HP 8414A Service manual

CERTIFICATION
Hewlett-Packard Company certifies that this product met its published specifications at the time of
shipment from the factory. Hewlett-Packard further certifies that its calibration measurements are
traceable to the United States National Bureau of Standards, to the extent allowed by the Bureau’s
calibration facility, and to the calibration facilities of other International Standards Organization
members.
WARRANTY
This Hewlett-Packard instrument product is warranted against defects in material and workmanship
for a period of one year from date of shipment. During the warranty period, Hewlett-Packard Com¬
pany will, at its option, either repair or replace products which prove to be defective.
For warranty service or repair, this product must be returned to a service facility designated by HP.
Buyer shall prepay shipping charges to HP and HP shall pay shipping charges to return the product to
Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to HP
from another country.
HP warrants that its software and firmware designated by HP for use with an instrument will execute
its programming instructions when properly installed on that instrument. HP does not warrant that the
operation of the instrument, or software, or firmware will be uninterrupted or error free.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance
by Buyer, Buyer-supplied software or interfacing, unauthorized modification or misuse, operation
outside of the environmental specifications for the product, or improper site preparation or main¬
tenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HP SPECIFICALLY DISCLAIMS THE IM¬
PLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES. HP
SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSE¬
QUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL
THEORY.
ASSISTANCE
Product maintenance agreements and other customer assistance agreements are available for Hewlett-
Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service Office. Addresses are
provided at the back of this manual.

8414A
POLAR DISPLAY
SERIAL NUMBERS
This manual applies directly to instruments with
serial numbers prefixed 981 and 1144A.
With changes described in Section VII, this manual
also applies to instruments with serial numbers pre¬
fixed 936 and 940.
For additional important information concerning
serial numbers, see INSTRUMENTS COVERED
BY MANUAL in Section I.
This manual does not apply to serial numbers pre¬
fixed 933 and below.
Copyright HEWLETT-PACKARD COMPANY 1970
1501 PAGE MILL ROAD, PALO ALTO, CALIFORNIA, U. S. A.
MANUAL PART NO. 08414-90016
Microfiche Part No. 08414-90013
Printed SEPT. 1973
Whol HEWLETT
mLnM Packard

Table of Contents
Model 8414A
TABLE OF CONTENTS
Section Page
I GENERAL INFORMATION .1-1
1-1. Description .1-1
1-4. Equipment Supplied .1-2
1-6. Instruments Covered by Manual. 1-2
1- 10. Options . 1-2
II INSTALLATION .2-1
2- 1. Initial Inspection.2-1
2-3. Repackaging for Shipment . . 2-1
2-4. Using Original Packaging . . 2-1
2-8. Using Other Packaging . . . 2-1
2-10. Preparation for Use.2-1
2-11. Installation.2-1
2- 13. Power Requirements .... 2-1
III OPERATION .3-1
3- 1. Introduction.3-1
3-3. Panel Features .3-1
3-5. Measurement Procedures . . . 3-1
3-7. Operating Information .... 3-1
3-8. Polar Display of Reflection
Coefficient and Phase Angle . 3-1
3-10. High Resolution Display of
Reflection Coefficient Meas¬
urements .3-1
3-12. Polar Display of Return Loss . 3-3
3-15. Polar Display of Transmission
Measurements .3-3
3-20. Scattering Parameters Measure¬
ment .3-4
3-22. Polar Display of Normalized
Impedance and Admittance . 3-4
3-24. Alternate Smith Chart Over¬
lays .3-5
3-29. Marking Frequency on the
Display .3-5
3-31. Display Blanking .3-5 '
3-33. Increased Accuracy for Reflec¬
tion Measurements by Min¬
imizing Directivity Errors . 3-5
3-36. H26-8414A Polar Display ... 3-7
Section Page
IV PERFORMANCE TESTS .4-1
4-1. Introduction.4-1
4-4. Equipment Required .4-1
4-6. Test Record .4-1
4-8. Accuracy Test .4-3
4-9. Horizontal and Vertical Output
Tests .4-4
4- 10. Marker and Blanking Input Tests 4-4
V ADJUSTMENT PROCEDURES ... 5-1
5- 1. Introduction.5-1
5-5. Factory Selected Components . 5-1
5-7. Equipment Required .5-1
5-9. Trace Alignment and Vertical
Gain Adjustment .5-4
5-10. Phase, Recorder Gain and
Pattern Shape Adjustments . 5-6
5-11. Astigmatism Adjustment . . . 5-8
5-12. Illumination Adjustment . . . 5-8
5-13. Intensity Adjustment.5-9
5-14. Manual Beam Centering Zero
Adjustment .5-10
5- 15. Phase Zero Adjustment .... 5-12
VI REPLACEABLE PARTS.6-1
6- 1. Introduction.6-1
6- 3. Ordering Information.6-1
VII MANUAL CHANGES .7-1
7- 1. Introduction.7-1
VIII SERVICE.8-1
8- 1. Introduction.8-1
8-3. Principles of Operation .... 8-1
8-5. Troubleshooting .8-1
8-7. Recommended Test Equipment . 8-1
8-9. Repair.. . 8-1
8-10. Part Location Aids .8-1
8-12. Circuit Board Repair .... 8-1
8-15. Component Replacement . . 8-1
8-17. Transistor Replacement . . . 8-2
8-19. Diode Replacement.8-2
8-21. Schematic Diagrams .8-3
li

