US2440418A - Cathode-ray beam deflecting circuit - Google Patents

Cathode-ray beam deflecting circuit Download PDF

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Publication number
US2440418A
US2440418A US653261A US65326146A US2440418A US 2440418 A US2440418 A US 2440418A US 653261 A US653261 A US 653261A US 65326146 A US65326146 A US 65326146A US 2440418 A US2440418 A US 2440418A
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US
United States
Prior art keywords
current
voltage
tube
condenser
inductor
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
US653261A
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English (en)
Inventor
Simeon I Tourshou
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.)
RCA Corp
Original Assignee
RCA Corp
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Filing date
Publication date
Priority to NL130803D priority Critical patent/NL130803C/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US653261A priority patent/US2440418A/en
Priority to FR942512D priority patent/FR942512A/fr
Priority to GB6545/47A priority patent/GB646779A/en
Application granted granted Critical
Publication of US2440418A publication Critical patent/US2440418A/en
Priority to DER1575A priority patent/DE974781C/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K4/00—Generating pulses having essentially a finite slope or stepped portions
    • H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
    • H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
    • H03K4/10—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only
    • H03K4/26—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth current is produced through an inductor
    • H03K4/28—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth current is produced through an inductor using a tube operating as a switching device

Definitions

  • the present invention relates to television systems in which the electron scanning beam of a cathode ray tube is electromagnetically deflected cyclically to eect the reproduction of an image, and more particularly relates to means for overcoming such distortion of the image as results from non-linear deiiection of the scanning beam.
  • Television systems of the above type frequently include a horizontal, or line, deflection circuit in which one or more power output tubes are connected to supply cyclically varying current through a coupling transformer to suitable beam deflection coils which are associated with the cathode ray image producing tube.
  • a so-called damper tube usually a diode or in some instances also a triode, shunted across the beam deflection coils.
  • the energy stored in the circuit inductance during the retrace periods of the cathode ray scanning beam causes a current iiow through the damper tube during scansion.
  • This current theoretically may be combined with the current output of the power tube or tubes toa summation characteristic which is linear with respect to time.
  • the theoretically linear summation current thus produced is that which actually flows through the beam deflection coils thereby to bring about a substantially uniform angular deflection of the cathode ray beam at line-scanning frequency.
  • a damper tube of the nature set forth above does not always completely remove the high-frequency oscillations which occur immediately following retrace, and that these high-frequency oscillations, if present, cause a number of vertical bands, or bars, to appear near one side of the image raster, with resulting distortion of the image in this region.
  • These high-frequency oscillations and the eiects thereof may be materially reduced by the use of additional damping means, such as a series 'resistance-condenser combination, acting in parallel with the damper tube circuit.
  • the voltage across the beam deection coils during scansion 1 may be maintained relatively constant. As a consequence, substantial linearity of scan is obtained.
  • One object of the present invention is to provide, in a television system in which a cathode ray scanning beam is electromagnetically deflected, means for causing such deection to occur at a. substantially linear rate with respect to time.
  • Another object of the invention is to provide, in a, television system of the nature set forth, means forl reducing the amplitude of the highfrequency oscillations which occur following retrace, and additionally to prevent the use of such means from aecting the linearity of scan near the end of the trace portion of each deflection cycle.
