Middleton W.M. (ed.) Reference Data for Engineers: Radio, Electronics, Computer and Communications
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49-24
REFERENCE
DATA
FOR
ENGINEERS
Magnitudes
The relations among
Xo,
Xo
,
bo,
and
f
are shown in
Fig. 6. Any two of these parameters applied to the
graph locate the other two. For example, supposef=
10
hertz and peak displacement
Xo
=
1
inch. From Fig. 6,
peak velocity
Xo
=
63 inches per second and peak
acceleration
Xo
=
log.
Natural Frequency
If damping is neglected, the natural frequency,
fo.
of
vibration of an isolated system in the vertical direction
can be calculated from
Eq.
12
from the static deflection
of the mounts. For example, suppose an object at rest
causes a 0.25-inch deflection of its supporting springs.
Then
fo
=
3.13/(0.25)”2
=
6.3 hertz
Resonance
In Fig.
7,
E
is plotted againstf/$o for various damping
factors. Note that resonance occurs whenf, Zfand that
the vibratory forces are then increased by the isolators.
To reduce vibration,
fo
must be less than
0,7f,
and it
should be as small as O.3ffor good isolation.
It is not possible to secure good isolation at all
vibrational frequencies in vehicles and similar environ-
ments where several different and varying exciting
frequencies are present and where the isolators may
have to withstand shock as well as vibration. In such
cases,
fo
is often selected as about
1.5
to
2
times the
predominantf. Information regarding vibration in typi-
cal vehicles is shown in Table
18.
Although all supporting structures have compliance
and may reduce the effects of vibration and shock, the
apparent stiffness of many “rigid” mountings is merely
a matter of degree, and in conjunction with the support-
ed mass, they can also give rise to resonance effects,
thus magnifying the amplitude of certain vibrations.
Damping
Damping is desirable to reduce vibration amplitude
when the exciting frequency is in the vicinity offo. This
occurs occasionally in most installations. Any isolator
that absorbs energy provides damping.
It is seldom practical to introduce damping as an
independent variable in the design of vibration isolators
for relatively small objects. The usual practice is to rely
on
the inherent damping characteristics of the rubber or
other elastic material employed in the mounting. Damp-
ing achieved in this way seldom exceeds
5
percent of the
amount needed to produce a critically damped system.
In vibration isolators for large objects, such as variable-
speed engines, the system often can be designed to
produce nearly critical damping by employing fluid
dashpots or similar devices.
Fig.
7.
Relative transmissibility
E
as a function of frequency ratioflfo
for
various amounts
of
damping
b.
Vibration Analysis,
by
N.
0.
Myklestad.
01944,
McGraw-Hill
Book
Co.)
(By
permission fTom
TABLE
18.
VIBRATION
IN
TYPICAL
VEHICLES
z
5
Approximate
0
Peak
rn
Range of Frequencies Amplitude Usual Choice
r
Ships
0
to 15 0.02 Engine vibration in diesel
or
reciprocating steam drive 6 hertz
for
vibration isolation in commercial vessels. 27
2
C
v)
U
D
5
8
3
Vehicle (hertz) (inches) Nature of Excitation of Isolator Resonant Frequency
to
30
hertz for shock isolation
on
naval vessels. These
latter mounts amplify most vibrations to some extent.
0
to
33
0.01 Propeller-blade frequency
=
(propeller rpm)
X
(number of blades)/60
Piston-engine aircraft
0 to
60
0.01
Engine vibrations Above
20
hertz. Amplitude of vibrations varies with
location in aircraft. Landing shock can be neglected.
0 to 100
0.01
Propeller vibrations. Aerodynamic vibrations due to
buffeting
Turboprop aircraft
0
to
60
0.01 Engine vibrations
=
(engine rpm)/60 Also aerodynamic
9
hertz
vibrations due to
buffeting and
turbulence
0
to 100
0.01
Propeller vibrations
Jet aircraft
Up to
500
0,001 Audible noise frequencies due to jet wake and combustion
9
hertz
turbulence; very little engine vibration
~ ~~~~~ ~
Passenger automobiles
1
6 Suspension resonance 25 hertz will usually avoid resonance with wheel hop and
-
suspension resonant frequencies.
8
to 12 0.02 Unsprung weight resonance (wheel hop)
20
+
0.002 Irregular transient vibrations due to resonances of structural
members with road roughnesses
Automobile trucks
4
5
Suspension resonance Above
20
hertz and should not correspond with any
structural resonance. It
is
not advisible to attempt to
isolate suspension and unsprung weight resonances.
