Tektronix 475A User manual

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Tektronix, inc.
P.O. Box 500

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 © 1976 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, inc.

TABLE OF CONTENTS
Page
LIST OF ILLUSTRATIONS iv BASIC OSCILLOSCOPE DISPLAYS
OP å NORMAL SWEEP DISPLAY
MAGNIFIED SWEEP DISPLAY
BEFORE
OPERATING
1
DELAYED
SWEEP
DISPLAY
INTRODUCTION 1 MIXED SWEEP DISPLAY
SAFETY INFORMATION 1 Dee ene
OPERATING VOLTAGE 1 SINGLE SWEEP DISPLAY
Line Voltage Selection 2
Regulating Range Selection 2 DM44 DISPLAYS AND MEASUREMENTS
OPTIONS 3
5 RESISTANCE
CONTROLS, CONNECTORS, AND VOLTS
INDICATORS 4 TEMPERATURE
VERTICAL 4 Accuracy Check
DISPLAY 7 TIME AND 1/TIME
DM44 7 :
TRIGGER 8
HORIZONTAL,
CALIBRATOR,
AND
POWER
12
APPLICATIONS
AND
MEASUREMENTS
REAR PANEL 14 PRELIMINARY
LEFT SIDE PANEL 14 Signal Ground
RIGHT SIDE PANEL 14 input Coupling Capacitor Precharging
475A/DM44 Operators
Page
16
16
17
7
18
18
19
20
20
22
24
24
27
28
28
28
28

APPLICATIONS AND MEASUREMENTS (cont)
TABLE OF CONTENTS (cont)
Page
OPERATOR’S ADJUSTMENTS AND CHECKS 29
Trace Rotation
Probe Compensation
Vertical Gain Check
Basic 475A Timing Check
DM44 Timing Check
External Horizontal Gain Check
PEAK-TO-PEAK VOLTAGE
MEASUREMENTS—AC
INSTANTANEOUS VOLTAGE
MEASUREMENTS—DC
ALGEBRAIC ADDITION
COMMON MODE REJECTION
AMPLITUDE COMPARISON
MEASUREMENTS
TIME-DURATION MEASUREMENTS
FREQUENCV MEASUREMENTS
RISETIME MEASUREMENTS
TIME DIFFERENCE BETWEEN TWO
PULSES FROM DIFFERENT SOURCES
TIME COMPARISON MEASUREMENTS
29
29
30
30
30
31
31
32
34
35
36
37
38
39
40
41
475A/DM44 Operators
APPLICATIONS AND MEASUREMENTS (cont)
PHASE DIFFERENCE MEASUREMENTS
HIGH RESOLUTION PHASE DIFFERENCE
MEASUREMENTS
PULSE JITTER MEASUREMENTS
DELAYED OR MIXED SWEEP
MAGNIFICATION
Magnified Sweep Starts After Delay
Triggered Delay Sweep Magnification
Page
42
43
44
45
45
46
BASIC 475A DELAYED OR MIXED SWEEP TIME
MEASUREMENTS
TIME DIFFERENCE BETWEEN REPETITIVE
PULSES (BASIC 475A)
TIME DURATION MEASUREMENTS
(BASIC 475A)
48
48
49
FREQUENCY MEASUREMENTS (BASIC 475A) 50
TIME DIFFERENCE BETWEEN TWO PULSES
FROM DIFFERENT SOURCES (BASIC 475A) 51
RISETIME (BASIC 475;
MIX {BASIC 475A)
52
53

