Tektronix 7S12 User manual

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon
070-1244-00
Product Group 42
Ibktronix-
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7S12
TDR/SAMPLER
S/N B020000-UP
INSTRUCTION MANUAL
97077 Serial Number
First Printing NOV 1971
Revised MAR 1985

Copyright ®1971 Tektronix, Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix. Inc.
Products of Tektronix, Inc. and its subsidiaries are covered
by U.S. and foreign patents and/or pending patents.
TEKTRONIX, TEK, SCOPE-MOBILE, and are
registered trademarks of Tektronix, Inc. TELEQUIPMENT
is aregistered trademark of Tektronix U.K. Limited.
Printed in U.S.A. Specification and price change privileges
are reserved.
INSTRUMENT SERIAL NUMBERS
Each instrument has aserial number on apartel 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 sequentially and are
unique to each instrument. Those manufactured in the
United States have six unique digits. The country of
manufacture is identified as follows:
BOOOOOO 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

7S12
TABLE OF CONTENTS
SECTION 1CHARACTERISTICS Page SECTION 4MAINTENANCE (cont) Page
Description 1-1 Readout Symbol Adjustment
Electrical Characteristics 1-1 C> and <3 4-2
Physical Characteristics 1-5 Repackaging for Shipment 4-3
Environmental Characteristics 1-5
SECTION 5PERFORMANCE
SECTION 2OPERATING INSTRUCTIONS CHECK/ADJUSTMENT
General Information 2-1 Introduction 5-1
Installation 2-1 Equipment Required 5-1
Controls and Connectors 2-1 Performance Check and Adjustment
First Time Operation 2-5 Record and Index 5-2
Voltage Reflection Coefficient 2-7 7S12 Checks 5-3
Impedance Scale Overlays 2-8 S-6, S-52 and 7S12 System Checks 5-5
Time or Distance Measurements 2-8 S-5, S-54 and 7S12 System Checks 5-7
High Resolution 2-11 Adjustment Procedure 5-9
Single Sweep Operation 2-11
PRESET Calibration 2-12
Application Connections 2-12 SECTION 6ELECTRICAL PARTS LIST
Using TDR Slide Rule 2-14
SECTION 7DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
SECTION 3CIRCUIT DESCRIPTION Symbols and Reference Designators
Introduction 3-1 Schematic Diagrams and Component
Vertical Circuits Block Diagram 3-1 Board Locations
Horizontal Circuits Block Diagram 3-4
Circuit Description 3-10
SECTION 8MECHANICAL PARTS LIST
SECTION 4MAINTENANCE Mechanical Parts List
Mechanical Parts List IllustraTron
Introduction 4-1 Accessories
Lubrication 4-1
Troubleshooting 4-1
Tape Dial Removal 4-2
Tape Dial Installation 4-2
Tape Dial Alignment 4-2
Revised NOV 1984 I

fIMC
DC OFFStT *1V TtMt/OIV
mVOlTS/OIV
SaSAMPLINO HEAD
Fig. 1-1. 7S12 TDR/Sampler unit,