0.05
Unsprung weight resonance
20
80+
0.005
Structural resonances
Military tanks
1
to
3
2 Suspension resonance Similar to automobile truck
Depends on speed
-
Track-laying frequency
~17.6 (speed in mph)/(tread spacing in inches)
1004
0.001 Structural resonances
~
Railroad trains Broad and erratic
Similar to automobiles with additional excitations
from
rail 20 hertz has been successful in railroad applications,
Shock with velocity changes up to
100
inchidsecond in
direction of train occurs when coupling cars
or
starting
freight trains.
joints and from side slop in rail trucks and draft gear
N
UI
Practical Application
Vibration can be accurately precalculated only for the
simplest systems. In other cases, the actual vibration
should be measured on experimental assemblies by
using electrical vibration pickups. Complex vibration is
often described by a plot of the
g
values against
frequency. These plots usually show several frequencies
at which the largest accelerations
are
present. The
patterns will vary from place to place in a complicated
structure and will also depend on the direction in which
the acceleration is measured.
After vibration has been measured and plotted in this
way, attention can be devoted to reduction of the
predominant components. The equations and principles
given above
are
used as guides in selecting the size,
stiffness, damping characteristics, and location of isola-
tors.
Shock
In many practical situations, vibration and shock
occur simultaneously. The design of isolators for vibra-
tion should anticipate the effects of shock and vice
versa.
When heavy shock is applied to a system using
vibration isolators, there is usually a definite deflection
at which the isolators snub or at which their stiffness
suddenly becomes much greater. These actions may
amplify the shock forces. To reduce this effect, it is
generally desirable
to
use isolators that have smoothly
increasing stiffness with increasing deflection.
Shock protection is improved by isolators that permit
large deflections in all directions before the protected
equipment is snubbed or strikes neighboring apparatus.
The amplitude of vibration resulting from shock can be
reduced by employing isolators that absorb energy and
thus damp OscillatoIy movement.
Probabilities of damage to the apparatus itself from
impact shock can be minimized by:
Making the weight of equipment components as
small as possible and the strength of structural
members as great as possible.
Distributing rather than concentrating the
weights of equipment components and avoiding
rigid connections between components.
Employing structural members that have high
ratios of stiffness
to
weight, such as tubes,
I
beams, etc.
Avoiding,
so
far
as
is
practical, stress concentra-
tions at joints, supports, discontinuities, etc.
Using materials such as steel that yield rather
than rupture under high stress.
US
GRAPHIC
SYMBOLS
The USA standard graphic symbols for electrical and
electronics diagrams cover both the communication and
power fields. Symbols of primary interest to communi-
cations workers are in Fig.
8.
They have been abstracted
from IEEE Standard
315-1975.*
Symbols that also
agree with Recommendation
No.
117
of the Interna-
tional Electrotechnical Commission are indicated by
“IEC.
”
Diagram Types
Block
diagrams
consist of simple rectangles and
circles with names or other designations within or
adjacent to them to show the general arrangement of
apparatus to perform desired functions. The direction of
power or signal flow is often indicated by arrows near
the connecting lines or arrowheads on the lines.
Schematic
diagrams
show all major components and
their interconnections. A single-line diagram, as indi-
cated by that name, uses single lines to interconnect
components even though two or more conductors are
actually required. It is a shorthand form of schematic
diagram. It is always used for waveguide diagrams.
Wiring diagrams
are complete in that all conductors
are shown and all terminal identifications are included.
The contact numbers on electron-tube sockets, colors of
transformer leads, rotors of adjustable capacitors, and
other terminal markings
are
shown
so
that a workman
having no knowledge of the operation of the equipment
can wire it properly.
Orientation
Graphic symbols are not considered to be coarse
pictures of specific pieces of equipment but are true
symbols representing the functions of parts in the
circuit. Consequently, they may be rotated to any
orientation with respect to each other without changing
their meanings. Ground, chassis, and antenna symbols,
for instance, may “point” in any direction that is
convenient for drafting purposes.
Graphic symbols may be correlated with parts lists,
descriptions, or instructions by means of reference
designations (MIL-STD-16).
Detached Elements
Switches and relays often have many sets
of
contacts,
and these sets may be separated and placed in the parts
of the drawing to which they apply. Each separated
element should be clearly labeled as part of the basic
switch or relay.
