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Патент USA US2404306

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July-16, 1946.l
' D. G. c. LUCK
_ 2,404,306
Filed April kJ., 1941
3 sheets-sheet 1
Äïiääy 36, i945.
I .
Filed April l,l 1941
3 Sheets-She’e‘l'. 2
' July 16, 1946.
D, G.
Filed April 1', 194i
5 sheets-sheet s
Patented July 16, v1946
David G. C. Luck, Haddon Heights, N. J .,` assignor
to Radio Corporation of America, a corporation
of Delaware
Application April 1, 1941, Serial No. 386,302
11 Claims. (Cl. Z50-G)
1 ,
vThis invention relates to communication sys
tems, and more particularly to systems of the
variable dot type, and has for its primary object
version of signal trains to variable dot signals,
in accordance with the prior art,
Figure 6 is also a graphical illustration of the
reconstruction of a signal from the variable dot
to provide an improved variable dot signalling
` `
train, in accordance with the prior art,
Heretofore, dots of variable lengths and con
stant repetition frequency were produced from a
signal wave by starting and stopping the dot at
instants when the sum of the modulation signal
Figure '7 is a, circuit diagram showing another
form of this invention for converting a signal
wave into a dot signal, the length of the dots de
pending upon the average value of the signal dur
and a triangular auxiliary Wave was zero. This 10 ing a predetermined recurring interval of time,
resulted in a train of variable dots from which it
Figure 8 is a graphical illustration of the pro
was difficult to reconstruct accurately the original
duction of a variable dot train from ,a signal
train, in accordance with the form of the inven
According to the` present invention, sequence
tion shown by the circuit diagram in Fig. 7,
switching of capacitance storage devices permit 15 Figure 9 shows a circuit diagram of another
dot length to represent actual signal value at se
form of this invention for reconverting modulated
lected uniformly timed instants so that similar
dots into a signal wave.
devices at the receiver may construct a recti
Figure 10 is a graphical illustration of the re
production of a signal wave from a variable dot
linear wave closely representative of the original
signal. If it ispreferred, the dot length may be 20 train, in accordance with the form of this inven
made to represent an average signal value over
tion as described in the circuit diagram of Fig. 9,
Fig. 11 is a circuit diagram showing one form
4periodically recurring and successive selected
Another object of this invention is to provide
of this invention employing electronic switching
a variable dot signal more nearly a correct rep
resentation of an original signal.
means for converting a signal wave into a modu
lated dot train.
Still another object of this invention is to pro
vide a system to reconvert a variable dot signal
Fig. 5 shows curve a which results from super
imposing an auxiliary saw-tooth wave train
into an original signal Wave more nearly a true
shown dotted as b having a’frequency, for ex
representation of the original signal.
v30 ample, of 30,000 per second on a signal c such as,
Other and incidental objects of the invention
for example, a sine wave signal of 8000 cycles per
will be apparent to those 'skilled in the art from
second and having an amplitude f2 of the saw
the following specification considered in connec
tooth wave amplitude,
tion with the accompanying drawings, in which,
It will be seen that, with such severe modula
‘Figure 1 is a circuit diagram showing one form
tion, portions ofthe originally rectilinear auxil
of this invention in which signal waves are con- "
verted into modulated dots whose duration de
pends upon the instantaneous Value of the orig
inal signal waves at predetermined reoccurring
Figure 2 is a circuit diagram showing one form "
iary wave become distinctly curved. It is the in
formation contained in this curvature that is lost
in a variable dot type of transmission by the use
of methods and means known to the prior art.
The light and dark segments of the zero line in
dicate the yoff and on dot elements produced by
of this invention for reconstructing an original
signal wave from a Vmodulated dot signal,
Figure 3 is a graphical illustration of the deriva
tion from a signal wave of the variable dot signal
limiting this wave to the neighborhood of zero,
one well known method of producing modulated
whose dot duration depends upon the instantane- `
'which indicate nothing but crossing of the zero
ous value of the amplitude-modulated signal, in
accordance with the form of this invention shown
in Figure 1,
It is clear that reproduction from these dots
line by the composite wave can never be exact.
Fig. 6 shows a trainr of variable dots derived
from the sine Wave in Fig. 5 by a method and
50 means of the prior art such as briefly described
Figure 4 is a graphical illustration of the re
construction of the original signal Waves from a
modulated dot signal, in accordance With one f
form of this invention, as illustrated by the cir
cuit diagram in Figure 2,
Figure 5 is a graphical illustration of the con- y.
'I'his shows clearlythe small resemblance be
tween the vvariable dot train .and the original
Among the systems of the prior art, there is no
VKposition such that the potential on the cathode
generally accepted method of reconstructing the
of the diode 9 is negative with respect to ground.
' original signal from such a train of modulated
As the condenser 'Ie is discharged through a
yconstant current device 9, condenser 'if is assum
dots. It is, however, obvious that when so few
clots per cycle of the signal wavev as shown in
Figs. 5 and 6 are transmitted, much of the in
ing its charge.
The voltage across the constant current device
9 is impressed upon the gas tube II `through a
formation in the original wave is necessarily lost
and any reconstructed wave must be appreciably
distorted.- The rather _complex relation between
rsecond commutator I3 connecting' terminals I5
the dot starting instants of the prior art system,
represented by Fig. 5, and the original signal ¿
¿leaks ofi through the constant current device 9
wave enhances the difficulty of keeping down the
such as to- cause the control electrode of the gas
and I‘I.