TABLE
OF
CONTENTS
(cont)
DM44
DELAYED
OR
MIXED
SWEEP
TIME
MEASUREMENTS
Page
54
TIME DIFFERENCE BETWEEN REPETITIVE
PULSES (DM44)
56
TIME
DURATION
MEASUREMENTS
(DM44)
57
FREQUENCY
MEASUREMENTS
(DM44)
58
TIME DIFFERENCE BETWEEN TWO PULSES
FROM DIFFERENT SOURCES (DM44)
RISETIME (DM44)
MIX (DM44)
OPERATOR'S SPECIFICATIONS
475A OSCILLOSCOPE
VERTICAL
TRIGGERING
DIFFERENTIAL TIME MEASUREMENT
(BASIC 475A)
DIFFERENTIAL TIME MEASUREMENT
(DM44)
HORIZONTAL
X-Y
CALIBRATOR
58
60
64
62
62
62
63
63
64
64
64.
64
OPERATOR'S SPECIFICATIONS (cont)
Z AXIS INPUT
OUTPUTS
AG POWER SOURCE
ENVIRONMENTAL
DM44 DIGITAL MULTIMETER
RESISTANCE
TIME
1/TIME
TEMPERATURE
DC VOLTAGE
ACCESSORIES
STANDARD ACCESSORIES
OPTIONAL ACCESSORIES
OPTIONS
OPTION 4
OPTION 7
475A/DM44 Operators
Page
65
65
65
65
66
66
66
66
66
66
68
68
68
69
69
69

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
10,
11.
12.
13.
14,
15.
16.
LIST OF ILLUSTRATIONS
Regulating range selector and line
fuse.
Vertical controls, connectors, and
indicators.
Display and DM44 controls,
connectors, and indicators.
Trigger controls, connectors, and
indicators.
Trigger controls, connectors, and
indicators.
Horizontal, calibrator, and power
controis, connectors, and indicators.
Rear pane! and left side panei controls,
connectors, and indicators.
Resistance.
Volts.
Temperature.
Probe compensation.
Basic 475A timing check.
DMAA timing check.
Peak-to-peak voltage of a waveform.
Instantaneous voltage measurements.
Algebraic addition.
Page
15
21
23
25
29
30
31
32
33
35
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32,
475A/DM44 Operators
Common-mode rejection.
Time duration.
Risetime.
Time difference between two pulses
from different sources.
Phase difference.
High-resolution phase difference.
Pulse jitter.
Delaved sweep magnification.
Time difference between tepetitive
pulses.
Time duration.
Time difference between two pulses
from different sources.
Risetime.
Time difference between repetitive
pulses.
Time duration and frequency
measurements,
Time difference between two pulses
from different sources.
Risetime. i
Page
36
38
39
40
43
43
44
46
49
50
51
53
56
57
59 kol
60 |

LIST OF TABLES
Page
Page
TABLE
1
Regulating
Ranges
2
TABLE
4
Centigrade
to
Fahrenheit
Conversion
26
TABLE
2
Resistance
Ranges
20
TABLE
5
DM44
Delayed
Sweep
Displays
54
TABLE
3
Volts
Ranges
22
475A/DM44
Operators
v

475A Oscilloscope with DM44 Digital Multimeter.
475A/DM44 Operators
2163-02

BEFORE OPERATING
INTRODUCTION
The Tektronix 475A Oscilloscope is a dual-channel
portable instrument. The dual-channel dc-to-250 MHz
vertical system provides calibrated deflection factors from
5 miltivolts to 10 volts/division. The sweep trigger circuits
are capable of stable triggering over the full bandwidth
capabilities of the vertical deflection system. The horizon-
tal deflection system provides calibrated sweep rates from
0.5 second to 0.01 microsecond/division along with
delayed sweep features for accurate relative-time
. measurements. A X10 magnifier extends the calibrated
sweep rate to 1 nanosecond/division. The instrument
operates over a wide variation of line voltages and
frequencies. Maximum power consumption is about 100
watts. z.
The Tektronix DM44 Digital Multimeter measures 0
ohm to 20 megohms, 0 dc volt to 1200 dc volts (+ or —), or
(using the temperature probe) ~55°C to +150°C. The
measurement is displayed on a 3-1/2 digital display while
the oscilloscope operates normally.
The digital multimeter and oscilloscope combine to
provide a digital readout of the time between any two
points on the oscilloscope display. Both time measure-
ment points are displayed on the crt at the same time. The
1/TIME function can provide direct measurement of
frequency.
SAFETY INFORMATION
The instrument is designed to operate from a single-
phase power source with one of the current-carrying
conductors (the Neutral Conductor) at ground (earth)
potential. Operation from power sources where both
current-carrying conductors are live with respect to
ground (such as phase-to-phase on a three-wire system)
is not recommended, since only the Line Conductor has
over-current (fuse} protection within the instrument.
The instrument has a three-wire power cord with a
three-terminal polarized plug for connection to the power
source and safety-earth. The ground (earth) terminal of
the plug is directly connected to the instrument frame. For
electric-shock protection, insert this plug only in a mating
outlet with a safety-earth contact.
@ | 475A/DM44 Operators 1

