Tektronix 519 User manual

INSTRUCTION
MIAN UAL
IMPORTANT
Before operating this instrument, be sure to remove
the plastic shipping clamps from the shock mounts
of the amplifier chassis. These clamps should
be saved and reinstalled as shown in the sketch if
the instrument is to be shipped. Be sure the tongue
is inserted next to the chassis to prevent damage
to the shock mount.
The clamp should be on the same side of the shock
mount as the nut.
SHIPPING CLAMP
~<a—— WITH TONGUE
TOWARD CHASSIS
RUBBER
MOUNT CHASSIS
Tektronix, Inc.
S.W. Millikan Way @ P. O. Box 500 @ Beaverton, Oregon 97005 @ Phone [phone] @ Cables: Tektronix
070-243

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General Information
The Tektronix Type 519: Oscilloscope is a wide-band
laboratory instrument designed expressly for the observation
and measurement of high-frequency phenomena. Fast
linear sweeps, high CRT accelerating potential, excellent
triggering sensitivity, wide-band trigger system, and vertical
bandwidth well beyond 1000 megacycles permit accurate
repetitive and single-shot displays to be observed and
photographed from fractional-nanosecond signals. An inter-
nal delay line in the vertical channel of the instrument
permits display of the leading edge of the signal triggering
the oscilloscope. Sweep delay control through 35 nano-
seconds permits viewing signals before and after the main
signal event.
The Type 519 incorporates two internal waveform gen-
erators. An adjustable repetition-rate fast-rise pulse gen-
erator and a fast-rise calibration-step generator supply
waveforms which can be used to check the calibration of the
oscilloscope itself, or to drive external devices. These wave-
form generators meet most requirements to complete a test
setup.
VERTICAL-DEFLECTION SYSTEM
Vertical Deflection Factor
With Type T519P-A CRT, less than 10 volts per cm. Exact
CRT deflection factor indicated on CRT face mask of each
instrument.
Passband
With Type T519P-A CRT, dc to 1000 megacycles minimum at
3-db down.
Risetime
With Type T519P-A CRT, less than 0.35 nanosecond *
Input Impedance
125 ohms.
* 1 nanosecond—=10°? seconds.
®
SECTION 1
CHARACTERISTICS
Maximum Allowable Input Power to Vertical
Channel
1.8 watts, corresponding to 15 volts de or rms.
Maximum Allowable Peak Signal Amplitude
+100 volts. Repeated pulses of higher voltage may dam-
age the 125-ohm signal termination resistor.
Internal Signal Delay
Approximately 45 nanoseconds, fixed.
Voltage Standing Wave Ratio
Nominally 1.25:1 to 1000 mc.
TRIGGER
Triggering Signal Sources
Internal from = applied signals, internal from the Rate Gen-
erator, internal from the Calibration-Step Generator, and
external from - trigger inputs.
External Triggering Signal Requirements
Pulse amplitude: 20 millivolts. Duration: 1 nanosecond
or longer. Maximum permissible external triggering signal:
+10 volts peak, higher with external attenuators. Repeti-
tion rate: to 1000 mc.
Internal Triggering Signal Requirements
Pulse amplitude: sufficient signal to produce a 2 trace-
width deflection on the screen (approximately 200 mv). Dur-
ation: 1 nanosecond or longer. Repetition rate: to 1000 mc.
Countdown
A sweep is obtained for each trigger signal at trigger signal
frequencies below the maximum sweep repetition rate. Trig-
gering circuits countdown for trigger signal frequencies
1-1

Characteristics—Type 519
higher than the maximum sweep repetition rate. Sine-wave
trigger requirements: 1 mc to 1000 mc, 20 mv peak-to-peak
external trigger input, or 200 mv peak-to-peak signal to verti-
cal input.
Pulse Amplitude or Sync
Single control adjusts pulse triggering level or high-fre-
quency sync. An additional control provides vernier sync.
Delay
Sweep-start delay over a range of 35 nanoseconds. Per-
mits waveform to be positioned horizontally within the
sweep, to display a selected time interval.
TIME BASE
Sweep Rates
Nine Ranges: 2, 5, 10, 20, 50, 100, 200, 500, and 1000 nano-
seconds per centimeter.
Accuracy
Typically within 2% of indicated rate on all ranges except
the 2-nanosecond range, which is within 3%. These specifi-
cations apply to the entire sweep except for the first 2 nano-
seconds or 2 mm (whichever is larger).
Single Sweeps
Normal or single sweeps selected by front-panel switch.
+ Trigger Output
Greater than 1-volt pulse into 50 ohms upon triggering.
Delayed + Gate
Greater than 1-volt gate into 50 ohms during sweep; delayed
with respect to + Trigger Output depending on the setting
of the sweep-delay control.
RATE GENERATOR
Risetime
Less than 0.8 nanosecond (0.5 nanosecond typical).
Pulse Repetition Rate
3 cps to 30 kc, continuously variable.
1-2
Pulse Duration
10 nanoseconds + or — 20% at the 50% amplitude points.
Output Impedance
50 ohms.
Amplitude
Approximately +15 volts.
CALIBRATION-STEP GENERATOR
Risetime
Approximately 0.1 nanosecond.
Repetition Rate
Adjustable from 400 to 850 step waveforms per second;
normally operated near reed-switch resonant frequency at
approximately 750 steps per second.
Output Impedance
125 ohms.
Amplitude
Into 125 ohms, 0 to 10 volts. Into 50 ohms through T50/T125
adapter, 0 to 1 volt. Voltages applied to both impedances
are continuously variable and calibrated. Uncalibrated volt-
ages up to 50 volts into 125 ohms.
Polarity
The ouput polarity can be selected by a front-panel switch.
CATHODE RAY TUBE
Type
T519P-A
Phosphors
Type P11 phosphor standard (recommended for single-shot
photographic recording at fastest sweep rate). Other phos-
phors available only on special request.
Usable Viewing Area
Two centimeters vertical, six centimeters horizontal.

Accelerating Voltage
24 kv.
Spot Diameter
0.004 inch (approximately 0.1 mm) at normal intensity.
Deflection
Electrostatic. Vertical deflection system is 125-ohm dis-
tributed-constant delay line. Conventional horizontal deflec-
tion plates.
CONSTRUCTION AND POWER REQUIREMENTS
Construction
Single-unit construction with light-weight aluminum-alloy
chassis and four-piece vinyl-finish cabinet. Side panels, top
and bottom panels are separately removable.
Ventilation
Filtered forced air with protective thermal cutout insures
safe operating temperatures.
Dimensions
Approximately 221%," high, 1434,” wide, and 251%,” long.
Characteristics—Type 519
Power Requirements
105 to 125 or 210 to 250 volts, 50 to 60 cycles, approxi-
mately 650 watts.
ACCESSORIES
Information on accessories for use with this instrument is
included at the rear of the mechanical parts list.
1-3

Operating Information—Type 519
INTENSITY
ASTIGMATISM SCALE ILLUM.
TYPE S19 OSCILLOSCOPE
SERIAL
TEKTRONIX, INC. PORTLAND, OREGON. U.S. A,
POSITIONING
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Fig. 2-1. Type 519 Oscilloscope front panel.

