Tektronix 3177 User manual

INSTRUCTION
MIAN UAL
TYPE 3177
SAMPLING
SWEEP UNIT
Tektronix, Inc.
S.W, Millikan Way @ P.O.Box 500 @ Beaverton, Oregon @ Phone MI 4-0161 @ Cables: Tektronix
070-333 763

Type 3177
WARRANTY
All Tektronix instruments are warranted
against defective materials and workman-
ship for one year. Tektronix transformers,
manufactured in our own plant, are war-
ranted for the life of the instrument.
Any questions with respect to the war-
ranty mentioned above should be taken up
with your Tektronix Field Engineer.
Tektronix repair and replacement-part
service is geared directly to the field, there-
fore all requests for repairs and replace-
ment parts should be directed to the Tek-
tronix Field Office or Representative in your
area, This procedure will assure you the
fastest possible service. Please include the
instrument Type and Serial number with all
requests for parts or service.
Specifications and price change priv-
ileges reserved.
Copyright ©) 1963 by Tektronix, Inc.,
Beaverton, Oregon. Printed in the United
States of America. All rights reserved.
Contents of this publication may not be re-
produced in any form without permission
of the copyright owner.

http://manoman.sghill.com

Type 3177
TYPE
3777
SAMPLING
SWEEP
nes
VARIABLE
SITION
TIME/DIV.
oO
ADJ
5
uSEC
2
1
HORIZ.
DOTS
UNCAI
MAG
PER
DIV,
@
x10
é
TRIGGER
ee
=
sensiriviry
|
MANUAL SCAN
OR EXT ATTEN,
SWEEP
MODE
NORMAL
pds han
MANUAL
RECOVERY
TIME
SINGLE
DISPLAY
RESET
SWEEP
OUTPUT
™’ iv, OV
(10 KA)
The Type 3T77 Sampling Sweep Unit.

SECTION 1
CHARACTERISTICS
General Information
The Type 3177 Sampling Sweep Plug-In Unit is designed
for use with all Tektronix Type 560-Series Oscilloscopes
except the Type 560 and Type 565. The Type 3177 is
equipped to drive a digital unit in the Type 567 Readout
Oscilloscope.
The Type 3177 must be inserted into the right-hand plug-
in compartment of the oscilloscope and a vertical sampling
plug-in unit (such as the Type 3876) must be inserted into
the left-hand plug-in compartment to complete the composite
sampling system.
Equivalent Sweep Rates
Variable in fifteen steps from 0.2 nsec/div to 10 usec/div
(0.02 nsec/div to 1 «sec/div with HORIZ. MAG. switch at
X10). Accuracy typically within 1%, and in all cases within
3% of the indicated sweep rate with HORIZ. MAG. switch
at X1. With HORIZ. MAG. switch at X10, accuracy is within
5%. The sweep rate at any given setting of the TIME/DIV.
switch can be increased by about 3 times with the VARIABLE
control.
Samples Per Division
10/div or 100/div.
External Triggering
Pulse Repetition Rate: Up to 3 & 10° pulses/second (300
megacycles}. Trigger circuitry counts down to a maximum
sampling rate of about 100 kilocycles/second.
Minimum Pulse Amplitude and Width: 10 millivolts, peak-
to-peak, with at least a 2-nanosecond width. With larger
pulse amplitudes (up to 800 millivolts) minimum pulse width
decreases. Overload damage occurs at 5 volts and above.
Sinusoidal Frequency Range: 100 kilocycles to 300 mega-
cycles; 10 to 800 millivolts amplitude.
Low Frequency Response (to trigger pulses}: 300 kilo-
cycles (3-db down point).
Jitter: 50 picoseconds or 0.001% fast ramp duration,
whichever is greater (for 50-millivolt amplitude, 2-nano-
second width pulses with a repetition rate less than 10
megacycles}, Jitter increases as pulse amplitude and/or
width decreases when repetition rates exceed 10 mega-
cycles.
Internal Triggering
Same characteristics as External Triggering but modified
by vertical plug-in unit used. When used with the Type
3876, all characteristics are the same except five times more
amplitude is required at the Type 3876 INPUT A or INPUT
B connectors and the low-frequency response is 3-db down
at 450 kilocycles.
External Sweep Input
Sensitivity: Adjustable from 5 to 25 volts per horizontal
division (50 volts required for a full 10-division display,
250 volts maximum).
Input Resistance: 28 to 100 kilohms, depending on setting
of EXT. ATTEN. control.
Sweep Output
Amplitude: 1 volt/div from a source impedance of 10
kilohms.
Delay
Variable through 100 nsec.
Mechanical
Construction: Aluminum alloy chassis.
Finish: Photo-etched, anodized front panel.
Weight: 5 pounds.
Accessories Supplied With the Type 3177
Tektronix Part
Number
2 500, 10-nsec cables (017-501)
RG-58/AU with General Radio
connectors.
1 Adapter, BNC-to-GR (017-025)
1 Adapter, male BNC-to-female (103-032)
UHF
2 Attenuators, 1OXT, 509 with (017-044)
GR connectors
2 Instruction manuals (070-333}
1-1