Model 8414A
List of Illustrations
LIST OF ILLUSTRATIONS
Figure
Title
Page
Figure
Title Page
1-1.
Model 8414A Polar Display ....
1-0
8-6.
Conversion of Typical Time-
8-8
3-1.
Model 8414A Front and Rear Panel
Amplitude Graph to Polar Graph .
Features .
3-2
8-7.
Polar Vector of Test Signal ....
8-8
3-2.
Return Loss Overlay .
3-3
8-8.
Horizontal and Vertical Vectors Re-
3-3.
Typical Smith Chart Display of Nor-
quired to Deflect CRT Beam . .
8-9
malized Impedance .
3-4
8-9.
Vector Graph of a Typical Test
8-9
3-4.
Smith Chart Plot of Admittance
Signal .
Point .
3-5
8-10.
Simplified Overall Block Diagram
8-9
3-5.
CRT Overlays .
3-6
8-11.
Test Point Locations .
8-11
3-6.
Measured Reflection Coefficient . .
3-7
8-12.
Detailed Block Diagram.
8-11
3-7.
Locus of Measured Reflection when
8-13.
Phase Shifter and Phase Detectors,
Load is Moved .
3-7 Component Identification ....
8-13
3-8.
Locus of Measured Reflection with
8-14.
Phase Shifter and Phase Detectors,
Directivity Cancelled .
3-7
Schematic Diagram .
8-13
3-9.
Reflection Coefficient Measurement
3-8
8-15.
Low Pass Filters and Horizontal and
3-10.
Transmission Measurement ....
3-10
Vertical Drivers, Component Iden-
3-11.
Typical Polar Displays During Initial tification .
8-15
Calibration Adjustment.
3-11
8-16.
Low Pass Filters and Horizontal and
3-12.
Model 8414A-H26 Polar Display and
Vertical Drivers, Schematic
Automatic System Interface Block
3-12
Diagram .
8-15
Diagram.
8-17.
Intensity Modulator, Component
4-1.
Performance Test Equipment Setup .
4-2
Identification .
8-17
5-1.
Setup for Trace Alignment and Vert-
8-18.
Intensity Modulator, Schematic Di-
ical Gain Adjustment .
5-5
agram .
8-17
5-2.
Setup for Phase, Recorder Gain and
8-19.
CRT High and Low Voltage Supplies
Pattern Shape Adjustments . . .
5-7 and +150 Volt Supply, Component
5-3.
Setup for Manual Beam Centering
Identification .
8-19
Zero Adjustment .
5-11
8-20.
CRT High and Low Voltage Supplies
5-4.
Setup for Phase Zero Adjustment
5-13 and +150 Volt Supply, Schematic
6-1.
Cabinet Parts .
6-11
Diagram .
8-19
8-1.
Examples of Diode and Transistor
8-21.
Mainframe Plug-In Connector Detail
Marking Methods.
8-3
for H26-8414A.
8-20
8-2.
General Information on Schematic
8-22.
Mainframe Plug-In Connector Detail
Diagrams .
8-5
for Standard 8414A .
8-21
8-3.
Schematic Diagram Notes.
8-6
8-23.
Interconnection Diagram .
8-21
8-4.
Setup for Troubleshooting ....
8-7
8-24.
Location of Adjustments, Chassis-
8-5.
Phase and Amplitude Relationship of
8-8
mounted Parts and Major Assem-
Typical Reference and Test Signals
blies.
8-23
LIST OF TABLES
Table
Title
Page
Table
Title
Page
1-1.
Specifications .
1-1
6-3.
Parts List Indexed by HP Part Num-
4-1.
Recommended Test Equipment
4-1
ber .
6-12
4-2.
Performance Test Record ....
4-5
6-4.
Code List of Manufacturers ....
6-15
5-1.
Recommended Test Equipment
5-2
8-1.
Recommended Test Equipment . .
8-0
5-2.
Adjustment Controls and Functions
5-3
8-2.
Printed Circuit Soldering Equipment
8-2
6-1.
Reference Designations and Abbrevi
8-3.
Ohmmeters Used for Transistor Test-
ations .
6-1
ing .
8-4
6-2.
Parts List Indexed by Reference Des
8-4.
Out-of-Circuit Transistor Testing
8-5
ignation .
6-2
8-5.
Intensity Modulator DC Voltage
Measurements .
8-16
iii