Introduction
The Type 519 Oscilloscope is a high speed laboratory
instrument designed for observing, measuring, and photo-
graphically recording phenomena in the nanosecond (milli-
microsecond) domain. However, before the instrument can
be used successfully, it is important for you to have an un-
derstanding of the operation of each control. This section
of the Instruction Manual is intended to help you acquire
this understanding. Much of the familiarity with the controls
will come only with actual use of the instrument. A brief
description of each of the front-panel controls follows. Front-
panel markings are shown in Fig. 2-1.
FUNCTION OF CONTROLS
CRT
FOCUS Used in conjuction with the ASTIGMATISM
control to focus the oscilloscope trace.
INTENSITY Adjusts the brightness of the trace.
ASTIGMATISM — Used in conjunction with the FOCUS con-
trol to obtain a round spot and a sharply
focused trace.
SCALE ILLUM. Adjusts the brightness of the graticule
markings.
Graticule A knurled knob located below the center
Control of the graticule permits graticule to be
moved down out of the viewing area.
TIME BASE
NANOSEC/CM _ Selects the desired time base.
DELAY Determines the delay of the start of the
sweep with respect to the trigger signal
input.
NORMAL-SINGLE Selects either normal or single-sweep
SWEEP operation.
RATE GENERATOR
CYCLES/SEC Used in conjunction with the MULTIPLIER
control to set the Rate Generator out-
put frequency.
SECTION 2
OPERATING
INFORMATION
MULTIPLIER Multiplier for the CYCLES/SEC control.
Should be set to OFF position when Rate
Generator is not being used.
CALIBRATION-STEP GENERATOR
RANGE Selects full-scale amplitude of the cali-
brated steps, a variable uncalibrated step
amplitude, or a standby condition. Should
be set to STANDBY when Calibration-Step
Generator is not being used.
VARIABLE Permits the step waveform to be preset to
an arbitrary desired amplitude up to about
50 volts into a 125-ohm load.
VOLTS Sets the output voltage of the calibration-
step waveform in the 10V and 1 V posi-
tions of the RANGE switch.
REED SWITCH:
DRIVE Adjusts the reed-switch magnetic excita-
tion for proper closures or permits single
reed operation.
FREQUENCY = Controls frequency of the reed-switch mag-
netic excitation to help minimize contact
bounce.
TRIGGER
PULSE AMPLI- = Selects triggering signal amplitude re-
TUDE OR SYNC * quired to operate triggering circuits, or ad-
justs synchronization.
VERNIER SYNC Used in conjunction with PULSE AMPLI-
TUDE OR SYNC control to synchronize the
sweep.
FUNCTION * Permits choice of triggered or synchronized
displays.
GAIN * Selects proper gain or attenuation for the
triggering signal.
TRIGGER Selects the triggering signal source and
SOURCE polarity.
* Also see TRIGGER OPERATION section of front-panel, Fig. 2-1.
2-1

Operating Information—Type 519
POSITIONING
VERTICAL Adjusts the vertical position of the trace.
AXIS ROTA- Aligns the trace parallel to the horizontal
TION graticule lines.
HORIZONTAL — Adjusts the horizontal position of the trace.
POWER
DIM ADJ. Used to adjust the brightness of pilot light
after 45-second warm-up period.
ON AC line switch.
PRELIMINARY INSTRUCTIONS
Cooling
A blower maintains safe operating temperature in the
Type 519 Oscilloscope by drawing air through a filter and
circulating it over the components. Therefore, the instru-
ment must be placed so that the air intake and cabinet
ventilating holes are not blocked. The air filter must be
kept clean to permit adequate air flow.
A thermal cutout switch disconnects the dc power if the
instrument becomes overheated. The pilot lamp will re-
turn to full brightness in the event that dc power is lost.
Brown-Yellow-Green
Lo
B
beats Black-White
117-VOLT OPERATION
Brown-Yellow-Green
Brown-Yellow-
Brown
Black-White
234-VOLT OPERATION
If this happens, check immediately for proper airflow into
the instrument. The blower continues to cool the interior
and reduces the time the thermal switch remains open. DC
power will be restored when the temperature drops to a
safe value.
Power Requirements
The regulated power supplies in the Type 519 Oscillo-
scope will operate with line voltages from 105 to 125 volts
(117 nominal) or from 210 to 250 volts (234 nominal). The
line voltage for which your instrument is wired at the
factory is indicated on a metal tag fastened to the rear
panel near the power receptacle. Transformer connections
may be changed for either 117- or 234-volt operation by
using the information given in Fig. 2-2. The power trans-
former is wound with two 117-volt primaries which are
connected in parallel for 117-volt operation and in series
for 234-volt operation. Since the blower motor is connected
across only one of the transformer primaries, no change in
the motor lead connections is required. When the trans-
former connections are changed, the voltage indicated on
the metal tag should be covered with another tag which
conforms to the new operating voltage.
For maximum dependability and long life, the line voltage
applied to the Type 519 Oscilloscope should be near the
voltage indicated on the metal tag located near the power
receptacle at the rear of the instrument. If the line voltage
exceeds the operating limits, or has a poor waveform (dis-
torted sine waves), unstable power-supply operation may
Fig. 2-2. Power transformer connections for operation of the Type 519 Oscilloscope at 117 or 234 volts.