OPERATING VOLTAGE
CAUTION
ANA IS MO ol MO MM?
This instrument may be damaged if operated with
the line voltage selector switch or the regulating
range selector set for the wrong applied line voltage
or if the wrong line fuse is used.
Line Voltage Selection
This instrument operates from either a 115-volt or a
230-vott nominal line voltage source, 48 to 440 hertz. To
convert from one nominal line voltage range to the other,
move the Line Voltage Selector switch (located on side
panel) to indicate the correct nominal voltage. A 115-to-
230 volt adapter may be required for the line-cord plug. Be
sure to use the correct line fuse for the line voltage
selected (see Table 1).
Regulating Range Selection
Tne Regulating Range Selector assembly (located on
the rear panel} is set for one of the line voltage ranges
shown in Table 1. It also contains the line fuse for overload
protection.
To change the regulating range:
1. Disconnect the instrument from the power source.
2. Loosen the two captive screws that hold the cover
on the selector assembly; then puil to remove the cover.
3, Pull out the range selector switch bar (see Fig. 1).
Select a range from Table 1 which is centered about the
average line voltage. Slide the bar to the desired position
and plug it in. Push the cover on and tighten the screws.
TABLE 1
Regulating Ranges
Regulating Range Ni
115-Volis 230-Volts
Nominal Nominal
Range Selector
Switch Position
lower holes)
CM (Switch bar in
middle holes)
Hi (Switch bar in
upper holes)
Fuse Size
_99 to 121 volts | 198 to 242 volts
104 to 126 volts 207 to 253 volts
216 to 264 volts
0.75 A 3AG
108 to 132 volts
1,5 A JAG
2
475A/DM44
Operators
@

OPTIONS
Options are available to alter oscilloscope performance
to meet particular applications. A number in either MOD
slot (see Hem 53, Controls, Connectors, and Indicators)
indicates a modified oscilloscope.
SELECTOR SWITCH BAR
(SHOWN IN MEDIUM POSITION} |
LINE FUSE
|
;
i
i
i
I
Fig. 1. Regulating range selector and line fuse.
e
475A/DM44
Operators
3

CONTROLS,
CONNECTORS
AND
INDICATORS
Fig. 2. Vertical controls, connectors, and indicators.
VERTICAL
1. CH 1 and CH 2 VOLTS/DIV—Selects the vertical
deflection factor in a 1-2-5 sequence (VAR control must be
in the calibrated detent for the indicated deflection factor).
2. VOLTS/DIV Readout—Consists of two small lamps
for each channel, located beneath the skirt of each
VOLTS/DIV knob. One or the other lamp will light up to
indicate the correct deflection factor when a probe with a
scale-switching connector is used. A probe without this
connector lights the X1 lamp.
3. VAR--Provides continuously variable uncalibrated
deflection factors between the calibrated settings of the
VOLTS/DIV switch, and extends the maximum vertical
deflection to at least 25 volts per division (10 volt position).
4. UNCAL Lamp—indicates when the VAR
VOLTS/DIV control is out of the calibrated detent and the
vertical deflection factor is uncalibrated.
475A/DM44 Operators @