Section I
General Information
Model 8414A

Model 8414A
Section I
General Information
SECTION I
GENERAL INFORMATION
1-1. DESCRIPTION.
1-2. The Hewlett-Packard Model 8414A Polar Dis¬
play (Figure 1-1) is a plug-in display unit for
Hewlett-Packard Model 8410A and Model 8407A
Network Analyzers. It displays, in polar form on a
five-inch CRT, the relative phase and magnitude of
the signals applied to the Network Analyzer.
1-3. The CRT’s internal graticule has five circular
magnitude divisions and 36 radial ten-degree phase
divisions. Full scale magnitude calibration is deter¬
mined by controls on the Network Analyzer. The
internal graticule, augmented by a set of snap-on
overlays, allows the display to be read directly in
reflection coefficient, impedance or return loss for
maximum convenience in viewing and photo¬
graphing displays. An additional convenience for
photographing displays is provided by panel-
controlled, internal graticule illumination elimi¬
nating the need for an ultraviolet light source in
the camera. A beam centering pushbutton, in con¬
junction with continuous action positioning con¬
trols, permits easy initial calibration and accuracy¬
improving offset adjustments. Rear-panel blanking
and marker inputs accept externally-generated
signals for between sweep display blanking and for
frequency marking by beam brightening. The hori¬
zontal and vertical components of the polar display
are available at separate rear-panel outputs for driv¬
ing external displays such as X-Y graphic recorders.
The polar display is fully transistorized, except for
the CRT, and is powered by the Network Analyzer
mainframe. Complete specifications are given in
Table 1-1.
Table 1-1. Specifications
Range: Normalized polar coordinate display;
magnitude calibration 20 percent of full
scale per division. Scale factor is a function
of gain setting on Network Analyzer. Max¬
imum scale factor 10, minimum 0.0316.
Phase is calibrated in ten-degree increments
over 360-degree range.
Accuracy: Error circle on CRT less than 3 mm
radius.
Output: Two dc outputs provide horizontal and '
vertical components of polar quantity. For
full scale deflection output is nominally
±2.5 volts, source impedance less than 100
ohms, minimum bandwidth (3 dB) 10 kHz.
Drift: CRT, <±0.2 mm/°C; auxiliary outputs,
<±10 mV/°C.
Beam Center: Pressing BEAM CTR pushbutton
simulates zero signal input to test channel
and allows convenient beam position adjust¬
ment for reference.
CRT: Five-inch, 5-kV post accelerator tube
with P-2 phosphor and internal polar
graticule.
Marker Input (rear panel): Accepts frequency
marker output pulse from HP 8690-series or
690-series Sweep Oscillators, -5 volts peak.
Trace is brightened for duration of marker
pulse.
Blanking Input (rear panel): Accepts -4 volt
blanking pulse from HP 8690-series and
690-series Sweep Oscillators to blank re¬
trace during sweep operation.
Background Illumination: Controls intensity of
CRT background illumination for photog¬
raphy. Eliminates need for ultraviolet light
source in oscilloscope camera when photo¬
graphing internal graticule.
Power: Additional 35 watts supplied by Net¬
work Analyzer.
Weight: Net, 11 lb (4,9 kg).
Dimensions: 6 in. high, 15-9/16 in. deep, 7-9/32
in. wide (15,2 x 39, 5 x 18, 6 cm), exclud¬
ing front panel knobs.
1-1

Section I
General Information
Model 8414A
1-4. EQUIPMENT SUPPLIED.
1-5. The Polar Display has 16 chart overlays
provided as accessories, 12 Smith Chart and four
return loss overlays. These overlays are plastic
sheets that snap onto the face of the CRT. Three
different Smith Chart scale factors are used and
four different styles of each scale are supplied for
different applications (refer to Figure 3-5).
1-6. INSTRUMENTS COVERED BY MANUAL
1-7. This instrument has a two-part serial number.
The first four digits and the letter comprise the
serial number prefix. The last five digits form the
sequential suffix that is unique to each instrument.
The contents of this manual apply directly to in¬
struments having the same serial number prefix(es)
as listed under SERIAL NUMBERS on the title
page.
1-8. An instrument manufactured after the print¬
ing of this manual may have a serial prefix that is
not listed on the title page. This unlisted serial pre¬
fix indicates that the instrument is different from
those documented in this manual. The manual for
this instrument is supplied with a yellow Manual
Changes supplement that contains “change inform¬
ation” that documents the differences.
1-9. For information concerning a serial number
prefix not listed on the title page or in the Manual
Changes supplement, contact your nearest Hewlett-
Packard office.
1-10. OPTION
1-11. The Option H26 modification to the stand¬
ard 8414A Polar Display allows computerized
control of magnitude and phase data in the 8542A
series Automatic Network Analyzer systems. See
Figure 3-12 for further information.
1-2

Model 8414A
Section I
General Information
SAFETY CONSIDERATIONS
GENERAL
This product and related documentation must be
reviewed for familiarization with safety markings
and instructions before operation. This product has
been designed and tested in accordance with inter¬
national standards.
SAFETY SYMBOLS
SAFETY EARTH GROUND
This is a Safety Class I product (provided with a
protective earthing terminal). An uninterruptible
safety earth ground must be provided from the
main power source to the product input wiring ter¬
minals, power cord, or supplied power cord set.
Whenever it is likely that the protection has been
impaired, the product must be made inoperative
and be secured against any unintended operation.
Instruction manual symbol: the
product will be marked with this
symbol when it is necessary for
the user to refer to the instruc¬
tion manual (refer to Table of
Contents).
Indicates hazardous voltages.
Indicates earth (ground) terminal.
BEFORE APPLYING POWER
Verify that the product is configured to match the
available main power source per the input power
configuration instructions provided in this manual.
If this product is to be energized via an autotrans¬
former make sure the common terminal is con¬
nected to the neutral (grounded side of mains
supply).
WARNING
CAUTION
The WARNING sign denotes a
hazard. It calls attention to a
procedure, practice, or the like,
which, if not correctly performed
or adhered to, could result in
personal injury. Do not proceed
beyond a WARNING sign until
the indicated conditions are fully
understood and met.
The CAUTION sign denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like, which, if not correctly
performed or adhered to, could
result in damage to or destruc¬
tion of part or all of the product.
Do not proceed beyond a CAU¬
TION sign until the indicated
conditions are fully understood
and met.
SERVICING
WARNING
Any servicing, adjustment, maintenance,
or repair of this product must be per¬
formed only by qualified personnel.
Adjustments described in this manual
may be performed with power supplied
to the product while protective covers
are removed. Energy available at many
points may, if contacted, result in per¬
sonal injury.
Capacitors inside this product may still
be charged even when disconnected from
its power source.
To avoid a fire hazard, only fuses with
the required current rating and of the
specified type (normal blow, time delay,
etc.) are to be used for replacement.
1-3/1-4

