Патент USA US2404306код для вставки
July-16, 1946.l > - ‘ ' D. G. c. LUCK ì ` I _ 2,404,306 COMMUNICATION SYSTEM. Filed April kJ., 1941 ' 3 sheets-sheet 1 Äïiääy 36, i945. D, G, C, LUCK I . 2,404,306 COMMUNICATION SYSTEM Filed April l,l 1941 „fr @mm1-Geiz" mame . L . 3 Sheets-She’e‘l'. 2 ~ ` ßnventor ' July 16, 1946. ' D, G. LUCK COMMUNICATION SYSTEM Filed April 1', 194i NN@. BB 2,4045306 5 sheets-sheet s Patented July 16, v1946 2,404,306 UNITED STATES PATENT OFFICE 2,404,306 COMMUNICATION SYSTEM 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) 2 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 system. ` ` 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 l 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 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, and Fig. 11 is a circuit diagram showing one form 4periodically recurring and successive selected periods. 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 instants, 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 dots. 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 above. form of this invention, as illustrated by the cir cuit diagram in Figure 2, Figure 5 is a graphical illustration of the con- y. signal. ' 'I'his shows clearlythe small resemblance be tween the vvariable dot train .and the original sa . Among the systems of the prior art, there is no '2,404,306 3 , ,4. 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. v , 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’. ' ‘ _ 30 Y 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 stants. 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 mined level.- ' ' ' ' ' ' ’ ' ' 2,404,306 ‘5 . ' During the intervalof time t2to t3, condenser > >6 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. plete 16 'tube I2 is `disconnected and condenser 'If is re _ turned-.to the Vcharging position, and the cycle is repeated. .Y » , , _ - 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 ' dotxinterval. . ` _ . n , ‘ï i , 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 ing circuit-of a constant. current ldevice such as a., positionl.` ' y . - . 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. ' » Í 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 axis. « ' 1; 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 fthe.tube 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 '.20 'dot-period. sitionzlíil’y is vthe snorting position- , Therefore, .the ' »dotted curved' will decrease rapidly lto zero las >shoWninFigA.. , , . . . . Y 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-` 2,5, . cui'ted„» The cycle thenrepeats itselfs. ' 1 ' It vvvillbe noted that threev condensers are Y such that duringeach dot periodthere îsone con denser on` charge anda diiîerent _condenser Aon discharge, and -.still another condenser'l Von short . î:.li‘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 charge the 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 saturateclfdiode-5i'.~V f Y' »ì 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. . . 2,404,306 .1() 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. ' A ' i ~ I ' `_’ » g ' ‘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 val. . ` ` _ i ' ‘ " ' ‘ 'j l _ . “l signal“,A such thatf’its output voltage will vary sud,-r f de’nly between apredeterrnined positive potential I 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. *n 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 ’ ` l ' I = 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 35 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 f _ i 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-> 50 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 55 ’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 11 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; Y » _ 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. ~ Y n ` 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. ‘ ' Y 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; ~l = " Y ^- f _»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 i -callyrecurringinstants.` " ' ' ' " ' 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 f 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. Y i . ' 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». „ 1 Y, 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 ' 13 14 v 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 Wave. > DAVID G. C. LUCK.