Field Trip To Grumman Plant

ft*
Volume 4
June, 1956
Number 10
Field Trip To Grumman Plant
GRUMMAN S2F-2 SUB KILLER
On June 19, at 7:30 P.M. the Long Island Section will conduct its annual
field trip. We are unusually fortunate this year having successfully arranged
a visit to the Bethpage plant of the Grumman Aircraft Company to see their
main aircraft production lines and assembly operations. Members and their
wives are cordially invited to make what promises to be an outstanding trip
to see fabrication of some of the country's best fighter aircraft.
The field trip will begin at the Grumman Aircraft Main Clearance Gate
on South Oyster Bay Road. Members and wives who plan to attend the field
trip should return the post card which is being mailed by the Long Island
(Continued on Page 71
GRUMMAN AIRCRAFT
FIELD TRIP, JUNE 19
7:30 P.M., Main Clearance Gate
South Oyster Bay Rd., Bethpage
Pre-Meeting Dinner
5:45 P.M., Howard Johnsons
Jericho Turnpike, Mineola
The PULSE of Long Island
The Institute of Radio Engineers
Long Island Section
PERKIN
The LEADER in Tubeless Magnetic
Amplifier Regulated DC POWER SUPPLIES
and AC LINE VOLTAGE REGULATORS
Ike
\J cnnccj
o
of
n
flew
DISTRICT
SALES E N G I N E E R I N G
OFFICE
SECTION OFFICERS
Paul Hansel, Chairman
David Dettinger, Vice-Chairman
H. Page Burr, Treasurer
Wilbert Frantz, Secretary
EDITORIAL STAFF
Waller Ruddy. Editor
Stuart Casper, Advertising Manager
Carlton Souder, Business Manager
Phad Herrick, Raymond Keogh. J.
A r t h u r Plantcrotli\Jumcs Randall,
Associate Editors.
Editorial and advertising deadlines
are the first of the month preceding
I he month of issue.
Address correspondence to:
THE PULSE OF LONG ISLAND
P. 0. Box 789, Mineola, N. Y.
The PULSE is mailed to IRE ineinhers who give as their address a
postoffice in Suffolk, Nassau, or
Queens Counties. In addition, members who live in Queens can receive
both The PULSE and The MONITOR
by requesting ihem from Headquarters.
Volume IV
To serve the
New York Metropolitan Area
at 1 060 Boad Street, Newark 2, New Jersey
Telephone MArket 3-1454
This issue of the Pulse completes
Volume IV. There will be no Pulse
published for the months of July
and August 1956. Volume V. consisting of ten monthly issue?, will
start in September 1956. Editorial
and advertising matter should be
addressed to our Minenla Post Office box.
ROLLER-SMITH CORPORATION
District Manager: MILLARD LEFF
Electrical
Measuring
Instruments
Unsealed — Sealed — Ruggediied
COrtlandt 7-5326
11 Park Place
New York 7, N. Y.
PERKIN ENGINEERING CORPORATION
WHEELER
LABORATORIES,
INC.
Consulting — Research — Development
R- f- Circuits — Lines — Antennas
Microwave Components — Test Equipment
Harold A. Wheeler and Engineering Staff
Great Neck, N. Y.
HUnter 2-7876
Page 2
June,
1956
Long Island IRE Section
Higher Grade
Transfer to Senior Member
J. P. Blewett
BBrookhavon National Lab.
Upton, L. I., N. Y.
H. N. Edelstein
Crest-Microtran Co.
Rockaway, L. I., N. Y.
J. A. Kenny
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
J. E. Lethin
Airborne Instruments Lab.
Mineola, L. I., N. Y.
M. S. Tanenbaum
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
Admission to Senior Member
R. H. Jauck
American Bosch Arma Corp.
Garden City, L. I., N. Y.
H. W. Tackel
Federal Television Corp.
Astoria, L. I., N. Y.
Transfers
B. L. Adams
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
Sperry Gyroscope Co.
J. C. Lott
Great Neck, L. I., N. Y.