Model 8414A
Section II
Installation
SECTION II
INSTALLATION
2-1. INITIAL INSPECTION.
2-2. Inspect the instrument for shipping damage
as soon as it is unpacked. Check for broken knobs
and connectors; inspect cabinet and panel surfaces
for dents and scratches. Check electrical perform¬
ance using procedures in Section IV. If the instru¬
ment is damaged in any way, or fails to operate
properly, notify the carrier and your nearest
Hewlett-Packard Sales and Service Office. In the
event of mechanical damage, the packing material
and carton should be held for carrier’s inspection.
For assistance of any kind, including instruments
under warranty, contact the nearest Hewlett-
Packard Sales Office.
2-3. REPACKAGING FOR SHIPMENT.
2-4. Using Original Packaging.
2-5. The same type containers and materials used
in factory packaging can be obtained through any
Hewlett-Packard office.
2-6. If the Model 8414A is being returned to
Hewlett-Packard for servicing, attach a tag indi¬
cating the type of service required, return address,
model number and full serial number. Also, mark
the container FRAGILE to assure careful handling.
2-7. In any correspondence refer to the instru¬
ment by model number and full serial number.
2-8. Using Other Packaging.
2-9. The following general instructions should be
used when repackaging with commercially-available
materials:
a. Wrap the 8414A in heavy paper or plastic.
(If shipping to a Hewlett-Packard serivce office or
center, attach a tag indicating the type of service
required, the return address, model number and
full serial number.)
b. Use a strong shipping container. A double¬
wall carton made of 350 pound test material is
adequate.
c. Use enough shock-absorbing material
(three to four inch layer) around all sides of the
instrument to provide firm cushion and prevent
movement inside the container. Protect the control
panel with cardboard.
d. Seal the shipping container securely, and
mark it FRAGILE to assure careful handling.
e. In any correspondence refer to the instru¬
ment by model number and full serial number.
2-10. PREPARATION FOR USE.
2-11. Installation.
2-12. Instructions for installing the Polar Display
in the Network Analyzer mainframe are in the Net¬
work Analyzer Operating and Service manual.
2-13. Power Requirements.
2-14. The Polar Display obtains power from the
Network Analyzer mainframe through the rear
connector, when it is properly installed.
2-1

Model 8414A
Section III
Operation
SECTION III
OPERATION
3-1. INTRODUCTION.
3-2. Signals from the Network Analyzer contain¬
ing phase and amplitude information are fed to the
8414A through a rear-panel connector. These
signals are resolved into vertical and horizontal
deflection signals and applied to the CRT, where
they are displayed in polar form. Signals from the
horizontal and vertical amplifiers are available at
rear-panel output connectors for use with an exter¬
nal X-Y recorder or oscilloscope. Controls on the
front panel provide centering, focus and intensity
adjustments for the CRT display.
CAUTION
MECHANICAL SHOCK. Do not bump or jar
the Polar Display as misalignment of the CRT
gun may result.
MAGNETIC FIELDS. Do not place the Polar
Display near a sweep generator containing a
BWO which has an unshielded magnet or the
CRT will be permanently magnetized, causing
poor focus. Separate the 8414A from any
magnetic source by at least two feet.
3-3. PANEL FEATURES.
3-4. Front and rear panel controls, connectors
and indicators are described in Figure 3-1. In this
figure the numbers on the illustrations match the
description numbers.
3-5. MEASUREMENT PROCEDURES.
3-6. General measurement procedures are given in
Figures 3-9 and 3-10. Measurement procedures
using a specific transducer are given in the Operat¬
ing and Service MahuaLor Operating Note for the
particular transducer.
3-7. OPERATING INFORMATION.
3-8. Polar Display of Reflection Coefficient and
Phase Angle.
3-9. If the device under test has an impedance of
50 ohms at all frequencies in the range being
swept, the display of its complex reflection coeffi¬
cient is a dot at the center of the graticule. If the
device does not have an impedance of 50 ohms at
all frequencies the display of complex reflection
coefficient is an irregular pattern which represents
at each point:
a. A specific frequency.
b. A reflection coefficient magnitude, and
c. Phase angle — The angle between the inci¬
dent voltage and reflected voltage at the plane of
measurement.
The magnitude of the reflection coefficient of the
device under test may be read on the concentric
circles, using the scale reflection coefficient T =
0.2/division, with zero at the center and 1.0 at the
outer circle. The phase angle may be read directly
in degrees by drawing a radial line through the
point on the display that represents the frequency
of interest and reading the angle off the outside
ring of the graticule.
3-10. High Resolution Display of Reflection Co¬
efficient Measurements.
3-11. A device under test which is close to 50-
ohms impedance produces a spot in the center of
the CRT. This center section of the CRT may be
expanded to give high resolution so that slight mis¬
match may be observed. To obtain higher resolu¬
tion, add additional gain to the test channel by
setting the Network Analyzer test channel gain 1
controls to a higher value. For instance, adding 14
dB gives full scale calibration of 0.2 and adding 20
dB gives full scale calibration of 0.1. Since initially
the system was calibrated for a reflection coeffi¬
cient of 1.0, determine the change in test channel
gain 1 required to expand the full scale calibration
to a desired reflection coefficient by:
-20 logio | r |
(which is equivalent to the Return Loss of the de¬
sired full scale reflection coefficient calibration).
^Display reference for 8407A.
3-1

