Tektronix 7D11 User manual

TEKTRONIX
7D11
DIGITAL D
OPERATORS
AY
INSTRUCTION
MANUAL
Tektronix, Inc .

P.O . Box 500

Beaverton, Oregon 97005
070-1329-00

772

WARRANTY
All TEKTRONIX
instruments are warranted
against
defective materials
and workmanship for one
year . Any
questions with
respect to the warranty should be
taken up
with your TEKTRONIX
Field Engineer or representative
.
All
requests for
repairs and replacement parts should
be
directed to the
TEKTRONIX Field Office or
representative
in your area .
This will assure you the fastest
possible
service . Please
include the instrument Type
Number or Part
Number
and Serial Number with all requests for
parts or
service .
Specifications
and price change privileges reserved
.
Copyright
© 1972 by Tektronix, Inc ., Beaverton,
Oregon .
Printed in
the United States of America . All rights
reserved .
Contents of this publication may not
be reproduced in any
form without permission of
Tektronix, Inc .
U .S .A . and foreign
TEKTRONIX products covered by U .S .
and foreign patents
and/or patents pending .
TEKTRONIX is a registered
trademark of Tektronix, In

TABLE OF
CONTENTS
SECTION
1
SECTION2
OPERATING
INSTRUCTIONS
Page
7Q11 Features
1-1
Preliminary
Information
Installation
1-1
Display
1-1
Controls and
Connectors
1-3
General
Operating Information
Signal
Connection
1-3
Count
Mode
1-4
Trigger Controls
1-4
Triggered Light
1-4
Trigger Coupling
1-4
Trigger Source
1-5
Trigger
Slope/Level
1-5
Events
Start Trigger
1-5
Delay Time or Events
1-6
Fine Delay
1-6
B Sweep Delay
Mode
1-6
Output Signals
Front-Panel
Output Signals
1-6
Output
Signals to Mainframe
1-7
Operating
Modes
Sweep Delay 1 - 8
Echo Delay Time
Mode 1
Applications '
General
1-9
Delayed-Sweep Time
Measurements 1-9
Displaying Complex
Signals with Delayed Sweep
1-9
Pulse Jitter
Measurements
1-10
SPECIFICATION
Introduction 2-1
Table
2-1, Electrical
Characteristics 2-1
Table 2-2, Environmental
Characteristics 2-2
Table 2-3,
Physical Characteristics 2-2

INS tol
ci"AM
Fig . 1-1 . 71311 Digital Delay .

71311 Features
The 71311 Digital Delay plug-in unit
is designed for
use
with TEKTRONIX 7000-Series Oscilloscope
mainframes
equipped with a readout system . The
71311 uses the
readout system to display
the selected delay count on the
CRT . A
delayed
trigger output is generated by counting
time or events . Digital delay time to one second is read out
in 100-nanosecond increments . Additional analog delay
time from zero to 100 nanoseconds selected from a
calibrated front-panel dial provides added resolution
. An
"echo" time-delay mode provides a divide-by-two scaler
to
read out the "one-way trip" time up to
two seconds for
radar ranging and TDR applications . Delay time
accuracy is
controlled by an internal crystal oscillator ; greater accuracy
can be obtained by the use of an external one-megahertz
standard . In the Count
by
Events mode,
the CRT readout
displays the integer number of events from one to 10 1
events at count rates up to 50 megahertz .
The 71311 can be used to delay a 7B-series time-base unit
in either a runs-after or triggerable-after delay time mode .
Other 71311 features include on-screen display of delay
interval by vertical signal or display blanking, trigger
pickoff from vertical amplifier unit, and blanking of all
zeros to the left of the most significant
digit (Count by
Time mode only) .
Installation
The 71311 is designed
to operate in any plug-in compart-
ment of TEKTRONIX 7000-series mainframes . However,
certain modes of operation require the 71311 to be installed
in a specific compartment . The unit must be operated
in
a
horizontal compartment to trigger from a signal
applied
to
OPERATING
INSTRUCTIONS
PRELIMINARY INFORMATION
Section 1-71311 Operators
a vertical
amplifier unit . The 71311 must be operated in the
A
Horizontal compartment to control
the
delay mode of a
time-base
unit in
the
B Horizontal compartment . Operation
in
a vertical
compartment is necessary to view the Delay
Interval
Pedestal
without the use of external cables .
To install the 71311 into a plug-in compartment, push
the unit in until it is seated flush against the front panel of
the mainframe . To remove, pull the release latch to
disengage the 71311 . Continue to pull the release
latch
to
remove the unit from the mainframe .
Display
The 71311' readout display is
presented on the CRT of
the mainframe,
along with information encoded by the
other plug-in units .
Digital delay time (in milliseconds) is
displayed
in
four
to eight digits . All zeros to the left of the
most significant digit are blanked out . The + symbol to the
right of the digital display reminds the operator to addany
analog delay time selected by the FINE DELAY (ns) dial to
the delay time . The number of events
being counted is
presented
in a seven-digit display .
The 71311 readout display appears on
the CRT in a
location corresponding to the plug-in compartment used .
The delay time or number of events will be displayed in the
top division of the CRT graticule . The delay-time measure-
ment unit (ms) will be displayed in the bottom division . It
is not necessary to select the 71311 with the mainframe
Vertical or Horizontal Mode switches to view the digital
display . In order to view the Delay Interval Pedestal
waveform, selection with the Vertical Mode switch is
required .

