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Патент USA US2405597

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Aug, 13, 1946.
o. R. MILLER
2,405,597
FREQUENCY MEASURINQ SYSTEM
Filed NOV. 5, 1942
'7 Sheets-Sheet l
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Aug. 13, 1946»
o. R. MILLER
2,405,597
FREQUENCY MEASURING SYSTEM
Filed Nov. 5, 1942
7 Sheets-Sheet 2
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0. R. M/l. L ER
ATTORNEY
Aug. 13, 1946.
2,405,597
o. R. MILLER
FREQUENCY MEASURING SYSTEM
Filed NOV. 5, 1942
'7 Sheets-Sheet 3
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O. R. M/L L ER
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Aug. 13, 1946.
O. R. MILLER
2,405,597
FREQUENCY MEASURING SYSTEM
Filed Nov. 5. 1942
'7 Sheets-Sheet 4
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Aug. 13, 1946.
Q_ R, M||_|_ER
2,405,597
FREQUENCY MEASURING SYSTEM
Filed NOV. 5, 1942
'7 Sheets-Sheet 5
, @S
/Nl/ENTOR
BV
0. R. M/L L ER
Aug. 13, 1946.
o. R. MILLER
2,405,597
FREQUENCY MEASURING SYSTEM
Filed Nov. 5, 1942
'7 Sheets-Sheet 6
di.
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ATTORNEY
Aug. 13, 1946.
2,405,597
O. R. MILLER
FREQUENCY MEASURING SYSTEM
Filed Nov. 5, 1942
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7 Sheets-Sheet '7
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atented
ug. 13, 1946
UNITED STATES PArNr
2,405,597
FREQUENCY MEASURING SYSTEM
Ohmer R. Miller, Morristown, N. J., assignor to
Bell Telephone Laboratories, Incorporated,
New York, N. Y., a corporation of New York
AApplication November 5, 1942, Serial No. 464,664
4 Claims.
l
(Cl. 175.-368)
This invention relates to measuring systems
and particularly to systems for the determina
tion of the periodicity of regularly occurring phe
nomena such as the frequency of alternating cur
rent or the velocity of high speed rotating mech- .
anism.
i
The object of the invention is to provide means
for measuring with great accuracy the frequency
2
lating and indicating means so that a direct
reading may be had.
In order to promote accuracy, the admission
of the train of regularly recurring impulses to the
first counting chain is delayed for a predeter
mined interval. This is especially important
where the train of impulses is applied in a man
ner where the impulses are at nrst very feeble
of an alternating current or the periodicity of a
and then gradually rise to full strength. This
train of electrical impulses.
1.0 time delay, therefore, allows the impulses to grow
to full strength lbefore being applied to the count
Another object of the invention is to provide
ing chain. Again it is practically impossible for
means for measuring with great accuracy the
velocity of objects moving through space at a
a person to close a circuit accurately at a given
high rate of speed. Many such objects such as
point in the train of impulses so that this method
projectileaaircraft and land vehicles rotate or 15 avoids a first impulse which might otherwise be
mutilated.
have some moving part which rotates at a rate
directly proportional toits forward movement.
Again, and for the same purpose, when the
Due to the rifiing of the barrel from which a
impulses are admitted to the counting chain a
predetermined number are allowed to operate the
projectile is fired it rotates at a rate depending
on its speed. The propeller shaft of an airplane 20 chain Ibut are not counted. In other Words a
predetermined number of impulses are absorbed
engine and the propeller shaft of a motor car
rotate at a rate which is proportional to their
before the> actual count is started. This insures
speed‘ through space. Any one of these devices
that the counting will always be started at the
may be fitted with a radio transmitter and a
same point in the cycle so that no undetermined
directional antenna so that if a radio receiver 25 partial cycles are counted.
A feature of the invention is a means for count
at an observation point is tuned to receive the
ing a predetermined number of cycles of the un
wave‘transmitted by such transmitter the result
known frequency or a predetermined number of
can easily be translated by well-known means
impulses of unknown periodicity, means respon
into- an alternating current. The object then is
to accurately measure the frequency of such 30 sive thereto for generating and transmittinga
alternating current.
start and a stop pulse at the beginning and end
ing of the counting operation and means for
In accordance with the present invention the
counting the number of cycles of alternating cur
alternating current is fed into an impulse gen
rent from a precision source between said start
erator which will translate such current into a
and stop pulses.
r
train of sharply defined impulses. This train of
impulses is then passed through an impulse
Another feature of the invention is a method of
measuring the frequency of an alternating cur
counting device which counts a predetermined
number thereof and marks the Ibeginning and
rent or the periodicity of a train of regularly re
ending of such count by a start pulse and a stop
curring impulses which consists of counting a
pulse. Thus a period of time is noted which may 40 predetermined number of such alternations or
. be measured by comparing it with the output of
a precision oscillator.