The voltage charge on the condenser 1e Y
tube I I to lgradually become less negative. When
distortion of a reconstructed signal wave. Y
the potential on the control electrode of the gasY
The transmission of relatively few Vdots, per
tube II reaches the igniting voltage, the tube II
will ignite and pass current until the plate cir
cuit of tube II is opened by commutator I3.
modulating cycle causes distortion Yand Vit _lis
therefore preferable that more dots per modu
lating cycle be transmitted. Since the use of
Vsharp edged dots is obviously necessary to the
noise suppressing function of theA systems, har
" During the interval in which the commutator
_I3 connects the segment I'I to the segment I5,
such as to connect the gas tube I I in the circuit,
n » monies of the dot frequency must be transmit
ted, and-for dots or radio frequency energy each 20 a third commutator I3 >connects the plateV I4 of
'ofth'eseharin’onics yie‘ldsQal pair'` of sidefb'an'ds.
Forretention oi ía reasonable~^bfandjwidth, itis
Iobvio‘usly 'necessary to reduce thenumber of dots
transmitted per modulated Cylòlè‘asfaras possi
Thus 'for a given‘degr'ee'of 'nöi'se'suppr'es
"sion, Vthe dot repetition v'frequency chosen must
the gas tube II to theY output circuit which con
tains a resistor I9 connected to a voltage source.
' While Athe tube VI I> is conducting, the voltage
across the output terminals'Zil will be small, bee
25 cause of the voltage drop across the resistor I9.
Thus it will beseen that the output voltage
will remain high for a period of time depending
directly upon thevoltage charge of condenser 1e,
bethe resultv of a'cornpror’niseïbetween fidelity
andband width.'v In'practice, the quality of re
or an amount which varies in direct proportionV
production obtained with only three or four dots .
per> cycle of maximum vmodulation frequency is
surprisingly good’. '
the magnitude of theincoming signal wave.
to Obviously
uniform repetition of the entire cycle
by using two storage capacitors 'Ie and if, gas tri
odesv II and I2 alternately will give a modulated
ï If only impulses marking the starting and stop
ping "instants of the dots are'to be transmitted,
.the frequency band required.A ofcourse, Vbecomes
very? much greaterf
` f `
dot train with dots ending at uniformly> spaced
instants ~and having durations proportionalY to
the values of the signal atr predetermined in
" By the use off sequence switches to charge'and
kdischarge condensers, it ispossible 'to .control dot
.duration'in accordance with'the 'magnitude of
fth'ef‘sig'nal at lthe'instant of stopping of the pre
cedingdot.. Transmission of this type supplies
It is necessary to provide atleast two
gas triodes I I and I2 rbecause of aY physical char- '
acteristic of a gas triode in which it isabsolutely
40 necessary that lthe tube be completely extin
'information' about the actual modulation values
at regularly timed selected instants. .-From this
vdot Í signal, corrí’r'zlicate'd,l but ' realizable, switching
¿arrangements permit a rectilinear wave having
the'same values as the original ‘modulation Vat the
Lchosen dot cessation instants to be constructed.
. (Fig. 1 Visy a circuit'of a system employing me
;_chanical switching means..> It is'well known that
a `capa'cito'r'connected across a low resistance load e
guished before being reignited. In the case of
high percentage modulation,Y the period allowed
Vfor extinguishing the gas tube will be very small
fand'in order to insurefproper operation, a pair
of gas tubes is employed alternately. ,A single
vacuum tube may be employedv in place of the gas
>tubes which makes it necessary to have only one
"tube to perform this/step as it requires no time to
lbe made non-conducting'.y
'in.`a` Vacuum tube plate circuit will always, be 50 _ Figure 3 is a graphical illustration of the oper
ation of the circuit shown in Fig. 1. For the
:charged with a `voltage proportionallto the in
purpose of illustration, a-sine wave is used and a
stantaneous value of the signal input tothe tube.
dot repetition frequency equal to that illustrated
Ii disconnected from the'tube and discharged
in Figs. 5 and V6 is also used.' The dotted curve e
vÍthr’ou'gh 'a constant current device, the time
rrepresents the potentialon the condenser 1e of
takento reach a iixed reference volta’geis pro
Fig; 1. ~It will be seen that during the interval
Íportional to the value of the input signal at ‘the
of timetI, t2, condenser .'íe is receiving a charge
’instant of disconnection.
and at t2, when Vit is disconnected from the
. A signal wave is applied to the input'circuit'of
charging circuit, its charged potential is equal to
‘a’ low impedance vacuum tube I whose plate cur
Äre'nt is supplied' through a resistor 3. A synchro 60 the instantaneous potential of the incoming sig
nal at the time r2.v Immediately upon'being dis
nous Vmotor 5 drives the commutator ’including
connected, it is connected tothe discharging cir
îcap'acitors 'le 'and 1f. The speed of the synchro'
cuit through the constantl current device such
'nous motor 5 will be Vdetermined by the repetition
that'its `potential decreases uniformly> as shown
_frequency of the desired modulated dot signal.