5. POSITION—Positions the display vertically. In the
X-Y mode, the CH 1 POSITION control positions on the X
axis (horizontally) and the CH 2 POSITION control
positions on the Y-axis (vertically),
6. CH 1 OR X and CH 2 OR Y—lnput connectors for
application of external signals to the inputs of the vertical
amplifier. in the X-Y mode of operation, the signal
connected to the CH 1 OR X connector provides horizon-
tal deflection and the signal connected to the CH 2 ORY
connector provides vertical deflection.
7. AC-GND-DC—Selects the method used to couplea
signal to the input of the vertical amplifier. In the AC
position, signals are capacitively coupled to the vertical
amplifier. The dc componentof the input signal is blocked.
in the GND position, the input of the vertical amplifier is
disconnected from the input connector and grounded to
allow the input coupling capacitor to precharge. Inthe DC
position, all components of the input signal are passed to
the input amplifier,
8. VERT MODE—Selects mode of operation for ver-
tical amplifier system.
CH 1: Channel 1 only is displayed.
ALT: Provides dual-trace displav of the signals of both
channels. Displav is switched between channels at the end
of each sweep. Useful at sweep rates faster than about 50
microseconds/division.
ADD: Signals applied to the CH 1 and CH 2 input
connectors are algebraically added, and the algebraic
sum is displayed on the crt. The INVERT switch in Channel
2 allows the display to be CH 1 pius CH 2 or CH 1 minus
CH 2. Useful for common-mode rejection to remove an
undesired signal or for dc offset.
CHOP: Provides dual-trace display of the signals of
both channels. Display is switched between channels ata
repetition rate of approximately 250 kHz. Useful at sweep
rates slower than about 50 microseconds/division, or
when a dual-trace, singie-sweep display is required.
CH 2: Channel 2 only is displayed. it must be selected
in X-V operation.
9. 100 OR 20 MHz BW/TRIG VIEW— Three-purpose
switch that limits the bandwidth of the vertical amplifier
system to approximately 100 MHz (first detent) or 20 MHz
(second detent) when pulled, or when pressed, causes the
signal applied to A Trigger Generator to be dispiayed on
the crt.
10. INVERT—Channel 2 display is inverted in the
INVERT (button in) position.
@ | 475A/DM44 Operators 5

ero
BANA
AR
ti
EN
Fig. 3. Display and DM44 controls, connectors, and indicators.
6 475A/DM44 Operators @

DISPLAY
11. Internal Graticule—Eliminates parallax. Risetime,
amplitude and measurement points are indicated at the
left-hand graticule edge.
12. BEAM FINDER—Compresses the display to within
the graticule area independently of display position or
applied signals and provides a visible viewing level.
13. INTENSITY—Controls brightness of the crt dis-
play.
14. FOCUS— Adjusts for optimum display definition.
15. SCALE ILLUM—Controls graticule illumination.
16.
ASTIG—Used
in
conjunction
with
the
FOCUS
control
to
obtain
a
well-defined
display.
It
does
not
require
readjustment in normal use.
17. TRACE ROTATION—Adjusts trace to align with
the horizontal graticule lines.
DM44
18.
Input
Connectors—Two
banana
jacks
provide
+
(red)
and
COM
(black)
inputs
for
voltage
and
resistance
oniv.
19. Probe Connector—input connector for the
temperature probe.
20. Readout—Negative polaritv indication is
automatic
for
negative
dc
voltage
and
temperature
witħ
no
polaritv indication for positive measurement. A blinking
display indicates overrange. The decimal point is position-
ed by the FUNCTION and RANGE controls for multimeter
operation and by the oscilloscope A TIME/DIV switch in
the TIME or 1/TIME modes.
21. RANGE—Selects from .2 V to 1.2 kV dc in 5 ranges
(1200
volts
is
the
maximum
safe
input
in
the
1.2
kV
dc
mode); from 200 ohms to 20 megohms in 6 ranges.
22. FUNCTION—Selects VOLTS, OHMS, TEMP (°C),
1/TIME, or TIME functions of the DM44.
23. Scale Factor Lamps—Two lamps.
In the TIME function, the Readout and Scale Factor
Lamps
indicate
the
time
difference
between
the
two
intensified zones on the crt display. One lamp or the other
will
light
to
indicate
ms
or
us.
No
lamp
lit
indicates
seconds.
In the 1/TIME function the Readout and Scale Factor
Lamps
indicate
the
number
of
measured
intervals
per
unit
of time. One lamp or the other will light to indicate intervals
per ms (1/ms lamp) or intervals per us (1/us lamp). No
@
475A/DM44
Operators
7