S. A. Cohen
Sperry Gyroscope Co.
Great Neck, L, I., N. Y.
R. VV. Olthius
Sperry Gyroscope Co.
Great Neck, L. I., N. Y
J. V. D'Agostino
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
C. N. Pagauo
Liquidometer Corp.
Long Island City, N. Y.
G. F. Dery
Airborne Instruments Lab.
Mineola, L. I., N. Y.
J. J Sterling
Sterling Transformer Corp.
Brooklyn, N. Y.
A. H. Fay
Electrical Mfgs. Service
E. Meadow, L. I., N. Y.
R. L. Strazzulla
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
G. S. Garbarini
Ford Instrument Co.
Long Island City, N. Y.
D. P. Tocci
CAA
N. Y. International Airport
Jamaica, L. I., N. Y.
A. H. Grebe
Filters, Inc.
Port Washington, L. I., N. Y.
J. Kawaller
American Art Platers, Inc.
New York, N. Y.
Transfer to Member
S. Abrahams
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
J. J. Kuhn
Harnett Electric Corp.
Rivcrhead, L. I., N. Y.
DC-AC
CHOPPERS
For 60 Cycle Use
Built to rigid
commercial
specifications.
Twenty-two types,
both single and
double pole.
Long life.
Low noise level.
Extreme reliability.
Write for
Catalog 370.
H. H. Waller
Northern Radio Co.
New York, N. Y.
Admission to Member
J. C. Barry
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
l C o n t i n u e d on Page 6 1
PORTABLE
OSCILLOSCOPE
DC TO 4 MC
TYPE 310, a portable precision
oscilloscope, combines accuracy
with convenience in both field
and laboratory applications. With
its small size... 10" h by 6%" w
by 17" d . . . a n d its light weight,
only 23'/2 Ibs
the Type 310 handles easily and
fits into tight spots, yet it is fully capable of performing much of your laboratory work. Features include:
Wide sweep range — 0.5 /usec/div to 0.6 sec/div,
continuously variable, 18 calibrated sweeps from
0.5 /isec/div to 0.2 sec/div, 5x magnifier. Verticalamplifier risetime 0.09 /*sec, calibrated sensitivity
from 0.1 v/div to 50 v/div in 9 ranges at dc to 4 me,
3 additional steps from 0.01 v/div to 0.05 v/div at
2 cycles to 3.5 me, continuously variable from 0.01
v/div to 150 v/div. 3" crt, regulated power supply.
For additional information, please call or write the
office listed below.
Price $595 f.o.b. Portland (Beaverton), Oregon
Tektronix, Inc.
NEW YORK
FIELD OFFICE
4» P.ndfl.ld load BronxvilU •, DC.rfi.ld 7-3771
SPOTLIGHT
ON
FUBINI
Meet Mr. Airborne Instruments
MINIATURIZATION
with increased reliability
new
EUGENE G. FUBINI. a 1954 Fellow of the Institute of Radio Engineers, and 1956-1957 Vice Chairman
of the Long Island Section, has long
been active in national committee
work, notably the Wave Propagation
and Papers Review in 1944-1953,
and more recently the Editors Review Committee. He is also the recipient of the Presidential Certificate of Merit.
Fubini attended the University of
Rome, from which institution he received his degree of Doctor of Physics in 1933. During the war he
served with the United States 8th
Air Force in England and engaged
in Operational Analysis in Radar
Counter Measures work. He joined
the Airborne Instruments Lab in
1945 and was recently made Director of the Engineering and Research
Division of the Company. His main
areas of interest are special electronic test equipment, microwave
plumbing, and microstrip.
IB BON
A former enthusiast of Alpine
mountain climbing he now brags
about a 25-foot hill on his Brookville land. Fubini's infectious smile
is comparable to Herb Shriner's,
but can Shriner climb the Alp*?
J. Arthur Planteroth
Gene Fubini, Airborne
Instruments Lab.