In _the position ofthe commutator shown,‘ the v65 by the uniformly sloping dotted curve e between
t2 and t3. VAs previously explained, as this“
condenser 'Ie receives a charge which amount is
charged potential on condenser 'Ie drops in a pos
proportional to the magnitude of the incoming
itive direction to Ithe igniting voltage of the gas
signal wave at the instant the condenser le is
`tube II, a current flows through the gas rtube I I
disconnected from the charging circuit.V As the
‘commutator revolves in ‘a counterclockwise di'-V 70 Vwhich causes a cessation `of the modulated dot,
rection, as shown by the arrow, condenser" ‘Ie
vmoves to the discharge position and'discharges
>through a constant current device shown, for ex
ample, as a saturated diode 9. It will be noticed
'that `the lcondenser is inverted in its discharge k75
which is shownA in a heavy line below >the dotted
curve e and extends from the instant t2, at which
“commutatore I3 and I3 connect’tub'e II in circuit,
until the dotted curve e arrives' at a predeter
' '
' During the intervalof time t2to t3, condenser
interval inwhich condenser 25g. is `connected' in
.1 fis receiving its charge, and at ytime t3 itis dis
the'plate circuit of the tube 2|.. This `positionvo'f
connected, atwhichtime its‘charge is equal to
¿the'condenser'25y is represented by. I...
the instantaneousvalue ` of ¿the incoming signal at
.time t3. Likewise, condenser 'If is allowed todis- ,
As lallthe condensers, includingcondenser. 23g., '
moveto the second position such that'con'denser
charge through vthe constant current device 49 such
25g,is` in position II the energy stored thereinis
that a potential across the condenser'lf decreases
used toy control the charging ‘current’ to >theintee.;
from a highly negative potential to the prede
grating capacitor 33-through a constant-current
termined reference voltage which ignites `the gas
device 35/by causing its control electrode'> 36 Ãto_ be
tube I2 such as to terminate a secondmodulated 10 maintained at a potential which amount 'isr pro
dot shown as the heavy line below the dashed
portional to the amount of the vcharge -received
linej in Fig. 3. The oif time of the modulated dot
in the. position ,I of condenser 25g. This potential
.determined by the charge on condenser 'If isV rep
resented graphically .by the extension of Vthe
`dashed curve f. and continues until time t4 when
lremains substantially constant-during one çcom.
'tube I2 is `disconnected and condenser 'If is re _ the Vcharging position, and the cycle is
- 1Fig.'2 showsV one form of this invention for re
' converting modulated dots into an approximate
vreplica of theïoriginal signal wave. In the re
construction process,.it is necessary to derive,
from' the successive dot durations, voltagesfcor
responding Yto instantaneous valuesA of. the desired
It will `be 'noted that the discharge device 35 is
vconnected in series with a second constantcurf
rent device 31. During the complete, dot interval
in which ycondenser 25g> is in position 1I for main
taining` the control electrode 36 of- tube 35 at-‘a
constant potential depending upon "its 'previously
»receivedcharge condenser 257“ has advanced to
position III and its charge which was accumu
lated while it was in position Icausesthe control
electrode 38 of tube V3'I to' be maintained at apo
replica Wave at the instants »of dot starting. and 25 tent'ialïwhich is proportional tothe amount.` of
then to connect these instantaneous values into
charge condenser 257' .received while in itslcharg-~
a continuous signal by rectilinearwave segments.
' `If va capacitor is connected across the output
It will be seen that the resulting. potential
circuit-of a constant. current ldevice such as a.,
across the integrating capacitor 33y is >an amount
pentode amplifier tube it will be `charged with an 30 which is controlled bythe current flowing> through Y
amount of energy just proportional to the dura
both tubes 35 and 3`I._ It th'ereforeïf'ollows that
tion of the constant charging Signal.' A replica
theV potential across the vcondenser~ 33 varies 1in-signal is »thus produced from a modulated vdot
early between values proportional to thel instan.
vsignal and is representative of the original dot
taneous values of the original signal atsîthe'in
vmodulating signal. This may be accomplished by 35 stants of dot starting.
' »
charging a capacitor with a constant current pro
As the set of condensers including condenser
portional to the length of one dot and simulta
25g moves to their next position, such thatV con;V
neously discharging it with a `constant current
denser 25g isvin position III,- the charge onîconà
proportional to the length of the `preceding dot.
denser 25g controls the potential on the control
, Dot lengths may determine constant voltages, for 4
controlling the above mentioned constant cur
rents, by controlling duration of Vconstant charg
ing current intoan auxiliary capacitor.` kThe se
quence of operations consists of four parts, each
electrode 38 of tube 31, while the condenser 25hl
is controlling the potential on' the control elec-A
trode 36` of the tube 35. During vthis interval‘con'- `
vdenser 251‘ is receiving its charge.
,In the Vïfourth position, that is such that‘co'n- Y
lasting for one dot and each requiring one aux
denser 25g is in position IV, the charge on 'the
iliary condenser. First, such an auxiliary capaci
‘condenser'25g is allowed to leakoif through a
short circuit and- in the next position the> complete
tor is charged under dot control. Secondly, it is
cycle is repeated.