Fig. 4. Trigger controls, connectors, and indicators.
475A/DM44 Operators
lamp lit indicates intervals per second. H the duration of
one event is being measured, the Readout and Scale
Factor Lamps indicate frequency. The 1/ms lamp in-
dicates
kHz,
the
1/us
lamp
indicates
MHz,
and
no
lamp
lit
indicates
Hz.
24. Å TIME—Used in conjunction with the DELAY
TIME POSITION control in the TIME and 1/TIME func-
tions. The A TIME control moves only the time-
measurement point. The DELAY TIME POSITION contro}
moves both the reference point and the time-
measurement point. With the time-measurement point to
the left of the reference point the Readout indicates a
negative time difference.
NOTE
You can modify your instrument to make the DELAY
TIME POSITION contro! move only the reference
point, The procedure for making this modification is
focated in the Maintenance section of the DM44
Service manual.
TRIGGER
25. TRIG MODE—Determines the mode of trigger
operation for A Sweep.
AUTO: Sweep is initiated by the applied trigger signal.
In the absence of an adequate trigger signal, or if the
trigger repetition rate is less than about 20 hertz, the
sweep free runs and provides a bright reference trace.

NORM: Sweep is initiated by the applied trigger signal.
In the absence of an adequate trigger signal, there is no
trace. When the trigger rate is too low for AUTO use
NORM.
SINGL SWP: When this pushbutton is pushed, the A
Sweep operates in the single sweep mode. After a single
sweep is displayed, further sweeps cannot be presented
until the SINGLE SWP button is again pushed. It is useful
when the signal to be displayed is not repetitive or varies in
amplitude, shape or time causing an unstable conven-
tional display. It can aiso be used to photograph a
nonrepetitive signal.
26. READY Lamp--indicates A Sweep is “armed” and,
upon receipt of an adequate trigger signal, will present a
single-sweep display.
27. TRIG Lamp--indicates that A Sweep is triggered
and will produce a stable display. It is useful for setting up
the trigger circuits when a trigger signal is available
without a display on the crt (for example, when using
external triggers).
28. A TRIG HOLDOFF—Provides continuous control
of time between sweeps. Allows triggering on aperiodic
signals (such as complex digital words). In the fully
clockwise position (B ENDS A), A sweep is reset at the end
of B sweep to provide the fastest possible sweep repetition
@
i
475A/DM44
Operators
rate for delayed-sweep presentations and low-repetition
rate signals. Use the A trigger controls for the best
possible display before using the A TRIG HOLDOFF
control.
29. COUPLING—Determines method used to couple
signals to the trigger generator circuit.
AC: Signals are capacitively coupled to the input ofthe
trigger generator, Dc is rejected and signals below about
60 Hz are attenuated.
LF REJ: Signals are capacitively coupled to the input
of the trigger circuit. Dc is rejected and signals below
about 50 kHz are attenuated. It is useful for providing a
stable display of the high-frequency components of a
complex waveform.
HF REJ: Signals are capacitively coupled to the input
of the trigger circuit. Dc is rejected and signals below
about 60 Hz and above about 50 kHz are attenuated. It is
useful for providing a stable display of the low-frequency
components of a complex waveform.
DC: AH components of a trigger signal are coupled to
the input of the trigger circuit. It is useful for providing a
stable display of low-frequency or low-repetition rate
signals, except the combination of the ALT (dual trace)
mode with the trigger SOURCE switch in NORM.

