US2581442A - Electric pulse generator - Google Patents

Electric pulse generator Download PDF

Info

Publication number
US2581442A
US2581442A US15581A US1558148A US2581442A US 2581442 A US2581442 A US 2581442A US 15581 A US15581 A US 15581A US 1558148 A US1558148 A US 1558148A US 2581442 A US2581442 A US 2581442A
Authority
US
United States
Prior art keywords
gap
pulses
pulse
cathode
discharge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US15581A
Other languages
English (en)
Inventor
Reeves Alec Harley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US2581442A publication Critical patent/US2581442A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/38—Cold-cathode tubes
    • H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/04—Distributors combined with modulators or demodulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/04—Distributors combined with modulators or demodulators
    • H04J3/042—Distributors with electron or gas discharge tubes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1676—Time-division multiplex with pulse-position, pulse-interval, or pulse-width modulation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/007—Sequential discharge tubes

Definitions

  • the present invention relates to an electric pulse distributor or modulator circuit arrangement employing a cold cathode gas filled discharge tube.
  • An electric pulse distributing arrangement comprises a cold cathode gas discharge tube having a sequence of discharge gaps, means for applying a potential to each of the gaps of sufllcient magnitude to maintain a discharge thereacross, but insufiicient by itself to initiate a discharge, means for applying a pulse to fire the first gap of the sequence, the arrangements being such that the remaining gaps are conditioned by ionisation migration to fire spontaneously in turn at one at a time, and means for deriving output pulses from the gaps.
  • Fig. 1 shows a diagram of a pulse train which may be produced by the circuit arrangement according to the invention:-
  • Fig. 2 shows a schematic circuit diagram of an arrangement according to the invention.
  • FIG. 3 and 4 show minor modifications of Fig. 2
  • Fig. 1 This type of train is illustrated in Fig. 1. From this figure it can be seen that the signalling time is divided into a number of equal signalling periods by a train of regularly repeated pulses 0 having some characteristic by which they may be distinguished from the channel pulses, such, for example, as a larger amplitude, as indicated in Fig. 1. will be called "coded pulses for convenience, and they do not carry any signal. Three successive coded pulses II are shown in Fig. 1.
  • nel pulses are initially generated as trains of pulses having a repetition frequency the same as that of the coded pulses and are interleaved so that in each of the above mentioned signalling periods each pulse belongs to a different channel. l are shown in each of the two signalling periods which are shown in Fig. 1.
  • the time positions of the channel pulses are varied by the corresponding modulating signals so that the time spacing between the pulse I of channel I and the preceding coded pulse 0 depends only on the instantaneous voltage of the signal carried by channel I, and so that in the case of any channel pulse 2, the time spacing between that pulse 2 and the preceding pulse I depends only'on the instantaneous voltage of the signal carried by channel 2, and so on. It will be understood, of course, that there may be any number of channel pulses in each signalling period.
  • Fig. 1 the unmodulated positions of the channel pulses are shown by the dotted lines, and these positions should preferably be equally spaced between two successive coded pulses.
  • the channel pulses I, 2, 3. 4 are shown variously displaced in the signalling periods in accordance with the corresponding si nal volta es.
  • Fig. 2 emplovs a multigap cold cathode gas filled dischar e tube which as alreadv stated is of the tvpe described in the specification oi' co-pending U. S. Application No. 14.184/48. It comprises an anode I I! which consists of a long straight metal p ate. and arran ed opposite the anode are a p uralitv of similar metal cathodes consisting of short cvlinders, and forming t erewith a seouence of discharge gaps.
  • cathodes are equally spaced apart in a straight line and the first of them III is the starting cathode and the remainder are channel cathodes and are used for generating the channel pulses I, 2, 3 etc. Only the first two and the last of these are shown and are designated IIIA, H43 and IIlN. It will be understood that there is one of these channel cathodes for each channel oi the system.
  • the channel cathodes are all enually spaced from the anode H3. but the starting cathode III is preferably placed rather closer to the anode.
  • the starting cathode is connected to ground through an adjustable resistance IIS. and the channel cathodes are connected to ground through the secondary windings oi corresponding transformers IIBA, IIBB etc. and HON. Resistances II2A, II 23 etc. and
  • the anode H3 is connected through the primary winding of an output transformer II8 to the positive terminal II! for the high tension source, the corresponding negative terminal I being grounded.
  • the secondary winding of this transformer' is connected through a network consisting of a series rectifier I2I and two shunt resistances I22 and I23 to a pair of output termi-