ï ‘ f
used to control charging current to an integrating
capacitor. Third, it controls discharge currents 60
It will -be seen that each of the condensers 25g',
kfrom the integrating capacitor and fourth, it is
25h, 251' and 255i will follow these operations seg
_discharged prior to repeating the cycle.
This series of operations may be produced by
_the circuits shown in Fig. 2. An input signal of
quentially- so that continuous operation Vresults
and the output across the integrating capacitor 3_3
is a signal wave whose instantaneous amplitudes
modulated dots is applied to the constant cur
55 at successive dot starting instants are respectively
rent device 2| with such a polarity'that the dot
proportional to the durations Aof the successive
causes this device to pass current. AV synchro
incoming modulated dots.
vnous motor 23 drives a commutator including
Fig, 4 uiustrates graphicauy the operation` of ~
condensers 25g, 25h, 252‘ and 257’. For the pur
the previously described -form of this, invention
pose of simplifying the explanation, condenser
60 under Fig. 2. For the purpose of facilitating >ex
25g and its associated connection/'are drawn in
planation the curves in Fig. 4_ are given letters
heavy lines. In the position shown condenser 25g
corresponding to the letters 'of' the` condensers
receives its charge during the dot portion of the
in Fig. 2._ The curves illustrate the potential> on
interval during which the condenser 25g is con
each condenser during the complete cycle. The
nected in the output circuit of the constant cur 65 input signal of modulated dots is represented by
-rent device 2I. It will be noticed that there is no
the heavy variable dots slightly below the zero
direct current connection between the source of
potential and the anode of the tube 2| but it will
During the interval t2, t3, condenser 25g is in
position I and receiving its charge throughl the
be remembered that the storing of energy in con
densers which are being periodically changed may 70 constant current device 21 during thedot por
supply anode current for the discharge device 2 I.
tion of the interval t2, t3. This is indicated by
It will thus -be seen that the series connection of
curve g which during the dot interval is increase
ingly uniform until> the time at which _thesdot
condenser 25g in the plate circuit will cause it to
have a charge whose voltage will be proportional
to the duration of that dot portionof thetime
stops. yAfter the dot signal stops between t2, >and
t3, ,itwin ,be noticedthat the a. çurregealeiaieâ
"egzioisoe' '
'rent device 5I -and asegmentöi connected'. to
a'áuniiorm .amplitude ¿untilltime `tilland.represents
theVl control electrode of the gas discharge .tube"51.
In positionII, the AchargeainV condenser 451cis
thevoltage `o'fáconde‘nse'r «2 5g.. It willibe seenth'at
the chargeproduced ongthe condenserV ZSgTLdurin'g
the no...signal rperiod, tl, .tzr .While .condenser s -257'
Wasinposition .I is carriedover‘to thetime in'
applied to the .control electrode . off’lthe. ~ gas. dis-'
charge device 51. At. the beginning `of theïldot -
period,l the Ycharge .acrossïthe Acondenser 4.5lcïis
terval t3, V#L15-During thetimeiinterval. t3,‘ t4,
f 'accompanying chart .wherein'it 'is .controlling the
large enough thatV the resulting negative` charge
on »the control electrode ofthe >gastube Y51pre
potential on 'the control electrode '2.6 oftheltube
vents its igniting. . V.This ' originalV charge . isi grad.
»condenser 25g isV in positionv Ii 'asfshownin'the
' 35. During `this same' interval `vlof time Y1:3‘, t4,
ually. leaking oiï thecondenser 45k so that" when
' [condenser 25'7‘ is .controlling the potential. on. the
the ‘-p0tential. .across .the - condenser V45k: :reaches
the l:tube igniting voltage, current .flows through '
control-electrodeßß of the tube 31.' It,‘ therefore,
followsA that the .- potential across „ the . integrating 51for the'remainder'of theldot period
capacitor-33 Will change linearly-iìromf‘theV po
at which time the tube .51 is disconnectedfrom
its source of anode voltagev which is’fedïto l.the
commutator »58 -and through .resistor 5&5. This
tentialY representative of . or. proportional to the
y potential across the condenserïîâi, whichisinturn 1
causes tube î51 to be..extinguished..V There re
proportiona1 to the .value of the original signal
sults a variable dot Whose length is proportional
Waveat instanttl, to that potentialrepresenta
to »theiaverage value of the `signalwave duringfthe '
tive of .thepotentialjacross kcondenser Zügywhich
is.proportional-tothe-value of the loriginal signal
sitionzlíil’y is vthe snorting position- , Therefore, .the
' »dotted curved' will decrease rapidly lto zero las
remaining .chargeronfthe .condenser #57o is al
lovved .tofdischarge becauseof. Ábeing* short. cir.
.„notimers.,thelpoœnuallacrosscondenser 257' '
, is shorted outibecauseas ,previouslydescribed po,
suchthat condenser 45k is .in`- position DI, `the
structed signal to‘ctake the form ofV theheavy"
curveofzlilig. 4.. l
_ As .the condensers rotate to their. .next position
1 at .instant t2.` This causesA the. outputY recon-`
The cycle thenrepeats itselfs.
' 1 '
It vvvillbe noted that threev condensers are
such that duringeach dot periodthere îsone con
denser on` charge anda diiîerent _condenser Aon
discharge, and -.still another condenser'l Von short .