Operating Instructions-7D11 Operators
Fig . 1-
2 . 7D11 front-panel controls and connectors
.

CONTROLS AND CONNECTORS
The major controls and connectors
for operation
of the
71311 are located on the
front panel
of the
unit .
Two
controls located
inside the unit for auxiliary functions are
described in the
General Operating Information
section .
The front-panel controls and connectors are identified in
Fig . 1-2 ; their functions are as follows :
COUNT MODE Switch
Selects mode of operation and clock-signal
source for Time count
mode .
B SWEEP DELAY MODE Switch
Selects the delay mode logic for time-base unit in
B Horizontal compartment
of mainframe .
TRIGGER SLOPE/LEVEL Controls
Select slope and amplitude point of input signal
where the delay is initiated .
TRIG'D Indicator
Lights when a trigger is produced .
COUPLING Switch
Selects the method of coupling the input signal
to the
Trigger circuit
.
6O SOURCE Switch
Selects Trigger input signal source .
EVENTS START TRIGGER SLOPE/LEVEL
Controls
Select slope and amplitude point of input signal
where the Events Start count is initiated .
DELAY TIME OREVENTS Control
Selects delay time or number of events counted .
Direction of rotation selects increase or decrease
in
delay time or number of events .
FINE DELAY (ns) Dial
Selects analog delay time
added to
digital
delay
time selected by DELAY TIME
OR EVENTS
control .
REV . JAN 1974
10

DLY'D TRIG OUT
Operating Instructions-71371
Operators
BNC connector for
Delayed
Trigger
output
signal .
EXT 1 MHz IN or EVENTS
START
TRIG
IN
BNC connector for input of external 1
MHz
time-reference signal or input of Events Start
Trigger input signal . Connector function is deter-
mined by setting of COUNT MODE switch .
DLY INTERVAL OUT
BNC connector for Delay Interval output signal
.
EXT TRIG IN
BNC connector for external input to Trigger
circuit (selected by SOURCE switch in the
external positions) .
GENERAL OPERATINGINFORMATION
Signal Connection
RESET
Resets the
DELAY TIME OR EVENTS
to
0000001 (EFF SN B030000 and up) .
In general,
probes offer the most convenient means of
connecting signals
to the 71311 external trigger inputs .
TEKTRONIX
probes are shielded to prevent pickup of
electrostatic interference . A 10X attenuation probe offers a
high input impedance and allows the circuit under test to
perform very close to normal operating conditions . Also, a
10X probe attenuates the input signal ten times .
TEKTRONIX
probes are designed to
monitor
the
signal
source with minimum circuit loading . The use of a probe
will, however, limit the maximum trigger frequency range .
To obtain maximum trigger bandwidth when using probes,
select a probe capable of compensating the
input
capacitance ; observe the grounding considerations given in
the probe manual . The probe-to-connector adapters and the
bayonet-ground tip provide the best frequency response .
In
high-frequency applications, requiring maximum over-
all bandwidth, use a coaxial cable
terminated at both ends
in
the characteristic impedance of the cable . To maintain
the
high-frequency characteristics of the applied signal, use
high-quality low-loss cable . Resistive coaxial attenuators
can be used
to
minimize
reflection if the applied signal has
suitable amplitude .

