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)
.