result. Check for proper line voltages and waveform before
checking for other causes of unstable operation.
Fuse Requirements
When the Type 519 Oscilloscope is connected for 117-
volt operation, use a 7-amp slow-blowing type fuse. When
the instrument is connected for 234-volt operation, use a
4-amp slow-blowing type fuse.
Time Delay
A time delay relay used in the Type 519 delays operation
of the instrument for approximately 45 seconds after the
instrument is switched on. The relay allows a brief tube-
warmup period before the dc operating voltages are applied.
When the ac-power pilot light dims, the instrument is ready
for use.
If the ac-power is interrupted for only an instant, the
normal 45-second delay will occur before the instrument
returns to full operation.
Dim Adjustment
The DIM ADJ. control is a screwdriver adjustment which
controls the brightness of the ac-power pilot light after the
45-second warm-up period. Normally, it is adjusted to a
setting which will reduce glare from the pilot light when
waveform observations are being made in a darkened room.
Camera Bezel
When one of the Tektronix cameras is used with the
Type 519 the bezel supplied on the oscilloscope must be
used. The bezel supplied with the camera will not take
the graticule assembly properly.
FIRST-TIME OPERATION
To place the Type 519 in operation for the first time,
the following procedure is suggested:
1. Set the front-panel controls as follows (controls not
mentioned may be placed in any position):
POWER Off
DIM ADJ. Centered
INTENSITY Fully counterclockwise
NORMAL-SINGLE SWEEP NORMAL
NANOSEC/CM 5
DELAY Centered
MULTIPLIER X1000
CYCLES /SEC 10
RANGE STANDBY
TRIGGER SOURCE RATE GEN.
GAIN NORMAL
FUNCTION PULSE
PULSE AMPLITUDE Fully counterclockwise
OR SYNC
VERTICAL Centered
HORIZONTAL Fully clockwise
Operating Information—Type 519
2. (The line voltage for which the instrument is wired at
the factory is indicated near the power cord receptacle.)
Connect the power cord to the rear of the instrument and
to the source of power.
3. Set the POWER switch to ON.
4. Allow about 45 seconds for the pilot lamp to dim, indicat-
ing that dc operating voltages are applied and the instru-
ment is ready for use.
CAUTION
Do not turn the intensity so high that a_ bright
glow surrounds the spot. Excessive brightness
of a stationary spot may damage the screen in
a
few seconds.
Advance the INTENSITY control until a visible spot
appears near the left center of the screen.
6. Adjust the FOCUS and ASTIGMATISM controls to produce
a small round spot.
7. Advance the PULSE AMPLITUDE OR SYNC control fully
clockwise to obtain a horizontal sweep across the screen.
Readjust the INTENSITY control for suitable trace bright-
ness.
mn
8. Rotate the HORIZONTAL positioning control to position
the start of the trace at the left marking of the graticule.
9. Adjust the AXIS ROTATION control until the trace is
parallel to the horizontal markings of the graticule.
10. Connect a T50/N125 adapter to the +-RATE 50Q con-
nector making certain that the 50-ohm connectors are
mated. If the wrong impedance connectors are mated, the
signal path remains open and the connections will not seat
fully.
11. Connect a 2-nsec 125-ohm cable from the 125-ohm end
of the adapter to the SIGNAL 125 connector.
12. Rotate the PULSE AMPLITUDE OR SYNC control slowly
counterclockwise and adjust the DELAY control until a stable
display of the Rate Generator pulse is obtained. Locate
the waveform vertically using the VERTICAL positioning
control.
13. Adjust the FOCUS, INTENSITY, and ASTIGMATISM
controls until a sharp trace with adequate intensity is ob-
tained. These controls are slightly interdependent. An exter-
nal signal and/or trigger may now be applied to the input
connectors. If external triggers are used, set the TRIGGER
SOURCE switch to + or — EXT. If internal triggering from
the input signal is used, set the TRIGGER SOURCE switch
to + or — INT.
CRT CONTROLS AND GRATICULE
Intensity
The INTENSITY control is used to adjust the brightness of
the oscilloscope display. Compensation can be made for
changes in brightness resulting from changes in the trigger-
ing rate or time base. The INTENSITY control is rotated
clockwise to increase brightness and counterclockwise to
decrease brightness. Care must be taken when using the
INTENSITY control that the brightness is not turned up to
the point where the phosphor on the face of the cathode
2-3

Operating Information—Type 519
ray tube (CRT) becomes permanently damaged. The intensity
of the beam should never be turned up to the point where
a bright halo forms around a stationary spot.
The FOCUS and ASTIGMATISM controls permit a sharp,
clearly defined spot or trace to be obtained. Perhaps the
best way to adjust the FOCUS and ASTIGMATISM controls
is to display a waveform on the oscilloscope and then adjust
the FOCUS and ASTIGMATISM controls alternately for the
best overall focus of the trace. It may be necessary to make
a new adjustment of the controls if the intensity of the trace
is changed.
The disappearing graticule used with the Type 519
Oscilloscope is accurately marked with 6 horizontal and 2
vertical 1-centimeter divisions. The minor division markings
on the horizontal centerline are 5 millimeters apart; those
on the vertical centerline are 2 millimeters apart. The grati-
cule markings allow accurate time and voltage measure-
ments to be made from the oscilloscope screen.
To move the graticule out of the viewing area of the
screen, loosen the knurled knob located just below the
graticule and slide it downward the full length of the slot.
Tighten the knob. To return the graticule to functioning
position, reverse the process.
The graticule cover and mask assembly is held securely
in place by four slotted graticule nuts and is provided with
hinge fittings for mounting the viewing hood. In addition,
the hinge fittings allow quick removal of the viewing hood
so that a Tektronix Model C-12 or C-19 camera may be
mounted. The Model C-19 camera is especially designed
to photograph the fast sweeps of the Type 519 Oscillo-
scope. When the camera is not being used, it can be
unlatched and swung away from the CRT screen.
Graticule IIlumination
The graticule is illuminated by two lamps located at the
top edge of the graticule. The SCALE ILLUM. control, located
below the oscilloscope screen, is rotated clockwise to
brighten the graticule markings and counterclockwise to dim
them.
Camera Jack
A camera jack, marked 6.3V CAMERA, provides a 6.3-volt
source for use with a camera. When the camera plug
is inserted in the jack, the SCALE ILLUM. control and oscil-
loscope graticule lights are automatically disconnected.
POSITIONING
Two controls, VERTICAL and HORIZONTAL, are used to
position the trace to the desired point on the oscilloscope
screen. A third positioning control, AXIS ROTATION, is
used to align the trace with the horizontal markings of the
graticule.
The VERTICAL position control has sufficient range to
allow the trace to be positioned completely off the top or
bottom of the screen, or to any intermediate point. The trace
2-4
moves up when the control is rotated clockwise and down
when the control is rotated counterclockwise.
The HORIZONTAL position control causes the trace to
move to the right when it is rotated in the clockwise direction
and to the left when it is rotated counterclockwise. The total
horizontal positioning range of the control is about 2 centi-
meters.
The AXIS ROTATION control is a screwdriver adjustment
located between the VERTICAL and HORIZONTAL controls.
This adjustment permits the trace to be rotated about an
axis through the center of the screen.
VERTICAL-DEFLECTION SYSTEM
Signal Input Connection
The electrical signal to be observed is applied externally
through a 125-ohm coaxial cable to the SIGNAL 125 con-
nector. If the impedance of the signal source is other than
125 ohms, corresponding cables and a suitable adaptor
should be used to prevent mismatches and resulting reflec-
tions. The signal passes internally first through a trigger
takeoff, then through a 45-nsec delay cable to the distributed
vertical deflection system of the CRT. The signal causes the
spot to be deflected vertically. The spot traces out the sig-
nal waveform on the screen as the spot is deflected hori-
zontally by the horizontal sweep circuits. The vertical size
of the display form can be adjusted to a suitable
amplitude by inserting external attenuators or an amplifier
in series with the signal-carrying cable. Or, if the Cali-
bration-Step Generator is being used as the signal source,
the vertical amplitude of the waveform can be adjusted by
means of the Calibration-Step Generator front-panel con-
trols.
The vertical sensitivity of the Type 519 Oscilloscope is
dependent on the CRT mounted in the instrument and on the
adjustment of the high voltage. The risetime and sensitivity
of each Type 519 CRT is measured at the factory. These
measurements are then recorded on the CRT face mask. The
sensitivity measurement can be checked at any time by using
the Calibration-Step Generator.
To check the measurement, connect a 125-ohm cable from
the OUTPUT 1250 connector to the SIGNAL 1250 con-
nector. Set the (CALIBRATION-STEP GENERATOR) RANGE
switch to 10V TO 1250 and rotate the VOLTS control to
10.00. Adjust the oscilloscope front-panel controls for a
stable presentation of the step waveform. Adjust the VOLTS
control until the portion of the waveform located 2 nsec
after the rise is exactly one centimeter high. The vertical
sensitivity in volts per centimeter can be read directly from
the VOLTS dial.
For example, if the VOLTS dial shows a reading of 8.70,
the vertical deflection factor is 8.7 volts per centimeter.
When connecting the oscilloscope to any signal source,
the connections should be made directly through 125-ohm
cables or through suitable impedance matching devices to
the SIGNAL 125 connector. However, when impedance
®