Operating Instructions-71311 Operators
High-level, low-frequency signals can be connected
directly to the external
trigger inputs with short, unshielded
leads
. When this
method is used, establish a common
ground between the 71311 and the associated equipment .
The common ground provided by line cords is usually
inadequate . If interference is excessive with
unshielded
leads, use a coaxial cable or probe .
A signal can also
be routed to the 71311 through an
amplifier unit via the internal trigger circuitry of the
mainframe (71311 installed in a horizontal compartment) .
This method of signal connection minimizes circuit loading,
especially
when
triggering a time-base unit in parallel with
the 71311 .
(NOTE : Only external signals can be used with
the Events
Start Trigger
.)
The front-panel output signals, DLY'D TRIG OUT
and
DLY INTERVAL OUT, should be connected to other
equipment with 50-ohm coaxial cables . The
cables should
be terminated in 50 ohms to maintain the rise
and falltime
characteristics of these signals .
Count Mode
General . Two
basic count modes, Time and
Events, can
be performed
by the 71311, as selected by
the COUNT
MODE switch . The
delay interval in both modes
is selected
by the DELAY
TIME OR EVENTS control
and is read out
on the
CRT .
TIME INT CLOCK . The 71311
counts precise
increments of time after the receipt of
a trigger . The
TRIGGER controls select and condition the
signal to start
the time delay . Accuracy in this mode is
determined by an
internal, crystal-controlled oscillator .
TIME
EXT 1 MHz . This count
mode is the same
as
TIME
I
NT
CLOCK except the accuracy
is derived from
an
external,
one-megahertz standard .
EVENTS . The
71311 counts events, periodic
or
aperiodic, at count
rates to 50 megahertz . The
EVENTS
START
TRIGGER provides a means of discriminating
between the
event that starts the delay and the
events to be
counted . The
events to be counted are selected
and
conditioned by the
TRIGGER controls .
REV . JAN 1974
Trigger Controls
The input signal may have a wide variety of shapes
and
amplitudes, many of which are unsuitable as
delay-initiating
triggers . For this reason, these
signals are first applied to a
trigger circuit where they are
converted to pulses of
uniform amplitude and shape .
This makes it possible to
start the delay
with a pulse that has a constant size,
eliminating
variations of the delay circuit operation caused
by
changing input signals . The TRIGGER controls
provide
a means to select the signal
source, filter unwanted
frequencies, and start the delay
at any voltage level on
either slope of the waveform
.
Triggered
Light
The
TRIG'D light provides
a convenient indication
of
the
Trigger circuit condition . If
the TRIGGER controls
are
correctly set
and an adequate
signal is applied, the
TRIG'D
light is on
. If the TRIG'D light is
off, no delay
interval is
started .
The cause might be an
incorrectly set
TRIGGER
control, low
signal amplitude, or
a signal repetition
rate
outside
the usable frequency
range . This feature can
be
used as
a general indication of
correct triggering when
there
is
no display on the CRT
.
The
Delay Interval
Pedestal and
Z-Axis Blanking
displays also
aid in obtaining
correct
TRIGGER control
settings . See the
discussion of these
features under
Output Signals to
Mainframe for further
information .
NOTE
When
the 71311 is used
in the EVENTS count
mode,
the EVENTS START
TRIGGER affects the
output
of
the Trigger circuit
but has no
effect on the
TRIG'D light .
Trigger Coupling
The TRIGGER pushbuttons located below the COUP-
LING title select the method in which the input signal is
connected to the Trigger circuit . Each position permits
selection or rejection of various frequency components of
the signal used to trigger the delay start .
AC . In this
position of
the COUPLING switch, the DC
component of the input signal is blocked . Signals with
low-frequency components below about 30 hertz are
attenuated . In general, AC COUPLING can be used for
most applications . However, if the signal contains unwanted
frequency components or if the delay is to be triggered at a
low repetition rate or DC level, one of the other switch
positions will provide better results .

The triggering point in the AC position depends upon
the average voltage level of the input signal
.
If the input
signal occurs randomly, the average voltage level will vary,
causing
the
triggering point
to vary also . This shift of the
triggering point
may be enough so it is impossible to
maintain
a stable delay start ; in such cases, use DC
coupling .
AC LF REJ . In this position, DC is rejected and
low-frequency input signals below about 30 kilohertz are
attenuated . Therefore, the delay is triggered only by the
higher-frequency components of the input signal . The AC
LF REJ position is particularly useful for providing stable
triggering if the input signal contains line-frequency
components .
AC HF REJ . This COUPLING switch
position passes
all low-frequency signals
between about
30 hertz
and 50
kilohertz . DC is rejected and signals above 50 kilohertz are
attenuated . This position is useful to trigger the delay from
the low-frequency components of a complex waveform .
DC . The DC position can
be used to
provide
stable
triggering from low-frequency or low-repetition-rate signals
which would be attenuated in other modes . It can also be
used to trigger the delay when the input signal reaches a DC
level
selected by the setting of the SLOPE/LEVEL control .
When
triggering
from the internal source, the setting of the
vertical
unit position control(s) affects the DC triggering
point .
Trigger Source
The TRIGGER pushbuttons located below the SOURCE
title select the source of the signal connected to the Trigger
circuit .
INT .
In this position, the input signal is derived from
the associated vertical unit . Therefore, the 71311 must be
installed in a horizontal compartment to use the internal
source . Further selection of the internal signal may be
provided by the vertical unit and mainframe ; see the
instruction manuals for these instruments for further
information .
LINE . In this SOURCE switch position, a sample of the
power-line voltage from the mainframe is connected to the
Trigger circuit . Line triggering is useful when the input
signal is time related (multiple or submultiple) to the line
frequency . It is also useful for providing stable triggering
from a line-frequency component in a complex waveform .
(K
REV . JAN 1974
EXT . A signal connected to the EXT TRIG IN
connector can be used to trigger the delay in the EXT
position of the SOURCE switch . An external signal can be
used to provide a trigger when the internal signal amplitude
is too low .
EXT =10 .
Operation in this position is the same as
described for EXT except the external signal is attenuated
10 times . Attenuation of high-amplitude signals is desirable
to extend the range of the LEVEL control .
Trigger Slope/Level
The TRIGGER SLOPE/LEVEL controls determine the
slope and voltage level of the input signal where the Trigger
circuit responds . Generally,
the best point on a waveform
for triggering the delay is where the slope is steep, and
therefore usually free of noise . Assuming a sine-wave input
waveform, the steepest slope occurs at the zero-crossing
point . This is the point selected for triggering when the
LEVEL control is set to 0 (center) . A more positive or
negative point on the waveform is selected as the LEVEL
control is rotated
clockwise or counterclockwise respec-
tively
from 0 (towards
+ or
- symbols on panel)
.
Before setting the TRIGGER LEVEL, the desired
SLOPE, MODE, COUPLING, and SOURCE
should be
selected . Then adjust the LEVEL control
so
the
delay starts
from the desired point .
Events Start Trigger
Operating
Instructions-71311 Operators
The Events
Start Trigger
is used
in
the
EVENTS count
mode to differentiate between the event that starts the
delay and the events
being
counted .
The EVENTS START TRIG IN connector provides the
input to the events-start signal . The EVENTS START
TRIGGER SLOPE and LEVEL controls select the ampli-
tude point and slope on the input signal where the delay is
triggered .
Generally, the best point on a waveform for triggering
the delay is where the slope is steep, and therefore usually
free of noise, Assuming a sine-wave input waveform, the
steepest slope occurs at the zero-crossing point . This is the
point selected for triggering when the LEVEL control is set
to 0 (center) . A more positive or negative point on the
waveform is selected as the LEVEL control is rotated
clockwise or counterclockwise respectively
from 0 (towards
+ or - symbols
on panel)
.