W
CONNECTORS
A M P H E N O L ' S new MicroRibbons are the first miniature connectors to provide
reduction in size with increase in reliability. Utilizing an improved 'ribbon'
contact design, M i c r o Ribbon connectors provide
easy, smooth insertion and
extraction even in blind entrance locations. There are
no tiny pins to bend or misalign but self-wiping, selfcleaning 'ribbon' contactsactive, flexing members that
assure excellent double contact action at all times. Dielectric material is AMPHENOL
blue diallyl phthalate, all
contacts are gold-plated and
shells are finished in accordance with military specification. Available in 14, 24
and 36 contacts.
For rapid delivery from
complete stock see BBH^^P
Schfff faff ELECTRONICS
122 Herricks Road. Mmeola, L.I., N.Y.
phone: Pioneer 6-6520
Pag* 4
MODEL 11
Pulse Cenento'S
f M SifMl 6m««W«
SHift ««• *•»«««««
VKUUIK Tub. Voltmtws
1-C-* •"*««
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SPECIFICATIONS
FREQUENCY RANGE: 5 to 100.000 cycles.
WAVE SHAPE: Rise time less than 0.2 microseconds with negligible overshoot.
OUTPUT VOLTAGE: Step attenuator giving 75. 50. 25. 15.
10. 5 peak volts fixed and 0 to 2.5 volts continuously variable.
SYNCHRONIZING OUTPUT: 25 volts peak.
R. F. MODULATOR: 5 volts maximum carrier input. Translation gain is approximately unity—Output impedance is 600
ohms.
POWER SUPPLY: 117 volts, 50-60 cycles.
DIMENSIONS: 7" high x IS" wide x 7 V j " deep overall.
MEASUREMENTS
BOONTON
CORPORATION
NEW JERSEY
The PULSE
New York Component Parts
Chapter Talk: Film Resistors
The New York Chapter of the
Professional Group on Component
Parts will hold its Annual Chapter
Meeting of the 1955-56 season at
the General Electric Auditorium.
51st Street and Lexington Avenue.
New York City, on Thursday J u n e
14th at 7:30 P.M. Three papers will
be presented on "The Characteristics of Metal Film Precision Resistors."
,The first paper will he presented
by Mr. R. J. Newman. General
Manager of the Daven Company.
Mr. Newman has been with the
Daven Company for the past eight
years, working on component development and systems engineering.
Previously he spent seven years with
the General Electric Company as the
head of the Radar Control Seel ion
of the Aeronautics and Ordnance
Engineering Department. He is a
senior member of the IRE and a
member of the ASTM. Mr. Newman's paper will cover metal film
ELECTRONIC
resistors in general, methods of
manufacture, and present types
available.
The second paper will be presented by Dr. S. J. Stein, Director of
Research of the International Resistance Company. Dr. Stein, who ha?
written several papers on high vacuum metal evaporation for the preparation of special resistor varieties,
has been working in this field since
1950. Dr. Stein's paper will treat
the characteristics and performance
of metal film resistors as compared
with conventional wire wound resistors.
The third paper will be presented
by Mr. H. C. Nelson, General Manager of the Polytechnica Research &
Development Co. Mr. Nelson's paper
will treat the characteristics of
metal film resistors, including lowlife temperature coefficient, high
temperature characteristics, resistance to thermal shock, and shelf life
stability.
ENGINEERING
EDgewood 4-5600-1
— REPRESENTING —
MICROPHASE
TWT Amplifier Packages
Special Test Equipment
Bridgers, Logarithmic
Audio Instruments
POLARAD ELECTRONICS COUP.
Amplifiers
COMMUNICATION MEASUREMENT LABS. INC.
Variable Frequency Electronic Generators
Stroboscopes, VTVMS, Automation Equip.
CUBIC
CORPORATION
Microwave Calorimeters, Ratio Computers
Klystron Power Supplies, VSWR Amplifiers
Waveguide Test Components
ELECTRONIC TUBE CORP.
INC.
Travelling Wave Tubes
Backward Wave Oscillators Solenoids
METRONIX,
INC.