Operating Instructions — Type 3177
f
TYPE
31777
SAMPLING
SWEEP
VARIABLE
Beet
eye
TIME/DIV.
GAIN
ADJ.
5
nSEC
2
1
HORIZ.
DOTS
UNCAL
MAG.
PER
DIV.
.
2 @
X10 | 10
7—- TRIGGERS
SENSITIVITY
x1
MANUAL SCAN
OR EXT. ATTEN.
SWEEP MODE
MANUAL NORMAL
= 100
nSEc RECOVERY TIME
SINGLE
DISPLAY ]
RESET
/ = y
_ + EXT. @
‘) SWEEP SWEEP ~
j INPUT OUTPUT
iv/DIV.
(10 Kn) : . j J
SERIAL 7
'
TEKTRONIX. INC. PORTLAND, OREGON, U.S.A.
Fig. 2-1. Front panel of the Type 3177.
2-0

SECTION 2
OPERATING INSTRUCTIONS
Introduction
The Type 3177 Sampling Sweep Plug-In Unit (with a ver-
tical sampling plug-in unit) equips any Type 561A, RM561A,
564, 567, or RM567 Oscilloscope for sampling-type opera-
tion. Front-panel operation of the Type 3177 resembles that
of non-sampling (real time} time-base units.
This section of the manual covers the operation of the
front-pane!l controls and connectors (see Fig. 2-1).
Function of Front-Panel Controls and Connectors
POSITION Conirol
Positions the display horizontally.
HORIZ. MAG. Switch
Selects X1 or X10 horizontal display magnification.
DOTS PER DIV. Switch
Selects either 10 or 100 samples per division.
SWEEP MODE Switch
NORMAL position: Permits automatic dot-by-dot advance-
ment through the oscilloscope display.
SINGLE DISPLAY position: Permits one display after the
RESET button is pressed. (Useful for photographing the
display.)
-++EXT. SWEEP INPUT position: Permits control of the
scanning function with an external voltage.
MANUAL position: Permits manual dot-by-dot advance-
ment through the display by turning the MANUAL SCAN
control. (For recorder applications.)
MANUAL SCAN OR EXT. ATTEN. Control
Provides an internal semi-intergated, variable voltage
for scanning when the SWEEP MODE switch is in the
MANUAL position, and serves as a variable attenuator
when the SWEEP MODE switch is in the +EXT. SWEEP
INPUT position.
+EXT. SWEEP INPUT Connector
For applying an external scanning voltage. Sensitivity
variable from 5 to 25 volts/div; input impedance variable
from 28 to 100 kilohms. Maximum input voltage 250
volts, peak.
SWEEP OUTPUT Connector
For monitoring the sweep voltage. (Output variable trom
about 3.5vde to about 15 vde; I-volt change equals 1
division of horizontal deflection with 10-kilohm source
impedance.)
TRIG. OUT Connector
For externally monitoring a positive trigger pulse after
each trigger event. The pulse width is at least 0.4 micro-
second at 0.15-volt amplitude.
®
EXT. INPUT Connector
For applying an external trigger. Input impedance: 50
ohms shunted by 12 microhenries.
INT.-EXT. Switch
Selects either an internal trigger (INT. position) from
the vertical plug-in unit, or an external trigger (EXT.
position) from the EXT. INPUT connector, and determines
whether triggering takes place on the positive (+) or
negative (—) slope of the input signal.
DELAY Control
Allows the start of the display to be varied through 100
nanoseconds with respect to the trigger event.
TRIGGER SENSITIVITY Control
Varies the sensitivity of the triggering circuit. Also causes
the trigger circuit to free-run when turned fully clockwise.
RECOVERY TIME Control
Varies the holdoff time of the trigger circuits to assure
stable triggering.
TIME/DIV. Switch
Sets the equivalent sweep rate of the display.
VARIABLE Control
Varies the sweep rate (uncalibrated) between TIME/DIV.
steps. The equivalent sweep rate at any given setting of
the TIME/DIV. switch can be increased about 3 times.
GAIN ADJ. (a front-panel screwdriver adjustment)
Adjusts gain to match oscilloscope deflection factor.
Installing the Type 3177 into the Oscilloscope
CAUTION
Turn off oscilloscope power while inserting or
removing plug-in units. Otherwise, power supplies
in the oscilloscope may fail to regulate momen-
tarily as plug-in units are removed or replaced.
The Type 3177 is designed to drive the horizontal de-
flection plates of the crt; it must be used in the right-hand
plug-in compartment. When inserting the Type 3177 into the
plug-in compartment, first check that the latch at the bottom
of the front panel is in a horizontal position. Then make
sure the interconnecting plugs are properly aligned. The
Type 3177 should then slip easily into the compartment.
Once the plug-in has been properly seated, turn the
aluminum knob of the plug-in unit a few turns clockwise
until it is hand-tight. To remove the plug-in unit, turn the
aluminum knob counterclockwise as far as it will go and
pull the plug-in unit straight out.
2-1