Operating Instructions-7D11 Operators
Delay Time
or Events
The
DELAY TIME OR
EVENTS control
selects the
digital
delay time in the TIME
count mode, and the
number
of events
counted in the
EVENTS count mode .
The delay
time in
milliseconds, or integer
number of events,
selected
is displayed
on the CRT readout
.
This control is a
spring-return-to-center
control that
increases or decreases the
count at which a
delayed pulse
will occur . The direction
of rotation determines
whether
the
count is increased or
decreased . The rate at
which the
count increments is
determined by the magnitude
of
rotation . After either extreme
of the range is reached,
the
next count starts from the
other end of the range .
For
example, if the delay time is
increased above 1000
.0000 ms
(one second), the count
will go to 0 .0001 ms .
Conversely, if
the delay time is
decreased past 0 .0001 ms, the
count will
go to 1000 .0000 ms .
Fine Delay
The FINE
DELAY (ns) dial selects
analog delay time
from zero to
100 nanoseconds
in the TIME count mode .
This
one-turn control provides
added resolution
to the
digital delay time selected
by the DELAY
TIME OR
EVENTS control . The delay
time selected by
the FINE
DELAY (ns) dial is read
from the calibrated
knob as the
analog delay time is not read
out on the CRT
. Each minor
division on the dial
represents two nanoseconds
.
B Sweep Delay
Mode
The B SWEEP
DELAY MODE switch
permits the 7D11,
under specific
conditions, to select the
delay mode of a
compatible time-base
unit . To use this feature,
the 7D11 is
installed in the A
Horizontal compartment and
the time-
base in the B
Horizontal compartment of
a four-plug-in
mainframe .
With this arrangement, the time-base
unit can
be controlled
through the mainframe
interface . Some dual
time-base
units are not compatible
with this feature ; see the
time-base
unit instruction manual for further
information .
INDEPENDENT
. The 7D11 and
the time-base unit
operate independently
.
B STARTS
AFTER DELAY . The
time-base unit pro-
duces
a sweep immediately
following the
selected delay
interval . This provides
the same mode of
operation as
triggering the time-base
unit with the
delayed trigger
output .
B
TRIGGERABLE
AFTER DELAY . The
time-base unit
produces
a sweep after
the first trigger
pulse is received
following the selected
delay interval .
This mode of opera-
tion provides
a stable
display of a signal
having time jitter .
Precision time measurements
cannot be
made in this mode
because the actual
delay time is only
partially dependent
on
the delay interval of
the 7D11 .
OUTPUT
SIGNALS
Front-Panel
Output Signals
General . The
Delay Interval and Delayed
Trigger out-
puts are available
at the front-panel DLY
INTERVAL OUT
and DLY'DTRIG
OUT connectors
respectively . These
outputs can be used
to control other
equipment during or
immediately
following the delay
interval . To maintain
the
rise and
falltime characteristics of
these signals, connection
to
other equipment should be made
with 50-ohm
coaxial
cable ; the
output of the cable
should be terminated
in 50
ohms .
DLY INTERVAL
OUT . This output
is
a
positive-going,
rectangular waveform
coincident with
the generated delay
interval . In time
mode DLY INTERVAL
OUT is approxi-
mately 20-30
ns shorter than
indicated delay time
because
of
internal propagation delays
and trigger
recognition time .
In the event mode,
the DLY INTERVAL
OUT is within
30 ns of actual delay,
usually
C
10
ns
.
DLY'D
TRIG OUT . This
signal is generated as
a
positive-going
rectangular pulse
coincident with
the end of
the delay
interval .
The front-panel output
signals are shown in Fig 1-3,
along with the input
signal . The input signal, Fig . 1-3(A),
is
comprised of one-
and ten-microsecond time markers .
The
7D11 is set for
a
0
.0038-millisecond delay time
after
triggering on the
ten-microsecond markers . The
resultant
Delay Interval and
Delayed Trigger outputs are shown
in
Fig . 1-3(B) and
(C), respectively . The
characteristics of
these
output signals are given in the
Specification section .
Fig . 1-3 .
Display showing time relationship
of : (A) Input signal
to the front-panel, (B)
Delay Interval,
and
(C)
Delayed
Trigger
outputs .
REV B, SEP 1978