Crystal Calibrators, Audio Oscillators
Q Meters, Capacitance Meters
"INSTRUMENTATION
June, 1956
Signal Generators,
Spectrum Analyzers
Receivers, General Lab. Equip.
T.V. Color and B/W Equipment
PROBESCOPE CO.
INC.
Audio Spectrum Analyzers, Miniature
Oscilloscopes Special Lab. Instruments
SPENCER KENNEDY LABS
IS OUR BUSINESS"
INC.
Electronic Filters, Distributed Wide Band
Amplifiers, Square Wave Generators
TELONIC INDUSTRIES
Dual Beam Oscilloscopes
Multi-Gun Cathode Ray Tubes
HUOGINS LABORATORIES
CORPORATION
Coaxial and Waveguide
Filters, Duplexers
AUDIO INSTRUMENT CO.
JAarka-Sweep
MARKAS W E E P
MODEL
VIDEO SOSweeping
oscillator
with marks
— provides
both 50 me
weep which includes low end of video
.pectrum, and a continuously variable I
weep, permitting observation of complete
spectrum to 50 me or any 4 me part over the
range. Range: 50 kc to 501 me markers—
both internal and external clystal-controlled
pulse-type
ttK.
'
MICROWAVE
MEGA-NODES —Calibrated
noise sources at microwave. Available in wave
guide sized 1200-1400 me. and 2600 40.000 me.
RG-49/U
$500. RG-5I/U
$295.
RG-48/U
295. RG-52/U
295.
RG-49/U
295. RG-9I/U
350.
RG-50/U
295. RG-53/U
350.
Prices include power supply
CALIBRATED MEGA-SWEEP - Wide range,
side sweep for aligning RF and IP amplifiers.
Has calibrated freq. control and single dial
tuning. 50 KC.-950 MC. Sweep width 40 me;
output 100 mv ................................. .•..........•.•.-••*•
,,
Model MI-A with zero level base line; 10
575.
me—950 me
REPRESENTATIVES
804 NEWBRIDGE AVENUE, W E S T B U R Y . L. I., N. Y.
ALFRED ELECTRONICS CO.
INSTRUMENTS
AUDIO
IF
VHF
UHF
INC.
Sweep Frequency
Generators
WESTPORT ELECTRIC CO.
INC.
Electronic Frequency Counters
Electronic Time Interval Meters
Preset Electronic Counters
YOUR LOCAL AREA REPRESENTATIVES ARE:
Jerry Fine and Howard I. Hoffman
MICROLTER MODEL SO.
completely new design
wide band, high frequency, low level vacuum
tube voltmeter with high
impedance probe. Measures 100 cycles to 50
megacycles. No tuning.
Switch provides full scale
steps of I. .3, .1, .03, .01,
.003, .001 v. with lowest
reading at 2 5 0
microvolts ....$495.
.,»JA"
n
£igna-Sweep
All electronic
sweeping oscillator with variable c e n t e r
frequency and
sweep
width,
and with high
o u t p u t automatically held
constant over frequency sweep and frequency
band. Covers & switched bands, TV, FM,
VHF, video, output 1.0 V RMS into 75 ohms,
sweep width variable to 20 me at VHF, direct reading dial
$350.
KAY ELECTRIC COMPANY
14 Maple Ave.
Pine Brook, N. 1.
CAIdwell 6-4000
Deaf. 11-5
Page 5
Long Island MCI £«><•< ion
Higher CpradV Traiisfor.s
I (Icmlimird
finin
I'ufjr
.'! i
R. A. Carlstrom
Grumman Aircraft Engrg. Corp.
Bethpage, L. I.. N. Y.
R. A. Carpentier
Spcrry Gyroscope Co.
Great Neck, L. I., N. Y.
announcing* 2 ALL NEW
HEWLETT-PACKARD OSCILLOSCOPES
New Versatility...New Convenience...New Dependability
-hp- 1504 High Frequency Oscilloscope
Sweep Range: 0.02 /iiec/cm lo 15 sec/cm.
