US2541134A - System for distributing successive electrical impulses to a multiplicity of output channels - Google Patents

Description

R M. G. TOULON 2,541,134 SYSTEM FOR mswx-usuw-mc- SUCCESSIVE ELECTRICAL IMPULSES TO A MULTIPLICITY OF OUTPUT CHANNELS Filed April 3, 1947 2 Sheets-Sheet l INVENTDR PIERRE MARIE GABRIEL TOULON BY 7/ z 1 E u ATTORNEYS Feb, 13,, 19511 Fehl3, 1951 v P. M. G. TOULON 2,541,134

- sYs'mM FOR DISTRIBUTING SUCCESSIVE ELECTRICAL IMPULLES TO A MULTIPLICITY 0F OUTPUT CHANNELS Filed April 3, 1947 2 Sheets-Sheet 2 IN VE N TU R PIERRE NAME GABRIEL TOULOM ATT U RNEY5 Patented Feb. 13, 1951 SYSTEM FOR DISTRIBUTING SUCCESSIVE ELECTRICAL IMPULSES TO A MULTIPLIC- ITY OF OUTPUT CHANNELS Pierre Marie Gabriel Toulon, Neuilly-sur-Seine,

France, assignor to Products & Licensing Corporation, New York, N. Y., a corporation of Delaware Application April 3, 1947, Serial No. 739,154 In France February 20, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires February 20, 1963 8 Claims. (Ci. 332-13) The present invention relates to systems for distributing, among a plurality of independent output channels, successive electrical impulses supplied through a common input channel, these systems being of the kind described in my copending U. S. applications, Ser. No. 739,018, filed April 2, 1947, for Improvements in Signal Distributing Systems and Ser. No. 739,019, filed April 2, 1947, for Electrical Transmission Systems and based upon the use of combined capacitors supplied with polyphase current or currents.

An object of my invention is to obtain high voltage electrical impulses in each of the independent channels. For this purpose, according to my invention, I make use of a gas discharge tube (for instance a tube containing helium or mercury vapor at low pressure), in particular of the cooled type with a big condensation chamber, and the conductivity of the tube is controlled so as to last, on each successive impulse, for a time which is a function of the amplitude of the impulse to be transmitted or stored up. I vary the time at which the arc is struck in accordance with the intensity of the current to be transmitted. This tube conductivity control may be performed by means of a tube different from that which serves to ensure the storing up of the impulse, but according to a preferred embodiment I make use of the multiple anode gas discharge tube which distributes the impulses to the different channels for simultaneously ensuring amplification. I employ for this purpose the known phase control" method for gas discharge tubes (a method which is now very much employed in mercury vapor rectifiers, thyratrons) Control of the grid potential, which ensures the starting of the current flow at the desired time in the gas discharge tube, may be ensured by means of suitable auxiliary vacuum tubes. For instance, I make use of a saw-tooth anode voltage, or of a tube having several control grids, one of the grids receiving the modulation, and the second a saw-tooth voltage. But, according to a preferred embodiment of my invention, I make use of a multiple anode tube including at least two successive control grids: the first of the grids receives the modulation, whereas the second receives a sawtooth voltage. At the same time each of the multiple anodes successively receives, as described in the above stated patent applications, a complex voltage which passes through a positive value (peak of the curve) for an extremely short time interval in the course of every period. This positive value is supplied successively to each of the anodes, which thus receive the amplified impulses.

The saw-tooth voltage is preferably obtained from oscillators synchronized to the scanning frequency, by means of a complex voltage generator as described in the above mentioned prior U. S. applications.

According to a preferred modification of my invention, the second grid is mounted like the anode of a relaxation oscillation generator, which permits of avoiding the use of a synchronized auxiliary voltage.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of indication and in which:

Fig. 1 is a diagrammatical view of a-tube arrangement according to my invention;

' Fig. 2 is a curve showing the form of saw-tooth oscillation preferably used according to my invention;

Fig. 3 is a diagrammatical view of an arrangement for compensating for parasitic capacities;

Fig. 4 shows a modification of the arrangement of Fig. 1 embodying the use of a two grid tube.