Output Signals to Mainframe
General . Signal outputs are provided to the mainframe
via the interface connector . The following discussion
describes these signals and the operating conditions neces-
sary for their use .
Delay-Interval Pedestal . This output provides an on-
screen display of the approximate delay interval . To view
the pedestal display, the 71311 must be installed in a
vertical plug-in compartment and be selected by the
mainframe Vertical Mode switch . The position of this
display is fixed near the vertical center of the graticule area .
The Delay-Interval Pedestal display is shown in Fig . 1-4 (A) .
The input signal, shown in Fig . 1-4 (B), is comprised of one-
and ten-microsecond time markers . The 71311 is set to
trigger on the ten-microsecond markers, and to generate a
0 .0038-millisecond delay time .
Delayed Trigger
. The Delayed Trigger output provides an
internal
Delayed Trigger source for a time-base
unit . A
time-base unit can be triggered
from the Delay Trigger
when the 71311 is in a vertical
compartment . To use this
output, the 71311 must be
selected by the appropriate
trigger source switch
(mainframe) .
Z-Axis Blanking . Z-axis
blanking provides an on-screen
display of the
approximate delay interval . This is ac-
complished by blanking
out the CRT display during the
delay interval . Z-axis
blanking can be obtained with the
71311 installed in any plug-in
compartment . The Z-axis
blanking display is selected by a
slide switch located inside
the unit (on the left side ;
see Fig . 1-6) .
Fig . 1-4 . Waveform display of :
(A)
Delay Interval Pedestal ;
(B)
input signal .
REV . JAN 1974
Operating Instructions-71311 Operators
A . 71311 triggered incorrectly
.
B .7D11 triggered correctly .
Fig . 1-5 .
Use of Delay-Interval
Pedestal
display to indicate : (A)
Incorrect triggering, and ; (B) correct triggering .
Fig . 1-6 . Location of Z-Axis Blanking Display switch (on left side
of unit)
.
The switch position towards the rear of the unit selects
Z-axis blanking .

Operating
Instructions-7D11
Operators
Sweep Delay
NOTE
At faster
sweep speeds
(100 nsldiv or
faster) care
must
be taken when
interpreting CRT
display because
relative propagation
delays through the
7D11 and
vertical amplifier
plug-ins are not
the same . This
appears as a
relative time shift
between delay
interval
pedestal or Z-axis
blanking
generated by
the 7D 11
and
the signal(s) viewed
through a vertical
amplifier
on
the CRT .
Changing the TRIG SOURCE
between
INT and EXT or EXT
-
10 will vary
this apparent
time
shift due to
differences in propagation
delays of
the signal path .
OPERATING
MODES
The 7D11
can be used to delay
the start of a sweep
for a
selected time
interval following the
receipt of a
trigger .
Low-jitter
sweep delay can
be used for accurate
time, jitter,
and
stability measurements
. Sweep delay can also
be used
to select a portion
of a complex signal for display .
A sweep
is delayed by
triggering the sweep from the
Delayed Trigger
output of
the 7D11, rather than
from the signal to
be
displayed .
Several methods of
coupling the Delayed
Trigger
to the
sweep are
possible, depending on the
application .
These
methods are
described in the following
discussions .
B Sweep
Delay Mode Switch . The
sweep produced by a
time-base unit
can be controlled
and delayed by a 7D11 via
the mainframe
interface and the
B SWEEP DELAY MODE
switch . To use
this mode of sweep
delay, the 7D11 must be
installed in the
A Horizontal
compartment and the time-
base unit in
the B Horizontal
compartment of a four-plug-in
mainframe . For
further information,
see B Sweep
Delay
Mode .
NOTE
The logic levels
provided to
the 7D11 from the
mainframe
are designed to
control a time-base
unit
delaying
sweep . For this
reason, the 7D11
might
become
locked out (no
output) when the
setting of
either the
B-Sweep unit
Time/Division
switch or the
B SWEEP
DELAYMODE
switch is
changed . If this
occurs, a
delayed sweep
will not be produced
. To
reset the
7D11, set the B
SWEEP DELAY
MODE
switch
first to INDEPENDENT,
then
select the
desired
delay mode .
REV . JAN 1974
Internal
Trigger . The sweep
produced by a
time-base
unit
in a horizontal
compartment can be
internally
triggered
from a 7D11 in a
vertical compartment
. To use
this sweep
delay mode, the
7D11 must be
selected by the
mainframe
trigger source switch
. Delaying
a time-base
sweep from
the internal
source can be used with
the units
installed
in either a three-
or four-plug-in
mainframe .
External
Trigger Source . A sweep
can be delayed
by
external triggering
from the DLY'D
TRIG OUT
connector .
This method can
be used with any
triggered sweep .
Echo Delay
Time Mode
The Echo delay
time mode provides a
CRT readout
of
the "one-way-trip"
time, or one-half of
the generated
delay time . This
mode of operation is
selected for use by an
internal switch (on
left side of unit, see Fig
. 1-7) .
In the
Echo mode, the
delay time is selected
by the DELAY
TIME
OR
EVENTS
control in 200-nanosecond
increments .
An
insertion delay of about
160 nanoseconds
in this
mode
requires adding
analog delay
time to the first delay
increment to
obtain a 200-nanosecond
delay interval .
This
can be accomplished
by displaying the
DELAY INTERVAL
OUT and
setting the FINE DELAY
dial for a
total delay
interval of
200 nanoseconds as
measured on the
graticule .
Fig
.
1-7 .
Location of Normal-Echo
Delay Time Mode switch
(on
left side of unit) . Set the
switch towards the front of the
unit to
select Normal Mode .