The next step is to operate a so-called “gatef’
such impulses, marking the beginning and the
ending of the counting operation and then count
ing the number of cycles of alternating current
by the start and stop pulses generated by the
from a source of known accuracy which occur
impulse counting device. This gate will then 45 between the said beginning and ending of the
admit to another pulse counting device the out
nrst counting operation. The last count will then
put of a precision oscillator for the exact period ,
bear a direct relation to the frequency of the
alternating current or the periodicity of the
then counted will bear a direct relation to the
train of impulses to be measurer.
time and thereby give an accurate measure 50
Still another feature of the invention is _la
thereof.
method of measuring the periodicity of a train
of time measured whereby the number of pulses
The impulse counting chain for counting the
number of cycles of alternating current admitted
thereto through the said gate from the precision
of regularly recurring electrical impulses which
consists of counting a predetermined number
thereof and comparing the time taken .to make
oscillator may be connected to a suitable trans- 55 such a count with the rate of a current of known
2,405,597
3
4
frequency characterized by steps taken to insure
the accuracy of such count consisting of delay
ing the application of the unknown periodic cur
rent to the counting means for la predetermined
time after the beginning of the operation and
then absorbing without counting a predetermined '
number- of such impulses after theY unknown
periodic current is applied to the counting means.
` Other features willappear hereinafter.
The drawings consist of seven sheets having
eleven figures, as follows:
,
_
Fig. 1 is a schematic circuit diagram showing
the relation of the various circuit units to ex
plain the general method of operation;
'
Fig. 2 is a block diagram showing how Figures
3 to 7, inclusive may be placed to make a com
plete detailed circuit diagram;
Fig. 3 vis a circuit diagram of the impulse gen
erator;
,
for instance, Just as the wave passes through zero
from the positive half wave to the negative half
wave.
'
The train of impulses now flowing into the
impulse counter 'I starts this device-into opera
tion with the result that two pulses are produced
thereby, one constituting a start pulse at the be
ginning oi' a count and the other constituting a
stop pulse at the end of an operation during
which a‘ predetermined number of pulses are
counted. Thus an interval of time A is meas
ured between the start and stop impulses which
is the time taken for a given number of rotations
of the projectile or a given number of cycles oi'
15 the alternating current from the source 4.
As will appear hereinafter. and for certain rea
sons having to do with the question of extreme
accuracy, several pulses incoming to the impulse
counter 'I at the beginning of the operation are
.
Fig. V4.- is a circuit diagram of the time-delay 20 absorbed and not counted.
The start and stop pulses produced by the lm
pulse counter 'I are employed to operate the gate
Fig. 5 is a circuit diagram of a pulse counter
circuit 8. This is a device effectively interposed
for'producing the start and stop pulses for oper
between a precision oscillator 9 and a recording
ating the gate circuit;
'
Fig. 6 is a circuit diagram of the gate circuit; 25 circuit I0. The recording circuit I0 will accu
rately ycount the cycles of alternating current
Fig. '7 is a diagram of the pulse counting and
flowing through the gate circuit 8 during the in
recording means, showing one unit thereof in'
circuit;
.
»
l
terval A, the gate being opened by the said start
full and indicating duplicate units schematically;
impulse and being closed by the said stop im
Fig. 8 is a nest of graphs useful in explaining
the operation of the time-delay circuit off-Fig. 4; 30 pulse.- Since the precision osillator Il may pro
duce a current of precisely regulated frequency
and of-a comparatively high frequency the in
terval of time A may` be measured with extreme
Fig. 10 is a characteristic curve of the gas tube
accuracy. In general, the recording circuit I0 is
which produces the impulses in the impulse gen
35 of the same nature as the impulse counter 1, as
erator of Fig. 3'; and
'
Fig. 1l is a nest of graphs useful in explaining
will be more fully set forth hereinafter.
The impulse counting circuit I0 operates an
the operation of the gate circuit of Fig. 6.
indicating circuit II which serves to giv/ë some
In Fig. 1 the invention is illustrated schemat
kind of an indication revealing the number of im
ically. `The Working starts where _an alternating
current is fed into the impulse generator I. As 40 pulses counted during the' time A while the gate
8 was open. llin accordance with one embodi
shown, this alternating current may be derived
ment of the invention this indicator consists of
from a projectile equipped with a radio trans
means to display a number such as 37,777. The
mitter having a directional antenna in the fuse
frequency of the source r9 being known, the numP
portion thereof. The radiations of such a trans
mitter are picked up by the radio receiver 2 in 45 ber 37,777 is then a direct measure of the time
interval A and therefore in direct proportion to
the form of oscillations periodically varying in
the velocity of the projectile or to the frequency
amplitude as illustrated by the graph below the
radio receiver 2. The variations in amplitude
of the source 4.
Considering now the detailed circuit drawings,
are caused by the rotation of the projectile in
several general lobservations may be made.
flight due to the rifling of known pitch of the
Throughout the drawings wherever ionic tubes
barrel from which it has been discharged. The
are shown the filaments for heating such tubes
frequency of such variations in amplitude bear a
are indicated but' the battery supply is not shown
direct relation to the velocity of such projectile
since the manner of making such connections is
in -flight. The output of the radio receiver 2 is
passed through a low frequency detector 3 and 55 well known and the addition of such circuits
would unnecessarily complicate the‘ drawings. In
produces therein an alternating current all in
various figures there are shown reset keys whose
accordance with well-known means and methods.
Or the alternating current which is fed into _ function it is to return the various circuits to
their normal conditions. It will be understood
the impulse generator I may be derived from
any other source, such, for instance, as the source 80 thatthese may be in the form of separate keys
as shown and described or they may all be in
of alternating current 4 ,and applied to the im
Fig. 9 is a nest of graphs useful in explaining
vthe operation of the impulse generator of Fig. 3;
t corporated in a single device so that at one stroke
pulse generator by any means such as the key 5.