SECTION 1
CHARACTERISTICS
Description
The 7S12 is adual-purpose plug-in unit for measurement
of recurring fast-rise signals or for time-domain
reflectometry. It occupies two compartments (one vertical
input and one horizontal input) of aTektronix 7000-series
oscilloscope.
The 7S12 has two compartments for plug-in heads. The
left-hand compartment (labeled SAMPLING on the 7S12
front panel) accepts Tektronix S-series Sampling Heads.
The type of sampling head selected determines the vertical
input characteristics of the 7S12. The right-hand compart-
ment (labeled PULSE GENERATOR) accepts S-series pulse
generators, trigger recognizers or trigger count-down heads.
The 7S12 has the following features: The vertical de-
flection factors, i.e., millivolts/div and millirho/div, are
from 2to 500 in a1-2-5 sequence. The time/div is cali-
brated from 20 ps/div to 1ys/div in a1-2-5 sequence. The
DC OFFSET control offsets the display in a±1 Vrange.
The HI RESOLUTION switch reduces the waveform noise
and jitter by signal averaging with acorresponding re-
duction of sweep rate. The LOCATE switch increases the
time/div and intensifies aportion of the display to locate
the time window relative to the total waveform. Front
panel outputs include OFFSET OUT (±10 Vrange),
VERTical SIGnal OUT and SWEEP OUT. Modes of sweep
operation include SINGLE sweep, REPetitive sweep,
MANual scan and EXTernal sweep IN.
The TIME-DISTANCE scale is calibrated for round-trip
time measurements of 0to 10 ys and one-way distance
measurements up to 4900 feet (1500 meters) air dielectric
or 3200 feet (975 meters) polyethylene dielectric. The
POLY scale may be calibrated for transmission lines which
have avelocity of propagation equal to or greater than that
of polyethylene. The Time-Distance scale may be ordered
with distance calibrated in metric units.
SECTION 1
ELECTRICAL CHARACTERISTICS
Characteristic Performance Requirement Supplemental Information
Deflection Factor
Accuracy Within 3%
Range 2units/div to 500 units/div irt a1-2-5
sequence. Units/div are labeled on the
sampling head.
Units/Div VARIABLE Range 'Provides continuous coverage from 1
to 770 units/div (mV or mp)
pCAL Range Allows calibrated reflection coefficient
(p) with pulse generators supplying
from 200 mV to 1Vpulse amplitude.
DC OFFSET Range Offsets display at least -M Vto —1 V.
OFFSET OUT
Range At least -MO Vto -10 V. OFFSET
OUT =10X (DC OFFSET) within 2%
Source Resistance 10 kfi within 1%

Characteristics—7S 1
2
Characteristic Performance Requirement Supplemental Information
VERTical SIGnal OUT
Amplitude 200 mV/div of signal display within
2%
VARIABLE control must be in CAL
position.
Source Resistance 10 within .5%
SWEEP OUT
Amplitude 1V/div of horizontal deflection within
2%
Range 0Vto greater than 10V
Source Resistance 10 kfi within 1%
TIME/DIV
Accuracy Within 3%
Range 20 ps/div to 1ps/div in a1-2-5
sequence
Time/Div VARIABLE Range Provides continuous coverage to at
least 8ps/div.
Display Modes
SINGLE Sweep Each sweep is initiated by pushing and
releasing the START button.
REPetitive Sweep Normal resolution: sweep rate is
continuously variable from at least 1
sweep in 20 ms to less than 1sweep in
5s.
HI RESOLUTION: sweep rate is con-
tinuously variable from at least 1
sweep in 200 ms to less than 1sweep
in 50 s.
MANual Sweep Any portion of the display may be
observed by manual operation of the
SCAN control.
EXTernal Input
Deflection Factor 1V/div within 5% to at least 15 V/div
Input Resistance 100 kfi within 10%
Maximum Input Voltage 150 V(DC +peak AC)
FINE (ZERO SET) Range Moves an unmagnified waveform at
least .9 div.
1-2