Operating Instructions — Type 3177
Displaying a Signal
The following procedure covers first-time operation of
the Type 3177. It will enable you to display a signal on
the ert. Use this procedure in conjunction with the vertical
plug-in unit instructions.
1. Set the Type 3777 front-panel controls as follows:
POSITION Midrange
TIME/DIV. 5 nSEC
VARIABLE CALIB.
DELAY Fully counterclockwise
TRIGGER SENSITIVITY Fully counterclockwise
HORIZ. MAG. Xl
DOTS PER DIV. 100
SWEEP MODE NORMAL
INT.-EXT. INT. {Set to polarity of
signal you wish to observe)
RECOVERY TIME
2. Insert the Type 3177 into the right-hand plug-in com-
partment of the oscilloscope and the vertical sampling plug-
in unit into the left-hand compartment. Turn on the oscillo-
scope power and allow a few minutes for warm-up.
Fully counterclockwise
3. Apply the signal you wish to observe to the input
connector of the vertical sampling plug-in unit. (Note: Make
sure the signal meets the triggering requirements described
in Section 1.}
4. Slowly advance the TRIGGER SENSITIVITY control for
a stable display. The RECOVERY TIME control may also
help stabilize the display.
5. Set the TIME/DIV. switch to the position where the
displayed signal covers the desired amount of horizontal
graticule divisions.
6. With the POSITION control, move the display hori-
zontally to the desired point on the graticule.
7. Turn the DELAY control and notice its effect on the
display. The action of the DELAY control is most significant
at faster sweep rates. The DELAY control varies the position
of the displayed pulse with respect to the start of the trace.
The position of the pulse with respect to the start of the
trace can be varied 100 nanoseconds with the DELAY
control.
8. Set the SWEEP MODE switch to MANUAL and turn
the MANUAL SCAN control. Note the horizontal scanning of
the electron beam on the crt.
9. Set the SWEEP MODE switch to SINGLE DISPLAY.
Press the RESET button. After pressing the RESET button,
the Type 3177 allows one complete scan of the electron
beam across the crt. This is particularly useful for photo-
graphing displays at slow pulse repetition rates.
Gain Adjust
The basic oscilloscope crt deflection factor varies slightly
from one oscilloscope to another. For this reason, the
GAIN ADJ. (a front-panel screwdriver adjustment) should
be checked and adjusted as necessary each time the Type
3177 is used in a different oscilloscope. Also, check the
2-2
GAIN ADJ. occasionally during regular use of the instru-
ment.
Checking or setting the GAIN ADJ. requires the use of
an accurate frequency source, such as the Tektronix Type
180A Time-Mark Generator. The frequency standard used
must have a frequency output of at least 100 kilocycles, and
preferably above 1 megacycle.
To check or adjust the Type 3T77 GAIN ADJ. control,
proceed as follows:
1. Insert the Type 3T77 and the associated vertical
sampling plug-in unit into the oscilloscope, turn on the power
and allow the instrument to warm up for at least 2 minutes
before proceeding.
2. Set the front-panel controls of the Type 3177 as follows:
POSITION Midrange
DOTS PER DIV. 100
TRIGGER SENSITIVITY Fully clockwise
VARIABLE CALIB.
SWEEP MODE NORMAL
HORIZ. MAG. X]
INT.-EXT. + INT.
Other controls may be set to any position.
3. From an accurate frequency source, apply a signal to
the Input connector of the vertical sampling plug-in unit and
adjust for a vertical deflection of 2 to 6 divisions.
4. Determine the time duration of one cycle of the signal
from the frequency source {time duration of one cycle (in
seconds) is the reciprocal of the frequency {in cycles per
second) ).
5. Set the TIME/DIV. switch for a sweep rate that will
display one-half to one cycle of the applied signal per
division of deflection.
6. Set the TRIGGER SENSITIVITY and RECOVERY TIME
controls for a stable display.
7. Check for the proper number of cycles per division.
If the number of cycles per division does not exactly agree
with the setting of the TIME/DIV. switch, set the GAIN ADJ.
for the proper timing. Use the POSITION control to align
the display with the graticule markings.
Triggering the Type 3177
The Type 3T77 can be triggered either internally or
externally. Internal triggering requires no signal connections
to the Type 3777 since the triggering signal is coupled
internally from the vertical sampling plug-in unit.
However, external triggering is more sensitive (see Section
1). External triggering is also independent of the displayed
waveform. Thus, when signals of different amplitudes are
applied to the vertical plug-in unit, the triggering controls
do not require resetting for a stable display. However, an
external triggering signal must be related in time to the
displayed signal to maintain stable triggering.
The + and — positions of the INT.-EXT. switch determine
whether triggering takes place on the positive- or negative-
@l