,Now upon the application of an alternating
the various circuits may be properly controlled.
current to the -impulse generator I, a time delay
' As explained hereinbefore, an alternating cur
circuit 6 starts into operation and delays for a 65 rent is fed into the impulse generator from one
given interval oi’ time the application of the out
or another source such asthe radio receiver 2
put of the impulse generator to the impulse count
and low frequency detector 3 or the source 4
er 'I. This is to insure .that the first impulses to
through some connecting agency such as the key
-be counted are of full strength.
v
5. In the impulse generator the alternating cur
The impulse generator I is a device which pro 70 rent flows in over conductor I2, through con
duces a single sharply deñned impulse from each
denser I3 and thence through the primary wind
cycle of alternating current fed thereinto.
Through novel means provided this single sharply y ing of a transformer I 4 to ground, it being as
sumed that a. ground connection is provided at
defined pulse may be made to occur at any par
ticular point in the cycle over a given range as 75 the said source of current. The secondary wind- l
Il
2,405,597
5
6
ing of transformer It thus becomes a source oi’
42 and 43 as indicated by the graph t5 from a
comparatively high positive potential to a com
alternating current to affect the triode it.
paratively low positive potential. .At the same
The cathode grid circuit of this tube may be
traced from the cathode through the resistance
time the potential on the grid of tube d6 falls,
i6, the secondary winding of the transformer IB, 5 as indicated by graph M, from a positive value
resistance il to the grid of tube l5. A condenser . to a negative value below the cut-ofi bias (in
IB is in parallel with both the resistance i5 and
dicated by the dotted line d8) oi the triode t6
a source of negative biasing battery comprising
so that this tube now becomes non-conducting.
This changes the potential of the potentiometer
the resistance i9 and the well-known network of
point between the resistances HB and 50, as indi~
rectiilers 2li, 2|, 22 and 23, energized by a source
cated by graph 52, from a comparatively low pos
of alternating current 2i and an interposed trans
itive value to a comparatively high positive value.
former 25. The potential supplied by this net
Thereupon the potentiometer point‘between re
work controls the anode-cathode current ilow in
sistances Ell and Si rises, as indicated by graph
the tube l5 between the battery connected to the
53, from a negative value through the trigger
anode thereoiand the resistances 2b and 2li to
potential of gas tube M (indicated bythe dotted
ground. Under these conditions a given potential
line 55)"to a positive value. 'Thereupon the con
" thus stands on the cathode'i'o'i‘tube iii, this being '
denser Iêi‘l begins to charge through resistance 56
a point on the potentiometer consisting of the
.in accordance with graph 5l, and when the trig
internal resistance of the tube and the two re
20 ger potential E5 of the tube tél is reached the con
' sistances 2d and El.
trol conductor 29 is effected, as follows. When
Now as an alternating current wavein the
-tube 5t becomes conducting the potentiometer
secondary winding of transformer iii rises from
point between the resistances £53 and 59 changes
a zero value to an increasing positive potential
its potential, as indicated by graph 6l, from a
the grid oi the tube becomes less negative and
comparatively high positive value to a compara
as a consequence the anode-cathode current in
tively low positive value. Thereupon the poten
creases. Therefore, the potential oi’ the cathode
tiometer point between reslstances 5d and Si)
with respect to ground increases, so that the po
drops, according to graph 62, from a positive
tential on the start conductor iii increases. This
value through the cut-off bias grid potential of
start conductor leads into the time-delay circuit
so that when the increase of potential thereon is 30 tube 63 (indicated by the dotted line fili) to a
negative value and tube lit becomes non-conductgreat enough the time~delay circuit will be tripped
ing. This in turn changes the potential on the
off and in a given time will raise the potential on
potentiometer point'between resistances
and
the control lead @il snmciently to allow the gas
iid, as indicated by graph @8, from a comparatively
tube il@ to function.
,
low positive value to a comparatively high posi
Normally the cathode oi the tube id is connect
tive value. This last potential change is com»
ed in av circuit with the right-hand pair oi ele
municated over control conductor 29 'to enable`
ments of.’ the double diode tube iii, resistance t2,
condenser
resistance 2i to ground, whereby
the condenser
may be charged as the potenn
tial of the cathode ci' tube iii'rlses. Normally
also the potential standing on the control con
' ductor
and communicated through the leit
hand pair of elements~ of the double diode iii di
rectly to the condenser 3s prevents the ai'oremen
tioned charging circuit from becoming effective.
In other words, the control conductor normally
the impulse generator.
The tubes of Fig. Li will now remain in the
-condition just described _regardless of the varia
tion in potential on the start conductor 2li until
the reset keys t9 and 'lil are operated to render
tubes ¿il and 5t again non-conducting.
A pair of cold gas signal tubes l'vi and l2 are
provided for visually indicating the operation of
this time-delay circuit. Tube 'il whose control
anode (indicated by the arrowhead) is normally
at a comparatively high positive potential is there
that the impulse generator cannot function.
fore normally glowing. When this potential is
If the alternating current fed into the input
conductor i2 is derived from the, radio receiver 2 50 dropped in accordance with graph ¿i5 this tube
becomes dark as an indication that the timing
the signals may at first be weak but as they grow
operation has started. Tube ‘i2 whose control
in strength a point Will be reached where the
anode is normally at a comparatively low positive
rise of potential on the cathode of tube i5 and
potential is normally dark. When this potential
on start conductor 28 is suiiicient to trip off the
is raised in accordance with graph 60 to a com
time-delay circuit. Thereafter, and after a pre
holds the voltage on the condenser 33 down so
paratively high positive potential this tube 'l2
determined time the potential on the control con
glows. The period of time during which both sig
ductor 29 will be raised to enable the impulse gen
nals are simultaneously dark is a measure of the
erator to operate as will be described hereinafter.