î‘ig. '1 shows a closely .relatedtype of converter
using a somewhat simpler .variable _dot-transmit-` ; circuit, so that continuous operation iresults.
n There is also provided two additional gaseous dis
ter;V Instead of transmitting instantaneous .sig
charge devices 6l and 63 which are connected to
nal values'at instants beginningeach- dot period
. and .joining these .values .by straight lines at the
reconverter, itis possible to transmit kaverage
Ysignal values over the dot period, and -maintain,
their respective segments 65 and 61 on the com
mutator _such that each of the. gas discharge» de.
vic‘esf51, 6I, and V63 operate only one-thirdof
>these value/s_overeth'e dot periodlat the recon- v p the time and are soconnected to the commuta
vertente give a- :stepped rectangular _approx
imation of the signal Wave.- On ¿thegconverten
' tor'thaty they operate sequentially.
Fig. 8 shows graphically the operation ofthe
averaging may .be accomplished by using a
.form of this inventionas set forth in Fig. 7., . _The
.constant current single tube plate _current‘to
letters representative of the storage condensers in
Fig. lT_„are used in each of the curves in Fig. 8. to
capacitor; _ _the cycle Vbecomes Y a
a'three-part one, and `in addition`> to the charge
vand discharge of the capacitor, .a .position "for
short _circuiting or completely dischargingthe
¿facilitate th'eexplanation ofthe operation, and
:the Ycurves in Fig. 7 are rrepresentative of the po-__tentials `across the storage l condensers., The
capacitor is also require'd'on'the sequence switch. y1 ,dashed line k represents the voltage of the Ícon
,denser 45k, the dottedline l represents th'e volt- .
¿ The receivercycleis also a _three-'part cycle,
`age on the/condenser _451,.and the A_dash-clot line m
represents the voltage on the condenser vllâm'. `A
>sine wave is used.- and is divided up'into> dot inter;
and one on discharge, short circ-uit. '
According to the form of this invention shown 50 vals similar to ’those vused in yprevious Avvexplana
using three capacitors cyclically-one on charge,
one'supplying output signal voltage (no current),
in Fig. '7, there isshown one form of this in
., ventio'n in which the average amplitude of the
incoming amplitude modulated signal is used to
charge a- condenser to Ybe later discharged. A
.signal Wave is applied .to the constant current dis- i
tions of other forms of'this invention, " ,
During the interval tlLtZ, the condenser 45k
is in .position I and is assuming a charge Vwhich is
proportional tothe average amplitude'ofthe'in
coming amplitude modulated signal during'the
"time interval tl, t2. At time t2, the commutator
has rotated such as' toy place condenser 457C in
115m., "lÃ/'_hile condenser'llâlcis in~ position I,> it is - ' ¿position IIÍat which 'time it starts to discharge
charge >'device 39. -Asynchronous motor ¿I3>- drives
a commutator includingcapacitors 451_c,'45vl.and
receiving a. charge which is proportional' to _the
Vthrough thev 'constant current device 5 l'. This ac"
time integral ' of `the‘vvoltage 1 impressed upon Athe 60 counts for |the uniform decline taken by curve k
‘discharge ' device vit by the vsignal Wave during
'the corresponding dot period. yThischarge vre
` v:starting at it?.
AlÄ/"Ihen’the potential on the con
"denserjéäfdecreasesto the potential at which the
lgastuloe will ignite, a cessation of the variable .
. 'dot' occurs, the length of the variable dot,r as pre
c-urrentoof tube "39. V'.Ait'the end of this-dotperiod, 65 ‘vivously described, continuing from the instant1t2
until the ignition of the tube 51. The condenser
. the- accumulated charge on condenser lilik i's‘pro
sults from the series connection of the condenser
45k Vfrom the voltage“ source supplying the ya'ni'od'e
portional to the time average _of the signaling
YWave,during the'period.
Í‘ >As the condensers ro'tateis’o’thatv condenser 'Mik
is imposition II, itis discharged'through _a con
>etant current _device which takes the- form of -a
Y' ȓ
y- «
`second‘co'mniuta-tor also driven «ïbyï-thelsym
chronous ‘moto-r '43 includesla«commonîsegment
» `tasconnected»to the-cathode@ theïconstant cur
125 continues along the base line between time in
terval t3 and tf1 during which time condenser 451C
is'inrposition IILzor discharge position. . At .time '
t4, condenser ¿55k is again in the charging position,
lor position I and assumes its charge at a, rate‘pro
`.portional to the area under th'e signal Wave or to
van amount which at t5 .is in turn proportional to
»the average amplitude of the signal Wave .during ,
vperiod t4 to t5. . .
yItwill loe-seen that each' of the condensers op;-
and- drop in potential immediately to the axis
where they remain until they again assume posi#
erate in a similar manner `and sequentially such
that they producethe desired variable dot signal.
Fig. 9 shows a reconverter circuit to reconvert
tion I-to take on acharge for the vnext'succe'ed
ing cyclej ofA operation.¿` It `will be readily seen
the variable dot train into a replica of a signal
that by repeating'this cycle of operation, a com
wave >whose averagel amplitude during one dot
plete reconstructed signal wave will be' produced.
period is proportional’to the dot length. The
modulated dot train is applied tothe control elec
Fig'. 1l shows one form of this invention' in
which electronic meansis used for switching
trode 64 of a constant Ícurrent_discharge device
65.y The output circuit also includes a commu
rather than the mechanicall means previously
shown and described.
tator driven by a synchronous motor4 |59.- The
commutator includes capacitors 1Ip, 1|q and 1|r.
