US2143932A - Method of synchronizing cathode beams - Google Patents

Method of synchronizing cathode beams Download PDF

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Publication number
US2143932A
US2143932A US2039A US203935A US2143932A US 2143932 A US2143932 A US 2143932A US 2039 A US2039 A US 2039A US 203935 A US203935 A US 203935A US 2143932 A US2143932 A US 2143932A
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United States
Prior art keywords
condenser
voltage
discharge
impulses
tube
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Expired - Lifetime
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US2039A
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English (en)
Inventor
Barthelemy Rene
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Compteurs Schlumberger SA
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Compteurs Schlumberger SA
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H04N5/067—Arrangements or circuits at the transmitter end
    • H04N5/073—Arrangements or circuits at the transmitter end for mutually locking plural sources of synchronising signals, e.g. studios or relay stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/12—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising
    • H04N5/123—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising whereby the synchronisation signal directly commands a frequency generator

Definitions

  • variable voltages applied between two pairs of parallel plates called the deflector plates of the cathode tube, the two pairs of plates being perpendicular to oneanother.
  • Two synchronizing channels are then utilized for the movement of the beam: one synchronizing channel for the electrodes of the rapid displacement and one synchroninizing channel for the electrodes of the slow displacement.
  • the rapid movemen it is known to produce and to utilize a rapid impulse of large amplitude at the end of each line ,of analysis.
  • Various processes can be utilized for the synchronization of the slow movement, that is to say, in order to produce at the receiver the swinging over of the variable voltage governing the slow displacement, or, in other words, in order to return the beam from the last line of the screen to the first line. so
  • the method of my invention enables me to dispense with the use of two synchronizing channels and to use but a single channel for synchronization.
  • the novel method consists essentially in rendering inoperative at the transmitter, at least 3:, once for each image, the signal produced at the end of the lines or to not produce a signal at the end of at least one line per image.
  • Such a discharge tube is a gas, or vapor filled tube in which the control electrode can normally only start the discharge or prevent it from starting, but which can regain control if the anode voltage 5 is momentarily reduced below a critical value.
  • this type of electric discharge tube is called "gas tube.
  • Figures 3 and 4 are graphs of the voltage of one of the condensers used in the apparatus as a. function of the time variation.
  • 5 1 In Figure 5 is shown-another method of coupling the two discharge tubes used in the device shown in Figure 2.
  • the variable voltage to be applied to each of the pairs of plates of the cathode tube is obtained by the charging of a condenser which is periodically discharged.
  • the voltage curve of a condenser during the period of charging, as a function of time is a curve as shown in Figure 1 and having as its asymptote the straight line ordinate U, U being the voltage of the source charging the condenser.
  • U being the voltage of the source charging the condenser.
  • the beginning only of the curve is used in order that the same may assume the form of a straight line-The voltage of the condenser will not be allowed to attain, for example, a value greater than about one-tenth of U.
  • the same is inserted in the anode circuit of a gas tube.
  • the discharge is produced by the application of a suitable voltage to the control grid of this discharge tube.
  • the process according to the present invention consists in producing the discharge of the condenser controlling the rapid movement by the application to the grids of its gas tube of an impulse produced by a signal sent out at the end of the each line except at the end of the penultimate line of analysis or at the end of several consecutive lines preceding the last line.
  • the suppression of the signal enables the condenser controlling the rapid-movement to attain at the end of the last line a voltage greater than that which it attains at the end of the other lines.
  • This greater voltage attained by the rapid movement condenser is utilized in order to give to the grid of the gas tube of the slow movement condenser a voltage such that-a discharge of this second condenser is produced.
  • the signals sent out at the end of each line of analysis by the transmitter produce impulses at the line frequency,-which impulses are fed to the ends of a resistance I through the intermediary of 5 a regulating device 2, which may be as described in my Patent No. 1,940,161, dated December 19, 1933.
  • the resistance I is inserted in the circuit of the control electrode 3 of a gas tube 4 which also comprises at least a cathode 5 and an anode i.
  • the electrode 3 is polarized by a source I.
  • a condenser 8 of which the terminals are connected to the two rapid movement plates 8 and 9 of the cathode tube, is inserted in the anode circuit 6 of the gas tube 4.
  • the condenser 8 can be charged by a source ll of electro-motive force U through the intermediary of a resistance l2.
  • the condenser 8 charges itself and the curve of its voltage as a function of time is of the form shown in Figure 1.
  • the source I is such that when an impulse is impressed upon the grid 3, the discharge is set up in the gas tube 4.
  • the condenser 8, which has attained a voltage u is sharply discharged.
  • the impulse received by the electrode 3 being almost instantaneous, the condenser 8 immediately recommences to charge itself.
  • the curve representing its voltage as a function of time during the sweeping of an image can be represented by Figure 3.
  • the voltage u is sufliciently small to ensure that the portions of the charging curve of the condenser 8 can be assumed to be straight lines.
  • the voltage of the condenser 8 continues to increase.
  • the condenser 8 will have a voltage of about 214 substantially double the voltage attained during the discharge ?at the end of the other lines. A more violent discharge will then take place at the end of the last line.
  • the curve of the voltages of the condenser 8 as a function of time during the passage from bne image to the next is of the form shown in Figure 4.
  • the cathode beam the displacements of which are substantially proportional to the voltages applied across the plates 8 and I0, is projected outside of the screen during the scanning of the last line at the transmitter. No useful purpose will then be served by modulating this last line.
  • a second condenser it of which theterminals are connected to the two slow movement plates l4 and i5, is inserted in the circuit of the anode l6 of a second gas tube 11 having moreover at least a cathode l8 and a control electrode Ill.
  • the condenser l3 can be charged from a source 20 of electro-motive force U through the intermediary of a resistance 2
  • the circuit of the control electrode IQ of th: gas tube I1 is coupled to the circuit of the anode 6 of'the gas tube 4 by a device 22.