Section III
Operation
Model 8414A
FRONT AND REAR PANEL FEATURES
/ \ /
10 8
1. BEAM CTR. Simulates zero test channel
signal so that beam can be moved to a refer¬
ence position.
2. HORIZ POS. Moves trace horizontally.
3. VERT POS. Moves trace vertically.
4. TEST IN. Included on H26-8414A. Test
channel amplitude signal input. Connect to
Network Analyzer mainframe TEST CHAN
OUT with coaxial cable such as HP 11086A
(refer to paragraph 3-37).
5. BLANKING. Input for between-sweep
blanking pulse from HP 8690 and 690 series
Sweep Oscillators. -4 to -10 volts blanks the
CRT display. Input impedance: >20k ohms.
6. MARKERS. Input for frequency marker
pulses from HP 8690 and 690 series Sweep
Oscillators. -4 to -10 volts intensifies CRT
display. Input impedance: >20k ohms.
7. HORIZONTAL. For driving X-Y graphic
recorders. Direct-coupled signal propor¬
tional to the horizontal deflection signal,
±2.5V, 100 ohms source impedance, 10 kHz
bandwidth. Output is not affected by the
HORIZ POS control.
8. VERTICAL. For driving X-Y graphic re¬
corders. Direct-coupled signal proportional
to the vertical deflection signal, ±2.5V, 100
ohms source impedance, 10 kHz bandwidth.
Output is not affected by the VERT POS
control.
9. Connector. Makes all necessary connections
with the Network Analyzer mainframe.
10. FOCUS. Controls sharpness of trace.
11. INTENSITY. Controls brightness of trace.
12. ILLUM. For photography. Brightens screen
for contrast with the graticule. Eliminates
the need for an ultraviolet light in the oscil¬
loscope camera.
13. Graticule. Radial lines divide phase scale
into ten degree parts. Circles divide ampli¬
tude scale into five linear parts. Graticule
center is amplitude zero. Amplitude scale
calibration depends upon setting of the Net¬
work Analyzer controls.
3-2
Figure 3-1. Model 8414A Front and Rear Panel Features

Model 8414A
3-12. Polar Display of Return Loss.
3-13. With the Network Analyzer test channel
gain 1 set to the calibration value, giving an indica¬
tion of F = 1.0 full scale, a Return Loss overlay,
such as the one shown in Figure 3-2 may be used
on the CRT to convert reflection coefficient mag¬
nitude to return loss. The Return Loss overlay has
concentric circles calibrated in dB, with zero at the
outer circle, 1-dB increments to 10 dB, and an
inner circle representing 20 dB. For return loss
measurements of greater than 10 dB, resolution
can be improved by changing the full scale calibra¬
tion. To obtain higher resolution, add additional
gain to the test channel by setting the Network
Analyzer test channel gain 1 controls to a higher
value. The outer or 0 dB circle will then equal the
change in test channel gain 1 . The total return loss
is the sum of the change in test channel gain 1 plus
the value indicated on the return loss overlay. For
example, if the initial display indicated a return
loss greater than 10 dB and a 12 dB increase in
Network Analyzer test channel gain 1 moved the
display indication to mid-point between the 0 and
1 dB graticule circles, the total return loss would
be 12 dB plus 0.5 dB or 12.5 dB.
3-14. Four return-loss overlays are furnished with
the Polar Display, two for viewing and two with
parallax correction for photographing. There is a
clear overlay and an opaque overlay for viewing, a
,oN LOSS (dB ) / Vl £w ..
flfc4 ^ <-20 LOG | 0 p)
Figure 3-2. Return Loss Overlay
Section III
Operation
clear and an opaque overlay for photographing.
The opaque overlays mask the internal graticule so
only the overlay lines are visible.
3-15. Polar Display of Transmission
Measurements.
3-16. A polar display of transmission measure¬
ments in dB or in transmission coefficient (t) and
phase angle can be obtained using the test setup
and procedures in Figure 3-10. During calibration
the display’s outer ring is calibrated for a gain of
one (0 dB) or r = 1. Phase angle for all transmission
measurements may be read directly in degrees by
drawing a radial line through the point on the dis¬
play that represents the frequency of interest and
reading the angle off the outside ring of the grati¬
cule.
3-17. Transmission Measurements of Attenuation
or Gain in Transmission Coefficient (r). If the unit
under test is a passive device, producing attenu¬
ation of the test signal, the transmission coefficient
magnitude can be determined in the same manner
as reflection coefficient; i.e., the magnitude of the
transmission coefficient may be read on the con¬
centric circles, using the scale t = 0.2/division, with
zero at the center and 1.0 at the outer circle. For
high attenuation measurements, resolution can be
improved by changing the full scale calibration. To
obtain higher resolution, add additional gain to the
test channel by setting the Network Analyzer test
channel gain 1 controls to a higher value. For
instance, adding 14 dB gives full scale calibration
of 0.2 and adding 20 dB gives full scale calibration
of 0.1. If the device under test is an active device,
producing gain of the test signal, the full scale
calibration must be increased by setting the Net¬
work Analyzer test channel gain 1 controls to a
lower value. For instance, removing 6 dB gives full
scale calibration of two, removing 14 dB gives full
scale calibration of five, and removing 20 dB gives
full scale calibration of ten.
3-18. Transmission Measurements of Attenuation
or Gain in dB. During calibration the display’s
outer ring is calibrated for 0 dB. The attenuation
or gain of the device under test may be determined
by noting the Network Analyzer’s test channel
gain 1 setting and changing the test channel gain 1
to return the display to the outer circle. The differ¬
ence in test channel gain 1 settings is the magnitude
of the attenuation or gain.
1 Display reference for 8407A
3-3