matching devices are used, you must consider possible signal
voltage changes produced by the devices. If the signal
amplitude is too great, it will be necessary to attenuate the
signal to a usable level before applying it to the SIGNAL
125Q connector. This can be done by inserting a 1250
attenuator (of known attenuation factor) between the signal
source and the SIGNAL 1250 connector. Attenuators may
be used individually or may be ‘“'stacked’ (connected in
series).
If the signal amplitude is too low to produce sufficient
vertical deflection, an external amplifier can be inserted
between the signal source and the SIGNAL 125 Q connector.
However, if the amplifier does not provide the correct input
and output impedance, severe waveform distortion may
result. In addition, if the amplifier stages have limited band-
width, or do not operate linearly, the signal will not be
reproduced faithfully on the CRT.
In general, to obtain an accurate waveform display and
to prevent unwanted reflection of high-frequency waveforms
or of fast-rise pulses, all cables should be terminated in
their characteristic impedances. An exception is described
under Accessories, part (4) Adaptor N50/N125 (page 2-11).
Delaying the Signal
The Type 519 Oscilloscope contains a fixed 45-nanosecond
signal-delay line which allows sufficient time for the trigger
circuits to process the trigger signal and start the sweep
before the leading edge of the input signal arrives at the
CRT. The internal delay cable provides about 10 nano-
seconds extra delay after sweep start and before display
of the triggering signal. At the slower sweep rates the trig-
gering signal will appear very near the start of the trace.
If you wish the signal to appear farther to the right, you
may insert additional 125-ohm delay cable, but at the ex-
pense of risetime. The extra delay cable must be added
after the trigger takeoff point to increase the signal delay.
The most common point of insertion is at the CRT end of the
fixed delay line.
The DELAY control provides a 35-nanosecond adjust-
ment in sweep starting time with respect to the triggering
signal. Within this range of adjustment, the DELAY control
can be used to select the display time and thus apparently
position the waveform horizontally on the screen with re-
spect to the trace.
For triggered sweep operation with externally-derived
trigger signals, the time relationship of the external trigger
signal to the input signal must fall within the adjustment
range of the DELAY control. If, for example, too much de-
lay is introduced by using long cables to couple the trigger
signal to the EXTERNAL TRIGGER 125 connector, the in-
put signal will arrive at the vertical deflection plates be-
fore the sweep is triggered. The signal input waveform,
having arrived early, will not be displayed on the screen.
To offset external delay of this type, shorten the external
trigger cable, if possible. If this is not possible, cable can
be added into the signal-carrying circuits, but only with loss
of bandwidth due to high-frequency attenuation in the cable.
The delay provided by a typical 125-ohm cable such as
the RG-63/U cables shipped with the oscilloscope is approxi-
mately 1.2 nsec per foot. If any portion of the input wave-
form is displayed on the screen, the amount of delay which
®
Operating Information—Type 519
24 n aoe rl n
T T — T T Tt
=
“4
~
(a)
4 j Se | 1
1 t ee any | 1
Fig. 2-3. Typical waveforms resulting from incorrect signal or trig-
gering signal delays. Waveform (a) results from either too much
triggering delay or too little signal delay. Waveform (b)
results either from too little triggering delay or too much signal
delay.
must be added or subtracted to display the waveform pro-
perly on the screen can be determined by the sweep rate
and the number of divisions that the display must be moved.
If the display must be moved to the right, less delay in the
trigger cable is required. Fig. 2-3 shows displays resulting
from incorrect signal or trigger delays.
When 30-megacycle or higher repetition-rate signals of
identical shape and amplitude are being displayed, the DE-
LAY control will always permit display of the complete
waveform. If all waveforms are uniform, it is not important
which one is displayed. The internal delay line may be
bypassed by direct connections to the CRT if desired, at the
sacrifice of internal triggering from the signal.
Triggering (or Synchronizing) the Sweep
In most applications it is desirable for a repetitive wave-
form to appear stationary on the oscilloscope screen so that
the characteristics of the waveform can be examined in de-
tail. As a necessary condition for this type of display, the
start of each horizontal sweep must be time-related to a
characteristic of the input waveform. In the Type 519 Oscil-
loscope this is accomplished either by triggering or syn-
chronizing the sweep with the displ or with
another waveform bearing a definite time relationship to the
pl More information about the horizontal
sweep. is given in the Time Base portion of this section of
the manual.
The following paragraphs outline the operation of the
various triggering controls in the TRIGGER section of the
front panel, in the order normally encountered. Usually,
the TRIGGER SOURCE switch would be set first, GAIN
switch second, and FUNCTION switch third. Finally, the
PULSE AMPLITUDE OR SYNC control is adjusted to obtain
a stable display for ‘triggered’ sweep operation. For
2-5