The operation of the time-delay circuit of Fig.
desired time interval. This may be adjusted as
d will be explained with the help of a nest of 60 desired by changing the value of the resistance
56 and the capacity of the condenser M1.
graphs shown in Fig. 8. Two vertical lines are
In this manner, then, the signals being fed
shown, one marked "start" and the other marked
into the impulse generator over conductor i2 grow
“controL” The distance between these lines is a
in strength, and the impulse generator is en
measure of the time interval desired.
'I'he start conductor 28 is connected through 65 abled a predetermined time after such signals
have reached a strength suñicient to trigger .off
a resistance 3i to an intermediate point on a
the tube 4I.
potentiometer comprising resistances 35, 3G and
With the rise of potential on control conductor
31 connected between positive battery 38 and neg
ative battery 39. As' the potential on the con
29 the impulse generator will function. This will
ductor 28 rises according to the graph fillv it 70 be explained with the help of Figures 9 and 10.
reaches a point where the gas tube M triggers
Tube 30 is a gas tube, one of whose character
on` and this is the start of the operation. Tube
istics is depicted in Fig. 10. For each given posi
4H becomes conducting and the anode-cathode
tive potential value on the anode thereof there
current iiow therethrough changes the potential
is a corresponding given negative value on the
at the potentiometer point between resistances 75 cathode at which the tube will fire or trigger off.
`
2,405,597
This is shown by the curve113 plotted between
positive anode potentials and negative cathode po
primary of the transformer 18 produces a single
sharply defined pulse shown bygraph 19, which
tentials.
may be inverted by the transformer 18 to a nega
In accordance with this inventionv a
positive anode potential is nrst established and
tive pulse. This is transmitted over the signal
thereafter the negative potential is increased (in
ing conductor to the impulse counter of Fig. 5.
a positive direction) until the corresponding point
Thus alternating current incoming over con
is reached, whereupon the tube fires.
ductor I2 is transformed into a train of sharply
In Fig. 9 the'graph 14 represents a cycle of
deñned unidirectional pulses, one for each com
alternating current as delivered by the secondary
plete cycle of alternating current. These pulses
of transformer I4. As the positive half wave 10 are then applied to the output circuit of the im
rises in value, the negative potential on the
pulse generator which is connected to the in
grid ofÍ tube I5 recedes until the tube becomes
put circuit of the impulse counter.
saturated and hence the change of potential on
>The pulses coming in over the input conductor
the cathode thereof rises to a particular value and
pass through condenser 80 and appear as sharply
then halts as indicated by the graph 15. This is 15 denned negative pulses leading to the suppressor
a measure of the potential being applied through
grids of two tubes 8| and 82.
the right-hand elements of the double diode 3| to
The tubes 8| and 82 form a counting pair, one
the condenser 33. Thus the charge on condenser . of which is always energized and in a conduct
ing state. The principle of operation is funda
33 rises, in accordance with graph 18, during the
rising part of the positive half wave of alternat 20 mentally the same as that of the well-known
ing current potential v14. However, due to the
Eccles and Jordan circuit, disclosed in British
unidirectional characteristics of the diode 3|- the
Patent 148,582. These tubes are, however, pen
positive chargeC attained on the condenser 33
todes with the anode of each connected to the
is maintained as the falling part of the positive
screen grid of the other. When the negative
half wave is reached. But at this time the cath 25 impulse is applied to the suppressor grid of both,
then both are rendered non-conducting. When
ode potential of tube 38 measured at the poten
tiometer point between resistances 28 and 21 be
gins to fall, in accordance with graph 11, until
the negative value B is reached. Since the posi
the said negative impulse has ceased the com
bination of the two tubes is left in an extremely
unstable state- so that the slightest influence will
tive potential C of condenser 33 is now placed 30 determine which of the two is to become conduct
through the primary winding of transformer 18
ing to the exclusion of the other. This extremely
on to the anode of tube 30, this tube will ilre and - slight innuence is supplied by a condenser 83
the condenser 33 will discharge through the
connected between the cathodes of the two tubes
anode-cathode circuit of tube 38 and the pri
which is charged in one direction while tube 6i
mary of transformer 18.
’
'
A35 is active and in the other direction while tube
In. the above description the negative value B
82 is active. When the negativev impulse is ap
of the cathode of tube 30 is described. Actually
plied to the two suppressor grids, ,condenser 83
the cathode of tube 38 is never at a value'negative
becomes discharged but there is left a slight resid
with respect to ground but if the actual potential
ual charge, the magnitude of which depends on
of this cathode at the static condition of the cir 40 the effective length of the said negative pulse.
cuit when the incoming alternating current Wave
At the- termination of this negative pulse the
is at zero is taken as a reference point, then the
said slight residual charge on condenser 83 ~is
cathode of tube 30 moves in a negative direction
suilicient to determine which of the two tubes
so that when the potential of the cathode of this
'will then become active. If tube 8| has been ac
tube is spoken of as becoming negative it will be 4. tive before the negative pulse, then tube 82 will
understood that it is increasing in a negative
become active thereafter. Thus one negative pulse
sense. Thus as the current in resistance 21 de
‘ will render tube 8| inactive and tube 82 active
creases the potential of the cathode» of tube 38
and a second pulse will reverse this condition
increases in a negative sense.
and render tube 82 inactive and tube 8| active.