Section III
Operation
Model 8414A
3-19. Another way to determine attenuation or
gain is to install a Return Loss overlay on the CRT.
The Return Loss overlay has concentric circles in
1-dB increments to 10 dB. For attenuation of 10
dB or less, attenuation can be read directly from
the overlay. For attenuation of greater than 10 dB,
or for gain measurements, use a combination of
change in Network Analyzer test channel gain and
the Return Loss overlay. For example, if the initial
display indicated an attenuation greater than 10 dB
and a 12 dB increase in Network Analyzer test
channel gain 1 moved the display indication to mid¬
point between the 0 and 1 dB graticule circles, the
total attenuation would be 12 dB plus 0.5 dB or
12.5 dB.
3-20. Scattering Parameters Measurement.
3-21. Measurement of scattering or s-parameters is
possible using the Polar Display. With two swept
tests for transmission and two for reflection, a
complete set of s-parameters for any two-port
device may be derived. The four parameters that
must be obtained are:
a. Sn, input reflection coefficient with the
output port terminated by a matched load.
b. S22> output reflection coefficient with
the input terminated by a matched load.
c. S21, forward transmission coefficient
with the output port terminated in a matched load.
Figure 3-3. Typical Smith Chart Display of
Normalized Impedance
d. S i 2 , reverse transmission coefficient with
the input port terminated in a matched load.
The input reflection coefficient (Sn) and the out¬
put reflection coefficient (S22) may be obtained
using the procedure and setup in Figure 3-9. The
transmission coefficients (S21 and S12) may be
obtained using the procedure outlined in Figure
3-10. Paragraph 3-17 describes how to read atten¬
uation or gain in transmission coefficient.
3-22. Polar Display of Normalized Impedance and
Admittance.
3-23. With the Network Analyzer test channel
gain 1 set to the calibrated value, giving an indica¬
tion of T = 1.0 full scale, a Smith Chart overlay
may be used on the CRT to convert the reflection
coefficient and phase angle directly to impedance
or admittance. The standard Smith Chart overlay
contains a horizontal line through the center repre¬
senting the resistance component of the load
impedance. The center of the resistance line is 1.0
corresponding to the normalized 50-ohm point.
Circles passing through the horizontal resistance
line are constant resistance lines. Numbers along
the outer circle of the Smith Chart represent the
reactive component of the impedance. Inductive
reactance is read in the upper half of the graph and
capacitive reactance is read in the lower half of the
graph. Lines of constant reactance originate from a
point at the center right edge of the graph and
extend to points along the outer circle. Figure 3-3
shows a spot on the graph representing a normal¬
ized impedance Z n = 0.6 -j0.4. The real part (0.6)
is found by following the resistance circle up to the
horizontal line through the center of the Smith
Chart overlay. The real part is read from the resist¬
ance scale where the resistance circle crosses the
horizontal line. The imaginary part (-j0.4) is found
by following the reactance circle to the outer edge
of the Smith Chart overlay. To determine the
actual impedance multiply each part of the normal¬
ized impedance by Z Q (50 ohms). In this case the
actual impedance is (50 x 0.6) -j (50 x 0.4) or 30
-j20 ohms. To obtain the corresponding admittance
value for a given impedance value, draw an admit¬
tance circle as shown in Figure 3-4, using the 1.0
point on the resistance line for the center, and the
impedance point as the circle radius. Draw a diam¬
eter line from the impedance point, through the
1.0 resistance point (center) to the opposite side of
the admittance circle. The admittance point is
where the diameter line intersects the admittance
circle opposite the impedance point. The normal-
^Display reference for 8407A
3-4