' ‘It will be noticed that two similar channels'are
provided for theconversion of a signal w’ave’into
As the condenserg are in such a position that con
a modulated"dotsignal and each channel'works
denser 1|p is in position I, the condenser 1|p is
receiving a charge whose stored energy will be 16 A squarewave generator 11 ofV any of the well'
proportional to the signal portion of a dot inter
kriown- types produces av push-pull; square Vwave
alternately. ,i
i '
signal“,A such thatf’its output voltage will vary sud,-r
f de’nly between apredeterrnined positive potential
As the condensers rotate such that condenser
1| p is in position II, the condenser 1 | p will main
tain across the output a' voltage corresponding
to the charge which it has accumulated; ’ The
and aV predetermined negative potential.
A -signal'wave input is applied'simultaneously
to the control electrodes 19and 8i) of' the dis
output signal will therefore have a magnitude
proportional to the length of >the dot which
Y charge devices' 8| `>an’df‘82; ‘Simultaneously the
output signal from the’square'wave generatoris
lcharged the condenser 1 I p when it was inthe iirst
appliedfto anauxiliary electrode 83 Yof the disi
position I.A
charge device 8| in a positive direction- such'that
f ‘
‘ As the condensers further rotate such that "con
denser 1| p is in positionv III, the condenser 1 | p is
it causes the discharge device 8| to 'pass ‘current’
short circuited such that the remaining energy
therein- is discharged. _ Therefore, when it g re
tial is being applied to _thè >auxiliary electrode
83, a negative potential‘is applied'to the auxiliary
turn's'to the chargin'giposition, the'voltage pro
duced across it is directly proportional Vtothe
electrode' 84 ofthe >discharge"device 82 such'that
the currentïflowing through'th'e discharge device
During the same interval that the positive poten.
82 will be blocked. » During this interval, a" storage
charge'whichl it accumulates. ’
condenser 85 ‘is’ receiving a vclriaJrge which is pro
cyclel'of operation so that there is a condenser on
charge for each incoming‘dot," and >at the same
.time thereis alsov one~ condenser in position Il,
`portionalto the* magnitude of theinput signal
by reason of the Yvoltagejdrop vthrough resistance
ysi and diseh'argecevice 'as` which has vbeen made
conducting during the vtime the discharge _device
and a third'conden'seris in the positionï of short
4circuit preparing itself for. its next charge. `
v8| isdrawing current,
The resulting signaiwave is appned tothe ‘con
Y „
~ During `the next succeeding dot interval, the
ftrol electrode _12 of the outputV tube 14. _It `-will 40 constant- current y deviceA -9| Y is >made ‘conducting
vby reason'of its auxiliary electrode 93 being con
be noted‘that tiere> isn'og'rid ieak‘fresister. This
Venables the condensers to'A holdV their charge
throughout the/timeïintervalas shown in Fig. 10.
nectedto‘ the output signal ,from4 the square wave
' generator, whichis at a positive potential Vduring
Fig. 10 is a graphicalillulstration of the opera
the interval;v
tion of the form of this invention shown in Fig'. 9. 45
denser 85 is prevented from leaking off through
DuringV the'dot portion of interval tl, t2 con
denser 1|p is'receiving its 4charge lthrough the
constant kcurrent device _65.- This may be seen
from the uniform slope of the dotted curve p.
When the variable dot signalvceases during the
time intervall t|„t2 ,thev tube 65 is biased beyond
cut-'olf so that the condenser 1|p reecives no fur
ther charge due to the Afact that no` current is
flowing in the outputcircuit of the tube 65. It
will be seen that during the no signalI portion of
The charge which has accumulated on vcon
resistor-81 'and`> tube 89_by reasony of theV tube 8S
being made noncon‘ductive during the interval
thatv th'ef'con‘stant current device 9| is made con->
ducting.' During this interval that _constantcur
rent device 9| is made conducting the charging
tube 8| is made non-'conducting by the negative
wave vapplied to its auxiliaryelectrode 83 by'- the
square wave generator 11. -
By reason of the fact that the constant current
device9| allows theA charge on the condenser 85
>time tl , t2, the dotted curve "p maintains „its arn
toA leak off therefrom at a uniform rate, the po
plitude and at time t2 when the condenser 1|p is ~
tential at thecontrol electrode 95 decreases uni
changed "to position I'I, the voltage across -the
formly. , It follows, in View of the phase revers
condenser 1,|"p_is connected across the output cir
cuit, and for the period_'t2, t8 the output signal 60 ing action of the discharge device 91., that the
potential on the control electrode 99 of the gase
iseequal to the voltage on the condenser 1 | p.,
»ous discharge device IUI, which is in a non
- , At time t2 condenser *1|'r is connected to the
vconducting state, increases in a positive` direction
¿charging circuit so that potential across 1|r in
during this uniform decrease of potential on the
creases as represented by dash-dot line r during
control electrode: 95,- of tube 91. When the po
the signal interval of time t2, t3. A'Upon cessation
’of the rvariable dot signal, the tube_85.again is
tential on the control electrode 99 reaches a pre