Terminals
The‘ terminal symbol need not be used unless it is
needed. Thus, it may be omitted from relay and switch
symbols. In particular, the terminal symbol often
shown at the end of the movable element of a relay or
-
*
Published
by
the
Institute
of
Electrical
and
Electronics
Engineers,
345
East
47th
Street,
New York,
N.Y.
MISCELLANEOUS
DATA
49-27
~~
ADJUSTABILITY
/
IEC
AMPLIFIER
-D-
ANTENNA
ATTENUATOR
LOUDSPEAKER
BATTERY
qF
IEC
MULTICELL BATTERY
WITH
3
TAPS
iITTil+
it
IEC
CAPACITOR
ADJUSTABLE
CAPACITOR
#
IEC
SPLIT-STATOR
CAPACITOR
CIRCUIT BREAKER
-
n-IEC
GROUND
1.
-
IEC
CHASSIS CONNECTION
IEC
COMMON
CONNECTORS
!
Or+
*
Replace with
identification
of
circuit.
MECHANICAL
CONNECTION
IEC
_------
FEMALE CONTACT
IEC
MALE CONTACT
IEC
ENGAGEDCONTACTS
-+--
EC
ENGAGED COAXIAL
CONNECTORS
(Outside conductor
carried through)
,vn-
IEC
JACK PLUG
0-
-
7,
DIRECTIONAL
COUPLER
X
DELAY LINE
I*
)-
'Replace with
length
of
delay
Vertical lines
show input
side
EN
V
E L
0
P E
0
IEC
GAS-FILLED
ENVELOPE
0
IEC
FUSE
--
IEC
HANDSET
0
INDUCTOR
IE
C
mn
or
qi)-p
SATURABLE-CORE
INDUCTOR
TELEGRAPH KEY
BALLAST LAMP
e
INCANDESCENT LAMP
METER
0
Replace with letter
designating type.
MICROPHONE
D-
OSCILLATOR:
GENERALIZED
ALTERNATING-
CURRENT SOURCE
COAXIAL CABLE
TIEC
PIEZOELECTRIC
CRYSTAL
UNIT
ilk
IEC
RECTIFIER. GENERAL
W)
IEC
BRIDGE RECTIFIER
RESISTOR
+
IEC
ADJUSTABLE
RESISTOR
IEC
RESONATOR
C
SEMICONDUCTOR
REGION WITH ONE
OHMIC CONNECTION
T
IEC
REGION ON N REGION
1
IEC
I
REGION ON P REGION
1
IEC
'
EMITTER ON N REGION
4
IEC
I
EMITTER
ON
P REGION
IEC
'NP TRANSISTOR
4/
IEC
#EMICONDUCTOR DIODE
IEC
#HELD
_-----
:INGLE-THROW SWITCH
1-
IEC
{OTARY SWITCH
80
0
SYNCHRO
Q
THERMISTOR
*
to
IEC
THERMOCOUPLE
u
IEC
TRANSFORMER
IEC
RELAY COIL
0
Fig.
8.
Selected graphic
symbols
from
IEEE
Standard
315-1975.
49-28
REFERENCE DATA FOR ENGINEERS
switch should not be considered as the fulcrum or
bearing but only as a terminal.
Associated or Future
Equipment
Associated equipment, such as for measurement
purposes, or additions that may be made later are
identified as such by using broken lines for both
symbols and connections.
BRITISH GRAPHIC SYMBOLS
Commonly used British block-diagram graphic sym-
bols are in Fig. 9. They have been abstracted with
permission from British Standard 530: 1948 and Sup-
plement No.
5
(1962), and superseding BS 3939
(1966-1969). The issuing organization is the British
Standards Institution, British Standards House, 2 Park
Street, London,
W.
1, England.
PAD
111
ATTENUATOR
Jy1
ARTIFICIAL LINE,
REACTIVE
DELAY NETWORK
111
El
El
El
H
BALANCING NETWORK
FILTER
General Symbol
High-Pass
Low-Pass
Bandpass
Band-Stop
ECHO SUPPRESSOR
SINGING
SUPPRESSOR
€I
ATTENUATION
EQUALIZER
FREQUENCY
CHANGER
CODE CHANGER
pJ
of
10
AMPLIFYING
EQUIPMENT
IDI
DETECTOR
AMPLIFIER^
DETECTOR
MODULATOR
El
STANDARDIZED GRAPHIC
SYMBOLS FOR LOGIC DESIGN
Symbols for logic design are
so
varied and in such a
state of flux that many authors use their own symbols.