Model 8414A
Section III
Operation
Figure 3-4. Smith Chart Plot of Admittance Point
ized admittance may be read directly from the
graph. In Figure 3-4 the normalized admittance
value is 1.15 + j0.77.
3-24. Alternate Smith Chart Overlays.
3-25. Twelve different Smith Chart overlay graphs
are furnished with the Polar Display. There are
three graph styles in the Smith Chart overlays; a
standard graph, an expanded graph and a com¬
pressed graph (refer to Figure 3-5). There are four
overlays for each of the graph styles, two for view¬
ing and two with parallax correction for photo¬
graphing. There is a clear overlay and an opaque
overlay for viewing, a clear and an opaque overlay
for photographing. The opaque overlays mask the
internal graticule so only the overlay lines are vis¬
ible.
3-26. Standard Smith Chart Overlay. When a
standard Smith Chart overlay is installed on the
face of the CRT, the standard calibration of the
Polar Display provides the correct scaling factor for
the Smith Chart. Scaling factors for the expanded
and compressed chart overlays are computed from
the standard calibration of the Polar Display.
Adjustment of the test channel gain for the
expanded and compressed graphs is explained in
the following paragraphs.
3-27. Expanded Smith Chart Overlay. The ex¬
panded Smith Chart enlarges the center of the
standard Smith Chart to full scale so that the
region close to 50 ohms can be analyzed in detail.
When the expanded Smith Chart is installed on the
CRT, the gain of the Network Analyzer test chan¬
nel amplifier must be increased by 14 dB to match
the scale of the overlay. This is accomplished by
first noting the calibration setting of the test chan¬
nel gain 1 controls on the Network Analyzer for the
standard Smith Chart. This calibration value is
added to 14 dB and the total value is set at the test
channel gain 1 controls.
3-28. Compressed Smith Chart Overlay. The
compressed Smith Chart overlay provides a display
in the negative-real impedance region. When the
compressed Smith Chart overlay is installed on the
CRT, the gain of the Network Analyzer test-
channel amplifier must be decreased by 10 dB to
match the scale of the overlay. This is accomp¬
lished by first noting the calibration setting of the
test channel gain 1 controls on the Network Ana¬
lyzer for the standard Smith Chart. Ten dB is then
subtracted from this calibration value and the
resultant number is set at the test channel gain
controls 1 .
3-29. Marking Frequency on the Display.
3-30. A rear-panel marker INPUT connector ac¬
cepts dc frequency-marker pulses from the Sweep
Oscillator. Markers appear on the trace as bright
spots. This allows measurements to be made at
specific frequencies on a broadband display.
3-31. Display Blanking.
3-32. Blanking pulses from HP 690 and 8690
series Sweep Oscillators may be applied to a rear-
panel blanking input connector blanking the CRT
during sweeper retrace. A blanking signal is also
obtained from the 8410A Network Analyzer main¬
frame. The 8410A Network Analyzer automati¬
cally produces a blanking signal whenever it is not
tuned to its input signals. This blanking signal is
fed internally to the 8414A. The 8407A main¬
frame does not produce this second form of blank¬
ing.
3-33. Increased Accuracy for Reflection Measure¬
ments by Minimizing Directivity Errors.
3-34. Directivity errors become significant in the
measurement of small reflection coefficients, but
the error can be calibrated out at single frequen-
^Display reference for 8407A
3-5

Model 8414A
Section III
Operation
CLEAR OVERLAYS
Internal graticule lines will show
through overlay.
6 5 !4 13 12 II |0
Return Loss/
Viewing
■ HP Part Number
Standard
Smith Chart/
Viewing
Expanded
Smith Chart/
Viewing
Compressed
Smith Chart/
Viewing
Note
OPAQUE OVERLAYS
Internal graticule lines are
masked so only the overlay lines
There is a photographic overlay similar to each overlay above. The photo¬
graphic overlays correct for parallax.
Figure 3-5. CRT Overlays
3-6

Model 8414A
Figure 3-6. Measured Reflection Coefficient
cies. The measured reflection is the vector sum of
the directivity vector plus the reflection coefficient
of the device under test, or a sliding load (see Fig¬
ure 3-6). The error can be calibrated out with a
sliding load. Figure 3-7 depicts the sliding load in
one position at a single frequency. As the sliding
load is moved, the magnitude of its reflection coef¬
ficient remains constant but the phase of the coef¬
ficient changes. As the load is moved its reflection
coefficient indication rotates in a circle of constant
magnitude about the directivity vector. The center
of this circle is the tip of therdirectivity vector.
When the magnitude of the directivity vector is
zero, the locus circle is centered about the origin as
shown in Figure 3-8. When the location of the cen¬
ter of the circle is known, the directivity vector can,
be subtracted from the measured reflection. The
Figure 3-7. Locus of Measured Reflection when
Load is Moved
Section III
Operation
resultant is the reflection coefficient of the device
under test.
3-35. The vector subtraction can be performed
directly with the horizontal and vertical controls
on the 8414A Polar Display. Increase the Network
Analyzer test channel gain 1 so full scale reflection
on the polar display is suitable for the component
you wish to measure. Attach a sliding load such as
the HP 905A in place of the device under test.
Slide the load and adjust the horizontal and verti¬
cal controls until the circle rotates about the center
of the CRT. The effect of directivity is now can¬
celled for this frequency and this test channel
gain 1 on the Network Analyzer. Remove the slid¬
ing load and connect the device under test. The
8414A display is now the reflection coefficient of
the device under test.
3-36. H26-8414A POLAR DISPLAY.
3-37. The H26 modification to the standard
8414A Polar Display controls the display of magni¬
tude and phase data in the Hewlett-Packard 8542
series Automatic Network Analyzer systems. The
H26-8414A contains circuits to achieve compati¬
bility with the automatic system. The H26-8414A
is also compatible with the standard Network Ana¬
lyzer except for the test channel amplitude signal.
For the standard Network Analyzer and 8414A the
test channel amplitude signal is fed to the 8414A
through a 24-contact rear-panel connector. For the
H26-8414A the test channel amplitude signal input
is through a rear-panel BNC connector (TEST IN).
To use the H26-8414A in a standard Network
Analyzer mainframe connect the Network Ana¬
lyzer rear-panel test output to the H26-8414A
TEST IN. See Figure 3-12 on page 3-12.
^Display reference for 8407A
Figure 3-8. Locus of Measured Reflection with
Directivity Cancelled
3-7