bleck'ed causing the condenser 1|r‘ to maintain
its- voltage through the Íremainder-'of the dot in
terval t2, t3, andv throughfthe interval t3. tellV dur
ing which time theV condenser 1_Ir is connected in
determined value, thetube ||l|> will become con
ducting. fIt will be clear that'the length of time
taken`> from the start'`>` of the discharge of con
denser .85 ‘to‘thefinstant' at which the tube |8| is
'the output circuit.v
' _Attime r3, the third condenser mi` does on
charge. The potential of the'condensers 1| qïisV
made conducting depends upon the amount of
«charge which-theßcondenser 85 originally received
byreason 'of thev magnitude of the inputsignal
'shown asl dashed line lq. As each of the Vcon
-densers reachLp'osition.ï III, they are discharged
at the>` instant when. the l condenser ' 85 was ' re
' -moved ‘fromwthe charging _circuit and-placed on
afrogsoc Y
occurringr at a predetermined >rate yand wherein
the duration of the dots is representative -ofY the
magnitude of ‘said’ signal Wave, comprising in
` ther discharging circuit Vby reason of Vthe control
‘ voltage from the square wave generator;
'Y 'Y
’ During that time which the tube’liìl »is con
combination means for sequentiallycharging .each
§ ducting,V the potential on the control ¿electrode
of a‘plurality -ofrcondensers atsaid rate and by
'i |03 Vof ‘the4 tube,V |05 .is low; resulting »in-an»- ac
an vamount determined bythe instantaneous mag
» companying high voltageon the îanode-lßluof the
nitude of said signaling wave at: instants reoccur.
tube-~|ll5~Y This results inl a .modulated dot ksignal
ring at said rate, `means for sequentially connect
ing each of said condensersîto a constant current
discharge device at said predetermined rate, and
1 whose durationis dependent upon, the time :which
thetube lill is conducting;
Because of the fact that’the'gaseous discharge
l device must be extinguished, an auxiliary gaseous
al discharge device connected to said constant cur
rent'- device' Ywhose conduction is- controlled by
` discharge device. I‘BSY-is provided 'whosecontrol
1 .electrode H I'is also connected to the‘square Wave
Ythe resulting'potential across said constant kcur
l generatori" such that the control electrode HI
rent device.
` will gopositive toV make the tube Ill-9 conducting
4. In a, signaling system; means for converting
" at jthe end of'the interval .during which tube- l0!
lis conducting. The instantaneous pulse resulting
a ~periodically reoccurring variable »dot train into
a signal wave wherein themagnitude thereof is
representative of the duration of the variable-dots
from the-tube-ÜlllllY becoming conductive-'is vim- '
comprising in Ycombination means 4for sequentially
changing the charge in -eachA of; a plurality ci
f pressed upon the> output Acircuit of tube lill
1 through a--coupling condenser’L Irlßv'such that it
` produceslafsuiiicient voltage dropY in the output
condensers at -said» ratev and by» an amount-deter-VV ’
2 circuit ofïtube ill-Ito cause -it to be extinguished
i -byreason of the fact that, when'the anodesupply „
i V_voltage-«of a 'gaseous discharge -device drops below
§ a predetermined amount, the gaseous rdischarge Y .Y
device is extinguished.
mined Aby theV duration of said-,variable dots, a
pair of constant current devices havinginput cir
cuits >and serially ‘connected output circuits,
»means for sequentially connecting said'condens
ers toY eachof said ¿input circuits in apredeterf
mined order and duringjeachgof the time intervals
,Y VIt will'be seen that, at eachV succeeding dot
Í interval, the channel is changed such -that alter@- '
nate dotsrof the Vmodi-il-ated'dotsig-nals are pro
ducedçby alternate-use off’the ¿channels shown. _
n The Aoperxgal-tion of the `second channelais precisely
occupied by avariable dot;
_»5. In a signaling system, .means for converting Y
a signal wave into a ‘trainfof' variable- dots -greoc'
curring at a predetermined rate and wherein ,the ~
> ì the, same as theA operationfcf the ñrst channel. Y‘
duration of the dots is representative of the mag
‘ Itwill be seen that this will producea train >of
, :modulated dots, the durationof'eachdot of which
nitude of said ’signal wave-comprising in'V com
` bination meansfor sequentially chargingxeachwof
` is representative ofthe :magnitude 'of the input ,
a plurality'of condensersatsaidîrate and v*by an
4 sig-nalaat one of aset of predetermined,y periodi- >
amount determined'byy the» magnitude Vof said`
f tion into eiîect have been »indica-ted and described, ‘
signaling wave, means for 'sequentiallyëconnect
ing each of said condenser'sï to a constant current
discharge device at said predeterminedrate,y ¿and
it will'rbe apparent'to «oneïskilled in the art that
means for controlling the» period, and means yfor
While several systems forïcarrying thissinven- f
this invention is by no means limited to the 'par- 140 controlling the period ofaconduction inïeachoi‘
a plurality "of “gaseous discharge devicesl during
ticular organizations Yshown- and described,` but
l thatgmany modiñcations may be made without ‘
predeterminedintervals reoccurrlng-at said periä-
Ydeparting from the scope of this invention asset
odic .rate with ¿the resulting lpl'ltential :across 'said
forth in the appended claims.