  • a further object of the invention is to provide, in connection 'with a television circuit of the nature set forth, which includes a damper tube, means whereby the ow of current through such damper tube may be controlled through the application thereto of a voltage which varies as a function of the current output of the power tube, and also to provide means for controllably delaying the phase of this voltage.
  • Fig. 1 is a circuit diagram of a preferred embodiment of the present invention
  • Figs. 2 and 3 are sets of waveform-s useful in explainingfthe operation of the circuit of Fig. 1;
  • Figs. 4 and 5 are modifications of the circuit of Fig. 1.
  • a television' deflection and high-voltage rectifier circuit which includes a horizontal power output tube I 0.
  • Power tube IIJ is adapted to supply, when voltage variations which may have a waveform such as indicated by the reference character I2 are applied to the control electrode thereof, cyclically varying current to a. pair of horizontal, or line. cathode ray beam deection coils I 4 through a coupling transformer I6.
  • Transformer I6 is provided with a primary winding I8, a step-up winding 20 forming in eiiect an extension of the primary winding I8,
  • This secondary cathode ray beam deflection coils I4 which, together with a pair of vertical, or ileld, deflection coils 24 preferably form part of a. yoke assembly encircling the neck of a cathode ray imagereproducing tube or kinescope 26.
  • the vertical cathode ray beam deflection coils 24 are energized by sawtooth current of field-scanning fre# quency from a deflection generator 28, which may be of any suitable design. It will not, therefore. be described in detail.
  • the current in the deilection coils I4 and transformer I6 does not disappear at the instant of cut-off of tube I0, however, due to the inherent distributed capacity of the circuit. This distributed capacity, at the instant of the beginning of retrace, is charged to a relatively low voltage.
  • the polarity of the voltage applied to the anode of the damper tube 40 immediately following retrace is such as to cause the damper tube 40 to conduct.
  • the waveform of the normal current ilow through tube 40 may be such as indicated 4 in Fig. 2 by the solid-line waveform portion 66.
  • the condenser 42 is chosen to be of relatively low value, and a resistor 52 is employed in parallel with the damper tube 40.
  • the R.C. combination 52, 42 is thus also shunted across the secondary transformer winding 22, and, together with the damper tube circuit 40, 42, results in substantially complete elimination of the highfrequency oscillations which normally are produced in the manner set forth above.
  • the upper plate (in the drawing) of condenser 42 is connected to the upper plate of a further condenser 58 through a variable inductance 60.
  • the lower plates of the two condensers 42 and 56 are Joined together.
  • the primary winding I8 of transformer I6 is connected to ⁇ condenser 58 in such a manner that when the plate current of power tube I0 varies duringscansion, as shown by the curve portion 36 in Fig.'2,ra.”varying voltage will be developed across condenser 58.
  • the waveform of this varying voltage may be such as indicated by the reference character 62 in Fig, 3. 'Ihe positive peak 63 o1' this voltage waveform 62 occurs substantially at the mid-point in the scanning portion of the deilection cycle.
  • the voltage thus developed across condenser 58 is applied to condenser 42 through the variable inductance 66.
  • the effect of inductance 60 on the voltage waveform 62 is to delay the occurrence of the positive peak 63 of the wave.
  • the voltage across condenser 42 may, therefore,
  • the amount by which the instant of occurrence of the positive peak 63 of wave 64 may be delayed is controllable by varying the value oi inductance Bil.
  • This inductance 60 may beofany suitable type such, for example, as a permeability-tuned inductor. Normally, the value of inductance 60 is selected so as to compensate for the non-linearity of scan introduced through the use of the R.-C. combination 52, 42, but it may also be selected so as to compensate for non-linearity which would otherwise result from an improper matching of damper tube current and power tube current as shown in Fig. 2.
  • the present invention is useful in overcoming non-linearity which is inherent in wide-angle kinescopes the faces of which are either ilat or substantially so. This is due to the fact that movement of the electron scanning beam across the surface of such fiatfaced kinescopes is a tangential function of the angular deflection of the beam.