General
The following information
describes the procedures and
techniques for making measurements
using a 71311 Digital
Delay unit . These applications
are not described in detail,
since each application
must be adapted to the requirements
of the individual
measurement . This instrument can also be
used
for many applications which are not described
in this
manual . Contact your local TEKTRONIX
Field Office or
representative for assistance in making specific
measure-
ments with this instrument .
Delayed-Sweep Time Measurements
The 71311 can be used to delay
the start of a sweep to
make accurate time measurements
. The following pro-
cedure describes one method of
determining the time
difference between two pulses displayed on
the same trace .
This application can also be
used to measure time
difference between two
signal sources or to measure the
time duration of
a single pulse . Other methods of delayed-
sweep time measurements with the 71311
are described
under General Operating Information
.
1 . Within the 71311,
set the Z-Axis switch to Z to select
the Z-Axis Blanking
display .
2 . Install the
71311, time-base unit, and amplifier unit in
the
A Horizontal, B Horizontal, and vertical compartments
respectively of a four-plug-in mainframe .
3 . Connect the signal to be
measured to the amplifier
unit .
4 . Set both the 71311 and time-base
unit to trigger from
the signal source .
5 . Set the 71311 for
TIME INT CLOCK operation in the
INDEPENDENT mode .
6 .
Set the time-base unit sweep rate to view
several
cycles of the applied signal .
7 . Set the 71311 TRIGGER controls to trigger the
delay
start . The TRIG'D indicator will light when
a trigger is
being produced .
APPLICATIONS
Operating Instructions-71311
Operators
8 . Turn the DELAY
TIME OR EVENTS control clock-
wise to produce a
blanked display . Set this
control to
position the
blanked portion to the left of the
first pulse .
9 . Set the 71311
B SWEEP DELAY MODE switch to
B
STARTS AFTER
DELAY .
10 . Set the time-base unit for
a sweep rate 100 times
faster than its
original sweep rate .
11 . Set the
DELAY TIME OR EVENTS and
FINE
DELAY controls to
move the first pulse to the
center
vertical line . Note the
total delay time read out on the
CRT
and the FINE
DELAY dial .
12 . Set
the DELAY TIME OR EVENTS
and FINE
DELAY
controls to position the second pulse
to the same
point .
Again note the total delay time .
13 . Subtract the first delay
time reading from the
second . This gives the time
interval between pulses .
Displaying Complex Signals
With Delayed Sweep
Complex signals often consist of a
number of individual
events of differing amplitudes .
Since
the
time-base trigger
circuits are sensitive only to changes
in signal amplitude, a
stable display can normally be
obtained only when the
sweep is triggered by the event(s)
having the greatest
amplitude . However, this may
not produce the desired
display of a lower amplitude
event which follows the
triggering event . The 71311 provides
a means of delaying the
start of the sweep by a
selected amount following the
event
which triggers
the 71311 . Then, the part of the
waveform
which contains the information of
interest can be
displayed . The following
procedure describes one method
of using the 71311 to display
complex signals .
1 . Within the 71311,
set the Z-Axis switch to Z to select
the Z-Axis Blanking
display .
2 .
Install the 71311, time-base
unit,
and
amplifier unit in
the A Horizontal, B Horizontal, and
vertical compartments
respectively of a four-plug-in
mainframe .
3 .
Connect the signal to be measured
to the amplifier
unit .

