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Патент USA US3082958

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March 26, 1963
J. L. BARKER
3,082,949
TRAFFIC SPEED nEvIATIoN COMPUTER
Eiled Nov. 9, 1959
4 Sheets-Sheet 1
March 26, 1963
J. L. BARKr-:R
`
3,082,949
TRAFFIC SPEED DEVIATION COMPUTER
`
Filed Nov. 9, 1959
4 Shée‘ts-Sheet 2
SER-VO MOT R
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S'ERVO
AM_OPLTIFRE
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INVENTOR.
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JoHN‘ß |_. BARKER
my@
ATTORNEY
March 26, 1963
J. l.. BARKER
3,082,949
TRAFFIC SPEED DEVIATION COMPUTER
Filed NOV. 9, 1959
4 Sheets-Sheet 3
w w#
IN VEN TOR.
JOHN L, BARKER
822mm@ATTORNEY
`
March 26, 1963
J. |_. BARKER
3,082,949
TRAFFIC SPEED DEVIATION COMPUTER
Filed Nov. 9, 1959
4 Sheets-Sheet 4
INVENTOR.
JOHN L. BARKER
BY
220.@ mêm.,
`ATTORNEY
United States Patent O ice
1
3,082,949
Patented Mar. 26, 1963
1
3,082,949
TRAFFIC SPEED DEVIATION COMPUTER
John L. Barker, Norwalk, Conn., assigner, by mesne as
signments, to Laboratory for Electronics, Inc., Boston,
Mass., a corporation of Delaware
Filed Nov. 9, 1959, Ser. No. 851,771
20 Claims. (Cl. 23S-151)
The present invention relates to a vehicular tra?lic
speed deviation measuring or indicating system or ap 10
2
Thus, with relation to vehicle speeds, standard devia
tion, or sigma or deviation equals the square root of the
remainder after the square of the arithmetic average
speed (fà-Ã?) of a predetermined number of vehicle
speeds is subtracted from the summation of the Squared
same vehicle speeds divided by the same predetermined
number of vehicle speeds, or root mean square speed
squared (m2).
Thus the formula may read deviation equals:
#mi
paratus, which in a general sense measures or responds
to the amount or degree of variation between the speeds
or the square root of the difference of the root mean
of individual vehicles of a series of vehicles in traffic pro
square squared minus the arithmetic average squared.
ceeding along a road or a trañ‘ic lane for example, and
I have used this formula in the electro-mechanical
which in a more particular sense in its preferred aspect
computation of speed deviation of vehicle trañ’ic. In the
computes a deviation representing the average departure
preferred system the various speed readings are obtained
of the individual speeds from the mean value of such
and a speed of the last car value'and a root mean square
speeds and provides an output representing the deviation
speed
squared value, in the form of D.C, voltages are
for indicating or control purposes. More specifically in
its preferred aspect the present system or apparatus com 20 developed electro-mechanically and are then- applied aS
individual inputs into the electro-mechanical computer
putes the square of the root mean square of the various
for computation of speed deviation.
i
speeds and also the square of the arithmetic average of
Prior
estimates
of
_and
mathematical
calculation
of
the
the same speeds, subtracts the latter square and takes the
raverage speed of vehicle traffic have been made in vari
square root of the difference Vas an output representing
ous manners employing mechanical speed determining
the deviation.
25 and measuring devices and/or electronic calculating
The invention is described herein with particular refer
devices.
ence to its preferred application to traiiic speeds but it
One method of determining the root mean square speed
will be appreciated that some aspects of the computation
or"
vehicle trañic through trañic actuation, with provision
of the deviation of a series of values in accordance with
the invention may have general application to factors 30 for obtaining an output representing the root mean square
other than trañic speed.
The invention has particular advantage in determining
the deviation in speeds of the latest desired number of
vehicles proceeding in the same direction past a sampling
point in a single traffic lane. Several deviation com
puters may be employed respectively in several adjacent
traffic lanes if desired, although one such computer in
one lane may serve as a sample of multi-lane traffic.
In the rlield of trai-lic control, the speed deviation of
’ vehicle traffic on a roadway may be used as a yardstick
of the quality of the trañic llow along that roadway.
Speed deviation of trañic ñow along a roadway may also
be used as a measure of the efficiency with which vehicle
traffic is passed along the roadway, with particular ern
phasis on restricted thoroughfares such as freeways,
bridges and tunnels for example, and thus may serve as
a guide in roadway design and in the monitoring of op
eration of such tra?lic facilities for example.
In determining the deviation of varying values of a
given factor several mathematical formulas may be em
ployed. Generally referred to as “sigma” or “standard
deviation,” one mathematical formula is presented at
page 165 in “Trañ‘ic Engineering Handbook,” second edi
tion, published and copyrighted in 1950 by Institute of
Traflic Engineers and Association of Casualty and Surety
Companies. Here, referring in particular to speed devia
tion of vehicle trañic, standard deviation is expressed in
>the formula
speed squared, and an output representing the speed of
the last vehicle is taught in my copending application,
Serial Number 732,248, filed May l, 1958, under the title
“Trafiic Monitoring System.”
Y
From one aspect the present invention provides a ve
hicle actuated traflic speed deviation indicating system
capable of determining and indicating speed deviation
currently or on a substantially continuous basis for traf
fic passing a given location on a roadway or traflic lane.
From another aspect the present invention relates to
ynovel apparatus and method for determining the average
speed of vehicle traliic on a roadway and for determining
and indicating speed deviation of the measured speeds
‘of vehicles in the traflic liow automatically.
My said copending application Serial Number 732,248
describes a vehicle traffic monitoring system for sensing
the presence and speed of each vehicle passing a partic
ular location in the roadway, and for indicating each ve
hicle speed, the root mean lsquare speed of a predeter
mined number of vehicles and the volume of trañc on a
roadway.
'
As more fully described in my said copending applica
tion, the presence of a vehicle is sensed and its road «speed
is evaluated through the cooperation of a radar sensing
unit R81 and a speed and volume impulse translator.
The detection and speed information of each vehicle so
sensed, is available in the forms of electrical output of the
speed and volume impulse translator. Detection infor
mation is available in the forni of closure of a normally
open contact as a vehicle passes under the radar sensing
unit while the speed information is available ín the form
of a D.C. voltage, the amplitude of which is proportional
-where
to the speed of the vehicle sensed, with 14 Volts equal to
SD means standard deviation and
.
100 miles per hour, for example.
M equals arithmetic average of all observations;
Each time a vehicle is sensed its speed is read and con
65
X equals value of a single observation;
verted into a D_.C. voltage proportional to its road speed
-F equals frequency of observation of one value;
at the moment of measurement. This D.C. voltage re
N equals number of observations
lierred to as being representative of “last car speed,” is
The lirst term under the radical may be interpreted as
available as one of the outputs of the speed averaging unit
the summation of the squares of all of the individual 70 of the said copending application.
(X) values of speed divided by the number of such
Another voltage, representative of the last car speed
„Drdylgrali.
speeds.
squared is also developed and several consecutive voltages
3,082,949
3
4
representative of several consecutive last car speed squared
values are averaged by electro-mechanical averaging cir
block 10, an associated Speed and Volume Impulse Trans
lator, block 11, a Speed Averaging Unit, broken line block
`cuits to obtain the root mean square speed squared of the
12 and a Deviation Unit, broken line block 13-.
The Radar Sensing Unit may be similar to the Radar
last predetermined number of vehicles passing a prede
'termined position. A D.C. voltage representing the root
means square speed squared (R.lvI.S.2) is also available as
one of the outputs of the Vspeed averaging unit of my said
Sensing Unit RSI disclosed in my copending application
Serial Number 732,248, filed May 1, 1958, under the title
“Trañ’ic Monitoring System” which detects the presence
copending application.
of a vehicle on the roadway and thereafter senses its speed
substantially the same vehicle speeds as the root mean
tion of a vehicle and a second output in the form of a D.C.
giving a composite signal output indicative of vehicle de
According to the preferred embodiment the D.C. volt
tection and speed combined.
age proportional to the last car speed and the D.C. voltage
The Speed and Volume Impulse Translator, may be
representing the root mean square speed squared are
similar to the Speed and Volume Impulse Translator dis
applied toÁ a deviation unit. The deviation unit receives
>closed in my said copending application Number 732,248,
the D.C. voltage proportional to the last car speed and
which translates the composite output of the Radar Sensing
electro-mechanically provides a D.C. voltage output rep
resenting the arithmetic average speed squared of the last 15 Unit into two separate informations. One output of the
Speed and Volume Impulse Translator is in the form of a
predetermined number of last car speeds; the output rep
normally open Contact which closes representing detec
resenting the arithmetic average speed squared is based on
voltage proportional to the speed of a vehicle or speed
all of these output voltages being referred back to a com 20 indication.
square speed squared output of the speed averaging unit
mon reference level.
,
The two outputs of the Speed and Volume Impulse
`
The D.C. voltage representing the arithmetic average
_speed squared, ÃÍÄÍZ, is subtracted from the root mean
square speed squared, B_MSZ, in a difference computer
circuit in the deviation unit providing a diiîerence voltage 25
.representing deviation squared. Through electro-me
chanical computation a D.C. voltage is obtained in the
Translator are in usable form for input into a Speed Aver
aging Unit, represented by broken line block 12. Broken
line block 12 may represent a Speed Averaging Unit simi
lar to the Speed Averaging Unit described and illustrated
in my said copending application Number 732,248 which
receives the outputs from a Speed and Volume Impulse
Translator and provides therefrom D.C. voltage outputs
'form of an output which may be used to drive a motor to
4individually representing the speed of the vehicle detected
'indicate speed deviation on a calibrated scale or such out
30 (last car speed) and the root mean square speed squared
put may be made to operate a circuit at a selected or
(R.M.S.2) where a last car speed of 0 to 100 miles per
selectable value of speed deviation.