  • the anode current which passes through the primary winding of the transformer I I8 increases abruptly by a constant amount, and since thetransformer acts as a differentiating device, a train of short pulses of one sign will be produced in the secondary winding of the transformer, which should be poled so that these output pulses will pass through the nals I24 which are connected to the line or other medium over which the pulses are to be transmitted.
  • a master pulse generator I25 generates two trains of short negative pulses having the same repetition frequency, of 10,000 pulses per second, for example.
  • the first of these trains comprises negative pulses of large amplitude (which will be called extinguishing pulses),' and is applied through the blocking condenser I26 to the anode I I3.
  • starting pulses moderate amplitude each of which occurs very shortly after the corresponding pulse of the first train and is applied over the blocking condenser I21 to the starting cathode Ill.
  • the master pulse generator I25 may be of any suitable known type and does not need detailed description.
  • the striking voltage of the gap corresponding to the cathode 'I MA may be lowered by 80 volts more than that corresponding to the next cathode IIlB is lowered. It follows that a short time after the discharge .from the cathode Ill has struck, a discharge will occur from the oathode I HA, but not from any of the other cathodes, becausethe striking voltage will not have been lowered sufllciently since they are further away.
  • cathode I HA acts 'in exactly the same way on the striking voltage correspondingto the next cathode 4B; and a discharge takes place from that cathode; 'It will be clear that the same process continues, each gap being fired shortly after the preceding gap until the last cathode I I 4N is reached.
  • the gaps will be fired in succession at substantially equally. spaced intervals of time, as soon as the discharge from the cathode .I I4 has been struck by the starting pulse.
  • extinguishingpulse which extinguishes all the gaps, and the tube is then ready for a fresh series of operations which commences with the starting pulse which immediately follows. Since this extinguishing pulse cuts off the current through the primary winding of the transformer, a short pulse of large amplitude but of opposite sign to the output pulses will be generated, and this is cut off by the rectifier I2I. However, it might be useful to transmit this large pulse for synchronising purposes, for example, and in that case the rectifier I2I and resistances I22 and I23 could be omitted.
  • the above mentioned output pulses will comprise the coded pulses 0 of Fig. 1, derived from the starting cathode Ill, and the channel pulses I, 2, 3, etc., derived in turn from the cathodes INA, 413, etc. and IIlN.
  • the minimum striking voltage of any particular cathode such a I B falls substantially uniformly with time when the preceding gap has been fired. Thecorresponding gap will therefore be fired when the striking voltage has fallen to the potential of the high tension source.
  • the initial conditions for the striking of the discharge from the first cathode I H may be conveniently adjusted by varying the resistance H5, which varies the rate of increase and final value of the corresponding current.
  • the gas mixture, pressure, and cathode gaps and spacings must of course be designed in accordance with the pulse spacings and time modulations desired.
  • An example is given below of design details of a tube suitable for generating a pulse train according to the present invention.
  • the repetition frequency of the coded pulses is assumed to be 10,000 pulses per second, and the time interval between any two adjacent pulses (Fig. 1) is assumed to be between 3 and 5 microseconds.
  • the details of the tube and its operation are as follows- Gas filling:
  • the tube shown in Fig. 2 has a flat straight anode plate and the cathodes are arranged in a straight line
  • the anode could be curved, and take other forms than that of a plate, and the cathodes could be arranged in other ways.
  • An improved control may also be obtained by the use of an extra cathode providing an additional priming gap across which a discharge is permanently maintained.
  • a priming gap should preferably be equidistant from the other cathodes, which therefore should be arranged in a circle with the extra cathode at the centre as shown diagrammatically, for example, in Fig. 3, which gives a plan view of a modification of Fig. 2. Elements not shown in Fig. 3 may be arranged exactly as in Fig. 2.
  • the use of a permanently discharging priming gap is described in thespecification of co-pending application No. 12086/47, now abandoned.
  • the anode H3 consists of a circular metal disc, and the necessary number of cathodes H4 are arranged concentrically therewith, and with the proper spacing therefrom. as already explained.
  • the extra cathode I28 is shown in the centre, and is connected through an adjustable resistance I29 and an additional voltage source I30 to terminal I2ll.
  • the cathodes H4 are supposed to be connected as shown in Fig- 2.
  • the extra cathode is so spaced from the anode H3 that a discharge takes place permanently therefrom.
  • the additional source is connected to augment the operating voltage for this cathode, and should be of such voltage that the dis-: charge is not extinguished by the extinguishing pulse applied through condenser anode H3.
  • the general ionisation level of all the other cathodes may be varied.
  • An increase in the general ionisation level has four principal effects on the other gaps:
  • Eifect No. 3 is very useful as it is desirable to reduce the extinguishing time in order to obtain the maximum channel space, and effect No. 4 is one factor which determines the relation between the signal voltage and the resulting time modulation, and can be used to adjust this relation.
  • Fig. 4 shows a slight. modification of the arrangement of Fig. 3.
  • the extra cathode I28 is provided with a corresponding extra anode I3I which is connected separately to the positive hi h tension terminal H9.
  • the additional source I 30 shown in Fig. 3 is then unnecessary, since the extinguishing pulses will not affect the .extra anode.
  • the anode H3 has been shown in the form of an annular disc, and the extra anode I3I is a centrallyplaced circulardisc insulated from the anode H3.
  • the ionisation level may be adjusted by means of the resistance I29.
  • the last of the channel cathodes. IMN should be well separated from the starting cathode H4, as indicated, to prevent it from being appreciably affected by the ionisation from the starting gap, so that premature firing of the last gap is avoided.
  • the arrangement shown in Fig. 2 may be adapted to operate as a pulse distributor for a multi-channel timephase modulation pulse communication system, for example.
  • the transformer H8 may be omitted, the anode I I3 being connected directly to terminal H9.
  • the remaining gaps are fired in turn at regular intervals and each therefore generates a short pulse which may be obtained from the corresponding transformer HIA, I I'IB, etc. and I I'IN.
  • transformers may therefore be connected to corresponding pulse time phase modulators (not shown) of conventional pattern instead of to the signal sources, and corresponding modulated trains of pulses may be obtained from these modulators properly timed for interleaving in the usual way.
  • the cathode H4 may be provided with a corresponding transformer (not shown) in order to obtain the coded pulses which define the signalling periods.
  • a distributor of this kind may be used to provide the gating pulses at the receiver of a multi channel time phase modulation system.
  • An electric pulse' modulator comprising a discharge device having a discharge gap, means for gradually lowering the resistance or said gap, means for applying a voltage to said gap while said resistance is being lowered to a value suificient to cause said gap to fire when the resistance has reached a predetermined level, means for applying a signal voltage to said gap for varying the effective voltage on said gap and the time or firing thereof, and means responsive to the firing of said gap for deriving an output pulse.
  • said discharge device is a gaseous discharge tube and said means for gradually lowering the resistance of said gap comprising a priming discharge gap, means for firing said priming gap,
  • said priming gap being arranged adjacent said first mentioned gap so that the ionization pro- .duced by the firing of the priming gap gradually migrates toward said first mentioned gap and gradually lowers its resistance.
  • a modulator according to claim 3 further including means for extinguishing said gap discharges.
  • a multichannel pulse modulation system comprising a discharge device including a plurality of successive discharge gaps arranged so that the resistance of each gap is gradually lowered upon the firing of its preceding gap, means .for firing the first gap, means for applying a voltage to each of the other gaps while said resistance is being gradually lowered to a value sufllcient to ca the firing of each of said other gaps at a predetermined time after the firing of its preceding gap, means for applying ing to claim 5, wherein said discharge device is 8 a gaseous discharge tube and said gaps are arranged adjacent each other so that the ionization produced by the firing o! a given gap gradually migrates to the next succeeding gap and lowers the resistance thereof.
  • a multichannel pulse modulation system in whichiall said other gaps have one electrode in common and said output pulses are derived from the common electrode.
  • cording to claim 5 in which all said other gaps have a common anode, further including means eliminating the extinguishing pulse from.
  • a multichannel pulse modulation system comprising a discharge device including a plurality of successive discharge gaps arranged so that the resistance of each gap is gradually, lowered upon the firing 01' its preceding gap, means for firing the first gap, means for applying a voltage to each 01' the other gaps while said resistance is being gradually lowered to a value sumcient' to cause the firing of each of said other gaps at a predetermined time after the firing of its preceding gap, means for applying signal voltages of different channels to each of said other gaps to vary the efiective voltage thereacross and their time of firing with respect to their preceding gaps, and means for deriving output pulses from the firing 01' said other gaps, all said other gaps having one electrode in common, said output pulses being derived from the common electrode, and said means for deriving output pulses from the firing of said other gaps comprising an output transformer having its primary arranged in series with said common electrode.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Lasers (AREA)
  • Particle Accelerators (AREA)
  • Gas-Filled Discharge Tubes (AREA)
US15581A 1947-03-20 1948-03-18 Electric pulse generator Expired - Lifetime US2581442A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7723/47A GB660253A (en) 1947-03-20 1947-03-20 Improvements in or relating to electric pulse generators