going slope of the triggering signal. The INT. or EXT. posi-
tions determine whether the triggering signal comes from
the vertical sampling plug-in unit or from the EXT. INPUT
connector.
Selecting the Equivalent Sweep Rate
The Type 31777 TIME/DIV. switch selects equivalent sweep
rates from 0.2 nanosecond per division to 10 micoseconds
per division. These rates, in turn, provide an equivalent 10-
division display width from 2 nanoseconds to 100 micro-
seconds. Setting the HORIZ. MAG. switch to X10 increases
the equivalent sweep rate 10 times at any setting of the
TIME/DIV. switch. This expands the display in both direc-
tions from the center graticule division to cover the entire
graticule (horizontally).
The VARIABLE control increases the equivalent sweep
rate at any setting of the TIME/DIV. switch about 3 times
(uncalibrated) when the control is fully clockwise.
Selection of sweep rate depends on the duration of the
applied signal and the specific portion of the signal you
wish to observe. The DELAY control aids in observing a
specific portion of the applied signal.
The equivalent sweep rates of the Type 3777 are accurate
within 3% of the TIME/DIV. control setting when the VARI-
ABLE control is set to CALIB. and the HORIZ. MAG. switch
is set to X1. This permits accurate time measurements di-
rectly from the oscilloscope display.
Selecting the Dots Per Division
In a sampling system, the applied signal is displayed as
a series of dots distributed across the ert. With a greater
number of dots in the display, the trace appears more con-
tinuous. With less dots in the display, there is less continu-
ity in the trace and the individual dots become more
apparent (see Fig. 2-2). The DOTS PER DIV. switch selects
either
10 dots per division or 100 dots per division. Proper
setting of the DOTS PER DIV. switch is a choice between
good trace continuity and flicker. Flicker will become ap-
parent with signals of low repetition rate when the DOTS
PER DIV. switch is set to 100. By changing the setting of
the DOTS PER DIV. switch to 10, flicker will become less
apparent. However, with 10 dots per division, make sure the
SMOOTH-NORMAL switch of the vertical sampling plug-in
unit is set to NORMAL. Otherwise, the display may be
distorted. Signals with fast repetition rates cause less
flicker; thus the DOTS PER DIV. switch may be set to 100
for best trace continuity.
When making time measurements from the crt, the indi-
vidual dots can serve as time markers. For example, suppose
the Type 3177 TIME/DIV. switch is set to 1 nSEC and the
DOTS PER DIV. switch is set to 10. In this case, each dot
@i
Operating Instructions —— Type 3177
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(b)
Fig, 2-2. (a) A typical display with the DOTS PER DIV. switch
set to 10. (b) The same signal with the DOTS PER DIV. switch
set to 100.
represents 0.1 nanosecond in equivalent time (1 nanosecond
per division divided by the 10 dots per division). This
application is easiest when the display contains 10 dots
per division (i.e., the DOTS PER DIV. switch must be set to
10 or the HORIZ. MAG. switch must be set to X10).
Under certain conditions it is possible to get a false
display when using a sampling-type system. This happens
when certain relationships exist between the frequency of
the applied signal and the equivalent time between dots. A
false display can be detected by changing the setting of
the DOTS PER DIV. switch or the TIME/DIV. switch. With a
valid display, a change in the equivalent time between dots
should not affect the displayed waveform. However, if the
display is false, it will change in apparent repetition rate
or disappear when the equivalent time per dot changes.
2-3