Fig.
10
shows a
short
set of standardized graphic
symbols for logic design selected from a revised draft of
ANSVIEEE Standard 91-1982.
SAFETY LEVELS FOR
EXPOSURE TO
EM
FIELDS*
The American National Standards Institute (ANSI)
has published recommendations concerning safety lev-
els with respect to human exposure to electromagnetic
fields in the frequency range from
300
kHz to
100
GHz.
7
The ANSI radio-frequency protection guides
*
This
section
contributed
by
Charles
A.
Cain.
'I'
Reference
1.
DEMODULATOR
H
DEMODULATOR
DETECTOR
COMPRESSOR
El
EXPANDER
H
HYBRID COIL OR
TERMINATING SET
TRANSFORMER
-OD--
CARRIER FREQUENCY
&
J
CARRIER FREQUENCY.
SUPPRESSED
?
I
I
0
I
PILOT FREQUENCY
ERECT SIDEBAND
L
0
fl
f2
INVERTED SIDEBAND
i\
0
il
f2
CARRIER AND
BOTH SIDEBANDS
u
0
fl
r2
r3
L.-nL
11
12
I3
r4
is
IF IT
IS
NECESSARY TO
INDICATE THAT THE
LOWER AUDIO FREQUENCIES
ARE NOT TRANSMITTED,
THE SIDEBANDS MAY BE
SHOWN TRUNCATED THUS:
0
SINGLE SIDEBAND,
SUPPRESSED CARRIER
(Lower sideband only
transmitted)
1
/-JT
0
fl
f2.
TWELVE CHANNEL GROUP
-
Detailed
Fig.
9.
Selected
British block-diagram graphic symbols.
Description
of
Logic Functions
AND
Accommodation
of
additional Inmts
Dot AND
OR
Accommodatlon
of
additional inputs
Dot
OR
Exclusive
OR
(one
and
only
onel
Logical
inversion
Rectangular-Shape
Symbols
P-
P-
9P
Distinctive-Shape
Symbols
Fig.
10.
Selected standardized graphic
symbols
for
logic
diagrams.
(Excerpted with permission from the revised draft
of
IEEE
Standard
Graphic
Symbols
for
Logic
Diagrams
(Two
State
Devices).
For a complete listing
of
all standardized
symbols
for
logic diagrams, including the relationship between
the new and superseded standards, see
ANSlllEEE
Std.
91
-
1982,
Appendix
C
.)
(RFPG) are intended to apply to both occupational and
nonoccupational exposure, but not to exposure of
patients for medical purposes. These guides specify
maximum allowable levels as a function of frequency in
terms of the mean squared electric and magnetic fields,
E
and
H,
respectively, and the equivalent free-space
plane-wave power density.
To
determine adherence to
this RFPG, the power density or squares of the field
strengths should be averaged over any 0.1-h period with
all measurements to be made at a distance
5
cm or
greater from any object. Table 19 is a summary of the
A detailed rationale for the ANSI C95.1-1982 RFPG
is given in reference 1. The frequency dependency of
the maximum allowable equivalent plane-wave power
density and of the mean squared field strengths is based
on research results which show that the whole-body-
average specific absorption rates* approach maximum
values when the long axis of the body is parallel to the
E-field vector and is approximately
0.4A
in length
where
A
is the free-space wavelength of the incident
field.? This resonance occurs at a frequency
of
about
70
MHz for a man of average size. To account for the range
of body dimensions from small infants to large adults,
the RFPG specifies a maximum allowable power densi-
ty of
1
mW/cm2 over the frequency range from
30
MHz
to
300
MHz. As indicated in Table 19, the allowable
incident intensities increase below
30
MHz and above
300
MHz.
The ANSI C95.1-1982 standard specifies an exclu-
sion from the recommended protection guides for
low-power devices. The levels in Table 19 may be
exceeded if the input power to a radiating device at
radio frequencies between
300
kHz and 1 GHz is seven
watts or less. The RFPG may also be exceeded between
300
kHz and 100 GHz if the exposure conditions result
in specific absorption rates below
0.4
W/kg as averaged
over the whole body and spatial peak specific absorp-
tion rates below 8 W/kg as averaged over any one gram
of tissue for any 0.1-h time interval.
The type of situation that this exclusion is meant to
address is illustrated by Table 20, which shows the field
strengths and power densities in the near field of a
50-cm monopole antenna radiating at 150 MHz and 2
W of input power. It is clear from these data that the
RFPG maximum recommended limits
of
field strength
or of plane-wave equivalent power density are exceeded
at locations near the antenna. However, this device
radiates less than
7
watts and may be excluded.