For certain applications, and in particular in the case of a high speed signal distributor intended to supply the vertical conductors of a tele vision receiving screen, as described in particular in my French Patent No. 860,481 of June 28, 1939, entitled Improvements in big screen television receivers, it is necessary to obtain in each of the independent channels a relatively high voltage (at least about one hundred volts). As the capacity of said vertical conductors is rather high (for instance 250 electrostatic units), in view of the high rate of the impulses (if the frame includes for instance 600 horizontal lines scanned twenty-five times per second the rate of the impulses is 15,000 per second) it is necessary to obtain a relatively high power in each of the channels (for instance 0.5 watt). The multiple anode distributing tube which feeds several of these channels simultaneously (for instance in the case of an arrangement including 800 points per line and 10 distributing tubes having each 80 anodes) must therefore be able to supply a very substantial power (theoretically 40 watts, but actually much more as a consequence of the bad transformation output). Furthermore, the supply tube must have a very low internal resistance, as the instantaneous current in the tube is to reach very high values (eighty times 1.5 milliamperes, i. e. milliamperes approximately). Accordingly, when high vacuum tubes are employed, it is necessary to make use of very big ones. Fig. 1 clearly shows the advantage resulting from the 8 woof gas discharge tubes of the kind including a control grid. In these tubes, and according to a known method, it is possible to obtain a progressive modulation by controlling, for each alternation and as a function of the impulse amplitude, the time at which the arc is struck. The supply voltage may be an alternating one but it may also have any complex shape provided that it passes through zero. Fig. 1 shows the application of this principle to my invention. I have shown at I the cathode, at 82 the control grid, at 08, 08', 88" some of the multiple anodes. According to the method above referred to, each of the anodes is given a complex voltage (diagrammatically represented by 84, 84', 64") having at a given time a very sharp positive maximum, these times occurring successively for the respective anodes. These voltages are obtained through the use of energizing distribution devices 65, 88, 81, 88 and 85, 88, 81' and 88' as already described in my above mentioned U. S. applications. But, according to the present invention, the distribution device which supplies the successive impulses (coming from the common input channel) is no longer caused to act upon the cathode SI of the multiple anode rectifier tube but upon the grid of a' control tube 12. I arrange so that each of the anodes becomes positive during the hatched period 84, 84', 84", etc. On the other hand thestriking of the arc is delayed (according to the now conventional method of phase grid control) more or less (at 69, 89', 89") under control of 'the modulation so that the mean value (hatched portion) of the current individually supplied to each of the anodes becomes a function of the impulse amplitude.

In order to obtain this result, I make use, on Fig. l, of an amplifier tube 12 on the plate of I which a saw-tooth voltage is impressed by a genthe tube grid, while saw-tooth generator I acts upon the plate. The plate current is shown by curve I5, 15" and the voltage drop across resistance I3 controls the grid potential of tube 82 in'such manner as to cause the arc to be struck at the desired time. The hatched portions 89, 89', 69" thus have respective areas which correspond to the amplitudes of the successive impulses.

The current thus supplied through each anode has for its effect to store up, owing to resistors I0, 1!,19", in each of the line condensers (80, 80', 80") a charge which depends upon the impulse amplitude. Suitable means (not shown) .are then provided todischarge these condensers.

In order to produce saw=tooth voltage l0, I may, according to my invention (Fig; 2) have recourse to a complex voltage generator based upon the principleof the static voltage distribution described in my above mentioned prior U. S. applications. I superimpose on the fundamental sinusoid 88 its first harmonic (or several harmonics if necessary) with a suitable choice of amplitude and phase, so as to obtain a resultant curve It which diifers but little from the desired sawtooth shape (dot and dash lines).

cording to another feature of my invention,

the voltage induced by the tube capacity in the anodes which receive the impulses is constantly balanced by a voltage of opposite sign equal (or proportional) at any time to the instantaneous value of the impulse. Fig. 3 shows a device for generating this compensating voltage. On this figure, 05 represents the coil through which are supplied the high freqency waves which carry the modulation. I make use of two oscillating circuits coupled with this coil and tuned to the carrier frequency: 88 and 89. The flrstof these circuits supplies a rectifier 90 which feeds impulses of a given sign to a resistance 9|. These impulses are fed to the cathode 92 of the multiple anode distributor tube. The second oscillator circuit 86 has its output connected to a second rectifier 81 which supplies oscillation of opposite sign to a resistor 88. The voltage thus obtained is to exert upon anodes 80, 94, etc., an influence capable of compensating that exerted by cathode 92. For this purpose, I make use of a capacitor 95, 95' of a capacity equal to that of the parasitic capacitor 921-94 (if voltage 88 is equal to that of 9|). If, on the contrary, the voltage of 88 is different from 9|, I make use of inversely proportional capacities.