Operating Information—Type 519
“synchronized” sweep operation, both the PULSE AMPLI-
TUDE OR SYNC and VERNIER SYNC controls may be ad-
justed to obtain a stable display.
Selecting the Trigger Source
The sweep can be either triggered or synchronized (de-
pending upon the setting of the FUNCTION switch) from
the following sources: (1) displayed waveform, (2) exter-
nally-derived waveform, (3) Calibration-Step Generator, or
(4) Rate Generator. The trigger source selection is by means
of the TRIGGER SOURCE switch. Each trigger source has
advantages for certain applications.
(1) Displayed Waveform. Triggering from the displayed
waveform is the method most commonly used. Triggering is
from the displayed waveform with the TRIGGER SOURCE
switch set to either the -+-INT. or —INT. position. Internal
triggering is convenient, since no external triggering signals
or connections are required. A displayed waveform that
produces at least two trace-widths of vertical deflection
with a time duration of one nanosecond or more is sufficient
for reliable triggering.
(2) Externally-Derived Signal. To trigger the sweep from
an external signal, connect the triggering signal to the EX-
TERNAL TRIGGER 125Q input connector. The external
triggering signal must be at least 20 millivolts in amplitude,
with a time duration of 1 nanosecond or more. The maxi-
mum amplitude should not exceed -2 volts peak except
when the GAIN switch is set to X.2. In the X.2 position the
external trigger should not exceed +10 volts. Larger trig-
gers may be attenuated externally. External triggering sig-
nals can be used when the TRIGGER SOURCE switch is
set to either +EXT. or —EXT. External triggering signals
preferably should be disconnected from the EXTERNAL
TRIGGER 1250 connector when some other mode of trig-
gering is used to reduce the possibility of stray triggering.
External
triggering provides definite advantages over
other methods of triggering in certain applications. With
external triggering, the triggering signal usually remains
constant in amplitude and shape (depending upon the
source). Also, time and phase relationships between wave-
forms at different points in a circuit can be seen. If, for ex-
ample, the external triggering signal is derived from the
waveform at the input to a device under test, it is possible
to observe the shaping, jitter, amplification, or delay of
the signal through the device without resetting the oscillo-
scope triggering controls for each observation.
(3) Calibration-Step Generator. In the +CAL. or —CAL.
positions of the TRIGGER SOURCE switch, the triggering sig-
nal is obtained internally from the Calibration-Step Gen-
erator. The signal is derived through the use of a trigger
takeoff circuit inserted near the termination of the gener-
ator. Therefore, it is necessary to keep in mind that the con-
trols which adjust the output amplitude of the Calibra-
tion-Step Generator also affect the amplitude of the trig-
gering signal available at the +CAL. and —CAL. posi-
tions
of the TRIGGER SOURCE switch. These two positions
of the TRIGGER SOURCE switch are used to observe a wave-
form which is time-related to the output waveform of the
Calibration-Step Generator. It is then possible to observe
and accurately measure shaping, jitter, amplification,
or delay at various points in the device under test. In
2-6
addition, the internal-trigger requirement for a minimum
signal height and duration can be circumvented. When the
step generator is not being used, it should be set on STAND-
BY.
(4) Rate Generator. The RATE GEN. position of the TRIG-
GER SOURCE switch provides triggering signals which can
be varied to cover a continuous repetition-rate range from
3cps to 30kc. These signals can then be used to trigger
the sweep at a known repetition rate within the above
range. To select the Rate Generator trigger, set the
TRIGGER SOURCE switch to RATE GEN. Then set the
MULTIVIBRATOR switch and CYCLES/SEC control to the
desired repetition rate.
Selecting the Trigger Polarity
The horizontal sweep can be triggered on either the ris-
ing (+slope) or falling (—slope) portion of the triggering
waveform as determined by the position of the TRIGGER
SOURCE switch.
In many applications the triggering polarity is important
since triggering on the wrong slope will make it impossible
to display the portion of the waveform which is of interest.
In many other cases, however, such as high-frequency repeti-
tive waveforms, the triggering signal polarity is usually not
important.
Selecting the Trigger Gain
A four-position GAIN switch permits incoming trigger sig-
nals to be attenuated or amplified as necessary for proper
triggering or synchronization. The four gain settings are:
X.2, NORMAL, X5, and X20. To aid in determining which
GAIN switch setting to use for reliable triggering, Table 2-1
is included. Additional information is given in the PULSE
AMPLITUDE OR SYNC control description.
TABLE 2-1
TRIGGER
SOURCE Approximate GAIN Switch Settings
Switch
Setting X.2 NORMAL | X5t X20t
RATE GEN. Always set
in this
position.
+CAL. * 8v to 50v|1.5v to} 0.5v to
50 v 50v
EXT. lvtol0v 0.2 v to 2v|0.04v to} 0.01 v to
(peak) (peak) 2v 2v
EINT. ** 10 v (pulse) to]2v to 20v|0.4v to | 0.1 v to
100 v (pulse) (pulse) 20 v 20 v
+ Used for small amplitude triggers up to 200 mc.
* Calibration-Step Generator output step amplitudes are listed.
Approximately 2.5% of the step amplitude is coupled to the + CAL.
and —CAL. positions of the TRIGGER SOURCE switch.
** Voltage ranges of signals applied to the SIGNAL 125 {2 con-
nector are given. Approximately 10% of the signal amplitude is
picked off and coupled to the --INT. and —INT. positions of the
TRIGGER SOURCE switch.