Operating Instructions-71311 Operators
4 . Set the 71311
and the time-base unit to trigger from
the signal source .
5 . Set the 71311 for TIME
INT CLOCK operation in the
INDEPENDENT mode .
Fig . 1-8 . (A) The circled portion of this display cannotbe viewed
at a faster sweep rate ; (B) Display blanked during delay interval ;
(C)
Area of interest displayed at faster sweep rate .
1-10
6 . Set the time-base
unit to view several cycles of the
applied signal
.
7 . Set the 71311 TRIGGER controls to trigger the delay
start . The TRIG'D indicator will light when a trigger is
being produced .
8 . Turn the DELAY
TIME
OR EVENTS
control clock-
wise to blank
that portion
of the
display preceding the area
of interest . The blanked portion of the
display represents
the delay interval .
9 . Set the B SWEEP DELAY MODE switch to B
STARTSAFTER DELAY . Set the time-base to a sweep
rate which displays the area of interest .
Example . Fig . 1-8(A) shows a complex waveform as
displayed on the CRT . The circled portion of the waveform
cannot be viewed in any greater detail because the sweep is
triggered by the larger amplitude pulses at the start of the
display ; a faster sweep rate moves this area of the waveform
off the viewing area . Fig . 1-8(B) shows the display blanked
out during the delay interval (delay interval is area between
the arrows) . Fig . 1-8(C) shows the sweep
triggered after the
delay at a faster sweep rate to display the area of interest
.
Pulse Jitter Measurements
In some applications,
it is necessary to measure the
amount of jitter on the
leading edge of a pulse, or jitter
between pulses .
Use the
following procedure :
1 . Install an amplifier
unit and the 71311 in the vertical
compartments of a mainframe
. Install a time-base unit in a
horizontal compartment .
2 . Set the mainframe for a
dual-trace vertical display
mode .
3 . Connect the
signal to the amplifier unit and to the
71311 EXTTRIG
IN connector .
4 . Set the time-base
unit to trigger on the applied signal
at a sweep rate
which displays the complete waveform .
A

5 . Set the 7D11 for TIME
INT CLOCK count mode . Set
the TRIGGER SOURCE
to EXT . Set the TRIGGER
LEVEL control for a
triggered condition as indicated by
the TRIG'D indicator
light .
6 . Set the
DELAY TIME OR EVENTS
control to select
a delay interval which ends just before the
pulse to be
measured .
7 . Connect the
DLY'D TRIG OUT to the
time-base
external trigger
input . Set the time-base to trigger from the
external source .
8 . Set the time-base
unit for a sweep rate which
displays
just the pulse or
leading edge to be measured .
9 . Pulse
jitter is shownby horizontal
movement of the
pulse (take
into account inherent jitter of
7D11) . Measure
the amount of horizontal
movement directly
from the CRT
graticule .
Operating
Instructions-7D11 Operators
Example . Assume the horizontal movement is 0 .2
division at a 200-nanosecond sweep rate (see
Fig .
1-9)
. The
amount of pulse jitter is then 0 .2 X 200
nanoseconds = 40
nanoseconds .
Fig . 1-9 . Measuring
pulse jitter .
DOrr
41 1
V2
&
I
~
I
.
I
t
~I
Jitter

Introduction
The electrical characteristics listed in Table
2-1 are valid over the stated environmental range for instruments calibrated at
an ambient temperature of +20 ° C to +30 ° C,
and after a 20-minute warmup unless otherwise stated .
TIME DELAY
Digital Delay-Selected by front-panel DELAY
TIME OR EVENTS
control . Range is 100 nanoseconds
to one second in
100-nanosecond increments
in Normal mode ; 200 nanoseconds
to two seconds
in 200-nanosecond increments in Echo mode .
Normal/Echo modes
are selected by internal Mode switch .
Analog
Delay-Selected by front-panel FINE DELAY (ns) control .
Range is continuously
variable from zero to at least 100
nanoseconds ;
accuracy is within two nanoseconds of indicated
delay
time ; resolution is one nanosecond or less .
Jitter with Internal
Clock-2 .2 nanoseconds or (delay time X 10 -7 ),
whichever is
greater .
Insertion Delay in Normal Mode-Zero within two
nanoseconds .
Insertion Delay in Echo Mode-Less than
160 nanoseconds,
adjustable to 200
nanoseconds within four nanoseconds with
FINE DELAY
dial .
Recycle Time-Not greater than 575 nanoseconds .
Time Base-500-megahertz
oscillator, phase locked to
internal or
external clock, as selected by COUNT MODE switch
. Internal
clock (TIME INT CLOCK) is a five-megahertz crystal
oscillator .
Accuracy is within 0 .5 part per million from
0 ° C to +50 ° C ;
long-term drift is one part or less
in 10 7 per month .
Oi 7
External clock (TIME EXT 1 MHz) requires a one-megahertz
signal applied to EXT 1 MHz IN connector . Input requirements
are : Frequency, one megahertz within 1% to insure phase
lock of
500-megahertz oscillator ; amplitude, at least 400 millivolts RMS
sinewave or pulse with 10% to 90% duty cycle . AC input
coupling . Input impedance is 50 ohms t2% . Maximum input
voltage is 5 volts RMS (DC
+
peak AC must not exceed 500
volts) .
TRIGGERING
Source-Selected by front-panel SOURCE switch .
INT-Internal from associated
vertical unit (71311 installed in
horizontal compartment)
.
LINE-Internal from power source
(AC) .
SPECIFICATION
TABLE 2-1
ELECTRICAL
1 Triggering frequency range is also affected by the bandwidth limits of the vertical plug-in unit used
.
REV . JAN 1974
TRIGGERING
(cont)
Section 2-71311 Operators
EXT-External from front-panel EXTTRIG IN connector .
EXT
-
10-External divide by ten (10X input signal
attenuation)
.
Coupling-Selected by front-panel COUPLING switch .
AC-Capacitive coupling .
AC LF REJ-Capacitive
coupling, low-frequency reject .
AC HF REJ-Capacitive coupling, high-frequency reject .
DC-Direct coupling .
Polarity-Selected by
front-panel TRIGGER LEVEL/SLOPE
control . Time delay
can be triggered from positive-going or
negative-going portion of
trigger signal .
Internal Trigger Sensitivity )
AC-0 .3 division of deflection, minimum, 30 hertz to 10
megahertz ; increasing to 1 .0 division at 50 megahertz .
AC LF REJ-0 .3 division of deflection, minimum, 30 kilohertz
to 10 megahertz ; increasing to 1 .0 division at 50 megahertz . Will
not trigger on sinewaves of three divisions or less below 120
hertz .
AC HF REJ-0 .3 division of deflection, minimum,30 hertz to
50 kilohertz .
DC-0 .3 division of deflection, minimum, DC to 10 megahertz ;
increasing to 1 .0 division at 50 megahertz .
Slope-0 .5 volt/nanosecond or greater
for
specified jitter and
accuracy ; slower
risetime signals
will
trigger
the instrument with
reduced accuracy and increased jitter .
External Trigger Sensitivity (SOURCE switch set to EXT ; triggering
signal
requirements increased 10 times for EXT
-10
position) .
AC-150
millivolts, minimum, 30 hertz to 10 megahertz ;
increasing to
500 millivolts at 50 megahertz .
AC LF REJ-150
millivolts, minimum,
150
kilohertz to 10
megahertz ; increasing to 500 millivolts at 50 megahertz .