,
hour is represented by a D.C. voltage of 0 to +110 volts,
It is therefore an-object of the present invention to pro
for example.
vide apparatus for use in a traffic monitoring system for
'providing an electrical output representing the root means
n
Within broken line block 12 is -a functional block dia
square of the speeds squared of a last predetermined `num 35 gram of -a speed averaging unit basically similar to the
functional block diagram presented in my said copending
ber of vehicles passing a predetermined position on a
Aapplication representing the disclosed Speed Averaging
itratîìc lane or roadway and for providing an electrical
output representing the arithmetic average of the speeds ' Unit. The present functional block diagram differs from
squared of the same last predetermined number of vehicles 40 rthe functional block diagram in my said copending appli
_cation in that a relay, AIN is shown in the Null, block
_and deriving therefrom speed deviation in the form of an
26; -a relay Ab is shown in Gate, block 24; and broken
'lines 37b and 41 areextended `from the block diagram.
The relay AIN represents that a relay, labeled AIN in the
electrical output.
`
It is another object to provide a trathc speed deviation
'measuring or indicating system that automatically deter
mines speed deviation of vehicle trañic passing a predeter 45 .circuit diagram in my said copending application, is op
ei'ated by the Null 26 while relay Ab represents that a
mined position on a trañic lane or roadway.
rel-ay, labeled Ab (along with a parallel connected relay
' Afurther object is to provide a vehicle actuated trafiic
VAa) in the 4circuit diagram in my said copending appli
speed deviation indicating system that provides speed devi
cation, is operated as Gate 24. The broken -line 37b
ation of the last predetermined number of vehicles so ac
~¿tuating the said trahie speed deviation indicating system. 50 indicates «that the Null 26 is used to operate “Not” Gate
«43 and Gate 45 in broken line block 13 and broken line
_ It is also an object ofthe invention to provide a devia
41 indicates that block 22, in broken line block 12, and
Àtion unit for cooperation with a speed averaging unit hav
Vblock 40, in broken line block 13, are adjusted »to select fthe
ing a last car speed output signal and a squared root mean
»same number of cars to be averaged.
>square output signal, to determine the speed deviation of a _
IFIG. 2 herein illustrates, partly in block and partly in
circuit form', a simplified form of 'another type of speed
averaging unit that may be used in association with
_desired number of vehicles or cars. ’
It is further object of the invention to provide an im
proved deviation computer.
'
block 13 of FIG. 1 thus providing an alternate form of
Other objects will become more apparent from a read
‘ing’ of the following detailed description with reference '
trañic speed direction indicating system. 'Iihe blocks 1U
to the accompanying drawings where:
vand 11 inFIG. 2 -are similar to the blocks 10 and 11 in
,
60
'A FIG. 1 represents, in block form, one form of trañic
speed deviation measuring or indicating system, in accord
ance with the present invention;
-,
IFIG. 2 represents, partly in block and partly in sche
FIG. 1 while the remainder of FIG. 2, «the simplified
-form of `a speed averaging unit, may be employed to pro
vide out-puts for input into block 13, the deviation unit.
The outputs lof the speed averaging unit, 12, of FIG. `1
matic circuit form, an alternate form of speed averaging 65 for input into »block 13 tare substantially in the same
form «as the outputs of «the speed averaging unit of FIG. 2.
unit that may be used as part of a complete trafiic speed
Thus FIG. 1 represents one form of trañic speed devia
deviation computer in accordance with the present inven
tion, and _
-
FIG. 3, including FIG. 3a and FIGfBb, illustrates, in u
tion indicating system while the combination represented
in FIG.î 2 plus a deviation unit, represented by block 13»
schematic circuit form the preferred embodiment of the 70 in FIG. » 1, -represents another form of trañic speed .de
viation indicating system.
Y Y
deviation unit.
Referring tovFlG. 1 in more detail, a block diagram of
one form of trañîc speed deviation indicating system is
presented including-a vehicle detection and speed sensing
unit, that maybe in the form of, the Radar Sensing Unit,
V
Block 13 represents a deviation unit and is illustrated
in full schematic circuit form in FIG. 3 including PIG.
3a and FIG. 3b.
t
, Y
In point of time, the >detector impulse output from the
3,082,949
5
speed and volume impulse translator is .applied to the
speed averaging unit followed shortly thereafter by the
speed indication output. Thus the detector impulse is
applied to speed averaging unit where the length of the
detector impulse is used to »determine the time the de
tected vehicle will be .at a predetermined position relative
to the radar sensing unit. This predetermined position
is at a position approximately at a 60 degree angle be
tween the vertical from the sensing unit to the roadway
and the line between the sensing unit and the vehicle.
With the detector impulse applied to block 15, Time
6
between the two outputs is reached which operates a re
lay, here indicated as relay AIN. A gate block 24 in
cluding a second relay, here indicated as relay Ab, is op
erated by null, 26 via lead 25 and 37a. At this moment
since the block 21 has also been adjusted to a new ÉC?
value, the block 23 has been adjusted to a new RMS.2
electrical storage value.
Operation of the gate, block 24, via lead 37a from the
block 26, permits adjustment of the RMS? Mechanical
Storage, block 2‘9.
The block 23, new R,M.S.2 electrical storage may, for
example, include a capacitor capable of storing and hold
ing an electrical charge representative of the RlVLS.Z
age, is fed via Gate 17, to Calibration Circuit 18, and to
L_C. Electrical Storage, 19, and >at a time as controlled 15 while the block 29, RMS? mechanical storage may, for
Delay to 60° Point, ‘and Speed Indication »applied to
Gate 17 the speed information, in the form of D.C. volt
by block 15, Gate 17 is operated via lead 16 »to cut olf the
voltage applied therethrough.
The speed indication in the form of a D.C. voltage
whose amplitude of from 0 to +l4 volts representing 0
example, be in the form of a lpotentiometer with an arm
adjustable through a servo mechanism so that the value
of the voltage output at the arm of the potentiometer may
be adjusted to equal the value of the voltage charge on
to 100 miles per hour, is applied to ya calibration circuit, 20 a capacitor in block 23.
The block 20 and the block 29 may, for example, each
block 18, which ladjusts the speed indication voltage so
include a servo amplifier section and a phase sensitive,
that a `scale of 0 to +10 volts equals 0 to 100 miles per
bidirectional servo motor which may be employed to
hour. rFhis last vehicle speed (LC.) indication of 0
drive the movable arms of the respective potentiometers
to +10 volts is applied to an LC. electrical storage, block
to a position where the output of the respective blocks,
19. Block 2G, LC. Mechanical Storage, is driven by
which is the voltage at the respective arm of the poten
means of a phase sensitive reversible servo motor to
tiometer, is equal to the input from the previous block
match the value stored in block 19 so that a voltage rep
or one servo amplifier may be employed and switched
resentative of the speed of the last Vehicle or LC. will be
as desired between the servo motors of the respective
stored both electrically, as for example by `a charge on a
capacitor representing L.C. and mechanically, as for ex 30 blocks as illustrated in my said copending application
Ntunber 732,248.
ample, ?by positioning the arm of a potentiometer so
Upon reaching a null between the output of block 23
that with a fixed voltage applied through the resistance
through gate 24 and the output of block 29“, the null,
ofthe potentiometer the voltage at the arm of the potenti
block 30, for example, may operate to open this circuit
ometer will be substantially equal to :the value of the
charge on the capacitor and thus each voltage value will 35 at gate 24 and reset the mechanism preparatory for re
ceipt of the next succeeding detector impulse and speed
be representative of the L.C.
The block 20 may include a servo lamplifier [and a
servo motor which may be used to position the arm of
indication.
Thus out of the block 12 an output representing the
speed of the last vehicle (L.C.) 35, is obtained from
the potentiometer of the L.C. mechanical storage, typical
circuitry Áof which is fully disclosed in my said copending 40 block Z6 and an output representing the root mean square
speed squared (RJNLSP) 36, is obtained from block 29
application Number 732,248.
with both outputs applied to block 13, the deviation unit
A squat-ing potentiometer is provided, lblock 21, with
as here illustrated.
the arm >of the squaring potentiometer connected to the
Last vehicle speed information (L.C.), lead 35, is ap
arm `of the LC. mechanical storage potentiometer so
that 4«as the arm of the potentiometer in block 26i is driven 45 plied to Number of Cars Averaged Circuit, 4tl‘ lin the
deviation unit7 broken line block 13. Broken line 41
to match electrical storage, the Áarm in block 2t? is driven
between block 22 and block 40 is to indicate that both
to a corresponding position and an output from block 21
number of cars averaged circuits are adjusted to select
is lobtained representing the last vehicle speed squared
the same numbers of cars to be averaged. Also applied
or ÍÍÍÍÍÃ
Thus when the gate 17 `operates to cut fofr" the voltage 50 to block 40 is a voltage from Arithmetic Average Speed
applied through the gate, as controlled ‘by 'time delay 15,
the L.C. value in block 19, having been recalibrated by
Mechanical Storage, block 46, via lead y42, representing
the old Arithmetic Average Speed from the mechanical
to a new value also.
4S so that block 46 may be adjusted to the new value
now on block 44 and also reverses the condition of the
“not” gate 43 so as to stop further adjustment of block
storage. Thus the speed of the last vehicle, LC. via lead
block 18, represents the speed of the last vehicle yand
35, is applied to the number of cars averaged circuit 40
block 29 is driven to match the value of block 19 thus
and is averaged with the old arithmetic average speed and
mechanically storing the LC. speed >while »block 21 is
applied through “Not” gate 43 to block 44 the new Arith
driven with block 20 to provide an output representing
metic Average Speed Electrical Storage (A.A.).