Calibration: 24 sweeps: 1-2-5-10 sequence,
0.1 /isec/cm to 5 sec/cm. 3% accuracy.
Triggering: Internal, line voltage or external
0.5V or more. Pas. or neg. slope, +30 lo
—30V trigger range. A "pre-set" trigger
mokes most triggering automatic.
HorUental Amplifier: Magnification 5, 10, 50.
100 times. Vernier selects any 10 cm part of
sweep. Pass band dc to over 500 KC. Sensitivity 50 mv/cm to 25 v/cm.
Vertical Amplifier: Pass band dc lo 10 MC.
Optimum transient response and rise time
less than 0.035 /isec. Signal delay of 0.25
/isec permits leading edge of triggering signal lo be viewed.
IMA High Frequency
Oscilloscope
Amplitude Calibration: It calib. voltages, 25-10 sequence, 0.2 mv la lOOv peak-to-peak.
Accuracy 3%. Appro*. 1KC square wave,
rise and decay better than 1.0 jitec.
Price*: -hp- 150* Hifh Frequency Oscilloscope, $1,000.00
-hp- 151A Hifh Giin Amplifier, JIOO.OO
-hp. 152A Dual Channel Amplifier (with Electronic Switching, $200.00
The I50A features a revolutionary new probe, unitized construction and
many more new advantages.
-hp- i 30A low frequency Oscilloscope
130A Low Frequency
Oscilloscope
Sweep Range: I Msec/cm lo 15 sec/cm.
Calibration: 21 sweeps; 1-2-5-10 sequence, I
/isec/cm to 5 sec/cm. 5% accuracy.
Triggering: Internal, line voltage or external
2V or mere, Poi. or neg. slope, +30 to
—30V trigger range.
•rent Trigger: Optimum-setting for auto-"
matic stable triggering.
Input Amplifiers: (Similar vertical and horizontal amps). DC to 300 KC. Sensitivity 1
mv/cm lo 20 v/cm. 14 calibrated ranges;
balanced input on the 5 most sensitive.
Amplitude Collb^ntleat 1 KC square wove.
5% accuracy.
Price: 145000
The "pre let" trigger, similar in design lo the one used in the 150A High Frequency Oscilloscope, is for the first lime available in a low frequency scope.
associates
170 Eosl «0lh St., New Yerk 11. N. Y. Tlafaloar » . J O J J
114 East Main St.. legeta. New Jeraey Dlomend J-S34J
J. B. Chatterton
Spcrry Gyroscope Co.
Great Neck, L. I., N. Y.
J. Doerschuck
U. S. Army
Ft. Meade, Md.
A. Dresner
Control Instrument Co.
Brooklyn, N. Y.
R. J. Fadem
Airborne Instruments Lab.
Mineola, L. I., N. Y.
P. L. Field
Fairchild Guided Missiles Div.
Wyandanch, L. I., N. Y.
M J. Flynn
IBM
Poughkeepsie, N. Y.
.J. J. Gordon
LEL, Inc.
Copiague, L. I.. N. Y.
A. W. Herzog
Office of Naval Research
Special Devices Center
Port Washington, L. I.. N. Y.
K. J. Hill
Spcrry Gyroscope Co.
Great Neck, L. I., N. Y.
D. R. Ingvverson
Sperry Gyroscope Co.
Great Neck, L. I.. N. Y.
S. M. Jacobs
Arnia Corp.
Garden City, L. I., N. Y.
J. Kowalsky
Airborne Instruments Lab.
MinRohi, L. I., N. Y.
D. T. Levy
U. S. Naval Shipyard
Brooklyn, N. Y.
W. W. Moretti
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
C. H. Ness
Sperry Gyroscope Co.
Great Neck, L. I.. N. Y.
S. A. Rosenthal
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
T. F. Rudiger
Sperry Gyroscope Co.
Great Neck, L. I., N. Y.