ANSI C95.1-1982 RFPG.
References
1.
American National Standard Safety Levels with
Re-
spect
to
Human Exposure
to
Radio
Frequency Elec-
tromagnetic Fields,
300
wiz
to
100
GHz,
ANSI
C95.1-1982. Institute of Electrical and Electronics
Engineers, 1982.
-
*
Specific absorption rate: the time rate per
unit
mass
of
radio-frequency electromagnetic
energy
deposition
in
biolog-
ical tissues.
'I
Reference
2.
49-30
TABLE 19. RADIO-FREQUENCY PROTECTION GUIDES
*
Frequency Power
Range
E2
HZ
Density
(MHz)
(V2/m2) (AZ/mZ) (mW/cm2)
0.3- 3 400
000
2.5 100
3- 30 4000 (900/f2)
0.025 (9001fz) 900/f2
30- 300 4000
0.025
1
.o
300- 1500
4000 (fl300) 0.025 (fi300)
f1300
1500-100
000
20
000
0.125
5.0
*
From ANSI
C95.1-1982.
Note:
f
=
frequency in megahertz.
2. Durney, C. H., Johnson, C. C., Barber, P. W., Systems. Radiating Systems. Englewood Cliffs,
Massoudi,
H.,
Iskander, M. F., Lords, J. L., Ryser,
D.
K.,
Allen,
S.
J., and Mitchell,
J.
C.
Radiofre-
quency
Radiation Dosimetry Handbook,
Second
Edition, May 1978, Report SAM-TR-78-22.
USAF
School
of
Aerospace Medicine,
Brooks
Air Force
Base, Texas.
3. Jordan,
E.
C.
Electromagnetic Waves and Radiating
N.J.: Prentice-Hall, Inc., 1950, p. 323.
Additional
Reading
The subject
of
safe levels
of
exposure to electromag-
netic fields is one
of
great continuing interest, with
much research being done worldwide. For an indication
TABLE 20. FIELD STRENGTHS
(E
AND
H)
AND
POWER DENSITIES
IN
PROXIMITY
TO
A
CURRENT-FED,
QUARTER-WAVE, RADIATING MONOPOLE ANTENNA*
Distance in Centimeters
0
10 20 30 40
E
=
64.3
Vlm
48.7
32.7
24.2 19.3
H
=
0.00
A/m
0.0217 0.0317
0.0341 0.0348
PD
=
1.10
mW/cm2
0.628 0.287
0.156 0.0985
*
* *
*
*
95.1 45.7 29.8 22.4
0.0524 0.0524
0.0489 0.0456
2.40
0.553
0.236 0.133
* * *
*
121 53.4 33.3 24.5
0.136 0.0856
0.0682 0.0533
3.88 0.757
0.295 0.159
*
*
*
*
110 51.7 33.3 25.0
0.229 0.124 0.089 0.0716
3.72 0.708 0.300 0.193
* * *
*
83.6 43.0 30.2 24.1
0.306 0.157
0.108
0.0531
3.54 0.931 0.437 0.261
~
3
Y
* * * *
50.1
32.0 26.2 22.7
In
0.358 0.180 0.120 0.0910
4.82 1.22 0.548 0.312
*
*
*
1;
27.7 26.3 24.3 22.1
0.375 0.188 0.125 0.0938
5.31 1.33 0.589 0.332
* *
*
*
*
From ANSI
C95.1-1982
A
50-cm antenna operating at
150
MHz and
2
W
of input power is assumed, with an input impedance
of
36
a.
Each asterisk
associated with a set
of
field measurements denotes the spatial point of measurement in relation
to
the antenna. The vertical and
horizontal distance between adjacent points of measurement is
10
cm. (Calculations based
on
reference
3.)
MISCELLANEOUS DATA
49-3
1
of ongoing research
on
the biological effects of EM
fields, and the efforts being made to promulgate regu-
lations in
the
United States relating to EM-field stan-
dards, see summary articles by Eric
J.
Lemer:
“Biological Effects of Electromagnetic Fields.”
IEEE
Spectrum,
May 1984, pp. 57-69; “The Drive to Regu-
late Electromagnetic Fields.”
IEEE
Spectrum,
March
1984, pp. 6370.