Selecting the Trigger Function
Three functions or modes of operation are provided in
the Type 519 Oscilloscope to cover a wide range of trig-
gering conditions: They are: PULSE, SYNC, and HF SYNC.
To determine the best trigger mode for a particular appli-
cation, it is best to have some understanding of all three
before making a selection.
Each of the triggering modes is designed to provide sta-
ble triggering from a certain type of waveform. For many
applications, however, more than one mode will work
well. For such applications, the triggering mode selected
is simply a matter of choice.
The PULSE mode permits choice of a free-running sweep or
a sweep triggered by signals at random or uniform repeti-
tion rates up to 50 mc. The upper repetition-rate limit varies,
depending upon the regularity of the pulse period. The
PULSE mode, when used in conjunction with the SINGLE
SWEEP feature, permits photographs to be made of single
events at any setting of the NANOSEC/CM switch.
The SYNC mode permits stable displays of waveforms
occurring at a constant repetition rate~up to approximately
150 mc. To select this mode, place the FUNCTION switch
in the SYNC position.
The HF SYNC mode permits the sweep to be synchronized
from high-frequency signals in the range from approximately
100 mc to more than 2kmc. To use the high-frequency syn-
chronization mode, place the FUNCTION switch in the HF
SYNC position.
Triggering or Synchronizing the Sweep
The last controls normally operated in the TRIGGER sec-
tion of the front panel are the PULSE AMPLITUDE OR SYNC
and VERNIER SYNC controls. These controls are used for
two functions: pulse amplitude selection and synchroniza-
tion, depending upon the setting of the FUNCTION switch.
If the FUNCTION switch is set to the PULSE position, the
PULSE AMPLITUDE OR SYNC control determines the level a
signal must reach to initiate the sweep. All triggers below
the set level are rejected. In order for the control to oper-
ate properly within its rotational range, sufficiently large
triggers must be available as explained earlier under Select-
ing the Trigger Gain.
Triggering on small signals is best when the control is set
just short of the point where the sweep free runs. The sweep
normally free runs when the PULSE AMPLITUDE OR SYNC
control is rotated clockwise past the RECURRENT arrow.
|
T
Pry
VOLTAGE
—nneneie
A
pigs
fi
TT
TIME >
Fig. 2-4. The usual oscilloscope display is a graphical presentation
of voltage versus time.
©1
Operating Information—Type 519
If the FUNCTION switch is set to either the SYNC or the
HF SYNC position, the PULSE AMPLITUDE OR SYNC con-
trol is used for making the coarse synchronization adjust-
ment. Final adjustment may be made with the VERNIER
SYNC control. The sweep repetition rate will synchronize at
the frequency of the triggering signal or at some sub-
multiple frequency.
The VERNIER SYNC control is normally set at midrange
until the coarse adjustment is made, then the VERNIER SYNC
control is adjusted to obtain a stable display.
TIME BASE
Horizontal Sweep
The Type 519 Oscilloscope graphically presents instantane-
ous signal voltage versus time (see Fig. 2-4). The signal volt-
age produces vertical deflection of the trace; time is repre-
sented through horizontal deflection. The horizontal sweep
is also known as the time base, since horizontal deflection
of the spot bears a definite relationship to time and provides
the means for making time measurements from the screen.
The NANOSEC/CM switch selects the desired sweep rate
from one of nine accurately calibrated rates available.
Time base steps range from 2 nanoseconds per centimeter to
1000 nanoseconds (1 psec) per centimeter. The sweep gen-
erator has been designed to provide long-term stability of
sweep calibration and linearity.
Single Sweep Operation
The Type 519 Oscilloscope permits a single-sweep pres-
entation to be obtained and eliminates all subsequent
sweeps so the signal can be clearly recorded without con-
fusion resulting from multiple traces. The single-sweep fea-
ture is selected by placing the NORMAL-SINGLE SWEEP
switch in the SINGLE SWEEP position. The RESET button
must be actuated to ‘arm’ the time base and permit a sin-
gle-trigger event.
When the FUNCTION switch is placed in the PULSE posi-
tion and the PULSE AMPLITUDE OR SYNC control is set
fully clockwise (past the RECURRENT arrow or line), a sin-
gle sweep runs immediately each time the RESET button is
depressed.
When the PULSE AMPLITUDE OR SYNC control is set for
triggered sweep operation, the single sweep does not neces-
sarily occur immediately after the RESET button is depressed.
Instead, the READY lamp lights to indicate that the sweep
is armed and ready to be triggered. When a trigger is re-
ceived, the sweep runs once and the READY light goes out.
Each time the RESET button is depressed the procedure is
repeated.
When the FUNCTION switch is placed either in the SYNC
or HF SYNC position, a single sweep runs immediately each
time the RESET button is depressed regardless of the set-
tings of the PULSE AMPLITUDE OR SYNC control.
The time base may also be reset externally, using the
3-conductor plug supplied in the accessory kit and a normal-
ly open push-button switch. Connect the two center terminals
of the plug through a cable to the two terminals on the push-
button switch and insert the plug into the EXTERNAL RESET
jack on the rear panel. With the NORMAL-SINGLE SWEEP
switch in the SINGLE SWEEP position, the push-button switch
may be used to arm the sweep.
2-7

Operating Information—Type 519
{1) Recurrent sweep.
{2) Triggered sweep.
See
(1) =a) TIME BASE
(1)
“SO NORMAL
Output from +TRIGGER 50 {7 tor
or DELAYED + GATE 50 or
+ RATE 50 © connector
are RATE GENERATOR
\
\
|
|
|
OPTIONAL
Output from external
circuit directly to crt if
less delay is required
'
Circuit to be
triggered = or
synchronized \
aap
cirevit to oscilloscope
input.
Fig. 2-5. Using the Type 519 Oscilloscope to drive an external circuit.
the oscilloscope for display.
Synchroscope Operation
In the usual oscilloscope application, the sweep is trig-
gered or synchronized by the input waveform. However,
in some applications it may be more desirable to reverse the
process and drive an external circuit from the oscilloscope.
In this ‘‘synchroscope” application, the sweep is caused to
free run or to be triggered by the Calibration-Step
Generator or the Rate Generator. The output signal
from the +TRIGGER 500, the DELAYED +GATE, the +
RATE 50, or the OUTPUT 125 connector is used to in-
itiate the input waveform (see Fig. 2-5).
The sweep can be made to free run in any position of the
FUNCTION switch. If the PULSE position of the FUNCTION
switch is used, the PULSE AMPLITUDE OR SYNC control
must be rotated fully clockwise past the RECURRENT arrow.
The sweep free runs at all times when the FUNCTION switch
is in either the SYNC or HF SYNC positions. The number of
free-running sweeps per second is determined by the settings
of the NANOSEC/CM switch (refer to Table 2-2).
A free-running sweep also provides a convenient refer-
ence trace on the oscilloscope screen without requiring an
input signal. The trace can then be positioned to a desired
point on the oscilloscope screen or can be used to establish
a zero-voltage reference line.
Delayed Trigger
A delayed triggering pulse is produced at the DELAYED
+GATE 50 connector of the oscilloscope at approximately
2-8
Output
from
a.
ff
lr
le
aie
se
ee
ee
ke
oe
ne
ee
ae
in
The output of the external circuit is then applied to the input of
TABLE 2-2
NANOSEC/CM SWEEP REPETITION RATES |
Switch Settings | (Recurrent Rates)
2 | Adjusted to 400 kc
5 200 ke nominal
10 100 ke nominal
20 50 ke nominal
50 20 kc nominal
100 10 ke nominal
200 5 ke nominal
500 2ke nominal
1000 1 ke nominal
the time of sweep start. The delay of the delayed trigger-
ing pulse with respect to the time that the trigger is accepted
and a pulse is produced at the +TRIGGER 500 connector
can be adjusted over a range of approximately 35 nanosec-
onds by means of the DELAY control.
RATE GENERATOR
The output pulse from a transistor operating in the ava-
lanche mode is coupled to the RATE GEN. position of the
TRIGGER SOURCE switch and to the +RATE 500 con-
nector.
The pulse risetime is less than 0.8 nanosecond, ampli-
tude is nominally +15 volts, and duration is approximately
10 nanoseconds. A typical Rate Generator waveform as
displayed on the Type 519 is shown in Fig. 2-6. To use the
®