,
the square of the last vehicle speed or EE?.
It should be observed that the “not” gate 43 and gate
The output of `block 21, EE?, is `applied to `a block 22,
45 are both connected, by broken line 37b and lead 2S
Number of Cars Averaged Circuit. Block 22 may, for 60 to null, block 26. “Not” gate 43 is the inverse of gate
example, include a voltage divider which may be adjust
45, that is, although both gates are operated simultane
able so that the number of car speeds averaged may be
ously via lead 37b, “not” gate 43 is closed when gate 45
adjustable, as desired. Also -applied to the block 22 via
is open and vice versa.
lead 31, is the output voltage of block 29, a volt-age rep
Concurrently as block 2&3 L.C. mechanical storage, is
resenting the old root mean square speed squared 65 being adjusted, prior to operation of the null relay AIN,
(Ril-5.2) so :that the last vehicle speed squared may be
the L.C. information is being fed via lead 35 to block 43,
averaged with the root mean square speed squared and
‘through block 43 and into block 44 so that block 44 is
a new root mean square speed squared may be applied to
being adjusted to a new value through “not” gate 43 be
New R.M.S.Z Electrical Storage, block 23.
fore the null occurs between blocks 19' and 20;
As block 2t) and block 21 are being adjusted to a new 70
When the null between blocks 19 and 2d occurs opera
value the electrical storage in block 23 is being adjusted
tion of null relay, AIN, reverses the condition of the gate
-
When the value of the output of block 20 or the LC.
mechanical storage equals the value of the output of
block 19, or the L_C. electrical storage, a null (block 26)
44 from block 40.
3,082,94a
8
MechanicalV Storage through closure of gate 45. Thus the
lead 88 of 0 to +14 volts D.C. representing 0 to 100 miles
per hour. The speed indication signal is applied to a
potentiometer 60 and «arm 61 picks olî a percentage »of the
A.A. mechanical storage, block 46 is driven to watch the
value of the new A.A. electrical storage block 44 at sub
stantially the same time as RMS? mechanical storage
position of approximately 60°, between «the vertical, :from>
' The new Arithmetic Average Speed Electrical Storage
data is now transferred' to the Arithmetic Average Speed
block 29, is driven to match new M.R.S.2 electrical stor
age block 23.
'
The Arithmetic Average Speed Squared, ETÀ-.2, block
47 is linked to block' 46 so that as the arm of the poten
tiometer in block 46 is adjusted to a new position the
arm of the potentiometer blocked block 47 is also ad
justed to a new position relative to the position of the
signal.
Since the vehicle speed will be measured atan angular
the sensing unit to the roadway and line between the
sensing unit and the vehicle, and since the vehicle’s speed
as stored on capacitor 64 should `be calibrated 0 to +10
volts equal lto 0 to 100 miles per hour speed; the setting
of arm 6l Iis such as to compensate for the angular posi
tion of the vehicle at the time contact T1 opens the cir
cuit, as will be described later.
arm in block 46.
Although yan angular position of 60° is »the preferred
posi-tion such angular position is not limited to 60° as
the arm 61 may -be positioned for recalibration of speed
taken at other angular positions as desired.
block 46 in FIG. l may include a chopper coupled to a
Thus the signal applied via lead 88 is recalibrated
servo ampliñer which drives a servo motor and a po
before
being applied through diode 62 and contact T1 to
tentiometer with the arm of the potentiometer mechani
cally connected, 'through suitable gearing, to the servo 20 capacitor 64. Capacitor `64 may -be called a last car speed
electrical storage since with contact T1 of relay T closed,
motor, which is illustrated as a phase sensitive, bidirec
the voltage picked off at arm 61, which represents the
tional motor.
speed ‘of the last car, is applied to and does charge capac
The output of block 47, a voltage representing the
itor 64 «to such voltage. The resistance `63 provides a
arithmetic average speed squared i7@ is fed via lead
25 bleed oit path so that capacitor 64 may discharge some
47a to block 48, a difference computer.
what if the speed indication of the previous vehicle was
The output R.M.S.2 of block 2.9‘ of the speed average
As illustrated in the circuit form partly in FIG. 3a and
partly in FIG. 3b block off by broken line block 46, the
unit, 12, is also applied via lead 36 to the deviation unit,
higher than the speed indication of the present vehicle
thus providing -for controlled charge and discharge to
13, into block 48 so that the RMS?, in the Íorm of a
assure that the charge placed on the capacitor 64 is sub
voltage representing the root mean square speed 30 stantially equal to the voltage at arm' 61 which represents
squared, which is on the same base as the KIZ, and the
the speed =of the vehicle.
'ÃTÃÍZ may be subtracted from each other so that the dif~
Operation of fthe speed averaging unit `ol? FIG. 2 com
ference voltage may be obtained, which represents speed
mences with energization of the relay 170 resulting in
closure of contact A. The detector impulse, which is
block 49. Block 49 in FIG. l may include a chopper 35 inversely proportional to the speed of the vehicle sensed
coupled to a high gain servo ampliiìer assembly, which
maintains the relay 179 energized -for such time period.
deviation squared, which may be mechanically stored in
drives a servo motor and a potentiometer, the arm of
which is mechanically connected, through suitable gear
ing to a phase sensitive, bidirectional motor, as illustrated
Closure of contact A of relay 170 in block 11 corn
pletes a pull-in circuit for relay R from a common ground
«through contact A, normally closed contact S1 of de
partly in FIG. 3a and partly in FIG. 3b block oft by 40 energized relay S, the coil of relay R to D.C. supply.
broken line block 49.
Relay R closes its contacts R1, R2 and R4 thus com
Block '50 may include la potentiometer, the arm of
pleting a holding circuit through contacts A, and R1.
which is linked :to the arm of a second potentiometer,
'in block 49 so that the arm in block 50 is positioned on
The opening of contact R3 and closure of R2 opens
the charging circuit -for capacitor CT and provides a bleed
its associated resistance corresponding rto the position of 45 off path through 4adjustable resistor S11, lafter having been
the arm in y.block 49 on its associated resistance with the
charged from a D.C. supply, vthrough adjustable resistor
output of the larm in block 50 applied to the resistance
52, »and contact R3. As soon ‘as the charge on capacitor
of the potentiometer in block 49. Thus `as the output of
CT reduces somewhat >'the relay T pulls in from D.C.
block 49 represents deviation squared, the output of block
supply through the coil of relay T, contact R2, `adjustable
50 is a voltage representing the square root of fthe de
resistor 51 to ground.
viation squared »and thus the value of the output at lead
The relay S, upon energization, via contact R4 opens
50a is the trafñc speed Ideviation which may be displayed
its contact S1 and closes «its contacts S2 and S3. Closure
on a meter suitably connected to the output as for exam
of contact S2 provides a holding circuit for relay S from
ple meter 232 in FIG. 3b.
DC. supply, Contact S2, normaly closed contact V4 of
FIG. 2 illustrates, pantly in block and partly in sche- r relay V to ground.
v
vmatic forma simplified form of speed averaging unit that
Closure of contact S3 completes a pull-in circuit for
may be used in yassoci-ation with the deviation unit to form
relay V but relay V is a delay act-ion relay, the delay
a tralhc speed deviation indicating system.
being on pull-in so that before the end of the delayed
The speed yaveraging unit illustrated in FIG. 2 differs
pull-in period, energized relay T :opens its contacts T2
somewhat 4from the speed averaging unit disclosed in my 60 thus breaking the pull-in circuit of delayed relay V.
said copending application Number 732,248 although the
Energized relay T closes its contacts T1 to permit ca
radar sensing unit, (R.S.'U.), .10, may bev similar to the
pacitor 64 to assume the potential at Aarm 61 on potenti
radar sensing unit R.S.'I. described in my said copending
ometer 69.
application and previously mentioned herein, .and the
speed and volume impulse translator (S.V.I.T.), 11 may
_be similar to the speed and volume impulse translator
described in my said copending application and previ
-ously mentioned herein.
The composite signal output of the radar sensing unit,
'block 10, will -be fed to Ythe speed and volume impulse 70
translator, block 11, as a vehicle passes under Vthe radar
sensing unit. The composite signal is translated into a
At termination of the detector impulse by lthe speed
and volume impulse translator, the relay 170 becomes
deenergized and its contact A opens thus opening the
holding circuit for relay R. Deenergized relay R releases
and opens its contacts R1, R2, and R4 and closes its con
tact R3.
y
,
l
'
Relay R cannot now pull-in again so long as relay S
remains energized since contact S1, in ythe pull-in circuit
'lof relay R, is heldopen vby now energized Vrelay-S. This
'detector impulse which operates a relay 170, to close a
prevents any succeeding false operations of contact A
pair of normally open contacts A, in block 11, for ex
ample, and into speed indication as a D.C. output via 75 =due to a succeeding salient reliec'tion on a long vehicle
3,082,949
j
9
or an impulse from an exceedingly close spaced second
vehicle -from getting into the sequence of speed averaging
until the first measurement is assimilated in the averaging
unit, as herein described.
10
to the potential on grid 65» which is equal to the charge on
capacitor 64 which charge represents the speed of the last
vehicle.