Characteristics—7S 1
2
ELECTRICAL CHARACTERISTICS
SYSTEM PERFORMANCE WITH S-6 AND S-52
Characteristic Performance Requirement Supplemental Information
Risetime 35 ps or less for the incident step, 45 ps
or less for the displayed reflection from a
short-circuited 1ns test line
Pulse Amplitude At least +200 mV into 50 0,
Input Impedance Nominal 50
Jitter Less than 10 ps (without signal averaging)
Aberrations Not more than +7%, —7%, total of 10%
P-P within the first 1.8 ns of the step edge
with the reference level at 1.8 ns from the
step edge; not more than +2%, —2%, total
of 4% P-P after 2.5 ns from the step edge
with the reference level at 0.3 ps from the
step edge.
TIME-DISTANCE Scale Time scale indicates round-trip time.
Distance scales (AIR and POLY
dielectrics) indicate one-way distance.
The usable TIME-DISTANCE ranges
for TDR measurements are limited by
the S-52 pulse duration.
Accuracy TIME scale within 1% of full scale. Distance scales are calibrated for the
nominal velocity of propagation of the
AIR and POLY dielectrics.
TIME-DISTANCE Multiplier
X.1 XI X10
TIME Range .1 ps 1AS lOps
i
Maximum of about 150
ns one-way cable delay.
AIR Dielectric Distance 49 feet 490 feet 4900 feet
Range 15 meters 150 meters 1500 meters
1
Maximum of about 150
feet (46 meters) cable
length.
POLY Dielectric Distance
Range
32 feet 320 feet 3200 feet
9.75 meters 97.5 meters 975 meters
Maximum of about 100
feet (30 meters) cable
length.
1-3

Characteristics—7S 12
Characteristic Performance Requirement Supplemental Information
PRESET Permits the calibration of the POLY
scale for dielectrics having avelocity
of propagation between those of poly-
ethylene and air.
Characteristic
Risetime
Pulse Amplitude
Input Impedance
Jitter
Aberrations
TIME-DISTANCE Scale
Accuracy
TIME Range
ELECTRICAL CHARACTERISTICS
SYSTEM PERFORMANCE WITH S-5 AND S-54
Performance Requirement
1.5 ns or less for the displayed reflection
from ashort-circuited test line
At least -t400 mV into 50
Less than 20 ps (without signal averaging)
Not more than -r4%, —6%, total of 10%
P-P within the first 17 ns of the step: not
more than +1.5%, —1.5%, total of 3%
after 17 ns.
TIME scale within 1% of full scale.
Supplemental Information
Nominal 50 ^2
Time scale indicates round-trip time.
Distance scales (AIR and POLY
dielectrics) indicate one-way distance.
TDR events out to 20 /ts (round-trip
time) may be viewed. This corresponds
to 9800 feet (3000 meters) in AIR
dielectric and to 6400 feet (1950
meters) in POLY dielectric. This
distance is the sum of the displayed
time window (10 ps maximum) and
the TIME scale readout (10 ps maxi-
mum).
Distance scales are calibrated for the
nominal velocity of propagation of the
AIR and POLY dielectrics.
TIME-DISTANCE Multiplier
X.1 XI X10
.1 ps 1ps 10 ps
An additional time range may be
viewed.
1-4

Characteristics—7S 12
Characteristic Performance Requirement Supplemental Information
AIR Dielectric Distance
Range
49 feet 490 feet 4900 feet
15 meters 150 meters 1500 meters
An additional distance range may be
viewed (in terms of time).
POLY Dielectric Distance
Range
32 feet 320 feet 3200 feet
97.5 meters 9.75 meters 975 meters
An additional distance range may be
viewed (in terms of time).
PRESET Permits the calibration of the POLY
scale for dielectrics having avelocity
of propagation between those of poly-
ethylene and air.
PHYSICAL CHARACTERISTICS
Characteristic Performance Requirement
Finish Anodized aluminum front panel
Weight
Net 4.7 lb
Domestic Shipping 7.2 lb
Export Packed 11.7 lb
Dimensions
Length (ex-
cluding knobs) 13.383 in
Width 5.464 in
Height 4.988 in
ENVIRONMENTAL CHARACTERISTICS
Characteristic Performance Requirement
Temperature
Operating 0°C to -t50°C
Non-operating -40°C to -i-65°C
ENVIRONMENTAL CHARACTERISTICS (cont)
^
1
Characteristic Performance Requirement
Altitude
Operating To 15,000 feet
Non-operating To 50,000 feet
Vibration
Operating 0.025 in P-P displacement at 55 Hz
Shock
Operating To 20 g's, 1/2 sine, 11 ms duration
Humidity
Non-operating
and Operating 5cycles (120 hours) to 95% relative
humidity referenced to
MIL-E-16400F (Paragraph 4.5.9
through 4.5. 9.5.1, Class 4)
Transportation Qualifies under National Safe
Transit Committee test procedure
1A, Category II
1-5