eI
bit
Tie
2 NSEC/CM
Fig. 2-6. Typical Rate Generator output waveform as displayed
on the Type 519 Oscilloscope.
Rate Generator, set the TRIGGER SOURCE switch to
RATE GEN. Then adjust the CYCLES/SEC and MULTIPLIER
controls for the desired repetition rate. Any frequency be-
tween 3cps and 30kc can be selected within an accuracy
of 10%.
Since the sweep can be triggered at the repetition rate
set by the Rate Generator from 3cps to 30kc, this fea-
ture
can be used for applications such as those described
previously under the headings ‘Selecting the Trigger
Source’, and ‘“Synchroscope Operation”. When the Rate
Generator is not used, it should be turned off by placing
the MULTIPLIER switch to the OFF position to reduce the
possibility of stray triggering.
CALIBRATION-STEP GENERATOR
Step Waveform
The step waveform from the Calibration-Step Generator
is generated by discharging a charged coaxial line into
LOO e* O82 ge ions g
eeeeeees” 9 6 80 ee
eee e. Soe eer
by goss ¥, o% 5098
< “fe0oe WY A; ry) Soest 66 ay, ss
OIL pee aet
Trigger Takeoff Line-Charging Network
(The complete Trigger (Can be disconnected so
Takeoff can be disconnect- that = additional charge
ed from the Type 519 and cable may be added.)
used in other 125-ohm sys-
tems.)
Fig. 2-7. Locations of the Calibration-Step Generator line charging
network and trigger takeoff.
®
Operating Information—Type 519
an external load through a magnetically-operated dry-
reed switch. The physical length of the charged line
determines the duration of the output step waveform. In
the Type 519, with no external charge line added, the
duration of the constant-amplitude portion of the step is
equal to twice the transit time of the built-in 1.5-nsec charge
line. (Transit time of the charge line is the time required
for a signal to pass from one end of the line to the other.)
For
the 1.5-nsec charge line, then, the duration of the output
pulse is 3 nsec. To obtain a longer duration step waveform,
an additional length of charge line (cable) may be added
to the Charge Line Connector located next to the Trigger
Takeoff (see Fig. 2-7). When an additional charge line is
added, the charging network and the charging voltage must
be disconnected. They must then be connected to the open
end of the added charge line. A typical display of the
Calibration-Step Generator waveform as seen on the Type
519 Oscilloscope appears in Fig. 2-8.
it
+
“ae.
ELS
et
LEA
ES
2
i
2 NSEC/CM
Fig. 2-8. Typical Calibration-Step Generator waveform as displayed
on the Type 519 Oscilloscope. It is not always possible to com-
pletely eliminate reed switch multiple contact bounce. Extraneous
traces, therefore, sometimes will occur in the display.
Polarity
Step polarity is selected by the POLARITY switch. The
polarity of the step at the output connector is the same as
the polarity of the charge voltage. The setting of the TRIG-
GER SOURCE switch should agree with the setting of the
POLARITY switch for normal triggering.
Amplitude
The step amplitude is dependent upon the amount of
charging voltage used. The charge voltage obtained from
the charging source at the instant of reed switch closure is
2 times the step voltage present at the OUTPUT 1250
connector when driving an external 125-ohm load. The
step voltage reading is accurately indicated by the settings
of the RANGE and VOLTS controls.
When the VOLTS control is set to 10.00, the RANGE
switch permits a choice of two full scale step amplitudes,
10 volts or 1 volt. When the RANGE switch is placed in the
10V TO 1250 position, 10 volts is produced across a 125-
ohm load. When the RANGE switch is set in the 1V TO
50 position, a T50/T125 adapter must be properly con-
nected to the OUTPUT 125 connector to obtain a 1-volt
step into a 50 ohm load.
The scale of the VOLTS control, when used with either of
the two above RANGE switch positions, indicates the step
2-9

Operating Information—Type 519
amplitude. The VOLTS control is the 0 to 1 multiplier for
the two ranges.
When the RANGE switch is set to the VARIABLE position,
the step amplitude may be preset by the VARIABLE con-
trol to any uncalibrated amplitude from 0 to approximately
50 volts when driving a 125-ohm load. To determine the
amplitude of the step for any setting of the VARIABLE con-
trol, apply the step waveform from the OUTPUT 1250
connector through a 125-ohm cable (and attenuator, if
needed) to the SIGNAL 12509 connector. Measure the
amplitude of the vertical deflection in centimeters and
multiply the distance measured by the sensitivity of the
oscilloscope (and attenuation if used).
Adjusting the Drive and Frequency
Two front-panel controls, DRIVE and FREQUENCY, con-
trol the movement of the dry-reed switch. These controls
are adjusted to cause the reed to make-and-break contact
with a minimum of contact bounce.
To adjust the two controls, they must first be preset fully
counterclockwise. Then advance the DRIVE control until the
reed vibrates (makes a buzzing sound). Advance the FRE-
QUENCY control until the reed fails to operate and then
rotate the control slightly counterclockwise to start the reed
operating again. Slowly rotate the DRIVE control counter-
clockwise while rotating the FREQUENCY control back and
forth to find the resonant frequency of the reed. The reso-
nant frequency is found when the drive is decreased to a
point where the reed will vibrate in only one small rota-
tional area of the FREQUENCY control range. For optimum
operation the DRIVE and FREQUENCY controls are then
adjusted to obtain the most stable waveform near the reso-
nant frequency of the reed. When adjusting the DRIVE con-
trol, use enough drive to get solid closures of the reed
contacts. The resonant frequency of most reeds is usually
within the range of 700 to 800 cps.
NOTE
The reed switches used in the Type 519 are
chosen to produce the best possible waveform.
The high requirements of these switches frequently
result in a short lifetime. To extend the life of
the reed switch set the RANGE switch to STANDBY
when the Calibration-Step Generator is not being
used.
ACCESSORIES
The following information pertains to the accessories
which are included with the Type 519 Oscilloscope. Other
optional accessories which are available are accompanied
by specific application notes. See also Section 7, Acces-
sories.
(1) 125 Q Termination
The 125Q Termination (Fig. 2-9) is supplied as a spare
for the T519P-A CRT termination or to terminate any 125-
ohm cable.
* The letter ‘‘T’’ in an adaptor type means ‘'Terminated"; ‘‘N"
means ‘‘Not Terminated".
2-10
A we \
2 125 Q DISC-TYPE |
|
150 91 SHUNT RESISTOR |
CONNECTOR™ | | sa i
NS ee ee per
Fig. 2-9. Construction of the 12592 Termination.
TYPE 519 OSCILLOSCOPE
CALIBRATION-STEP GENERATOR
our T SIGNAL
1 12,
PA
O
125 Q CABLE
O
RANGE control
set to 1 V to 50
50Q
CONNECTOR 1T50/T125
ADAPTOR
125 2 CONNECTOR
502
150/T125 DEVICE
ADAPTOR UNDER
TEST 1252
50 & CABLE CONNECTOR
502
50 9 INPUT CONNECTOR
502 125 Q
CONNECTOR CONNECTOR
(64.6 Q DISC-TYPE 96.8 © SERIES *
ISHUNT RESISTOR™ S RESISTOR
Vv
{
I
a
1
/ ;
Py
ONAL
Fig. 2-10. Construction of the T50/T125 Adaptor. Also shown are
two typical applications for this adaptor.
(2) Adaptor T50/T125*
This adaptor (Fig. 2-10) is commonly known as a mini-
mum loss matching pad. Designed to match between a
50-ohm line and 125-ohm line, the attenuator presents
minimum loss and reflections. It contains a network com-
posed of a shunt and a series resistor. Though the attenu-
ator presents a correct impedance match “in either direc-
tion’, the signal voltage transmission factor of 0.225 in
going from 125 ohms to 50 ohms is less than the N50/N125
adaptor described later. In going from 50 ohms to 125 ohms,
the signal voltage transmission factor is approximately 0.564.
The primary advantage of the T50/T125 adaptor is that it
receives signals into either end without producing reflections.
(3) Adaptor T50/N125
This adaptor is usually called a 50-ohm termination
adaptor and the internal circuitry is shown in Fig. 2-11. In
actual use the 83.3-ohm resistor is shunted by the 125-ohm
input impedance of the load. The combined resistances
present a total input impedance of 50-ohms to the signal
source.