The voltage on lead 67 is applied .to a chopper, block 68
The period of energization -of relay R is substantially
and such voltage is employed as a reference to which a
equal to the period of closure tof contact A, which periods
voltage on lead 70 may be adjusted by oepration of a two
fare both inversely proportional to the speed of the ve
phase bi-directional servo motor, block 91 which is con
hicle detected. The length of the period :of energization
nected through suitable gearing to the arm 71 of poten
of relay R determines the -amount of discharge of timing
tiometer 7 1/72.
capacitor CT -through timing resistance. The »amount of 10 `With +10 volts D.C. applied through resistor 72, the
discharge of capacitor CT determines the amount of time
voltage at arm 7'1 will be a fraction of the -f-"vlO volts ac
necessary for controlled recharging of the capacitor. The
cording to the position of the arm 71 relative to the ex
amount of time necessary for recharging of capacitor CT
tremes ofthe resistor 72. For example, with the arm 71
determines the time `delay between the opening of the
at a point three quarters of the way up from the bottom
energizing circuit for relay T and the fall out of relay T. 15 of the resistor, a voltage of 7.5 volts which is three quar
Thus the speed of the vehicle as it passes under the
sensing unit is utilized to determine when the vehicle will
be in a certain desired position with relation to the sensing
unit. Since the detector impulse is inversely proportional
ters of the total applied voltage, will be applied at arrn 71.
' When the voltages on leads 70‘ and 67 are unequal this
difference is sensed Áby the chopper 68 and the difference
voltage is passed by capacitor 69 in the form of an alter~
to vehicle speed, a slow moving vehicle will provide a 20 nating current (AiC.) to the servo amplifier, 90 via con
tact W2. The relation between the two voltages, on leads
longer detector impulse and hold relay R energized for a
longer period of time thus providing for greater discharge
67 and 70, is expressed in the phase oñ the A.C. passed by
capacitor 69. The relationship of the phase of .the A.C.
than a more rapid moving vehicle. Thus the slower
passed by capacitor 69 with reference to the A.C. operat
moving vehicle is given more time to arrive at a desired 25 ing the chopper and the servo motor, block 91, which is
of capacitor CT and longer delayed fall out of relay T
position, than a more rapid moving vehicle is given to
arrive at the same position.
When relay R becomes deenergized, at the end of the
detector impulse, contact R3 is closed and provides a cir
substantially the same A.C., determines the direction of
rotation of the servo motor resulting in repositioning of
arm 71 of potentiometer 71/72. The servo motor, block
91 is substantially the same as servo motor, block 91a
cuit to charge capacitor CT from D.C. supply, through 30 and both may be similar to the servo motor illustrated in
FIG. 3b blocked oíf in broken line 91’. As explained
capacitor CT is also being charged from D.‘C. supply
below this motor may be a two phase, bi-directional motor.
through the coil of relay T to capacitor CT to ground.
Thus the arm 71 will be driven to a position on resist
When contact R3 is first closed, after being held open by
vance 72 through which is applied a 10 volt D.C., so that
relay R, the voltage across relay T will be suñ‘icieut to 35 the voltage at arm 71 which is applied to the chopper 68
maintain relay T energized although the energizing circuit
via lead 70 will be equal to the voltage applied to chopper
resistor 52, Contact R3 to capacitor CT to ground while
ñor relay T has been opened. When the charge on ca
69 via lead 67.
pacitor CT increases to suñìcient value so that the voltage
With the two applied voltages, via leads 67 and 70 sub
across relay T can no longer maintain the relay energized,
stantially equal there will be no output from the chopper
relay T drops out and reverses its contacts, contact T1 40 and therefore will be no input into the servo ampliñer all
becoming open and contact T2 becoming closed.
as described and illustrated in FIG. 3.
Upon closure of contact T2 the pull in circuit for relay
The Voltage at arm 71 is applied through the resistor 74
V is completed from D.C. supply through the coil of relay
of potentiometer 73/74 and the arm 73- may be linked
V, contact T2, contact S3, conta-ct X3 to ground, and,
mechanically to the arm 71 so that as arm 7-1 is positioned
after a short delay the relay V pulls in and opens its con~ 45 on resistor 72 the arm 73 is positioned on resistor 74 rela
tacts V1, and V4 and closes its contacts V2, and V3.
tive to the position'of arm 71 on resistance 72?.
Closure of contact V3 provides a holding circuit for
n Thus the potentiometer 73/ 74 may be referred to as a
relay V while closure of contact V2 provides a bleed olf
`squaring potentiometer since the fraction of the ratio be
circuit through adjustable resistor 54 lfor capacitor CW,
the total applied voltage (+10 v.) and the voltage
which capacitor became fully charged from D.C. supply 50 tween
at arm 73` will be thesquare oli the fractional position of
through the adjustable resistor 53, contact V1 to capacitor
CW and from D_C. supply through the coil of relay W to
capacitor `CW with capacitor CW returned «to ground.
. With capacitor CW discharged somewhat relay W be
comes energized and opens its contact W1 to open the
ground connection to the servo ampli-tier of block 90 and
closes contact W2 thus connecting the chopper, block 68
to the servo ampliñer through coupling capacitor 69. The
chopper, block 63 may be similar tothe chopper, block
68a and each may be similar to the chopper schematically f 60
the arm 71 on the resistor 72..
Thusthe voltage at arm 71, since the arm will be driven
to a position where the voltage at arm 71. will equal the
voltage at lead 6.7, which will equal the charge on ca
pacitor 64, will represent the speed oñ the last vehicle or
LC. `Since the voltage of arm 71 represents the speed of
the last vehicle then the voltage at arm 73- may represent
the speed of the last vehicle squared or m2.
The output via lead 35 represents the last vehicle speed
or LiC. and is in substantially the same form as the output
illustrated in FIG. 3a blocked off by a broken dotted line
represented by lead 35 in ythe block diagram in FIG. l.
block labeled 68’. The servo ampliñer, block 9@ may be
The `voltage at arm 73, representing the last vehicle
similar to the servo amplifier block 90a and each may be
speed squared (ETC-.2) is fed through resistor 75 to junc
similar to the servo ampliñer schematically illustrated in
FIG. -3a blocked off by a broken dotted line block, labeled 65 tion 76. Also applied to junction 76 is a voltage from
arm ‘7.9 of potentiometer 79/80l through lead 78, adjust
90' except the servo amplifier in block 90 and 90a do not
able resistance 77 to the junction 76'. The voltage on arm
have their respective outputs shorted out as illustrated in
FIG. 3a at junction 1431, via contact 45a.
79 corresponds to the old root mean square speed squared
With the opening of contact T1 the charge on capacitor
of the last predetermined number of vehicles excluding the
64 remains and such charge is applied to‘the grid 65 of 70 present last car speed all as described below. The resis
cathode follower 66.
tors 75 and 77 and junction ’76 form a voltage divider
The amount oli power drawn by cathode follower 66
at junction 76. Depending upon the ratio between the
is proportional to the potential applied to grid 65. so that
value of the resistances 75 and 77 and the value of the
the voltage on lead 67, which is a fixed percent of the
voltages applied at arms 73 and 79 respectively a voltage
power drawn by the cathode follower 66, is proportional 75 is applied via junction 76, contact X1 to the capacitor 85
3,082,94e
Y
1l
,
Y
t
12
,
equal to the new root mean square speed squared
Thus it has been described that a D.C. voltage output on
(Rl/1.5.2) of the last predetermined number of vehicle
speeds sensed, including the present last car speed.
lead 35, representing the speed of the last vehicle and a
D.C. voltage output on lead 36, representing the root
When the relay W became energized, contact W4 was
opened and contact W3 was closed. 'This provides a
controlled bleed ott circuit for the capacitor CX to there
mean square speed squared may be obtained in a manner
somewhat different than that described in my said copend
ing application Number 732,248 and these outputs may
'be applied .to the deviation unit, described below to provide
an alternate form of trañic speed deviation system, the
relay X pull in, after energiza-tion ot relay W may be
present invention herein.
somewhat less than one second, for example, to allow
=It should be noted that the pull-in circuit for the relay
suñicient time for the repositioning of arm 71 and thus 10
R includes a “break” contact of relay S so that if relay S is
the repositioning of arm 73` and the adjustment of the
energized relay R cannot again be energized if the relay R
charge on capacitor 8S before relay X pulls in.
had previously become deenergized as by termination
When relay X pulls in ‘from the D.C. supply through
of the detector impulse.
the coil of relay.X contacts W3, adjustable resistance 55 y
>It should also be noted «that due to the sequential op
to ground, contact X1 is opened and contact X2 is closed.
eration of the relay assembly a second detector impulse
Contact X3 in the holding circuit of relay V is also opened.
may cause energization of the relay R and initiate a second
With contact X3 open relay V becomes deenergized
upon energize relay X after a time delay. The delay on
cycle of operation prior to the complete termination of
and opens its contacts V2 and V3V and closes contacts V1
the original cycle without interfering With normal com
and V4. Closure of contact V1 provides for controlling
charging of capacitor CW to time a delayed fallout of 20 pletion of the cycle then in progress.
rrrI’hus a simplified form of speed averaging unit, employ
relay W.
ing a timed sequential relay operation has been described
The delayed fallout of relay W ensures that sutiicient
from which unitris obtained the speed of the last car in a
time has occurred to reposition the arm 71 so that the
D.C. voltage based on 0 to +10 volts representing 0 to
voltage at arm 71 via lead 70 and the voltage via lead 67
have been adjusted so that the voltages are substantially 25 100 miles per hour and a voltage representing the R.M.S.2
speed for a predetermined number of last vehicle speeds
equal.
through outputs 35 and 36 respectively.