Publications (1)

Publication Number Publication Date
US2581442A true US2581442A (en) 1952-01-08

Family

ID=9838524

Family Applications (1)

Application Number Title Priority Date Filing Date
US15581A Expired - Lifetime US2581442A (en) 1947-03-20 1948-03-18 Electric pulse generator

Country Status (5)

Country Link
US (1) US2581442A (enrdf_load_stackoverflow)
CH (1) CH269005A (enrdf_load_stackoverflow)
ES (1) ES183294A1 (enrdf_load_stackoverflow)
FR (1) FR963489A (enrdf_load_stackoverflow)
GB (1) GB660253A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744159A (en) * 1950-02-28 1956-05-01 Int Standard Electric Corp Multiplex electric signalling system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1863278A (en) * 1929-10-07 1932-06-14 Communications Patents Inc System and apparatus for the electrical production of images
US2088474A (en) * 1934-08-08 1937-07-27 Westinghouse Electric & Mfg Co Translating apparatus
US2404920A (en) * 1940-09-27 1946-07-30 Research Corp Electronic discharge apparatus
US2443407A (en) * 1947-06-18 1948-06-15 Jr Nathaniel B Walcs Gaseous discharge device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1863278A (en) * 1929-10-07 1932-06-14 Communications Patents Inc System and apparatus for the electrical production of images
US2088474A (en) * 1934-08-08 1937-07-27 Westinghouse Electric & Mfg Co Translating apparatus
US2404920A (en) * 1940-09-27 1946-07-30 Research Corp Electronic discharge apparatus
US2443407A (en) * 1947-06-18 1948-06-15 Jr Nathaniel B Walcs Gaseous discharge device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744159A (en) * 1950-02-28 1956-05-01 Int Standard Electric Corp Multiplex electric signalling system

Also Published As

Publication number Publication date
ES183294A1 (es) 1948-06-01
CH269005A (de) 1950-06-15
FR963489A (enrdf_load_stackoverflow) 1950-07-11
GB660253A (en) 1951-11-07

Similar Documents

Publication Publication Date Title
US2428149A (en) Impulse generator
US2403210A (en) Multiplex pulse modulation system
US2645680A (en) Pulse distributor, including electric discharge devices
US2516888A (en) Sequential gating system utilizing incrementally delayed and undelayed pulse trains of different frequencies
US2551101A (en) Electrical ignition system
US2076335A (en) Selecting device
US2581442A (en) Electric pulse generator
US2554886A (en) Synchronizing circuit for electrical commutators
US2462100A (en) Demodulator system for time modulated pulses
US2511595A (en) High-frequency pulse generator
US2137039A (en) Method and apparatus for communication by television
US2601096A (en) Modulator
US2537843A (en) Pulse regeneration apparatus
US2595301A (en) Line pulse modulator
US2427500A (en) Cathode-ray tube modulator in a pulse multiplex transmitter
US2520171A (en) Electric discharge device
US2614210A (en) Pulsed radio signaling
US2534261A (en) Line pulse modulator
US2645742A (en) Electric discharge device
US2955263A (en) Thyratron modulator for short pulse radar and the like
US2521710A (en) Pulse time demodulator system
US2593486A (en) Electric discharge tube
GB699889A (en) Improvements in gating arrangements for pulse amplitude modulation time division multiplex signalling systems
US2597038A (en) Two-way electric pulse communication system
US2629856A (en) Ptm modulator and demodulator system