SECTION 3
APPLICATIONS
The procedures in this section describe some basic
applications for the Type 3177.
Time and Frequency Measurements
The Type 3177 is accurately calibrated to indicate equiva-
lent time per division along the horizontal axis of the
oscilloscope display. Thus, the following procedures concern
measuring time and frequency of electrical events.
Time Duration. To measure the time duration of an
electrical event, proceed as follows:
1. Obtain a stable display of the event you wish to
measure.
2. Set the TIME/DIV. switch so the distance between the
two points you wish to measure covers a large portion of
the graticule.
3. To get the time duration, count the number of grati-
cule divisions between the two points, multiply by the TIME/
DIV. switch setting, then divide the result by the HORIZ.
MAG. switch setting.
To illustrate this procedure, assume the TIME/DIV. switch
is set to 5nSEC and the HORIZ. MAG. switch to X1. Then,
assume the distance between the two points on the display
is 4.8 major graticule divisions. Thus, the time duration
would be 4.8 divisions multiplied by 5 nanoseconds/divi-
sion (TIME/DIV. switch setting), or 24 nanoseconds,
Risetime. The risetime of a pulse is, by definition, the
time required for the pulse to rise from 10% to 90% of
2.2 div. or .44 nsec
—
! "TT 90%
f point
TTTETT
TTT
TAT
TY
Ty
10%
point
+t
ttt
HH
i
Pitisi
ris
tig
4
4+
tt
4+
+
+
.2 nsec/div.
Fig. 3-1. Determining pulse risetime.
®
its maximum amplitude. To measure pulse risetime or fall-
time proceed as follows:
1. Set the TIME/DIV. switch and the DELAY control to
display the leading edge of the pulse. (Or, for falltime
measurement, display the falling edge.) For best accuracy,
the rising portion of the pulse should span at last two
horizontal graticule divisions.
2. Set the vertical plug-in unit so the display covers two
to eight vertical graticule divisions.
3. Measure the horizontal distance between the 10% and
90% amplitude points on the waveform. See Fig. 3-1.
4. The risetime is the number of divisions in step 3 multi-
plied by the setting of the TIME/DIV. switch (divided by
the HORIZ. MAG. switch setting).
Frequency or Repetition Rate. Frequency or repetition
rate is the number of complete electrical events occurring
in a second. To measure the frequency or repetition rate of
the displayed signal in cycles (or pulses} per second, pro-
ceed as follows:
1. Find the time duration of a complete event as described
under ‘Time Duration’.
2. The frequency or repetition rate of the applied signal
is the reciprocal of step 1.
To illustrate this procedure, assume the TIME/DIV. switch
is set to 20nSEC and the HORIZ. MAG. switch to X10.
Then, assume one event covers 6.4 major graticule divisions.
Thus, the frequency or repetition rate would be 6.4 divisions
multiplied by 20 nanoseconds/division (TIME/DIV. switch
setting) divided by 10 {the HORIZ. MAG. switch setting), or
12.8 nanoseconds. The frequency is then the reciprocal of
12.8 nanoseconds, or about 78.1 megacycles.
An alternative method for measuring frequency or repeti-
tion rate is as follows:
1. Set the TIME/DIV. switch for a 2- to 10-cycle display
of the input signal.
2. Count the exact number of cycles (including fractional
cycles) occurring in 10 major graticule divisions.
3. Multiply the number of cycles obtained in step 2 by
the Frequency Multiplier value opposite the appropriate
TIME/DIV. switch setting in Table 3-1.
TABLE 3-1
TIME/DIV. Setting | Frequency Multiplier
1 nSEC 100mc™
10 nSEC 10 mc
1 SEC 1 me
1 »SEC 100 ke
10 wSEC 10 ke