It, for example, a trañ‘ic speed deviation system would
include a speed averaging unit similar to that just de
W4 provides for controlled charging of capacitor CX to
30 scribed with reference to FIG. 2 the relay DX of the
time a delayed fallout of relay X.
kdeviation unit, illustrated in FIG. 3a may be energized
During energization of relay X contact X2 is closed and
the same time relay X is energized and could be con
the voltage charge on capacitor 85 is applied to the
nected so that the coil of relay X and the coil of relay
lchopper, 68a, which compares the voltage at arm 79 of
DX are connected in parallel or may be connected so
potentiometer 79/80, which is fed via lead 78 to chopper
that the energizing circuit of relay DX includes a “make”
68a, with the voltage charge on capacitor 85. Any dif
contact of relay X. The latter proposed circuitry may
ference in voltage is sensed and is passed by capacitor
Upon deenergization of relay W contacts W2 and W3
open and contacts W1 and W4 close.
Closure of contact
69a, as an A.C. to the servo amplifier, 90a, which in turn
'ampliíies the A.C. and feeds the servo motor 91a. The
servo motor 91a is driven according to the phase of the
include a source of power, as for example a D.C. supply,
connected to one side of a “make” contact, as contact X4
79 of potentiometer 719/80 is driven to a positon on resis
tor 80 where the voltage at arm 79 is substantially equal
to a common ground.
in phantom form, for example, the other side of contact
A.C. passed by capacitor 69a with reference to the A.C. 40 X4 connected to one side of the coil of relay DX (of
_FIG. 3a) and the other side of the coil relay DX returned
operating the chopper 68a and the motor 91a. The arm
Operation of the deviation unit, schematically illus
trated in its preferred form in FIG. 3a and FIG. 3b, will
to the voltage lcharge: on capacitor 85 and both voltages
represent the root means square speed squared (R.lvI.S.2) 45 now be explained relative to its operation in a tratîic
_speed deviation indicating system.
of the last predetermined number of vehicle speeds.
Because of the size and complex circuitry of the devia
When both voltages applied to chopper 68a are sub
tion
unit the circuit drawing includes two figures, FIG. 3a
stantially equal there is no input into the servo ampliiier
and FIG. 3b. Certain leads interconnect between FIG.
land the motor stops operating.
"Ilhus the arm 79 has been repositioned so that the volt 50 A3a and FIG. 3b and these leads are identically labeled
and extend to the edge of the respective drawings thus
age on arm- 79 is substantially the same as the charge on
indicating they are interconnected between the ñgures
capacitor 85.
to a lead identically labeled.
The dual potentiometer arrangement 81/82 and 79/ 80
The power supply for the deviaton unit, in FIG. 3 is
is similar to the dual potentiometer arrangement 71/72
Íand 73/ 74. A D_C. voltage of +10 volts is applied to 55 generally represented by a triangle, in FIG. y3b repre
senting +300 volts D.C. for example; a circle labeled
Aresistor 82 of potentiometer 81/82 and the arm Slis posi
+10 representing +10 volts D.C. for example; a plus in
tioned mechanically on the resistor 82 corresponding to
a square representing +155 volts D.C., for example; a
‘the’ position of arm 79 on its resistor 80. The Voltage at
minus in a circle representing -10 volts D_C. for ex
arm 81, which is a fraction of the applied `+10 volts, the
fraction being equal to the position of the arm 811 interum 60 ample, and two closed circles labeled + and '- A.C.,
representing a 60 cycle per second 120 volt A.C. source,
the ends of the resistor 82, is applied to resistor 80 and
for example.
-the voltage at arm 79, which is _in a corresponding me
. Speed information, such as the speed of the last ve
-ohanical position on resistor 80, may be considered the
hicle (LC.) and the root mean square speed squared,
(m2) in the form of D.C. voltages similar to the
voltages developed and applied as outputs of the speed .
square of the voltage at arm 81, as a fraction of the total.
Thus the potentiometer 79/80 may be referred to as a
squaring potentiometer since the fraction of the radio be
tween the total applied voltage (+10 v.) and the voltage
averaging unit of my said copending application Number
,732,248 and in tbe form of speed averaging unit illus
at arm 79 will be the square of the fractional position of
trated in FIG. 2 herein are illustrated as being applied
Thus the output of arm 79 via lead 3:6 is a D.C. voltage 70 to the deviation unit via leads 35 and 36 respectively» in
`the arm 81 on the resistor 82.
FIGS. 3b and 3a respectively.
that represents the R.M.S.2 speed and is substantially equal
Coordination of operation between the speed averaging
to the charge on capacitor 85.
When the Vrelay X becomes deenergized the relay
sequence terminates and the speed averaging unit returns
to rest.
unit» and the deviation unit is obtained through controlled
5
operation of the relay DX, illustrated in FIG. 3a, by the
speed averaging unit. Normally relay DX is maintained
3,082,949
13
14
deenergized with both its contacts 43a and 45a closed.
Last car speed information, in the form of a D.C~
voltage with 0 to +10 volts representing 0 to 100 miles
arm 1-15, the old arithmetic average speed, and the volt
age at lead 35, the last vehicle speed as modified via the
voltage divider action and applied via lead 104, etc., to
>per hour speed, is applied through lead 35, FIG. 3b, re
the capacit-or, to the Contact 107.
The chopper 1-08 is operated »from a 60 cycle per sec
ond alternating current (A_C.) supply and arm 111 ‘alter
nately connects between contact 107 Iand contract 109.
The difference voltage between the potentials at contacts
sistance 102 to a junction 103. This last car speed signal
applied to junction 103 is modiñed somewhat by action
of a voltage divider including adjustable resistance 120
and associated resistance 122 and the resistance 102 con
nected to junction 103, as more fully described below.
107 and 109 is sensed at capacitor 113 and passes as
With contact 43a closed, this modified signal is applied 10 an A.C. voltage whose amplitude is equal to the difference
via lead 104 to FIG. 3a Via contact 43a, lead 105 to the
between :the potentials applied to contacts 107 and 109
'storage capacitor 44a, which represents the new arith
and whose electrical phase is determined «by the relation
metic average speed electrical storage.
ship between the two >different potentials.
When the voltage potentials at contacts i107 and 109
junction 101 in the servo amplifier and effectively grounds 15
are substantially *the same, the difference voltage will be
any signal that may be applied to the junction 101. This
zero and without change in potential applied to capacitor
prevents the servo amplifier from “floating” and prevents
113. Thus capacitor 113 senses a D.C. potenti-al which
Yamplified electrical noise from being applied to drive the
is substantially lblocked.
'servo motor to erroneous settings. This is one method
The .amplitude of the A.C. volt-age substantially equals
of control that may be used, other methods well known
The contact 45a supplies a ground connection to -a
to those skilled in the art, may be used for control of the
servo ampliñer.
The broken line box '43 and the broken line box 45
in FIG. 3a illustrates one type of “not” gate and gate
respectively that may be found in the block diagram in
blocks 43 and y45 respectively in FIG. 1.
The broken line box 44 in FIG. 3a illustrates one type
electrical storage such as may be found in the block
diagram in block >44 in FIG. l. The charge on the ca
pacitor 44a is applied through resistance 106 to contact
107 of chopper 108.
The broken line box 48 includes circuitry that may be
included in block 48 in FIG. 1 while broken line box 49
in FIG. 3a includes part of the circuitry that may be in
cluded in block 49 in FIG. 1. The remainder of the cir
cuit components included in block 49 in FIG. 1 may be
vseen inbroken line box 49 in FIG. 3b.
The broken line box 46 in FIG. 3a includes part of
the circuitry that may be included in block 46 in FIG. 1
while the remainder ofthe circuit components included in
block 46 in FIG. l are illustrated in broken line box 46
Ain PIG. 3b.
Broken lines boxes 47 and 50, in FIG. 3b, include cir
cuitry that may be included in block 47 and 50 respec
20 any `dii-ference kbetween the two potentials Iat 107 ’and 109.
The electrical phase of the difference potential appearing
25
as an A.C., is determined by the relationship between
the two potentials with respect to the Ihigher of the two
potentials. 'Thus the electrical phase of the A.C. is deter
mined ~by whichever is the higher potential and thus
determines the direction in which the arm 115 must be
driven on the resistance 114 iso that the voltage at arm
-115 or Icontact 109 is made Ito be substantially equal to
30 the voltage charge on the capacitor 44a or contact 10’7.
The 60 cycle per second A.C. 'operating the choppers
10-8, i175 and 159, as illustrated in FIG. 3a, and the 60
cycle per second A.C. Ioperating the servo motors 144
and 223, las illustrated in FIG. 3b is here assumed to be
35 Vsubstantially 4the same source of A.C. or may be separate
sources of A_C. but substantially in phase with each other,
and are used as a reference to determine the electrical
phase of the A.C. passed by the capacitor 113, 13S and
166, as described below.
40
'
Let it be assumed, for example, that arm 111 connects
with contact 109 I_and then with contact 107. Let it also
be assumed that the potential at contact 109 is a greater
positive value than the potential at contact 107. Under
such conditions the wave form a may represent the A.C.
tively in FIG. 1 While the lead labeled (42) in FIG. 3b, 45 wave passed by capacitor 113. This condition may indi
between broken line boxes 47 and 40 may illustrate the
lead 42 in block form FIG. 1. Broken line box 40, in
FIG. 3b includes circuitry that may be included in block
cate that the voltage »at arm 115 must be reduced to equal
the potential Iat capacitor 44a and therefore that arm 115
must be repositioned to la lower position on resistance
114 of potentiometer 114/115.
.4o in FIG. 1.
yIn FIG. 3b, at terminal 160, a +10 volt D.C. supply 50~ It on the other .hand the value at contacts 107 and
109 were reversed, that is that lthe potential at contact
is applied through resistance 114 of potentiometer
109 were of a less positive value than the potenti-al at
114/115. The value of the D.C. Voltage at arm 115,
value of the voltage at junction 110, with respect to
contact 107 then the wave form b may represent the A.C.
wave passed by capacitor 113. This condition may indi
ground.
cate that the voltage at arm 115 must lbe increased to
with respect to ground, is> substantially the same as the
‘
. ' The voltage at junction 110 is applied via lead (42)
equal the potential at capacitor 44a and therefore that
through part of the voltage divider including resistance
the arm 115 must be repositi-oned to a higher position
on resistance 114 of potentiometer 114/115.