  • the anode of the power output tube Ill is connected to the B+ terminal in Figa-1 through a D. C. path which includes the primary Winding I 8 of transformer I6, the inductance B0, the resistor '52, and the secondary transformer winding 22.
  • the voltage developed on the capacitor B2 during operation of the system is of such polarity as to increase, or boost the voltage of the power source connected to the said B+ terminal.
  • the energy thus recovered from the secondary circuit may be utilized to obtain greater scanning power in the manner set forth, for example, in a copending United States patent application of Otto H. Schade, Serial No. 593,161, led May 11, 1945, or in a copending United States patent application of Charles E. Torsch, Serial Number 610,368, filed August 11, 1945.
  • the power source connected to the said B+ terminal may be reduced in value by an amount substantially equal to the value of the energy recovered, while maintaining the same scanning output.
  • Figs. 4 and 5 show modications of the circuit of Fig. 1.
  • the inductor 60 is of fixed value, and a pair of additional variable inductors 66 and 68 are employed, the inductor 66 being eiectively in series with the capacitor 42, as
  • a second tap 10 on inductor Il has connected to it the lead from primary winding i8 of transformer i6, so that another portion oi' the inductor 60 is eifectively in series with capacitor IB.
  • a power output tube is adapted to deliver cyclically varying current through a coupling transformer to the electromagnetic beam deilection means associated with a cathode ray tube wherein an electron beam is developed and then deiiected by the passage of said current through said deflection means so as, to scan a target area
  • means, including a diode are provided in shunt with said coupling transformer for damping out oscillations which would normally be produced during a portion of each current cycle in part by the inductance of said coupling transformer and said deection means
  • phase-delaying means is adjustable to vary the delay interval.
  • FIG. 5 utilizes the adjustable inductor 60 of Fig.. 1, but illustrates the manner in which the cathode of damper tube 40 may be connected to a tap on this inductor so a permeability-tuned inductor.
  • the means for deecting said electron beam includes means for generating a cyclically varying current, at least one deflection coil associated with said cathode ray tube, means i'or coupling said generating means to said deilection coil, and means including a two-element electron discharge device for damping out undesired voltage oscillations produced across said deflection coil, the combination of means for developing a voltage which varies as a function oi' variations in the current output of said generating means, means for altering the Waveform of the said 'developed voltage, and means for applying the voltage the waveform of which has been so altered to one element of the said two-'element electron discharge device.
  • waveform-altering means comprises means for delaying the phase of said developed voltage.
  • a damper tube having at least an anode and a cathode, and a first condenser connected in series across said pair o: deiiection coils so as to reduce the amplitude of oscillations which would normally be produced during a portion of each deiiection cycle in part by the inductance of said coupling transformer and said deflection coils
  • a further condenser means for connecting said further condenser to the primary winding of said coupling transformer so as to develop across said further condenser a voltage which varies as a function oi variations in the current flow through said primary winding, an inductor
  • a television system according to claim 7, further comprising means for varyingthe value of said inductor.
  • a television system according to claim '7, fui'- ther comprising an impedance element connected in parallel relation with said damper tube so as to further reduce the amplitude of said oscillations.
  • a diode having an anode and a cathode the anode of said diode being connected to one end of said cathode ray beam deflection coil, a iirst condenser, a second condenser, one plate of each of said condensers being connected to the remaining end of said cathode ray beam deiiection coil.
  • an inductor means for connecting the ends of said inductor between the remaining plates of said rst and second condensers, means for connecting the cathode of said diode to a tap on said inductor, and means for connecting said inductive coupling member to a further tap on said inductor.