Specification-71311 Operators
AC
HF REJ-150 millivolts, minimum,
30 hertz to 50
kilohertz .
DC-150
millivolts, minimum,
DC
to
10 megahertz
; increasing
to
500 millivolts at 50 megahertz .
External Trigger Input
EVENTS DELAY
Delay Range-One to 10 7 events .
Delay Increment-One event .
Insertion Delay-35 nanoseconds t five nanoseconds .
Recycle Time-500 nanoseconds or less .
Maximum Events Frequency-50 megahertz or greater .
Events Start Triggering
2-2
TRIGGERING (cont)
Maximum Input Voltage-500 volts (DC
+peak AC),
500 volts
peak-to-peak AC at 1 kHz or less .
Input Resistance-One megohm within 2% .
Input
Capacitance-20 picofarads within two picofarads .
LEVEL Range-At least +1 .75 volts
to -1 .75 volts in EXT, at
least +17 .5 volts to -17 .5 volts in EXT
-
10 .
Source-External
only from EVENTS START TRIG IN
connector .
Coupling-DC .
Maximum Input Voltage-150
volts
(DC
+peak
AC) .
Sensitivity-40 millivolts, minimum, 30 hertz to four megahertz ;
increasing to 100 millivolts, four megahertz to 20 megahertz ;
increasing to 250 millivolts, 20 megahertz to 50 megahertz .
Input Resistance-Approximately one megohm
TABLE 2-2
ENVIRONMENTAL CHARACTERISTICS
Refer to the Specification for the associated oscilloscope
.
TABLE
2-1 (cont)
REV . JAN 1974
EVENTS DELAY (cont)
Input Capacitance-Approximately 20 picofarads
LEVEL Flange-At least
+
three volts to - three volts .
OUTPUT SIGNALS
Delayed Trigger-Positive-going, rectangular pulse available at
front-panel DLY'D TRIG OUT connector .
Amplitude-Two volts or greater into open circuit ; one volt or
greater into 50-ohm load .
Risetime with 50-Ohm Load-Two nanoseconds or less .
Falltime with 50-Ohm Load-Five nanoseconds or less .
Pulse Width-200 to 250 nanoseconds .
Delay Interval-Positive-going, rectangular waveform available at
front-panel DLY
INTERVAL
OUT connector
.
Amplitude-Two volts or
greater
into open circuit ; one volt or
greater into 50-ohm load .
Rise and
Falltime with 50-Ohm Load-Five
nanoseconds or
less
.
Accuracy-Delay interval pulse width is equal to the generated
Events Delay within 30 nanoseconds and equal to the generated
Time Delay less 20 to 30 nanoseconds .
Relative Timing of Delayed Trigger and Delay Interval Output
Signals-Leading edge of Delayed Trigger pulse is coincident with
falling edge of Delay Interval pulse within two nanoseconds .
Pedestal Display-CRT analog display of the delay interval, available
when 71311 is used in vertical compartment . (Pedestal Display
pulse ends coincident with Delayed Trigger start .)
De-Intensified Display-Signal to
dim
CRT display during delay
interval . (De-Intensified Display selected by internal switch .)
TABLE 2-3
PHYSICAL
Size

Fits
all
7000-series plug-in
compartments
.
Weight

2 Pounds 11 Ounces (1219 grams)