122, part of adjustable resistance 120 to selector arm 121
to junction 103. Also applied to junction 103 through
Thus the phase of the A.C. passed through capacitor
resistance 102 is a voltage representing the last car speed 60 113, with respect to the phase. ofthe reference A.C. is
`via lead 35. The resultant voltage of the voltage divider
employed to drive «the motor in the desired direction to
reposition the arm to a position Where the potential at
action is applied via lead 104, to FIG. 3a, contact 43a,
lead 105 to capacitor 44a. This charge applied to ca
the rar-m 115 >is substantially equal to the potential on
capacitor 44a.
pactor 44a represents 'the> new arithmetic average speed
65
of the last predetermined number of vehicles.
Returning momentarily to FIG. l, it should be under
The output .of potentiometer 114/115, the arithmetic
stood that when «the voutput ot block 19, which is the last
average speed mechanical storage, -applied to junction 110
car speed electrical storage, ditîers lfrom the output of
is `also applied to lead 1116 to FIG. 3a, through impedance
block 20, the last car speed mechanical storage, the null
117 and resistance 118 to contact 109 lof chopper 10S.
26, fed 'by «both outputs, is not attained. As Iblock 20
The charge on capaci-tor 44a is >applied through resistance 70 is being adjusted so that its output will be equal to Äthe
106 to Contact 107 of chopper 108.
loutput of block l19 (prior t-o attaining -the'null) the output
The voltage potential on contact 109 of chopper 108
of block 20 is ybeing fed via lead 35 to the deviation unit,
Vrepresents the old arithmetic avenage speed while the
block 13, into block 40. The signal -fed Via lead 3'5 is
'Í voltage potential on contact 107 of chopper 108 represents
modified -by block 40 and passed by “not” gate 43 to
the new arithmetic >average speed; that is the voltage at 75 block 44, the new «arithmetic average speed electrical stor
3,082,949
.
v
16
15
ground through cathode load resistance 135.
ymodified by block 40.
The coil 148 of servo-motor 144 is connected to a 60
When the outputs of block 19 and block 20 are sub
cycle per second A.C. source which is substantially in
phase with the 60 cycle per second A.C. source operat
stantially equal a null between the two outputs is at
tained. At this moment the output of block 20 represents
the speed of the last car (L.C.), `and this output has, via
flead 35,» been »applied to and m'odiñed by the deviation
ing the chopper 108.
The servo-motor 144 represents a phase sensitive, two
phase motor which rotates clockwise or counterclockwise
according to the phase relation of the electrical current
in coil 140 with respect> to the electrical phase of the
buit so that the output of block 44 now represents a new
_arithmetic laverage speed (A.A.).
Generally, the relay AIN, may con-trol the pull-in cir
»
servo-motor 144 and through to the center tap to B-i
supply. The cathode 147 of: tube 137 is connected to
equals the value of the out-put of block 20 somewhat
With the occurrence of the null between the outputs
of blocks 19 and 20 a relay, for example AIN, shown in
block 26 is operated.
~
FIG. 3b to lead 146 to the upper tap on coil 140 of
age. 'lihus as «block 20 is being adjusted to a. new value
the block 44 is also being adjusted to a new value which
reference electrical current in coil 148. These currents
are normally displaced 90 degrees in phase with respect
15 to each other and since the coil 148 is connected across
cuit for -a relay Ab, tor example, shown in gate, block
24, after which the relay Ab holds through its own con
tacts.
the A.C. line the 90 degree displacement is secured on
the other coil 140, through the combination of the ca
pacitor connected across it, the tuning capacitor associ
ated with windings 128 and 129 of the coupling trans
The coil of relay DX, shown in FIG. 3d, may be con
nected in parallel- with the coil of relay Ab` so that as 20 former, and through the mechanical phase lag of the
armature 111 with respect to its driving coil in chopper
relay Ab is energized relay DX is also energized.
108 which is driven from an A.C. essentially in phase
Thus the relays Ab »and DX may -be controlled by relay
with the A.C. across coil 148.
'
AIN for initial energization but each .thereafter hold
An indicator lamp L1 which is connected across coil
through contacts of relay Ab, independent of relay AIN.
y140 is illuminated when the motor 144 is operating.
Relay DX, »as shown in FIG. 3a controls two sets of
contacts. rIlhe block 43 represents one set of contacts
while the block 45 represents the second set of contacts.
With relay DX deenergized, that is prior «to reaching
Thus according to the phase relationship of the signal
passed through capacitor 113, relative to the phase of the
A.C. operating the chopper 108 the phase sensitive servo
motor 144 is driven clockwise or counterclockwise to re
-a null between blocks 1‘9 rand 20, the contact in -block 43
position the arm ¿L15 until the voltage at arm 115, applied
is closed to permit passage of the L.C. signal from lead 30 through junction 1410, lead 116, impedance 117 and re
35 through block 40, through gate 43 to block 44, for
sistance 118, to contact 109 is substantially equal to the
Vadjustment of «the new A.A., while the contacts in block
_voltage applied to contact 107 from capacitor 44a.
45 are closed to complete a ground connection to short
When the two potentials are substantially equal the
out Vthe output of the servo amplifier and, in etîect nullify 35 -output of the chopper is substantially zero, thus the signal
the el’r'eet of the servo iampliiier on the servo motor.
on grid 124 is reduced to substantially zero.
When the null is attained the relay AIN is operated
Now the new arithmetic average speed value is stored
to operate relay Ab and DX. With relay DX energized
on the potentiometer -114/115 with the new value rep
“not” gate 43 is opened to stop charging or adjusting of
resented by the voltage at arm 115.
block 44 and gate 45 is opened to permit adjustment of 40 The arm 115 is mechanically connected to the motor
Vblock 46 breaking or opening the connection to ground
144 by suitable gearing and is driven in the desired di
thus permitting the servo amplilier to apply its output
to the servo motor and thus drive block 46 to a new
>rection according to the electrical phase relationship be
_tween the current in the coils 140 and 148. The arm 15-1
position according to the value ot block 44.
is linked mechanically to arm 115 so that as arm 115 is
Thus it may be seen that although the “not” gate 43 45 positioned on the resistance 114 the arm 151 is positioned
and gate 45 both are illustrated in FIG. 3a as break
on the resistance 152 corresponding to the position of
contacts on relay DX the functional operation of the two
gates are opposite to each other.
,
A D_C. voltage, of the order of +10 volts for example,
Returning to FIG. 3, with a diiïerence signal between
is applied at» terminal 160 to the resistance ‘114 of po
the values applied to the contacts 107 and 109 of chopper
tentiometer 114/115 to ground. ‘
108 the varying potential ,on moving arm 111 is passed
The voltage at arm 115 is applied via lead 42 to junc
through capacitor 113 as an A.C. This A.C. signal is
tion 110 and through to the contact 109 of chopper 108
arm 115.
applied through resistance 123 to ground.
’
~
'
'
Y as previously described and also applied to the resistance
The A.C. potential is applied to grid 124 of tube 125,`
152 of potentiometer 151/152. The'arm 151 is posi
the tube 125 being of the conventional triode type gen# 55 tioned on resistance 152 according to the position of
erally employed for ampliiication.- The plate circuit of
tube 125 is coupled through resistance/capacitance cou
_pling to the grid of a second stage of amplification, in«
cluding tube 126. The ampliiied A.C. signal is passed
through coupling capacitor 127 to junction 101 andlwhen
contact 45 is open, the signal is applied through coil 128
to ground. The A.C. signal applied to coil 128 causes
induced current in coil 129 of transformer 128/ 129.
>The induced A.C.,potential in coil _129 is applied to the
grids 130 and 136 causing alternate conduction of the
associated tubes 133 and 137 respectively so that when
tube 133 is conducting tube 137 is non-conducting.
The plate circuit of tube 133 follows via lead 138 to
FIG. 3b to lead 139 to the lower tap on coil 140 ot servo
-rnotor 144. The center tap of coil 140 is connected to
`B-l- voltage of the order of +300 volts D.C'. for ex
ample. The cathode 134 of tube 13-3 is connected to
lground through cathode load resistance 135.
The tubes 133 and 137 are illustrated as beam power
,tubes connected for push-pull ampliñcation.
The plate circuit of tube L37 follows via lead 145 to
, arm 115 relative to resistance 114, as previously described
and the voltage at arm 151 is equal to the square of the
fractional position of arm 115 on the resistance 114.
For example, with »F10 D.C. volts applied through the
.resistance 1,14 of potentiometer 11'4/115 and an arithmetio average speed of 50 miles per hour, represented
¿on a voltage scale of _0 to +510 volts equal to 0 to 100
miles per hour, the arm 115 will be positioned at` the 1/2
_ position interim the ends of the resistance 114. 'Thus
65 5 volts or 1/2 the applied voltage of 10'volts will be picked
oiï the resistance 114 by arm 115 and will represent the
arithmetic average speed of 50 miles per> hour. The 5
volts at arm 115 will be applied through the resistance
152 of potentiometer 151/152 to ground. The arm 151
70 which is positioned on the resistance 152 corresponding
to the position of arm 115 on resistance 114, ywill also
be positioned at the 1/2 position intermediate the ends of
resistance 152. Thus with 5,volts applied through re
sistance 152 from arm 115, the voltage at arm 151 will
75 be 1/2 the applied voltage of 5 volts or 2.5 volts above
3,082,949
1?'