As in the preceding arrangements, I produce in anode 94, 94', etc., a complex voltage by means of capacitors 98, 98', etc. The utilization circuit is connected through a rejector coil 99. A capaeitor 91 and a reactance coil 91' compensate the induction produced in the utilization circuit by capacitor 98. The voltages necessary for obtaining these inductions are obtained from oscillators 98 synchronized with the line impulses 88. Discharge is obtained, accordingto a feature of my invention, by means of a valve I00 the anode of which, connected with a capacitor I 02, receives a variable voltage of substantially rectangular form. This voltage is obtained through a system for the distribution of polyphase voltages of different frequencies supplied by an oscillator synchronized with impulses 98 and of a bias battery I06. The stored up voltage corresponding to the impulse acts upon the grid of an amplifier tube I01 placed in the independent output line.

According to a preferred embodiment of my invention, the striking of the are at the desired time can be controlled without having recourse to an auxiliary control tube (tube I! of Fig.1), by making use of a gas discharge tube having several control grids. Fig. 4 illustrates this embodiment. The second grid III is connected with a relaxation oscillation generator, including a capacity H2 and a high resistance H3. The voltage impressed on the successive anodes II, II5,-I I8 is represented, as a function of time, by curves H1, H8, II9. Modulation I00 is applied between cathode H0 and the first grid I09. On the drawing I have shown two diflferent amplitudes I20 and I2! of the modulation (correspondingto two successive impulses. for instance).

Discharge of condenser H2 into anode grid III causes the striking of the are at the proper time, because the working'otanode grid I II depends upon the potential of grid I09. Explanation of the operation appears clearly by referring to Fig.

4: It has been supposed that at I23 the tube ceases to be ionized (to act as a conductor) due to the fact that the anode voltage II'I becomes zero. In these conditions, the potential of the condenser assumes a given value I20, always the same. From this time on, as the tube acts as an insulating element, the voltage across the terminalsofcondenscr III graduallyal 5 illustrated by inclined line l2l. then given a voltage such as I24, the arc is struck between cathode H and anode grid ill at point I25, which makes it possible for anode to discharge (hatched portion I26). The tube keeps acting as a conductor as long as the anode is discharging, that is to say as far as point I28. From this time on, the tube acts as an insulating element. Condenser H2 is again charged as represented by inclined straight line I29. If, at this time, control grid 109 has anothervalue, such as I21, more negative than its preceding value, anode grid III is energized at a later time, at I30, thus starting a current 131 (hatched portion) in anode I it less important than the current which has been started in anode H5 and so on. It is thus possible to replace by a single tube having several grids a relatively complicated arrangement which would necessitate several tubes and means for producing a saw-tooth voltage.

The features above set forth can be employed in combination for ensuring high speed static distribution of the impulses in a multi-ele mentary television receiver screen or in a multiplex telephony system.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eflicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims,

What I claim is:

1. In a system of the kind described, the combination of a single input channel carrying successive electrical impulses of different amplitudes and equal durations, a plurality of independent output channels, a gaseous discharge device having a cathode, at least one control electrode and a plurality of anodes, means connecting each of said anodes to a different one of said output channels, means for impressing on said anodes one at a time and in succession periodic voltage variations having sharp maxima, said voltage variations extending positively with respect to said cathode and means comprising said control electrode forv varying the time of current flow from each of said anodes to said cathode in response to said periodic voltage variations in accordance with the amplitudes of said impulses.

2. A system for distributing successive impulses from a single input channel to a plurality of independent output channels which comprises, in combination, a gas discharge tube including a cathode, at least one control grid and a. plurality of anodes connected with said independent output channels respectively, means for impressing on said anodes, at the frequency of the incoming impulses, periodical voltage variations with sharp maximums occurring successively in a predetermined order for the respective anodes, to bring said anodes successively into cooperating voltage relation with said cathode, and means, including at least said control grid and a generator of saw-tooth voltage variations connected with said grid, for varying the time at which the arc is struck in said tube in the course of each voltage variation period in accordance with the amplitude of the incoming impulse corresponding to this period.