PATENT, COPYRIGHT, AND
TRADE SECRET PROTECTION
OF
INVENTIONS
Intellectual Property
Protection
of
Technology in
the United States*
Depending on the nature of the invention or other
development, the owner may seek protection in the
United States by means of trade secret, patent, or copy-
right law.+ Each nation is responsible for its own intel-
lectual property laws, and
on
various points the law in
many nations differs from that in the United States.
Trade Secret Protection
of
I
nven
t
ions
What
Is
a
Trade Secret?-One widely used defini-
tion is that a trade secret is “information, including a
formula, pattern, computation, program, device,
method, technique, or process, that: (i) derives inde-
pendent economical value, actual or potential,
from
not being generally known to, and not being readily
ascertainable by proper means, by other persons who
can obtain economic value from its disclosure or use,
and (ii) is the subject of efforts that are reasonable
under the circumstances to maintain its secrecy.” Basi-
cally, when a business has secret information giving it
a
commercial edge over competitors who don’t have it,
the business may seek to protect the information
as
a
trade secret. Although trade secret protection often
extends to such commercial items
as
customer lists
and cost data, much of the information protected by
trade secret law is technological.
For example, one may maintain
as
trade secrets
chemical processes used in the trade secret owner’s
plant, or the structure and functioning of machines
used
by
the owner’s licensees who have agreed
to
keep
these items confidential. And, along with copyright
protection, trade secret law is quite commonly used to
protect computer programs. However, a device mar-
keted to consumers and embodying
a
“trade secret”
*
This
section
contributed
by
David Bender,
White
&
Case,
LLP.
t
In
addition,
a
special
type
of
protection,
known
as
semi-
conductor
mask
work
protection,
is
available
for
protecting
the
structure
and
design
of
semiconductor integrated circuits.
whose characteristics are obvious from
a
casual
inspection, would not be a good candidate for trade
secret protection after marketing commenced, because
there would then be
no
secret. Any person who law-
fully comes into possession of a product embodying a
trade secret, and is not contractually precluded from
doing
so,
is entitled (if clever enough) to “reverse engi-
neer” the product and learn the trade secret.
The Law of Trade Secrets-The basic rule of trade
secret law is
as
easy to state
as
it is difficult to apply:
a
person may not make unauthorized access
to,
or use or
disclosure
of,
another’s trade secret. Such conduct
constitutes misappropriation of the trade secret. It is
not necessary that any tangible object be taken for mis-
appropriation to occur; rather, misappropriation can
occur on the basis of use or disclosure of information
existing in a person’s memory.
Unlike patent and copyright law, trade secrets are
governed largely by state (rather than federal) law. One
result of this is that trade secret law often differs from
state
to
state, although in recent years some 42 states
have enacted the “Uniform Trade Secret Act,” which
has introduced more uniformity into trade secret law.
Under certain circumstances,
in
many states trade
secret misappropriation may constitute a crime, and it
does constitute
a
federal crime.
However, unlike patent rights, trade secret rights do
not extend to preclude another
from
use or disclosure
of information independently developed or otherwise
lawfully acquired free of restrictions. Accordingly, a
trade secret owner
is
continually subject to loss of the
trade secret through the lawful conduct of others.
General Requirements for
a
Trade Secret-In
many lawsuits, the following six factors have been
viewed
as
important in determining whether a trade
secret exists:
(1)
The extent to which the information is known
outside the owner’s business. Obviously, if
everyone in the industry knows it, there is no
secret. But if one or two others know it, and
maintain it
as
a secret, it may still be
a
trade
secret.
(2) The extent to which it is known by employees
and others involved in the owner’s business. A
business that restricts internal proliferation of
its secrets
on
a “need to know” basis is in
a
bet-
ter posture to claim that it has trade secrets.
guard the secrecy of the information. The owner
will rarely be required to duplicate the security
features of Fort Knox.
But
if the owner permits
people
to
walk in off the street and roam around
in
areas where this information is available, it
will be difficult to convince a court that it con-
stitutes
a
trade secret.
(4)
The value
of
the information to the owner and
his
competitors. Value embodies the commercial
importance and desirability of the information.
(3) The extent
of
measures taken by the owner to
49-32
Without such value, it is difficult to see how the
information gives its owner an advantage over
competitors.
The amount of money or effort expended by the
owner in developing the information. This may
be looked to as one indicator of value. More-
over, as an equitable matter, a court or jury may
be reluctant to permit a defendant to reap where
he or she has not sown.