18
ground and will be the equal to 1A of the entire original
input voltage of +10 volts and will be equal to the square
of the fraction of the position of the arm 115, the square
of 1/2 which is (1A).
With the voltage at arm 151 representing the arithmetic 5
to ground. Induced current in the other coil 197, of the
couplin<7 transformer provides a potential to the grids 20'1
and 267 of beam power tubes 2.1M and 208 respectively.
These tubes are connected for push-pull power amplifica
average speed squared, :1.5.2, the voltage is applied via
'The preamplifier and two stage servo amplifier section
are arranged for high gain amplification to provide for
amplification of very small amplitudes of A.C. at junction
lead 155 to FIG. 3a to resistances 156 and 157 to con
tion.
i
tact 155 of chopper 159.
The resistors 156 and 157 and chopper 159 are part of
165 so that very small diíierences between the A.C.v at
the subtracting circuit illustrated in block form in FIG. 1 10 chopper 173 and the A.C. at chopper 159 may be sensed
and labeled 43.
and amplilied. Therefore with such high gain amplifica
The voltage representing the root mean square speed
tion an A.C. of a relatively large amplitude at junction
16S may produce an excessively strong signal induced in
squared, R.M.S.'-", is applied to lead 36 from the speed
coil 197. The diodes 215 and 211 are provided to reduce
averaging unit and was determined from the same number
of cars as the arithmeti-c average speed squared (M2) 15 any excessively strong signal to a maximum limit so as
to prevent overdriving of the amplifier output stage.
the number of cars being determined by the setting of arm
Since the choppers 175 and 153 are operated by the
121 of adjustable resistance 120. rl`he voltage represent
same A.C. power, the electrical phase of the A.C. poten
ing the BALS? is fed via lead 36 through resistance 164
tial at junction 168 and the phase of the A.C. operating
and 165 to contact 161 of chopper 1519.
Since the root mean square speed squared, RMS?, 20 the choppers 175 and 155 determines the direction of
drive of the motor 223 in FlG. 3b in a similar manner as
value represents an average value of the squared speeds
that described for directional control of the motor 144
and the arithmetic average speed squared M2, value
with respect to the relation between the A.C. at capacitor
represents the squared average of the speeds, and both
113 and the A.C. operating chopper 108.
the root mean square (KMS.) value and the arithmetic
The plate circuit of the tube 264 includes lead 214 to
2.5
average (AA.) value are based on the same vehicle
FIG. 3b, to the lower tap of coil 216 to the center tap of
speeds, it may be assumed that the Bah/1.5.2 value will be
coil 216, lead 217 to the B-i- supply. The cathode of
higher than the m2 value to the extent that there is any
tube 20K-‘.- is connected to ground via resistance 205.
differences in the speeds of the cars from which the
"l"he plate circuit of the tube 20S includes lead 218 to
measurement is taken.
FiG. 3b, to the upper tap of coil 216 to the center tap of
The di erence voltage between the R.M.S.2 value and
coil 216, lead 217 to ‘B+ supply. The cathode of tube
is connected to ground via resistance 205.
the m2 value will be sensed at the capacitor 166 as the
moving contact 162 of chopper 159 alternately connects
The A.C. in coil 225' is an A.C. substantially in phase
between contacts 158 and 161. The diiîerence voltage
with the A.C. operating the choppers 175 and 158, and
in the form of an A.C. will pass through capacitor 166 35 the A.C. in the coil 216 _is related in phase to the A.C. at
and through resistance 157 to junction 163.
junction 165. Thus according to the phase relationship
The A.C. voltage applied to junction 163 from chopper
between the
in coil 220 and the A.C. in coil 216 the
159 is opposed by an A.C. voltage applied to junction 168
servo motor 223 will be caused to rotate either clockwise
via resistor 169 from moving contact 173 oñ chopper 175.
or countercloclcwise. An indicator lamp L2, which is
rlîhe A.C. voltage passed by moving contact 173 is the 40 connected across the coil 216 is illuminated when the
motor 223 is operating.
diñerence voltage between the potential at contact 176,
and the potential value at contact 174. The voltage at
The arm 185 of the potentiometer 154/185 is suitably
»Contact 176 is essentially at Zero, with respect to ground,
geared to the motor 223 so that the arm 185 is positioned
which zero potential is obtained by adjustment of arm 17S
on the resistance 154 so that the voltage at arm 135, which
on the potential divider network 177 between a positive 45 is applied via lead 186 to FiG. 3a, through resistor 179
DC. of the order of +155 volts and a negative D.C. of
to contact 174, may be above ground zero, in a positive
_l5 volts, for example, with ground connected in the
direction, the same amplitude as the magnitude of the
network.
difierence between the two voltages applied to contacts
155 and 161 of chopper 159. ‘
i
The voltage at contact 1741 is applied from the arm
135 of potentiometer 154/155 in PEG. v3b the deviation 50
The arm 185 may be mechanically connected to arm
squared potentiometer, through lead 186 and> resistor 179
and modiiied somewhat by the voltage divider >circuit 137
to the contact 174 depending on the position o1 adjustable
225 so that arm 22.5 is positioned on the resistor 224 of
potentiometer 22d/225 corresponding to the position of
arm 185 on the resistor 184.
Y
1t will be observed that of the two voltages applied to
contacts of chopper 175 that applied to contact 176 is nor
This arrangement is similar to the arrangement of the
potentiometers 114/ 115 and 1‘51/152 and their associated
DC. supply. As vfor example, a DC. supply of substan
mally lower than that applied to contact 174 and of the
two voltages applied to contacts of chopper 159 that ap
tially the Vsame amplitude, +10 volts, is `applied through
arm 11i-tl.
resistorv 224 and the voltage at arm 225 is applied through
resistor 184. With the positions of arms 225 and 1,85
to Contact 158; and that the moving contacts 173 and 162 60 corresponding to each other the `fraction of the voltage
will operate in unison and connect respectively with con
at ‘arm 155, rela-tive to the entire applied voltage (+10
tacts 176 and 161 at the same time. Thus the potentials
volts), -is equal to the square of the fractional position
applied to junction 165 will be 180° out of phase with
of the -arrn 225 relative to its position on the resistor
each other and when the A.C. voltages at the moving con
224. Thus the potentiometer 1841/185 may be considered
plied to contact 161 is normally higher than that applied
tacts 173 and 16?. are substantially or" the same amplitude 65 the deviation squared mechanical storage and potentiom
the potential at junction 168 will be substantially zero
eter 224/225 may be considered the square root of devi
since the two applied A.C. potentials are equal and oppo
ation squared yor deviation mechanical lstorage with >the
site and effectively cancel each other.
output voltage at arm 225 via lead 230 corresponding to
When the two A.C. voltages are unequal in amplitude
~
an A.C. signal equal in amplitude to the difference in 70 deviation.
magnitude of the two voltages is passed through capacitor
18S to the grid of the power amplilier 189. The signal
output of tube
is ampliiied successively by t-riodes
1% and 194 and the amplified output is applied
,through coupling capacitor 195 and fed through coil k1% 75
Thus the arithmetic aver-age speed squared (m2) of
a predetermined number of vehicle speeds is »subtracted
from the root metan square speed squared (R.M.S.2) of
substantially t-he same vehicle speeds in a chopper 159.
The result of the subtraction, a voltage representing the
3,082,949
19
2t)
remainder which is the square of the speed deviation, is
ksnatched by the output of a second chopper 175, the out
-put of chopper 175 being referenced to a desired zero
including means for indicating said deviation on a visual
scale.
3. A traffic speed deviation computer -as in claim ‘1 and
approximating ground. The magnitude of the output of
chopper 175 «above zero, is representative of the voltage
providing a further output in response to said deviation
at arm 185 of squaring potentiometer 1184/185.
output exceeding a predetermined value.
The
‘square root of Ithe value at arm 155 is represented at arm
`225. Therefore speed deviation, which is the square root
of'the remainder of the subs-traction of AA? from the
RJVLSÍZ is represented by the output voltage at »arm 225
'which 'output may be applied via lead 239 to »a meter
232, which may -be calibrated in terms of speed deviation,
or to »a terminal 23261.
Connected to the output lead 232e is the grid of a tube
` 235 so that the voltage output representing deviation may
be Iapplied to such grid.
In the plate circuit of tube
235 is a relay 236 which may -be energized when tube 235
ípasses current. Adjustable cathode bias of tube 235 is
provided so that the tube may provide current to energize
the relay only above a certain value of deviation, as
desired.
At and above certain values of deviation, as adjusted
"by adjustment of the cathode bias, the tube 235 will pass
current causing energization of relay 236 which relay will
vthen close its normally open `contact 237 which may corn
plete a circuit to do Work or operate «an alarm, as desired.
The output at arm 115, the arithmetic average speed
may be applied to -a meter 228 or to ya terminal 228g.
Thus on meter 223 one may read the arithmetic average
including means controlled by said deviation output for
4. In a traffic speed deviation computer, means `for con
tinuousiy sensing the individual speeds of individual ve
hicles successively passing a point along a roadway, means
for providing a iirst electricm output representing the
square of the root mean square of such speeds of a prede
termined number of vehicles having most recently passed
s-aid ypoint and sensed by said sensing means irrespective of
variation in time spacing between successive individual
speeds, means for providing a second electrical output
representing the square of the arithmetic average of such
speeds of said most recently passed predetermined nurn
ber of vehicles sensed by said sensing means irrespective
of variation in time spacing between successive individual
speeds, means for receiving said first ‘and second outputs
and continuously deriving therefrom an output represent
ing the dilierence between said first and second outputs.
