS/DIV
positions is matched to within 0.5 pF.a
Input R (50 Q)
Resistance 50 fi ±1% .a
VSWR (DC to 300 MHz) 1.3:1 or better.3
Maximum Input Voltage 5 V rms; 0.5 W-sec for any one-second inter al for instantaneous
oltages from 5 V to 50 V.
■Performance Requirement not checked in the manual.
1-7

Specification—2440 Ser ice
Table 1-1 (cont)
Characteristics Performance Requirements
ACQUISITION SYSTEM--CHANNEL 1 AND CHANNEL 2 (cont)
Maximum Input Voltages
Input Coupling Set to DC, AC, or GND 400 V (dc -)- peak ac); 800 V p-p ac at 10 kHz or less.®
Common-Mode Rejection Ratio (CMRR); ADD Mode
with Either Channel In erted At least 10:1 at 50 MHz for common-mode signals of 10 di isions
or less with VARIABLE VOLTS/DIV adjusted for best CMRR at
50 kHz.
POSITION
Range ± (9.3 to 10.4) di ., at 50 mV per di ision with INVERT off, when
Self Cal has been done within ± 5°C of the operating
temperature.
Gain Match between NORMAL and SAVE ± 3 DLs for positions within ± 5 di isions from center.
Low-Frequency Linearity
Normal or A erage Mode 3 DLs or less compression or expansion of a two-di ision,
center-screen signal when positioned anywhere within the
acquisition window.
20-MHz Bandwidth Limiter
- 3 dB Bandwidth 13 MHz to 24 MHz.
100-MHz Bandwidth Limiter
- 3 dB Bandwidth 80 MHz to 120 MHz.
Rise Time 2.9 ns to 4.4 ns.a
With a fi e-di ision, fast-rise step (rise time of 300 ps or less)
using 50-fi dc input coupling and VOLTS/DIV setting of 10 mV.®
■Performance Requirement not checked in the manual.
1-8