30. SLOPE—Selects the slope of the trigger signal that
starts the sweep.
+: Sweep can be triggered from the positive-going
portion of a trigger signal.
~: Sweep can be triggered from the negative-going
portion of a trigger signal.
Correct SLOPE setting is important in obtaining a
display when only a portion of a cycle is being displayed.
31. LEVEL—Selects the amplitude point on the trigger
signal at which the sweep is triggered. It is usually
adjusted for the desired display after trigger SOURCE,
Fig. 5. Trigger controls, connectors, and indicators. COUPLING and SLOPE have been selected.
10 475A/DM44 Operators @

32. SOURCE—Determines the source of the trigger
signal coupled to the input of the trigger circuit.
NORM: Trigger source is displayed signal(s). It does
not indicate time relationship between CH 1 and CH 2
signals. However, stable triggering of non-time-related
signals usually can be obtained by setting VERT MODE to
ALT, SOURCE to NORM and COUPLING to LF REJ.
Carefully adjust LEVEL for a stable dispiay.
CH 1: A sample of the signal available in Channel 1 is
used as a trigger signal. CH 2 signal is unstable if it is not
time-related.
CH 2: Asample of the signal available in Channel 2 is
used as a trigger signal. CH 1 signal is unstable if itis not
time-related.
LINE (A Trigger circuit only): A sample of the power-
line frequency is used as a trigger signal. It is useful when
the input signal is time-related (multiple or submultiple) to
the line frequency or when it is desirable to provide a
stable display of a line-frequency component in a complex
waveform.
EXT: Signals connected to the External Trigger Input
connectors are used for triggering. External signais must
be time-related to the displayed signal for a stable display.
It is useful when the internal signal is too small or contains
undesired signals that could cause unstable triggering. lt
is useful when operating in CHOP mode.
EXT + 10 (A Trigger circuit only): External trigger
signal is attenuated by a factor of 10,
STARTS AFTER DELAY (B Trigger circuit only}: B
Sweep runs immediately after the delay time selected by
the DELAV-TIME POSITION control. When making
differential time measurements you must use this mode to
obtain valid measurements. On instruments equipped
with a DM44 you must use this mode to obtain valid
measurements when using the TIME or 1/TIME functions.
33. External Trigger Inputs—Input connectors for ex-
ternal trigger signals.
@ get 475A/DM44 Operators fi

Fig. 6. Horizontal, calibrator, and power controis, connectors,
and indicators,
HORIZONTAL, CALIBRATOR, AND
POWER
34a,
A
AND
B
TIME/DIV
AND
DELAY
TIME—A
TIME/DIV
switch
(clear
plastic
skirt)
selects
the
sweep
rate
of
the
A
Sweep
circuit
for
A
sweep
only
operation
and
selects
the
basic
delay
time
(to
be
used
by
the
DELAY-
TIME
POSITION
control)
for
delayed
sweep
operation.
B
TIME/DIV
switch
(pull
out
and
rotate
to
unlock)
selects
the
sweep
rate
for
the
B
Sweep
circuit
for
delayed
sweep
operation
only.
A
VAR
control
must
be
in
the
calibrated
detent
for
calibrated
A
Sweep
rates.
When
both
TIME/DIV
switches
are
fully
counterclockwise
to
the
X-V
position,
the
horizontal
(X-axis)
display
is
the
CH
1
input.
34b. DM44 A AND B TIME/DIV AND DELAY TIME—
The controls operate in the same manner as 37a above.
The A TIME/DIV switch also controls the TIME lamps and
decimal point location when the DM44 is in the TIME
or 1/TIME MODE.
35. FINE/POSITION— Positions the display horizontal-
iv for A sweep and B Sweep.
36. X10 MAG—Increases displayed sweep rate by a
factor of 10. It extends fastest sweep rate to 1
nanosecond/division. The magnified sweep is the center
division of the unmagnified display (0.5 division either side
of the center graticule fine).
12
475A/DM44
Operators
e