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  • Details Of Television Scanning (AREA)
US653261A 1946-03-09 1946-03-09 Cathode-ray beam deflecting circuit Expired - Lifetime US2440418A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL130803D NL130803C (en, 2012) 1946-03-09
US653261A US2440418A (en) 1946-03-09 1946-03-09 Cathode-ray beam deflecting circuit
FR942512D FR942512A (fr) 1946-03-09 1947-02-27 Perfectionnements aux systèmes de déviation du pinceau électronique dans des tubes à rayon cathodique
GB6545/47A GB646779A (en) 1946-03-09 1947-03-08 Improvements relating to beam-deflecting circuits for cathode ray tubes
DER1575A DE974781C (de) 1946-03-09 1950-04-25 Strahlablenkschaltung fuer Fernsehbildroehren

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US653261A US2440418A (en) 1946-03-09 1946-03-09 Cathode-ray beam deflecting circuit

Publications (1)

Publication Number Publication Date
US2440418A true US2440418A (en) 1948-04-27

Family

ID=24620131

Family Applications (1)

Application Number Title Priority Date Filing Date
US653261A Expired - Lifetime US2440418A (en) 1946-03-09 1946-03-09 Cathode-ray beam deflecting circuit

Country Status (5)

Country Link
US (1) US2440418A (en, 2012)
DE (1) DE974781C (en, 2012)
FR (1) FR942512A (en, 2012)
GB (1) GB646779A (en, 2012)
NL (1) NL130803C (en, 2012)

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2474474A (en) * 1947-02-25 1949-06-28 Rca Corp Power recovery circuit for cathoderay apparatus deflection systems
US2476164A (en) * 1947-04-21 1949-07-12 Hartford Nat Bank & Trust Co Circuit arrangement for generating a sawtooth-shaped current in a coil
US2494241A (en) * 1946-04-17 1950-01-10 Hartford Nat Bank & Trust Co Circuit arrangement producing a direct voltage for supplying a cathode-ray tube
US2512400A (en) * 1948-09-21 1950-06-20 Rca Corp Television horizontal deflection
US2524530A (en) * 1946-12-14 1950-10-03 Pye Ltd Scanning circuits particularly for television apparatus
US2536838A (en) * 1949-05-24 1951-01-02 Rca Corp High-efficiency cathode-ray beam deflection system
US2536839A (en) * 1949-05-24 1951-01-02 Rca Corp Power recovery cathode-ray beam deflection system
US2543720A (en) * 1949-08-10 1951-02-27 Rca Corp Electromagnetic deflection circuit
US2543305A (en) * 1949-12-16 1951-02-27 Avco Mfg Corp Circuit for suppressing undesired oscillations in television receivers
US2543831A (en) * 1948-02-10 1951-03-06 Belmont Radio Corp Protection of cathode-ray tube screens
US2545346A (en) * 1950-03-22 1951-03-13 Avco Mfg Corp Automatic frequency control for television receivers
US2555827A (en) * 1948-10-26 1951-06-05 Rca Corp High-voltage power supply
US2565392A (en) * 1949-04-16 1951-08-21 Tele Tone Radio Corp Horizontal deflection circuit
US2574245A (en) * 1948-09-17 1951-11-06 Pye Ltd Apparatus incorporating a cathoderay device, particularly television receivers
US2579014A (en) * 1947-12-04 1951-12-18 Motorola Inc Saw-tooth current generator
US2587420A (en) * 1948-08-31 1952-02-26 Rca Corp Linearity control for cathode-ray tubes
US2599798A (en) * 1950-01-13 1952-06-10 Avco Mfg Corp Linearity control circuit for television receivers
US2611106A (en) * 1949-07-20 1952-09-16 Motorola Inc Television sweep system
US2621309A (en) * 1948-04-09 1952-12-09 Emi Ltd Circuits for producing saw tooth currents
US2621237A (en) * 1948-11-24 1952-12-09 Emi Ltd Electron discharge tube circuits for generating electrical oscillations of saw-tooth wave form
US2621308A (en) * 1949-03-31 1952-12-09 Rca Corp Electronic tube and circuits
US2627051A (en) * 1950-08-29 1953-01-27 Rca Corp Electron tube voltage protection circuit
US2644103A (en) * 1951-12-11 1953-06-30 Motorola Inc Television deflection system
US2702875A (en) * 1951-03-09 1955-02-22 Zenith Radio Corp Deflection system
US2702874A (en) * 1950-12-13 1955-02-22 Zenith Radio Corp Deflection system
US2837692A (en) * 1953-08-19 1958-06-03 Rca Corp Cathode ray beam deflection apparatus
DE977115C (de) * 1951-12-19 1965-03-11 Philips Nv Zeilenablenkschaltung fuer Elektronenstrahlroehren
US3733513A (en) * 1969-04-30 1973-05-15 Hunt Electronics Co Circuits for centering pictures on television screens