Beta Electric Corp • Sudd • Stanley Co. Int. • John Fluke Mfg. Co. • Hewletl • Packard Co.
• Kay lab • Pimei Inc. • Sorenien 4 Co.. Inc. • Varian Aisociolti
M. A. Sant Angelo
Sperry Gyroscope Co.
Great Neck, L. I.. N. Y.
H. N. Saphin
Republic Aviation Corp.
Farmingdale, L. I., N. Y.
Page 6
The PULSE
C»r iiin ma ii Trip
(Continued from Page 1)
Section. The \n>-\d will h a \ a
printed declaration <>f citizenship,
and must licin the'hands of the field
trip committei one week hefore the
trip. Those who do not return the
post card will lie admitted to the
plant if they produce evidence of
citizenship the night of the field
trip.
Impedance
Comparator
The
l!elhpat;e
jiianl
ul
( ii 1 1 1 1 1 1 1 1 : 1 1 1
can be reached by turning south oil
Grand Central Parkway at Exit 36.
One meter reads phase-angle differences to
and
following South ()\ster Hay Road.
0.0001 radians. Another meter simultaneously reads differences in magnitude to 0.01% accuracy.
Coming by the Southern State ParkImpedance Range
way t u r n north at Kxil 2!! and follow
Resistance: 2 ohms to 20 megohms
Internal Test Frequencies:
Route
115 (Wanlagh Avenue). A
Capacitance: 40 MM' ^50<M
100 _ i QOO - 10,000 and 100,000 cps.
Inductance: 10 nh to 10,000 h
t h i r d route is to follow lioute I d . "
Type 1605-A Impedance Comparator... $790
(Broadway) southeast out of Hick-Write for Complete Information
ville.
SUB-KILLER
t"»»^e of the more interesting of
these
airplanes is the S2F-2 subG E N E R A L RADIO Company
bridge 39. Ma
killer s h o w n in the accompanying
Branch Engineering Office in NEW YORK
photograph. It is the first airplane
90 West Street New York 6, New York
specifically
designed to detect, i d e n t Telephone WOrth 4-2722
i
f
y
,
track
and
destroy enemy subC. WILLIAM HARRISON
GEORGE G. ROSS
marines. Equipped w i t h the mos!
modern detection and destruction devices, the S2F utilizes radar, sonobuoys. and M a g n e t i c A i r b o r n e detector gear to pinpoint the suli and
then choose either torpedoes, depth
charge* or rockets to effect the kill.
MANUFACTURERS REPRESENTATIVES FOR.
ALLISON LABORATORIES
Precision Variablt Audio Filters 10 cpi
to 20 kc
•
LABORATORY FOR ELECTRONICS
DC-10 MC Oscilloscope, Microwave
Oscillators, 10 MC Time Rate Indicator,
Delay Lines
•
LABSCOPE, INC.
DC 200 KC Oscilloscope, Calibrator
•
MAGNETIC RESEARCH CORP.
Tubeless DC Power Supplies, Magnetic
Amplifiers
•
NARDA CORP.
Frequency Meters, Waveguide Test
Equipment, Bolometers, Thermistors
DONNER SCIENTIFIC COMPANY
Audio Oscillators, Wave Analyzers,
Accelerometers, Analog Computers
•
NJE CORPORATION
Standard and Laboratory Grade
Regulated DC Power Supplies
E L E C T R O - I N S T R U M E N T S INC.
Precision Direct Reading Digital
Voltmeters, Ohmmeters
•
ROGER WHITE ELECTRON DEVICES
Microwave Gas Control Tubes,
Bad ward Wave Oscillators, Traveling
Wave Tubes
•
SERVO CORP. OF AMERICA
Servoscope, Servoboard, Amplifiers,
Infra Red Bolometers, VHF Receiver
•
SIERRA ELECTRONIC CORP.
Reflection Coefficient Meter, Directional
Couplers, Carrier Voltmeters, Wattmeters
AREMAO ASSOCIATES
Oscilloscope Cameras
BRUSH ELECTRONICS COMPANY
Direct Writing Oscillographs, Amplifiers,
Audio and Acoustic Test Instruments,
Digital Counters
CASCADE RESEARCH CORP.