Thus the difference of ` potential between the
Throughout the circuits to be described a large
terminals of condenser 33 increases both dur
number of these counting pairs are employed all
ing the rising value of the incoming half wave
of which operate in the same manner. 'I'he de
of alternating current and the following decreas
tailed description of. the operation of a single pair
ing value of this half wave until the tube 3|) is
will therefore be suilicient. It will be found that
triggered ofi'.
.-
'
s This action will continue as long as the po
tential of conductor 29 is maintained at a com
paratively high value by the tube 63 whereby
the upper tube of each pair is normally active;
that is, it is in a conducting state and has a
low potential on its anode. Conversely the lower
tube of the pair is normally inactive; that is, it
is in a non-conducting state and has a high po
the charge on condenserV 33I is prevented from
being dissipated over the path including con (if) tential on its anode.
.
ductor 29 and tube 63, as it is during the inac
It will be noted that the anode of each tube
tive periods of the impulse generator of Fig. 3.
It is to be noted that the value of the negative
bias of tube |5 may be regulated so that the
value of the positive potential attained on the
anode of tube 38 may be adjusted >as desired.
This may particularly be adjusted so that this
positive potential attained or established on con
denser 33 may just match the negative potential `
attained on the cathode of tube 30 as the alter
nating current wave 14 passes through zero from
the positive half wave to the negative half wave.
'I‘hus the discharge of the condenser 33 may be
made to occur at any desired point.
- is in a potentiometer circuit.
For tube 8| this
potentiometer circuit may be traced from a high
positive battery through resistance |58 and re
sistance |5| to ground. The anode of the tube
8| is connected to the potentiometer point be
tween resistances |50 and I5I. Also a circuit
constituting a potentiometer may be traced from
resistance |58, the anode cathode path within the
tube, resistance |52 and resistance |53 to ground.
The resistances of the tube |52 and |53 are thus
in parallel with resistance |5I. Now when the
tube is non-conducting or inactive there being
little if any current flow in this potentiometer
The discharge of condenser 33 through the 75 circuit, the potential of the anode (and the screen
e
2,405,597
9
l0
grid of the companion tube) is at a comparatively
with such pulse being passed on to the following
high positive value. Thus the tube 82 is enabled
by a comparatively high positive screen grid po
However, when a negative potential is
' tential.
applied to both suppressor grids both tubes be
pair or stage.
v
Thus in the impulse counter`- of Fig. 5 eight
stages of these counting pairs of tubes are pro
vided. 'I'he first pulse renders tube 8i inactive;
the second pulse renders tube 85 inactive and
come non-conducting and hence a comparatively
high positive potential is applied to the screen
grid-of each. Hence, when the negative poten
tial is removed from the suppressor grids both
tube 86 active.
As tube 86 passes from the in
active to the active stage a negative pulse is gen
erated and passed over conductor 81 where it
tubes are in a condition to become active or con 10 functions as a `start signal to the gate circuit of
Fig. 6. The two hundred and fifty-sixth pulse
ducting.. The choice of which one prevails 'rests
returns all the upper inactive tubes to normal
with the condenser 83 as hereinbefore pointed
and generates a negative pulse which now passes
out.
.
When tube 8| is in an active or conducting
over conductor 88 where it functions as a stop
state theY current flow in its anode-cathode cir 15 signal to the gate circuit. Thus the difference
cuit aii’ects the potentiometer point between the
between two hundred and fifty-six and two or
resistances i5ß and i5! so that the potential
two hundred and nity-four pulses is counted, the
thereof is at a. comparatively low positive value.
first two being effectively absorbed. The gate
circuit thus opens a circuit for the flow of alter~
Hence the screen grid of the companion tube is at
a comparatively low positive value and this tube 20 nating current from a precision oscillator for the
length of time of two hundred and iiIty-four
isD held in a non-conduction or inactive state.
pulse cycles from the- impulse generator. The
The potentiometer circuit for tube 8| has been
impulse counter may be arranged to count any
described. Tube 82 has a similar potentiometer
other number which would be more suitable un
circuit consisting of the resistances I5ë, |55, IE6
25 der the circumstances under which this appa
and l53.
It should be noted that as a tube goes from a
ratus may be used.
non-conducting to a conducting state its poten
tiometer point suddenly drops from a compara
tively high t0 a comparatively low positive value.