7S12
SECTION 2
OPERATING INSTRUCTIONS
General Information
This section of the manual provides the basic infor-
mation required for operation of the 7S12 TDR/Sampler
including installation, front panel information, and First
Time operation instructions.
The 7S12 is acombined horizontal and vertical,
double width sampling unit for use in any 7000-series
Oscilloscope. The 7S12 accepts two plug-in heads, a
sampling head and agenerator head, which determine
the characteristics of the TDR system. If atrigger recog-
nizer head such as the S-53 is used in the 7S12 gener-
ator head compartment, general purpose sampling can be
accomplished using the S-53 to trigger the 7S12 sweep.
INSTALLATION
The 7S12 can be powered by any Tektronix 7000-
series Oscilloscope. Since the 7S12 is acombined hori-
zontal and vertical unit, it must be installed in the
center two compartments of a7000-series Oscilloscope
containing 4 compartments, or into the right two com-
partments of a7000-series Oscilloscope containing 3
compartments. Avertical unit such as a7S11 can be
installed in the left compartment of either Oscilloscope
for dual-trace operation. Then J641 (a fixed shoe
connector) provides astrobe connection to the 7S1 1.
Three methods of installation are shown in Fig. 2-1.
Part Ashows the 7S12 installed in the center two com-
partments of a7504 Oscilloscope. The 7S11 and samp-
ling heads are shown for TDR and dual-trace use. Part
Bshows the 7S12 installed with the 7S11, 7M11, and
sampling heads for General Purpose Sampling and dual-
trace use. Part Cshows the 7S12 installed with the
7S11 and sampling heads in the 7403N (or 7503)
3-compartment Oscilloscope for TDR and dual-trace use.
For General Purpose sampling, use the 7M11 outside the
Oscilloscope, and the sampling heads as shown for
installation B.
Installing the 7S12 in the Oscilloscope
Insert the 7S12 into avertical and ahorizontal com-
partment of a7000-series Oscilloscope (See Fig. 2-1).
Slide the 7S12 completely into the two compartments.
The 7S12 will lock into place with aspring loaded latch
knob.
To install ahead into one of the two 7S12 compart-
ments, insert the head into the compartment with the
latch knob free to move until completely in the 7S12.
Then push the latch to lock the head in place. To
remove, pull the latch knob away from the panel, then
pull the unit from the 7S12.
Mating
The 7S12 vertical output amplifier gain must be
matched to the oscilloscope deflection factor for
accurate gain measurements. The VERT GAIN control, a
screwdriver adjustment on the front panel, adjusts the
vertical output amplifier gain of the 7S12. Adjustment
of this VERT GAIN control using the Oscilloscope Cali-
brator as asignal source is shown under First Time
Operation in this section of the manual.
The 7S12 horizontal gain must be matched to the
horizontal deflection factor of the oscilloscope. Hori-
zontal gain is set by the SWEEP CAL adjustment lo-
cated on the 7S12 front panel. The adjustment is made
for full rotation of the SCAN control for 10 divisions
with the MAN button pushed in. The HORIZ POS
adjustment is used to position the spot on the CRT.
The HORIZ POS control is also located on the front
panel. The adjustment method is discussed in First Time
Operation.
CONTROLS AND CONNECTORS
Abrief description of the function and operation of
the controls and connectors of the 7S12 follows. Fig.
2-2 shows the 7S12 front panel with asampling head
and apulse generator installed.
Vertical Section
DC OFFSET ±1 VPositions the display vertically by
applying an internal offset voltage
REV. B, JULY, 1976 2-1