Microwave Ferrite Equipment
ELECTRO-PULSE, INC.
Wide Range Pulse and Time Delay
Generators
EMPIRE DEVICES PRODUCTS CORP.
Noise, Field Intensity, Microwave Test
Equipment
WHAT IS YOUR PROBLEM?—Ask your Bur/ingame Field Engineer
ROBERT CRANE
June, 1956
Military Group
Being Formed
A Chapter of the Professional
Group in M i l i t a r y Electronics
(PGMIL) is being formed within
the Long Island Section. Captain
C. H. S. Murphy, l]SN, Commanding
Officer and Director of the Sperkil
Devices Center, is acting as Chapter
Organizer. The establishing petition
is now being prepared.
Any Section member who is interested in joining the 1'G.VIIL or
wishes to participate in the Chaptei
activities should get in tougeh with:
Captain C. H. S. M u i p l n
Special Devices Center
Port Washington. !Ne\k
T e l e p h o n e : POrl Washington
FLushing 7-!«(M) - \2.V>
Page 7
Previous issues of the PULSE have carried articles
on this page containing some results on narrow
band microwave bandpass filters. This month some
further design information that has found much
use at AIL will be discussed. We hope that this
information will be as useful to you as it has been
to us.
We have come to the conclusion that it is
not best to design a narrowband filter with a
Tchebycheff (overcoupled) type response when
midband insertion loss must be kept as low as
possible and the unloaded Q of the filter elements is the limiting factor. In other words, a
filter with a Tchebycheff response shape will
have higher midband insertion loss and less
off-band rejection than a filter with a maximally
flat (critically coupled) response shape employing a larger (by one or more) number of resonant elements. The curves in figure 1 below
show, for a given Qu* and filter Ql** that the
designer pays a price of higher insertion loss
when he chooses a Tchebycheff response shape.
It should be noted that a Tchebycheff response
shape becomes preferable only in such cases
where the designer cannot afford to increase
the number of resonant eleemnts because of
space limitations and must necessarily realize
higher insertion loss.
In previous PULSE ads (Nov. and Dec.
1955), we discussed a general minimum Qu
criterion originally proposed by Dishal. The
which ihe resonant elements must have in order
to realize an exact response shape with resulting
infinite insertion loss. The higher the resonator
unloaded Q's are above the minimum Qu, the
lower the insertion loss. It is interesting to note
that, by normalizing the actual unloaded Q to
the minimum unloaded Q, the cunrs of minimum possible insertion loss reduce to a single
curve for all bandpass filters with an error less
than 0.7 db for high insertion loss (smaller
errors for low loss filters—e.g. 0.4 db at 3 db
insertion loss).
^^
We believe that this "universal" m i n i m u m
insertion loss curve, shown in figure 2. is very
useful to designers of narrowband filters liecause it tells him how much higher his unloaded
Q must be above the minimum Qu in order to
achieve the desired insertion loss.
We would like very much to further discuss
this subject with members of the Long Island
Section of the IRE. We welcome an exchange
of ideas. The people to be called at AIL are
Gene Fubini. Bruce Bogner. Jesse Taub or Bob
Ayward.
Q . = resonotor unlooded O
° ,=
-,';
20
where -if = filter 3db
frequency bondwidth
50
O.
100
c,...".
INSERTION IOSS CURVE!
*Qu = unloaded Q of the
filter elements.
**Q1 — center frequency divided by the 3 db
fremienrv bandwidth.
2
FIGURE 1
AIRBORNE
INSTRUMENTS
LABORATORY
5
Qv =
resonator unlooded O
O
— lowest value of unlooded Q
alii
response shape
MPN
10
20
50
UNIVERSAL INSERTION lOSS CURVES
Advtrtistment
160 OLD COUNTRY ROAD
Pioneer 2-0600 -
Page 8
MINFOIA. N. Y.
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