Hence as tube 8| becomes active the potentiome
, ,
The purpose of absorbing one or more pulses
at the beginning oi’ the. train is to insure the
measurement of a definite time interval and avoid
30 error which might come from a false start if the
first impulse transmitted from the impulse gen
erator were not of full strength.
and condenser 84 translates this sudden drop in
potential into a negative impulse to be applied
The reset key H48, when operated. will return
to the suppressor grids of tubes B5 and 8E.
the impulse counter to normal by rendering all
Thus the pair of tubes iii and d2 provide a 35 the lower tubes of the various stages inactive.
means which sets up a- stable condition which will
The action of the gate circuit, Fig. 6, will be
remain fixed, but which instantly responds to a
explained with the help of a set of graphs, Fig. ll.
ter point between resistances |50 and iii drops
negative incoming pulse to reverse the previous
Here a number of tubes are employed some of
condition of the two tubes. Also the tubes in
which are paired as in the pulse counter. For in
their reversal will generate a like negative pulse 40 stance, tubes 90 and Si form one pair and tubes 92
when the reversal in condition is in a given direc
and 93 form another pair. Tubes 90 and 92 are
tion so that for every two incoming negative
normally active and tubes 9|, 93 and Si are nor
pulses asingle outgoing negative pulse is gen
mally inactive. The connections of the tubes are
erated.
much as before except that the condenser between
The impulse counter consists of a plurality of 45 the cathodes'of the tubes of a pair is not employed
pairs arranged to count the impulses according
so that a negative pulse coming in over the start
to a binary geometric progression system. Thus,
conductor Bl and passing through the condenser
the first pulse renders tube d2 active. The sec- . ’ 8s will reverse the condition of the tubes 90 and
ond pulse rendering tube di again active will also
ill, rendering tube 90 inactive and the tube 9|
generate a negative pulse through condenser 8d 50 active. A potentiometer is formed between the
to the pair of tubes 35 and du and will result in
positive battery 95, resistance 9E and resistance
rendering tubes 82 and 85 inactive and tubes 8i
Sl to ground, and the anode of tube 90 and the
and 86 active. The third pulse will render tube
grid of tube 9i are _connected to this potentiom
di inactive and tube’tZ active.
eter at a point between resistances 96 and 97.
It may be noted that if each of the lower tubes 55 Due to the current now while tube 9U is active the
oi all pairs is given a value of zero and each of
potential of this point is held at a comparatively
the upper tubes is given a value according to a
low positive value. When the negative start pulse
geometric progression as l, 2, LS., 8., i6, 32, 64, 128,
comes in over conductor 81 to the suppressor grid
256, etc.,.the sum of the values of the inactive
of tube 9i! this tube becomes non-conducting with
tubes will be a count of the number of pulses. 60 the consequence that the potential of the anode
Thus, at the beginning all the inactive tubes will
in the said potentiometer circuit rises to a com
have a value of zero and the‘sum of such values
will be zero. After the first pulse, tube iii will be
inactive and the sum now becomes l.
After the
second pulse tube t5 is inactive and tube iii is
paratively high positive value, as indicated by
graph 9B (Fig. 11) .
Since this comparatively
high positive potential also appears on the grid of
tube 9 i, this latter tube now becomes conducting.
Here again a potentiometer is formed of positive
active so that the sum becomes 2. After the
third pulse tubes di and t5 are inactive so that
battery 95, resistance lSi! and resistance itl!) to
the sum becomes l+2=3. With two pairs oi
ground, The potential on the potentiometer
tubes three pulses may be counted as the next
point between resistances 99 and itil! is normally
or fourth pulse will return both pairs of tubes to 70 a comparatively high positive potential but as
normal while passing such fourth pulse on the
tube 9i becomes conducting this drops to a com
next pair of tubes to be counted there. With
eight stages two hundred and fifty-’five pulses
may be counted, all pairs being returned to nor-v
mal on the two hundred and nity-sixth pulse 75
paratively low positive potential as indicated by
graph i t i, This being communicated to the grid
of tube S0 holds this tube non-conducting after
the termination of the negative start pulse.
' 2,405,597
.
11
12
.
As the potential of the anode of tube 9| drops,
the condenser |02 responds by discharging be
-tween resistances |03 and |00, forming a negative
pulse, graph |04, applied to the suppressor grid of
Y
'I'he inter
` y pulse is received whereupon it glows.
val during which both tubes are dark is there
fore _a measure of the time interval between the
start and stop pulses.
`
`
tube 92. Tube 92, normally conducting’now be..
The control electrode of tube |25, indicated by
comes non-conducting with the result that the
the arrowhead, is connected to a potentiometer
potentiometer point between resistances |05 and
|01 rises from a comparatively low positive value
to a comparatively high positive value, as indi'
cated by graph |08. This causes tube 93~to be
point leading through resistance |21 to ground.
The potential of this point is controlled by tube
come conducting so that the potential on the po
tentiometer point between resistances |09 and | |0
now drops from a comparatively high positive
value to a comparatively low positive value, as in
9| over resistance |28 and by tube 93 over resist
ance |29. When either of these tubes is active
the tube |25 is held inactive but when both these
tubes 9| and 93 are inactive, as under normal
conditions, then the „potential of the point be
dicated by graph |||. This drop of potential
communicated to the grid of tube 92 holds this
tween resistances 99 and |00 and the potential of
the point between resistancesr|09 and l l0 is at
a comparatively high positive value and tube |25
tube non-conducting after the termination of the
a's a consequence, glows.
.
negative impulse from condenser |02.'