The ease or difficulty with which the informa-
tion could be properly acquired or duplicated by
others. If it is a trivial matter for another
to
acquire it, it should not be protected.
Relationships Giving Rise to Trade Secret Rela-
tionship-The
owner of a trade secret has rights,
not
against the world, but only against one who unlawfully
acquires, uses, or discloses the trade secret. Typically,
the owner’s right to restrain use or disclosure arises
from a “confidential relationship” that exists between
the owner and the other party, whereby the other
agrees to maintain the information as confidential.
This confidential relationship may arise from a con-
tract expressly creating it, or it may be implied from
the relationship of the parties. For example, a confi-
dential relationship arises generally from the owner’s
employment of an employee to work
on
developing a
process or product.
Also,
employers sometimes require certain key
employees to sign a “covenant not to compete.”
In
such a covenant, the employee agrees that for a speci-
fied period following employment by the employer, he
or she will not, perhaps in a particular geographic
region, undertake activities of the type in which he or
she engaged for the present employer.
Who Owns Rights in a Trade Secret?-It
is
not
always easy to determine who owns rights to a trade
secret. For example,
in
the employer-employee situa-
tion, some factors that a court would look to in adjudi-
cating that issue might be: the terms of any contract
between the two; whether the employee was hired to do
research and/or development work; whether the secrets
in question are the result only of the employee’s efforts;
whether the work resulting in the trade secret was
assigned to the employee by the employer; and
whether the work done by the employee was done
on
the employer’s premises, during normal working
hours, and with the use of the employer’s facilities and
materials.
Patent Protection
of
Inventions
Nature
of
the Patent Grant-A
United States
patent grants to its owner the right to exclude others
from making, using, selling, offering for sale, or
importing the claimed invention
in
the United States
for the term
of
that patent.*
A
patent can be asserted
even against one who invents independently and with-
out copying from the patent owner. Patents issuing
on
applications filed today will expire twenty years after
the filing date.t Most importantly, a patent does not
confer
on
its owner the right to practice that invention,
for one or more other patents may also cover the
invention.
So,
for example, if a patent for a carburetor
coexisted with a patent for a dual-bmelled carburetor
(an improvement
on
the basic carburetor), the owner
of
the latter could not lawfully manufacture his or her
invention without a license from the owner of the
former. However, when the patent expires, the owner
loses all right to exclude. Once an application for a
patent is filed, it is freely assignable as an item of per-
sonal property, as
is
an issued patent.
What Can be Protected by Patent?-A
patent
may be obtained
on
any new and useful process,
machine, manufacture, or composition
of
matter, or
any new and useful improvement thereof. The patent
standard of novelty is a strict one.$ One novelty
requirement is that the inventor must have made the
invention before it was used or known by others in the
United States, and before it was patented or described
by others in a printed publication anywhere
on
earth.
Even beyond novelty itself, the claimed invention must
be nonobvious, when made, to a person of ordinary
skill in the area of technology
to
which it pertains.
Computer Programs and Methods
of
Doing Busi-
ness-In
recent years, many inventors of progam-
related inventions, and of methods of doing business,
have obtained patents
on
them. Since at least 1981; it
has been clear that the US Patent and Trademark
Office (the PTO) will issue patents for program-related
inventions.
An
important court case in 1998 has made
it clear that a business method, at least when imple-
mented by computer, is patentable subject matter.
Since that case was decided, there has been a huge
surge of patent applications from the financial services
sector and others.
Recognizing Invention-If
an
original develop-
ment appears to be of commercial significance (or if
there is some other reason why a patent is desired), the
*
There are other less commonly exercised rights as well,
including the right to preclude importation into,
or
sale, offer-
ing for sale or
use in, the United States
of
a product made
abroad by a process patented
in
the United States.
t
Patents on applications filed prior to June 9, 1985 gen-
erally expire on the later of twenty years after the filing date
or seventeen years after the issue date.
$
The following hypothetical example shows just how
strict the standard is. Suppose a person makes a simple, me-
chanical invention, yet one
so
ingenious that no person alive
has contemplated it before. The inventor obtains a patent. A
year later a cave is discovered
in
Massachusetts with wall
paintings indicating that in 1795 the local tribe of native
Americans publicly used that invention. Under this set of
facts, the patent would be invalid.
MISCELLANEOUS
DATA
49-33
inventor may wish to transmit the pertinent details to a
patent attorney or patent agent in order to have a patent
search done to assess whether the invention meets the
patent standards of novelty and nonobviousness. The
attorney or agent will generally compare the invention
with issued U.S. patents and other items of “prior art”
in reaching this determination.