constant current device during said interval.Y ' ‘ '
IA. claim as. myl invention:
6. In a'signaling system,V means :for «converting
1_„In a :signaling system, means for 'ccnverting
a signal wave into a' train nf variable,dots¿renc'l `currin-gat a predeterminedrate and vwherein the Y
Y a'signal wave~into- a train of variable dotare
occurring »at Y aw-predetermined 'ra-te- and wherein
the duration of the dots is îrepresentative ofthe
duration> ofïthe dots ï is> representative» of- the ,50 magnitude of saidV signal wave comprising gin com"
magnitude-of AVsaid signal wave comprising in com
-binationV a pair -of signal channels, means for al
bination,A _means for sequentially charging each
ternately applying'toeach of said channels alter
of` a plurality of condensers a-t'saa’d rate .andby
nate dots of said variable dot?train, each channel '
an amount determined by the magnitudeofzsaid
includingna condenser, »meansfor applyingtosaid
into a signal wave wherein the magnitudethere
condenser a charge representative Aof the magni
tude-of said signal wave in the respective dot in
terval; a constant current .deviceA connected'V to
said condenser, means for- applying the potential
across said constant current device to the input
circuit of one o1“ a pair of »gaseous discharge de
vices whose output circuits are connected in par-V
allel fo;i controlling theignition thereof, ymeansV
connected to the input circuit of the other of said
gaseous discharge devices for ignitingthe other
.dots comprising in conrbinatien,Y means for se*
of therespective dot intervalto'uextinguish the - Y '
Y signaling wave, means for sequentially connect
ing; eachV of said condensers to a constant .cur
rent discharge device at `said predetermined’rate, g
and av discharge device connected .to said con-`
' stant current;A device whose conduction is con
trolled by the resulting potential across said con
stant current device.
2.' In a signaling system, means for' convert
- ing a'periodically reoccurringî variable dot train
Vofis representative of thesduration-of the variable 65 of said gaseous discharge devices at the beginning
.quentially changing the chargein each , of` a -plu-_v
iirst of said gaseous ¿discharge devices, and»Y a
,ralityof condensers atìsaidïateandby anamount ‘
variable dot transmissionchannel connected to
determined :by the «durationof said variable dots,
Vboth of said signal channels for .transmittingïthe ~
va :signalftransmission circuit Vandvrrneans for se
" Y_i'.luentially connectíngsaid: condensers to» said;
transmissionîcircuit for controlling the` produc
resulting train of variable dots».
7. VThe method of signaling which» comprises
j the steps Yof -sequentiallygderiving individual elec- ~
, ,tionY of a signal wave'in` said .transmission circ'zuit@V _ tric charges' proportional to the magnitudefofaf
3 ,g ‘ >^3.,In-asignaling. system, .means for converting» j Y.signaling jwave, .allowing .the energy. in` eachgoi
a signal'wave into a .trainyof variabledots .re->
the charges to'be dissipatedfat. a¿ constant; =rate
2,404,306 '
and utilizing the charge to control the ñow of
current in each of a plurality of discharge devices
sequentially to produce a train of periodically
reoccurring dots Whose duration is proportional
lto the magnitude of the said signal Wave.
8. The method of signaling which comprises
the stepsy of sequentially deriving individual elec
tric charges proportional to the duration of the
variable dots of a variable dot train and sequen
tially utilizing the charges to produce a signal 10
Wave whose magnitude is proportional to the
duration of the variable dot train.
9. The method of signaling which comprises
charge dissipation for producing electrical pulses
varying as the periods of said charge dissipation,
Wave signaling receiving apparatus including
means for sequentially producing another plu
rality of electrical charges at said rate and of a
magnitude determined by the duration of said
pulses, and means sequentially `responsive to said
other electrical charges for reconstructing said
signaling Wave.
11, The combination of a Wave signaling trans
mitting apparatus including means for Vsequen
tially charging one plurality of condensers at a
predetermined rate and by an amount deter
mined by the magnitude of the signaling Wave,
the steps of sequentially deriving individual elec
tric charges proportional to the magnitude of a 15 means for sequentially connecting each of said
condensers to a constant current discharge device
signaling Wave, allowing the energy to be dissi
-V pated at a constant rate and utilizing said charge
to control the ignition of each of a plurality of
gaseous discharge devices sequentially to produce
at said predetermined rate, a discharge device re
sponsive to the potential of said constant current
device for producing electrical pulses varying as
a train of periodically reoccurring dots whose 20 the potential of saidconstant current device, a
wave signaling receiving apparatus including
duration is proportional to the magnitude of said
means for sequentially changing the charge in
signal wave.
each of another plurality of condensers at said
10. The combination of a wave signaling ap
rate and by an amount determined by the dura
paratus including means for sequentially produc
f tion of said pulses, andmeans sequentially re
ing one plurality of electrical charges at a pre
sponsive to the charges of said other electrical
determined rate and of a magnitude dependent
condensers for reconstructing said signaling
on the magnitude of said signaling wave, means
for sequentially dissipating said charges at said
predetermined rate, means- responsive to said
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