2 Q 50 e
EXTERNAL To Type 519
PULSE OR CW [-}—202 CABLE AY 1 95[ Je SIGNAL 125 2
GENERATOR (ANY LENGTH) Connector
125 Q
50 Q eanateme iia Hoi Rae Se a)
\, 83.3 2 DISC-TYPE \
| SHUNT RESISTOR
\
i
fet
;
2. $ |
vi }
howe sien sm sm it te ste on
Fig. 2-11. Construction of the T50/N125 Adaptor. A typical appli-
cation
for this adaptor is also shown.
The adaptor. is designed to handle pulse or continuous-
wave signals originating from a 50-ohm source. It is not
generally used to handle a signal traveling in the 125-ohm
to 50-ohm direction, since it does not provide a termination
for the 125-ohm connector. When a T50/N125 is used to
connect a 50-ohm signal to the 519 signal input con-
nector, the signal voltage is unchanged and the signal
cable is fully terminated. The vertical deflection system
has 50 nsec of delay before it is terminated in 125 ohms.
Any reflections from the CRT, its connections, or termination,
would return through the delay fine and reflect from the
nonterminating end of the T50/N125 to reappear at the
CRT 90 to 100 nanoseconds after the original signal.
(4) Adaptor N50/N125
Also called an unterminated adaptor, this accessory (Fig.
2-12) is a straight-thru connector which connects a 50-ohm
line directly to a 125-ohm line. This unit is used primarily
for pulse applications. If a pulse from 50 ohms is applied to
the 50-ohm end of the adaptor, the pulse amplitude
increases 1.43 times at the 125-ohm end due to the reflec-
tion at the end of the 50-ohm system. In going from 125
to 50 ohms, approximately a 0.572 transmission factor
results. This is more than for any of the other adaptors.
Since it is a nonterminating unit, it will produce a high
VSWR when used with high-frequency sine waves.
502 50 *
EXTERNAL ‘0 Type 519
TEST PULSE LENGTH OF 4 0 pasos Lee siGNal 125.0
GENERATOR 50 2 CABLE onnector
RG-8A/U
; T= Pulse Duration
| ‘ ; | T
a Cable Length= ->
CONNECTOR, Soe os oe CONNECTOR
‘i \ \
Li |
oT |
4 }
Ne /
<<" SIGNAL
Fig. 2-12. Construction of the N50/N125 Adaptor. Also shown
is a typical application for the adaptor.
®
Operating Information—Type 519
When the adaptor is used for pulses, the abrupt discon-
tinuity inherent in the unit causes a reflection to occur
which may interfere with the displayed form unless
certain precautionary measures are taken. To prevent a
reflection from occurring on the displayed waveform, make
the electrical length of the cable supplying the adaptor
equal to or more than T/2, where T is the length of the
pulse to be observed. The reflection will then appear
after the displayed waveform.
TABLE 2-3
SIGNAL VOLTAGE
TRANSMISSION FACTORS
SIGNAL SIGNAL
DIRECTION ADAPTOR DIRECTION
500 to 1250 TYPE 1259 to 500
564 T50/T125 .225
1.000 T50/N125 Not Used
Not Used N50/T125 400
1.43 N50/N125 572
1.58 Theoretical 633
Maximum Power
Transfer
(5) 125 Insertion Unit
This unit is a hollow tube with 125-ohm connectors on
each end and access holes located on each side to permit
small components to be mounted inside. A snap-on sleeve
cover permits adequate shielding of components and pro-
vides minimum discontinuity in the line. The unit facilitates
125-ohm (or 50-ohm, if desired) connections for pulse testing
components such as diodes or transistors. It can also be
used for testing or design of networks such as filters, attenu-
ators, impedance-matching circuits, etc., and measurements
on amplifiers and many other devices. The device makes
it unnecessary to use a chassis with long leads and poor
impedance matching. Instead, the components or circuit can
be mounted in the small insertion unit and used as part
of the 125-ohm system.
For series tests, the effective impedance of the test cir-
cuit is 2Zo. For shunt tests, the effective test circuit imped-
ance is Z)/2. Thus, for tests using 125-ohm cable, a series
measurement is with 250 ohms equivalent series resistance
while a test from center conductor to ground is with a
62.5-ohm equivalent source resistance. The above condi-
tions assume proper termination impedances in both direc-
tions from the test point.
(6) 125 © Coupling Capacitor
The 125Q Coupling Capacitor connector contains a
silvered-ceramic, wafer-type capacitor connected in series
with the inner conductor. ‘A slight amount of compensating
inductance is supplied by the conductors butt-soldered to
the capacitor. (See Fig. 2-13).
This unit is normally used for ac-coupling high-frequency
signals to the Type 519 Oscilloscope with minimum reflec-
tions. Low-frequency signals and dc are blocked. Its char-
acteristics are: ;
Coupling Capacitance: 0.01 uf +20%, 0.0082 uf
GMV.
2-11

Operating Information—Type 519
CENTER CONDUCTOR
BUTT-SOLDERED
125 Q TO CAPACITOR 125 Q
CONNECTOR
SILVERED CERAMIC
WAFER-TYPE CAPACITOR
Fig. 2-13. Construction of the 1252 Coupling Capacitor.
400 volts.
Negligible.
Voltage Rating:
Reflections:
Low-Frequency Cutoff
in 125 Q: Approximately 65 kc.
(7) 125 Q 1 KMC Timing Standard
The 1259 1KMC Timing Standard is a Sweep Calibrator
which can be used to make periodic sweep calibration
checks of the 2- and 5-nanosecond/cm rates. Refer to the
Calibration Procedure section of this manual.
2-12
(8) 125 QO Delay Cables
Different length cables are supplied for use in coupling
the signal and/or trigger to the appropriate input connectors
on the front panel of the Type 519 Oscilloscope. The loss
per foot of RG-63/U cable is 0.06db at 1kmc. The delay
time marked on each cable is the time required for a signal
to travel from one end of the cable to the other.
(9) 125 Q Cable Connector Parts
(a) Double Button Assembly. Used for replacing a dam-
aged or worn insert in any of the 125-ohm front-panel
connectors or cable connectors.
(b) Panel Adaptor Assembly. Replacement for any of
the front-panel 125-ohm connectors.
(c) 125Q Cable Connector. Replacement for any of the
cable connectors.
(10) Reed Switch
Two spare reed switches are included as replacements
for the reed switch used in the Calibration-Step Gen-
erator. To replace the reed switch refer to the Mainte-
nance section of this manual.