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251851A (en) * 1939-06-16 1941-08-05 Philco Radio & Television Corp Electron-beam deflecting circuit
GB534705A (en) * 1939-09-18 1941-03-14 Philco Radio & Television Corp Improvements in deflecting output circuits for cathode ray tubes
US2382822A (en) * 1942-06-30 1945-08-14 Rca Corp Cathode ray beam deflecting circuits

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2494241A (en) * 1946-04-17 1950-01-10 Hartford Nat Bank & Trust Co Circuit arrangement producing a direct voltage for supplying a cathode-ray tube
US2524530A (en) * 1946-12-14 1950-10-03 Pye Ltd Scanning circuits particularly for television apparatus
US2474474A (en) * 1947-02-25 1949-06-28 Rca Corp Power recovery circuit for cathoderay apparatus deflection systems
US2476164A (en) * 1947-04-21 1949-07-12 Hartford Nat Bank & Trust Co Circuit arrangement for generating a sawtooth-shaped current in a coil
US2579014A (en) * 1947-12-04 1951-12-18 Motorola Inc Saw-tooth current generator
US2543831A (en) * 1948-02-10 1951-03-06 Belmont Radio Corp Protection of cathode-ray tube screens
US2621309A (en) * 1948-04-09 1952-12-09 Emi Ltd Circuits for producing saw tooth currents
US2587420A (en) * 1948-08-31 1952-02-26 Rca Corp Linearity control for cathode-ray tubes
US2574245A (en) * 1948-09-17 1951-11-06 Pye Ltd Apparatus incorporating a cathoderay device, particularly television receivers
US2512400A (en) * 1948-09-21 1950-06-20 Rca Corp Television horizontal deflection
US2555827A (en) * 1948-10-26 1951-06-05 Rca Corp High-voltage power supply
US2621237A (en) * 1948-11-24 1952-12-09 Emi Ltd Electron discharge tube circuits for generating electrical oscillations of saw-tooth wave form
US2621308A (en) * 1949-03-31 1952-12-09 Rca Corp Electronic tube and circuits
US2565392A (en) * 1949-04-16 1951-08-21 Tele Tone Radio Corp Horizontal deflection circuit
US2536839A (en) * 1949-05-24 1951-01-02 Rca Corp Power recovery cathode-ray beam deflection system
US2536838A (en) * 1949-05-24 1951-01-02 Rca Corp High-efficiency cathode-ray beam deflection system
US2611106A (en) * 1949-07-20 1952-09-16 Motorola Inc Television sweep system
US2543720A (en) * 1949-08-10 1951-02-27 Rca Corp Electromagnetic deflection circuit
US2543305A (en) * 1949-12-16 1951-02-27 Avco Mfg Corp Circuit for suppressing undesired oscillations in television receivers
US2599798A (en) * 1950-01-13 1952-06-10 Avco Mfg Corp Linearity control circuit for television receivers
US2545346A (en) * 1950-03-22 1951-03-13 Avco Mfg Corp Automatic frequency control for television receivers
US2627051A (en) * 1950-08-29 1953-01-27 Rca Corp Electron tube voltage protection circuit
US2702874A (en) * 1950-12-13 1955-02-22 Zenith Radio Corp Deflection system
US2702875A (en) * 1951-03-09 1955-02-22 Zenith Radio Corp Deflection system
US2644103A (en) * 1951-12-11 1953-06-30 Motorola Inc Television deflection system
DE977115C (de) * 1951-12-19 1965-03-11 Philips Nv Zeilenablenkschaltung fuer Elektronenstrahlroehren
US2837692A (en) * 1953-08-19 1958-06-03 Rca Corp Cathode ray beam deflection apparatus
US3733513A (en) * 1969-04-30 1973-05-15 Hunt Electronics Co Circuits for centering pictures on television screens

Also Published As

Publication number Publication date
NL130803C (en, 2012)
GB646779A (en) 1950-11-29
DE974781C (de) 1961-04-27
FR942512A (fr) 1949-02-10

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