Likewise, tube |29 is under control of tubes
Another potentiometer is formed between posi
90 and 93 so that only .after the gate circuit has
tive battery 95, resistances |06, ||2 and`||3 to 20 completely functioned and tubes 90 and 93 are
negative battery lill.Y The potential of the point . simultaneously inactive is tube |26 conditioned to
between resistances ||2 and | I3 in general follows
glow. Thus tube |25 glowing indicates that the
the potential of the point between resistances |06 ` gate circuit has not yet functioned and tube |28
and |01, as indicated by graph H5, and hence as
glowing indicates that the gate circuit has com
this point rises in potential the tube 94 is ren v25 pletely functioned.
dered active so that pulses from the precision os
cillator connected to input lead | I6 may be passed
through the tube 94 to the output lead ||1 as a
The train of negative pulses transmitted over`
conductor ||1 feed into a chain of pulse counters "
in Fig. '1 represented by the recorder circuit |0
of Fig. 1 similar to those shownsin Fig. 5. In
| I8.
~
30 yorder to count a number of ypulses of the order of
The output of the precision oscillator is practi
16,000 it would be necessary to provide about iii-_
cally a sine wave. It is, however, connected
teen pairs of tubes. As pointed out hereinbefore,
` through a condenser ||9 and a resistance |20 to
with fourteen pairs'of tubes and after a counting
a potentiometer ypoint between resistance |2|
operation in which the upper or normally con
leading to positive battery and resistance |22
ducting tube of each pair has been rendered non
leading to negative battery. whereby the tube 94
conducting a number 1l, 111, 111, 111, 111 in ac
is biased to cut-off so that only the peaks of the
cordance with the simple binary geometric
positive half waves affect the tube tol produce at
progression scheme of counting -would be re
its anode and on conductor | l1 a series of negative
corded. This number, translated into the com
pulses. Before thev start pulse has rendered the 40 monly used decimal system would mean that a
tube „non-conducting the screen grid of tube 94
train of 16,383 pulses had been counted. How
is held down to> a comparatively low positive po
ever, since the first of these numbers is awkward
tential (graph ||5) so that the `tube 94 is blocked.
to handle the arrangement shown in Fig. '1 may
When, upon the occurrence of the start pulse, the
be employed. Here, a set of fifteen pairs of tubes
potential ofthis screen grid rises to a compara 45 is employed, arranged in five sets of three pairs
tively high positive potential this tube becomes
each. Each such set of tubesr represents the
train of negative pulses, as indicated by the graph
unblocked and the'distorted wave from the pre- g
means for recording a single “digit” in a system ,
cision oscillator passes to the output | |1 as a train
using the digits 0 to 7, inclusive, so that 16,383
of negative pulses. `The conditions thus far de
pulses counted would be recorded as the number
scribed hold until the stop pulse is received over 50 37,777.
As hereinbefore pointed out, if the three lower
conductor 88.
'
'
When the stopvpulse is transmitted over con
tubes |38, |39 and |40 are given the value zero
ductor 88 it passes through condenser |23 and
each and the three upper tubes |4|, |42 and |43
appears as a negative pulse on the suppressor grid
are given the value 1, 2 and 4, respectively, then
of tube 93, whereupon the condition of the two 55 the “digit" recorded on this unit will be equal
tubes 92 and 93 will become reversed, 92 becom
to thefsum of the value_s of the three tubes which
ing conductingl and 93 becoming non-conducting.
are simultaneously inactive. A group of eight
It will be seenA from graphs |08, |||, ||5 and ||8
glow tubes |30 to |31, inclusive represented by the
that the _flow of negative pulses over the output
indicator circuit ||- of Fig. 1, is used to indicate
circuit | |1 is thus'abruptly terminated.
"60 the number recorded on this unit having the
The circuit will remain in the present condition,
values 0 to '7. inclusive, respectively. Thus, if the
with tubes'9l and 92 active and tubes 90, 93 and
three lower tubes |33, |39 and |40 are all inactive,
94 inactive until the circuit is returned to normal
as in normal condition, the glow tube |30 will be
' condition by the operation of the reset key |24,
active and by glowing will indicate the “digit”
which, by temporarily placing negative potential 65 zero. If, on the other hand, all three upper tubes
on the control grids of tubes 9| and 93 insures
|4|, |42 and |43 are inactive, then glow tube
|31 by glowing will indicate that the “digit” 7
` that tubes 90 and 92 become active and tubes 9|,
93 andY 94 become inactive.
(equal to the sum of 1+2+4) has been recorded.
As in the case of the time-delay circuit de
It will be noted that each glow tube. such as
scribed hereinbefore, this circuit unit is provided 70 the tube |30, is connected to a network having a
with a pair of glow tubes to indicate the condition
resistance leading to one tube of each pair. Thus
of the apparatus. Tube |25 is normally active,
resistance |44 is connected to the anode 0f tube
and becomes dark as soon as the start pulse is d |38, resistance |45 is connected to the anode oftube |39 and resistance |46 is connected to the
received andv remains dark thereafter. Tube |26
is normally dark and remains dark until the stop 75 anode of tube` |40. It is only when these three
r
‘
2,405, 597
14
13
Fig. 5--direct current for anode potentiometers.
tubes |38, |38 and IW are simultaneously inactive
that the potential of the control electrode of 810W
+255 volts
“
ît‘ig. â-direct current for reset key |48, -150
tube |30 is sufficiently high to render the tube |30
active. From the above it will readily be seen
vo
s
`
Fig. 6-95. +255 volts
that these tubes are connected in a network based 5
Fig. G-direct current for indicating lamps |25
on a permutation code whereby only one of the
and E26, -130 volts
glow tubes |30 to |31 is rendered active at any
one time.