Section III
Operation
Model 8414A
REFLECTION COEFFICIENT MEASUREMENT
MECHANICAL SHOCK. Do not bump or jar the Polar Display as misalign¬
ment of the CRT gun may result.
MAGNETIC FIELDS. Do not place the Polar Display near a sweep genera¬
tor containing a BWO which has an unshielded magnet or the CRT will be
permanently magnetized, causing poor focus. Separate the 8414A from any
magnetic source by at least two feet.
DEVICE UNDER
TEST
REFLECTOMETER
3-8
Figure 3-9. Reflection Coefficient Measurement (Sheet 1 of 2)

Model 8414A
Section III
Operation
REFLECTION COEFFICIENT MEASUREMENT
CALIBRATION
1. Connect equipment as shown in setup.
2. Connect a coaxial short such as the HP
11565A to the reflectometer unknown
port.
3. Phase lock the Network Analyzer over the
desired frequency band.
4. Push and hold the 8414A BEAM CTR push¬
button and adjust HORIZ POS and VERT
POS controls to place the dot in the center
of the graticule. To bring the dot onto the
display rotate each positioning control
about five turns counterclockwise or until a
slight increase in resistance to movement is
encountered. Then turn each control about
two and one-half turns clockwise.
NOTE
If an input signal does nit deflect the
CRT beam, SI, the TEST-NORMAL
switch, may be in the TEST position.
Refer to Figure 8-24 (last foldout) for
location of SI and set SI to
NORMAL.
5. Obtain equal reference and test channel
electrical lengths by adjusting the Line
Stretcher to collapse the trace to a dot or
smallest cluster.
6. A djust the Network Analyzer phase vernier,
test channel gain 1 and amplitude vernier
controls to place the dot or cluster for a
reference indication of F = 1 /_180° (see
Figure 3-11, Display B).
MEASUREMENT
1. Remove the coaxial short and connect the
device under test to the reflectometer un¬
known port.
2. Read the reflection coefficient, magnitude
and phase (or impedance using a Smith
Chart overlay) from the display.
NOTE
For small reflection coefficients the
8414A resolution can be improved by
increasing the Network Analyzer test
channel gain 1 . For example, increas¬
ing the test channel gain 1 by 20 dB
changes the full scale calibration from
1.0 to 0.1 at the outer circle (see para¬
graph 3-10). For increased accuracy
by minimizing directivity errors, see
paragraph 3-33.
^Display reference for 8407A.
Figure 3-9. Reflection Coefficient Measurement (Sheet 2 of 2)
3-9

Section III
Operation
Model 8414A
TRANSMISSION MEASUREMENT
CAUTION
MECHANICAL SHOCK. Do not bump or jar the Polar Display as misalign¬
ment of the CRT gun may result.
MAGNETIC FIELDS. Do not place the Polar Display near a sweep genera¬
tor containing a BWO which has an unshielded magnet or the CRT will be
permanently magnetized, causing poor focus. Separate the 8414A from any
magnetic source by at least two feet.
SWEEP OSCILLATOR
PWR
DIVIDER
LINE
STRETCHER
DEVICE UNDER
TEST
NETWORK ANALYZER
REFERENCE
CALIBRATION
1. Connect equipment as shown in setup with¬
out the device under test.
2. Phase lock the Network Analyzer over the
desired frequency band.
3. Push and hold the 8414A BEAM CTR push¬
button and adjust HORIZ POS and VERT
POS controls to place the dot in the center
of the Polar Display. To bring the dot onto
the display rotate each positioning control
about five turns counterclockwise or until a
slight increase in resistance to movement is
encountered. Then turn each control about
two and one-half turns clockwise.
NOTE
If an input signal does not deflect the
CRT beam, SI, the TEST-NORMAL
switch, may be in the TEST position.
Refer to Figure 8-24 (last foldout) for
location of SI and set SI to
NORMAL.
4. O btain equal reference and test channel
electrical lengths by adjusting the Line
Stretcher to collapse the trace to a dot or
smallest cluster.
5. A djust the Network Analyzer phase vernier,
test channel gain and amplitude vernier
controls to place the dot or cluster for a
reference indication of t = 1 Z.0°.
MEASUREMENT
1. Insert the device under test.
2. Note the Network Analyzer test channel
gain 1 setting. This is the calibrated gain
setting. Adjust the test channel gain con¬
trols 1 to locate the CRT display on the
outside ring. The difference in test channel
gain 1 settings is the magnitude of the trans¬
mission gain or loss of the device under test.
^Display reference for 8407A.
Figure 3-10. Transmission Measurement
3-10