  • a device 22 can be in the form of two inductances coupled electro-magnetically or in the form of a transformer, as is shown in Figure 2, or in the form cf a condenseras is shown in Figure 5.
  • 'I'he'electrode I9 is polarized by a source 23 in such a manner that a discharge is produced in the gas tube I! when the condenser 8 attains the voltage 2u.
  • the anode current set up by the discharge of the condenser 8 having attained the voltage 211 induces in the circuit of the electrode I! a voltage such that a discharge of the condenser I3 is produced to return the beam from the last line of the screen to the first line.
  • the apparatus is adjusted in such a manner that the voltage induced in the circuit of the electrode I9 upon the discharge of the condenser 8 charged to u is insumcient to set up the discharge of the condenser I! through the gas tube l1.
  • the coupling of the two gas tubes by inductances presents an advantage.
  • the discharge of the condenser 8 being very rapid, which corresponds to a very high frequency for the discharge current, it is suflicient to have a very feeble inductive coupling between inductances of a few turns.
  • This coupling is inoperative for the lower frequency and hence operates as a protection for the gas tube I1.
  • the electromotive force which occurs in the inductive couplings, is, due to the great velocity in variation of the discharge current, of relatively substantial magnitude despite the small number of turns of these inductances.
  • Method for controlling by a single series of signals the periodic discharge of two condensers each of which is progressively recharged by a source of current during the full time interval separating two of its consecutive discharges consisting in controlling the successive discharges of the first condenser by successive electric impulses, arranging said impulses in groups separated by a time interval greater than the interval separating two successive impulses of the same group whereby said first condenser acquires at the end of the interval separating two groups a voltage greater than the voltage attained at the end of the interval separating two successive impulses of the same group, and utilizing said greater voltage to control the discharge of the second condenser.
  • Apparatus for the periodic discharge of two condensers comprising means “for progressively recharging each condenser during all the time interval separating two of its successive discharges, a source of electric impulses supplying groups of successive impulses, said groups of impulses being separated by a time interval greater than the interval separating two successive impulses of the same group, a first d scharge tube comprising an anode and a control electrode and the circuit of said anode comprising the first condenser, means for applying to the control electrode of said discharge tube the said impulses for the purpose of discharging the first condenser at each of said impulses, a second discharge tube comprising an anode and a control electrode and the circuit of said anode comprising the second condenser, and means for controlling the voltage of the control electrode of the second tube by the intensity of the discharge of the first condenser whereby the discharge of the second condenser is produced at the end of the interval separating two successive groups of impulses.
  • a method of synchronizing the beam of a cathodic oscillograph comprising two pairs of defiecting plates connected respectively to the terminals. of two condensers each condenser being periodically discharged, then progressively recharged by a source of current during the whole time interval separating two of its successive discharges, said method consisting in controlling the successive discharges of the first condenser by successive electric impulses, arrangingsaid impulses in groups separated by a time interval greater than the interval separating two successive impulses of the same group whereby said first condenser acquires at the end of the interval separating two groups a voltage greater than the voltage it attains at the end of the interval separating two successive impulses of the same group, utilizing said greater voltage to control the discharge of the second condenser, applying the voltage of said first condenser to one pair of deflecting plates to control the cathode beam in one direction, and applying the voltage of the second condenser to the second pair of deflecting plates 'from a transmitter, comprising a first con
  • said signals comprising groups of successive impulses the time interval separating two successive groups being greater than the interval separating two successive impulses of the same group, means for dischargingv the first condenser at each of the impulses, and means controlled by the intensity of the discharge of the first condenser for discharging the second condenser at the end of the interval separating two successive groups of impulses, said means for charging said two condensers'recharging each condenser progressively during the whole time interval separating two of its successive discharges.
  • Apparatus for synchronizing the beam of the cathodic oscillograph of an image receiving apparatus by means of synchronizing signals sent out from a transmitter comprising a first condenser connected to the plates controlling the rapid movement of the cathodic beam, a second con-' denser connected to the plates controlling the slow movement of said beam, means for charging said two condensers, means for receiving the signals of synchronization transmitted by the transmitters said signals comprising groups of successive impulses the time interval separating two successive groups being greater than the interval separating two successive impulses of the same group, a first discharge tube comprising an anode and a control electrode the circuit of said anode comprising the first condenser means for applying said impulses to the control electrode of said discharge tube to discharge the first condenser at each of said impulses, a second discharge tube comprising an anode and a control electrode the circuit of which anode comprises the second condenser, and means to control the voltage of the control electrode of the second tube by the discharge of the first conden
  • a device comprising two coupled inductances as coupling means between the anode circuit of the first tube and the control electrode circuit of the second tube.
  • a device comprising a third condenser as couplirv, means between the anode circuit of the first tube and the control ENE BARTHEIEMY.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Particle Accelerators (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US2039A 1934-04-10 1935-01-16 Method of synchronizing cathode beams Expired - Lifetime US2143932A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR45317T 1934-04-10

Publications (1)

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US2143932A true US2143932A (en) 1939-01-17

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Country Status (4)

Country Link
US (1) US2143932A (enrdf_load_stackoverflow)
FR (2) FR780779A (enrdf_load_stackoverflow)
GB (1) GB432783A (enrdf_load_stackoverflow)
NL (1) NL41739C (enrdf_load_stackoverflow)

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Publication number Publication date
FR45317E (fr) 1935-07-22
GB432783A (en) 1935-08-01
NL41739C (enrdf_load_stackoverflow)
FR780779A (fr) 1935-05-03

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