Fig. G-direct current for reset key |26, _150
«
volts
The arrangement of the six tubes §38 to |43,
Fig. S-I M, -150 volts
inclusive, may be considered a recording and in- 10
Fig. 7-direct current for anode potentiometers,
dicating means for the last “digit” in a system
+255 volts
based on the use of digits 0 to 7, inclusive. Other`
Fig. 'Z-direct current for reset key, -150 volts
Fig. 7-direct current for upper cathode of in
digital recorders are indicated by the broken line
rectangles to the right. All of the various pairs
of tubes are arranged serially so that if the upper 15 dicating lamps, -150 volts
Fig. T-direct current for lower cathode of in
tube of each pair were given a value according to
dicating lamps, +140 volts
the simple binary geometric progression l, 2, 4,
8, 16, 32, 64, 128, 256, 512, 1,024, 2,048, 4,096,
Fig. 'l-alternating current for lower cathode
of indicating lamps, 11G-volt E50-cycle alternating
8,192, 16,384 and the upper tubes oi’ the first four
teen pairs were active, then the sum of such 20 current
values would be the sum of the first fourteen »
members of the above progression, of 16,383.
Appendix
By way of example, the following lists of values 25
and types of resistanees, capacities, voltages and
tubes are given. It should be noted that other
values may be used and it is quite possible that
further experiment might prove that improve
ment in operation could be secured through de- 30
viation from the values and types given:
Resistors
llt-5,0000»
ll--5,000w
2â--9,000a
2l---5,000w
:i2-5,0000,
@ll-ln
u9-125ß00w
l10n-lil
ills-.1n
ißt-125,000@
iii-.25u
Mil-_1n
35-.50
.fit-0400,00@
lil-150,000@
M-lOuOOOw
illu-425,000@
i lll-_liz
i |2--.5Q
i i3-2n
Alt-_.551
itil-»50,00%
¿lt-.50
ca_-30,000@
til-150,000@
tät-100,00@
i 22-50,000w
lil-»5u
t i-looßûûw
tt-o-io
528-59
irs-5o
35
What is claimed is:
l. Means for measuring the periodicity of a
train of regularly recurring electrical impulses
comprising a delay means for preventing the ad
mission of impulses to they rollowing measuring
w means for a predetermined time after the be~
' ginning of the operation, a means for counting a
predetermined number of said impulses, said
means generating and transmitting a start im
pulse marking the beginning and a stop impulse
45 marking the ending of said counting operation,
a source of impulses of known and accurate pc
riodicityJ a means for counting impulses from said
source and means operated by said start and stop
impulses for admitting impulses from said ac
50 curate source to said last counting means.
2. Means for measuring the periodicity of a
5t--l(iil,li0uw
i5u-l25,000w
til-_.59
tti-«5u
itl-1Q
@a2-_820e
train oi' regularly recurring electrical impulses
tt-«öubiluw
itt-1,50%
mission of impulses to the following measuring
tt-.Zeil
til-.til
itt-125,00@
itt-_la
tt-l25ßtlia
itt-820e
Condense'rs
comprising a delay means for preventing the ad
55 means for a predetermined time after the be
ginning of the operation, a means for counting a
predetermined number of said impulses, said
means generating and transmitting a start im
pulse marking the beginning and a stop impulse
marking the ending of said counting operation,
a@ said means also being responsive to impulses ad
mitted thereto by said delay means for absorb
Condenser associated with grid of tube fil,
ing a predetermined number of said impulses be
E13-«l mi.
ia-so
35i-.002 mf.
2G mi’.
5.5-.5 mi’.
tt--öll mm1’.
tél-«.03 mi”.
tid-«50 mini’.
@Q_-50 mmf.
HB2-_125 mmf.
i lt-.l mi.
voltages
fore transmitting said start impulse, a source of
@E impulses of known and accurate periodicity, a
means for counting impulses from said source
and means operated by said start and stop im~paises for admitting impulses from said accurate
source to said last counting means.
3. Means for measuring the frequency of an
tél-llo volts Sli-cycle alternating current
m alternating current, comprising an impulse gen
erator for translating said alternating current in
Alternating current source to indicating lamps
to a train of impulses of like periodicity, a delay
li and l2, lill volts, Sli-cycle alternating current
means for preventing the admission of impulses
¿t9-_+ 150 volts
75 to the following measuring means for a predeter
2,405, 597
_
mined time after the beginning o: the operation,
a, means for counting a predetermined number
of said impulses, said means generating and trans
' 'is
,
the admission of said alternating current to means
for counting the cycles thereof for a predeter
mined time, absorbing without counting a pre
mitting a start impulse marking the beginning
determined number of said cycles after admis- '
and-a stop impulse marking the ending of said 5 sion to said counting means, thereafter count
counting operation, a source of impulses oixknown
ing a predetermined number of cycles of said al
and accurate periodicity, a means for counting
impulses from said source and means operated
by said start and stop impulses for admitting im
ternating' current, marking the beginning and
the ending of the said counting operation and
simultaneously counting the number of cycles of
pulses from said accurate source to said last count 10 alternating current from a known source of great
ing means.
accuracy which ‘occur between the said begin
4. The method of measuring the frequency or
» an alternating current which consists of delaying
ning and ending of said ñrst counting operatiom
OHMER R. MILLER.
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