Who
Is
the Inventor?-Patent law recognizes that
invention comprises two stages: (1) conception of the
idea, and
(2)
its reduction to practice (which amounts
to
either constructing the invention or making a
detailed written description in a patent application).
The person(s) actually responsible for the conception
and reduction to practice is (are) the inventor@).
If
a
person’s contribution to an invention does not rise
above the level of ordinary mechanical skill, that per-
son
is not an inventor. Supervisors should not, as a
matter of course, be named
on
patent applications as
inventors. They (and anyone else) should be named
only where they actually participated in the invention.
The Inventive Proces-The question of whether
an invention is patentable does not depend
on
the man-
ner in which it is made.
In
particular, the fact that an
invention is made by accident, or serendipity, will not
negate patentability. Often the inventive process com-
prises the following steps: someone identifies either a
problem to be solved or a result to be achieved; the
inventor conceives a way of solving the problem or
effecting the result; and the inventor reduces the con-
ception to reality, either by actually building or prac-
ticing the invention, or by making a detailed written
description of it.
Obtaining
a
Patent-One seeks a patent by filing
and prosecuting a patent application with the PTO.
There are many requirements that must be met in the
application. The application must include: a written
description of the invention, and the manner and pro-
cess of making and using it, in such full, clear, concise,
and exact terms as to enable any person skilled in the
appropriate technology to make and use it; a statement
of the best mode contemplated by the inventor at the
time of filing; and one or more “claims” distinctly
pointing out the subject matter regarded as
the
inven-
tion. The preparation and prosecution of a patent appli-
cation is a very technical and detailed task. By law, an
application can be filed and prosecuted only by the
inventor or by a registered patent attorney or patent
agent.
Each year,
over
200,000 patent applications are
filed in the United States, and some 140,000 patents
issued. The time between filing of the application and
issuance of the patent varies considerably from appli-
cation to application and currently averages between
1
1/2 and
2
years.
Interferences-On occasion, different inventors
independently file patent applications claiming the
same invention. (The PTO maintains all patent appli-
cations
in
secrecy for at least eighteen months,
so
that
when an application is filed, the applicant may be
unaware of other applications.)
In
the United States,
the first person to invent
is
entitled to any resulting
patent. When the
€TO
identifies applications by differ-
ent inventors claiming substantially the same inven-
tion, the PTO declares an “interference” proceeding to
determine the first to invent. Similarly, if two interfer-
ing patents inadvertently issue, the first inventor may
be determined by suit in federal court.
In
most foreign
countries, the first inventor to file a patent application
is entitled to any resulting patent. Thus, the US patent
owner may be a different person than the owner of for-
eign patents.
Publication-For a valid United States patent to
issue, an application must be filed within one year of
publication or public use of the invention. However, it
is generally unwise publicly to disclose an invention
before a patent application is filed. The law in some
foreign countries is such that publication before filing
for a patent will extinguish the right to obtain a patent
there.
Importance
of
Records-In certain instances, the
patent owner may be called upon to prove various facts
associated with his or her patent rights.
In
an interfer-
ence, he or she will be expected to prove when the
invention was conceived, when it was reduced to prac-
tice, and perhaps that due diligence was exercised in
the interim.
In
licensing negotiations, the owner may
be challenged
to
show similar facts. And in litigation,
the owner will be expected to show these and other
facts relating to the invention. Interferences, licensing
negotiations, or litigation may occur years-even
decades-after the invention was made. Memories dim
and witnesses die. With clear and detailed contem-
poraneous documents and models, it is less difficult to
reconstruct precisely what happened and when.
Such documents may consist of the lab or engineer-
ing notebooks of the inventors and others, memoranda,
and sketches. The notebooks in particular are often of
prime importance, and certain characteristics may ren-
der them more credible as evidence:
(1)
They should be bound, rather than loose-leaf.
(2)
Entries should be in chronological order, writ-
ten clearly and completely in ink, without blank
pages or spaces.
through material to be deleted (but not obliterat-
ing
it).
(4) Erasures and removal
of
pages should be
avoided.
(5)
Where other materials must be included in the
notebook (e.g., small lab samples, graphs),
these should be fastened securely to the appro-
priate page, referenced
on
that page, dated,
signed, and witnessed.
the events recorded and should be dated and
signed when made.
(3)
Changes should be made by drawing one line
(6)
Each entry should be made at or shortly after