3. A system for distributing successive impulses 11 grid I09 18 from a single input channel to a plurality of independent output channels which comprises, in combination, a gas discharge tube including a cathode. a control grid and a plurality of anodes connected with said independent output channels respectively, means for impressing on said anodes, at the frequency of the incoming impulses, periodical voltage variations with sharp maximums occurring successively in a predetermined order for the respective anodes, to bring said anodes successively into cooperating voltage relation with said cathode, an auxiliary control tube including a plate, a grid and a filament, means for impressing on said plate a sawtooth voltage of the same period as the above mentioned voltage variations, means for impressing on said last mentioned grid the voltage impulses from said input channel, and means for coupling the plate circuit of said auxiliary control tube with the grid circuit of said gas discharge tube, whereby the arc is struck in said last mentioned tube at a time in each period which varies in accordance with the amplitude of the impulse corresponding to this period.

4. In a system of the kind described, the combination of a single input channel carrying successive electrical impulses of different amplitudes and equal durations, a plurality of independent output channels, means for distributing successive ones of said impulses from said single input channel to successive ones of said output channels comprising a gaseous discharge tube having a cathode, a plurality of anodes and at least two control electrodes interposed in current flow controlling relation between said cathode and said anodes, means for impressing periodic positive voltage pulses on said anodes in succession and in synchronism with said electrical impulses, means for impressing on one of said grids a recurrent periodic saw-tooth voltage synchronized with said impulses, and means for impressing said electrical impulses on the other of said grids.

5. A system according to claim 2 in which said" generator of saw tooth voltage variations ispf the kind adapted to combine a fundamental sinusoidal oscillation with at least one harmonic thereof.

6. A system for distributing successive impulses from a single input channel to a plurality of independent output channels which com prises, in combination, a tube including a cathode and a plurality of anodes connected with said independent output channels respectively, means for impressing on said anodes, at the frequency of the incoming impulses, periodical voltage variations with sharp maximums occurring successively in a predetermined order for the respective anodes, to bring said anodes successively into cooperating voltage relation with said cathode, means for impressing the incoming voltage variations on said cathode, and means for imparting to each of said independent channels a voltage opposed in direction and proportional in magnitude to the instantaneous value of the corresponding impulse voltage, to compensate that induced in said independent channel by the capacity of said tube.

7. A system for distributing successive impulses from a single input channel to a plurality of independent output channcls which comprises, in combination, a tube including a cathode and a plurality of anodes connected with said independent output channels respectively, means for impressing on said anodes, at the frequency of the incoming impulses, periodical voltage variations with sharp maximums occurring successively in a predetermined order for the respective anodes, to bring said anodes successively into cooperating voltage relation with said cathode, means for rectifying the incoming voltage impulse variations and impressing the rectified voltage on .said cathode, a plurality of condensers each connected on one side to one of said independent channels, means for rectifying said incoming voltage impulse variations in opposition with said first mentioned rectifying means and impressing the rectified voltage thus obtained to the other sides of said condensers, to compensate the voltage induced in said independent channel by the capacity of said tube.

8. In a system of the kind described, the combination of a single imput channel for supplying successive electrical impulses of successively difi'erent amplitude and equal duration, a plurality of independent output channels for successive ones of said electrical impulses, a gaseous discharge device having a cathode, at least one control electrode, and a plurality of anodes, means connecting each of said plurality of anodes to a diilferent one of said output channels, means for impressing on each or said anodes, one at a time and in succession, a similar positive voltage pulse, and means comprising said at least one control electrode for controlling the duration of current flow from each of said anodes to said cathode in accordance with the amplitude of that one of said electrical impulses which occurs while that anode is subjected to one of said positive voltage pulses.

PIERRE MARIE GABRIEL TOULON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,932,606 Schramm Oct. 31, 1933 2,064,469 Haeff Dec. 15,1936 2,233,126 Haefl Feb. 25, 1941 2,307,188 Bedford 'Jan. 5,1943 2,403,210 Butement July 2, 1946 FOREIGN PATENTS Number Country Date 550,856 Germany May 23, 1932 497,367 Great Britain Dec. 19, 1938 523,363

Great Britain July 10, 1940

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