5. A tratiic speed deviation computer including means
-for continuously sensing ‘the speeds of a series of vehicles
and developing therefrom an electrical signal representing
the squared root mean square of such speeds, means for
continuously sensing the speeds of said series of vehicles
and providing another electrical signal representing- the
speed and on meter 232 one may read the speed deviation.
square of the arithmetic average of such speeds, means
for storing each of said electrical values, said means pro
InV FIG. 3b the adjustable resistance 120 is provided
Vso that selection maybe made to average various number
means square and squared `arithmetic average of such
of vehicles through changing the position of selector
switch 121.
'In FIG. 3a a potential divider 187 `is provided with ad
justable selector 190 to provide selection of 4a percentage
of the signal applied contact 174 of chopper 175. This
viding electrical signals representing the squared root
speeds including means for varying its individual stored
value in proportion to a predetermined number of ve
hicles, means -for continuously sensing the difference be
tween said st-ored electrical signals to provide an elec
trical signal representing the square of the deviation of
such speeds and means for deriving the square root of
the last named signal to provide an output representing
40 the deviation of such speeds.
Considering the foregoing specification `and accompany<
6. A traiiic speed deviation computer as in claim 5 and
,ing drawings, 4alternate forms of the present invention
in which said last named output is an electrical value and
have been presented thus accomplishing the stated and
said computer includes a meter for indicating said elec
other objects. Obviously other modiñcations, substitu
tions and rearrangement of parts may ybe resorted to 45 trical value in terms of deviation of speed.
7. A system for continually computing the root mean
without departing from :the spirit of the invention.
square deviation of a continually varying series of a pre
I claim:
determined number or" speed values representing the speeds
l. A traffic speed deviation computer including means
of a continually varying series of vehicles in tr-atiic, in
for sensing the individual speeds yof a series of vehicles
cuding means for receiving said speed values and de
having variable speed and variable time spacing, first
provides for selection of difference calibration on the
meter 232.
' means for providing a iirst -output representing the square
of the root mean square of such speeds sensed by said
sensing means irrespective of variation in time spacing
between successive individual speeds, said first means in
cluding means for varying the value of the ñrst output
,in proportion to the diiîerence between said first output
and each particular speed signal and in proportion :to a
predetermined number of such vehicles, yand second means
for providing a second output representing the square of
.the arithmetic average of such speeds sensed by said sens
ing means irrespective of variation in time spacing be
tween successive individual speeds, said second means in
- cluding means for varying the value of the second output
in proportion to the »diñerence between said second out
50 termining a mean square average of said values and pro
viding an electrical output representing said average,
means for receiving said same speed values and deter
mining an arithmetic average of said values and provid
ing an electrical output representing the last named aver
age, means for squaring said last named 4average output,
means for continually comparing said squared last named
average output with said mean square average output to
continually derive an electrical output representing the
ditïerence between said average Outputs, means for de
riving fthe square root of the last named electrical output
-to provide an output representing said deviation.
8. A system `as in claim 7 :and including means for
adjusting said averaging means to vary said predetermined
number of vehicles and corresponding number of received
-put `and each particular speed signal and in proportion 65 speed values for such averaging.
-to sai-d predetermined number of such vehicles, means
9. A system as in claim 8 in which said adjusting means
for receiving said ñrst and second outputs and deriving
`therefrom an output representing the diñerence between
are cooperatively adjusted for the respective squared aver~
age and average square signals whereby the last named
signals will be averaged on corresponding numbers of
vehicles.
said Iiirst and second outputs, and >means for deriving the
` square root of said difference output to provide an out
put representing the average »deviation «of the sensed
speeds from the average of said predetermined number
` sensed speeds.
l0. A Isystem las in claim 7 in which said means for
providing said squared average and average square signals
are recycled in response Ito each new received speed value
2. A traiñc speed deviation computer as in claim 1 and 75 -to readjust the last two named signals for each said new
3,032,949
21
22
received speed value whereby `said deviation output will
be substantially continuously adjusted for the latest desired
cycle in place of the previous said value, and providing
an electrical output therefrom, means for squaring said
latest value and storing said squared value in said cycle,
number of vehicles.
11. A system as in yclaim 7 and including means for
adjusting the deviation output in relation to the received
means for storing the average of the squares of the latest
predetermined number of isaid values from the previous
said cycle, means for readjusting said stored squared
average by a fraction of the difference between the previ
speed value.
12. In a system for determining the average devia-tion
of a number of values from an -average of such values land
ous stored squared average value and the latest stored
squared individual such value based on the said prede
having means for sensing the individual values in suc
cession and developing therefrom electrical signals repre
senting each latest individual value and the lsquare of »the
root mean square of the latest predetermined number of
termined number to provide and store the new latest
squared average of the values, means for ldeveloping and
storing an arithmetic average of said latest predetermined
said values respectively irrespective of variation in time
number of individual values `and which said >arithmetic
spacing between successive individual val-ues, the combi
average is readjusted by a fraction of the difference be
nation of means for receiving each said latest individual 15 tween the previous stored arithmetic average and the new
value and -developing an electrical signal representing the
latest individual stored value, means for squaring said
square of the arithmetic average yof said latest prede
stored arithmetic average and storing said squared average
termined number of values irrespective of variation in
to complete the cycle, means for comparing the two
time spacing between successive individual values, means
stored squared averages to derive and store .the difference
for comparing said squared root mean square electrical
between them as the square of `the deviation, and means
signal and said squared arithmetic average electrical signal
for deriving and storing the square root of the last named
to derive a further electrical signal representing thedif
difference as representing the deviation.
ference between the compared signals, and means for de
16. Electrical apparatus for substantially continuously
veloping from said further signal ian electrical output
determining the root mean square deviation of speeds of
signal representing the square root of said difference signal 25 vehicles proceeding past a given location along a traflic
to represent said deviation.
lane having variable speed and variable time spacing, in
13. A combination as in claim l2 in which said com
cluding means for sensing the individual speeds of said
paring means includes a chopper having alternate inputs
vehicles, means for deriving from the speeds s0 sensed a
connected to the respective compared signals land an out
first electrical signal representing the square of the root
put alternating between said inputs, Iand a capacitor in
mean 4square of the speeds of the latest predetermined
series with said output t-o provide an alternating current
number of said vehicles, means for deriving -from the
speeds so sensed a second electrical signal representing
`output therefrom, and means controlled by said alternating
the square of the arithmetic average of the same latest
current output for providing said fur-ther electrical signal.
predetermined number of said vehicles, means for deriv
14. A combination as in claim l2 and in which said
ing from said first and second signals a third electrical
comparing means includes a chopper having two inputs
ysignal representing `the difference »between said first and
connected to the respective compared signals and an out
second signals, and means for deriving from said third
put alternately connected to its respective inputs and a
signal an output signal representing the square root of
capacitor in series with its output, and in which said square
said third signal, whereby the last named output signal
root >deriving means includes two potentiometers having
stationary resistance elements and contact arms mechani 40 will represent said deviation of speeds for said latest pre
determined number of vehicles.
cally linked to be movable together over the respective
17. A trañic lspeed deviation computer including means
resistance elements, the resistance element of one of said
`for continuous sensing of the individual speeds of each of
potentiometers being connected across a predetermined
the successive vehicles passing a point along a roadway,
direct current voltage and the other resistance element
means for providing a first electrical output continu
being connected between the arrn of said one potentiome
ously representing the square »of the root mean square of
ter and one end of its resistance element, a second chopper
the `speeds of a group of vehicles most recently having
having two inputs one of which is connected to the arm
passed said sensing point, means for providing a second
of the second of said potentiometers and the other input
of which is connected to a reference `direct current volt 50 electrical output representing the square of `the arith
metic average of the speeds of said most recent vehicles,
age for ysetting zero reference with respect to the output
means for deriving an output continuously representing
voltage on the last named contact arm, and said chopper
the difference between lsaid first and second output sig
having an output alternately connected to its respective
nals, and means for deriving the square root of said dif
inputs, a servo-amplifier having an input and output,
signal to provide an output representing average
impedance means interconnecting the outputs of the re 55 ference
vehicle speed deviation.
spective choppers to provide an alternating current input
18. A combination as in claim 17 in which said squared
to said servo-amplifier of amplitude substantially propor
root mean square and arithmetic averaging means in
tional to the difference between the outputs of said chop
clude means for varying their output in response to each
pers and ywhose phase reverses for reversal of relative
vehicle inversely in proportion to the number of vehicles
amplitude of the outputs of said choppers, and a servo 60 desired to be averaged.
motor controlled by said servo-amplifier to move said
19. A combination as in claim 17 in which said averag
Contact arms so that the output voltage of the arm of
ing means include means for averaging over an adjustable
number of vehicles.
'
said other potentiometer with respect to the zero refer
ence corresponds with the output of the iirst chopper and
20. A combination as in claim 17 in which at least one
thus to the diiîerence between the average squared signal 65 of said averaging circuits includes a servo motor, servo
amplifier, chopper and potentiometers connected to de
and the `squared average signal and thus to the square of
rive the potentiometer to balance at -a null point and to
the deviation, and the output of the arm of the said one
derive the squared function from the tap on one of the
potentiometer represents the square root of said differ
ence and thus the deviation.
’
15. In a system Ifor determining the deviation of the
latest predetermined number of a continuing random
spaced series of varied electrical values, means for re~
potentiometers.
70
ceiving each said value and initiating a computing cycle
therefrom, means for storing the latest said value in said 75
References Cited in the file of this patent
UNITED STATES PATENTS
2,789,760
2,965,300
Rey et al. ___________ __ Apr. 23, 1957
Radley et al. _________ __ Dec. 20, 1960
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