US3119898A - Circuit arrangement for controlling a colour television display tube - Google Patents

Circuit arrangement for controlling a colour television display tube Download PDF

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US3119898A
US3119898A US76345A US7634560A US3119898A US 3119898 A US3119898 A US 3119898A US 76345 A US76345 A US 76345A US 7634560 A US7634560 A US 7634560A US 3119898 A US3119898 A US 3119898A
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signal
signals
index
phase
controlling
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Davidse Jan
Cornelissen Bernardus He Jozef
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/16—Picture reproducers using cathode ray tubes
    • H04N9/22—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information
    • H04N9/24—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information using means, integral with, or external to, the tube, for producing signal indicating instantaneous beam position

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  • This invention relates to a circuit arrangement for controlling a colour television display tube comprising a display screen with colour strips and index strips and a control-electrode for controlling an electron beam produced in the tube, this beam being deflected across the screen by means of signals obtained from horizontal and vertical deflection generators with the aid of deflectors, the index strips emitting secondary electrons when they are struck by the beam, which secondary electrons produce an index signal which is fed, after being added to the television signal to be reproduced, to the controlelectrode of the tube.
  • the invention also relates to a circuit arrangement for controlling a colour television display tube comprising a display screen with colour strips and index strips and two control-electrodes, in which tube a signal fed to the first control-electrode is capable of controlling a pilot beam and a signal fed to the second control-electrode is capable of controlling a writing beam, the signal controlling the pilot beam having a considerably higher frequency than the signal controlling the writing beam, these beams being deflected across the screen by means of signals obtained from horizontal and vertical deflecting-generators with the aid of deflectors, an index signal being formed by filtering out the signal which is developed when the index strips are struck by the pilot beam, these strips thus emitting secondary electrons, which index signal, after being added to the colour television signal to be reproduced, is fed to the control-electrode for controlling the writing beam.
  • the circuit arrangement according to the invention is based on quite different principles to correct the said errors in the transit time and is characterized in that in order to correct the phase error in the index signal produced owing to the diflerence in transit time of the sec- 3,l 1 .93% Patented Jan. 2%, 1964 ice iond'ary electrons emanating from index strips at the edges and at the centre of the screen an opposite phase error is introduced into the signal fed to the control-electrode by means of a phase-shifting member included in the arrangement, to which member correction signals are fed which are derived from signals obtained from the horizontal and vertical deflecting-generators.
  • FIGURE 1 shows a first embodiment comprising an index tube with two electron beams, in which the phase of the signal controlling the pilot beam is varied by a direct variation of the phase of the pilot signal; this figure illustrates, moreover, the possibility of varying the phase of the signal derived from the incoming reference signal before :it is use-d in working up the index signal.
  • FIGURE 2 shows a second embodiment also comprising an index tube with two beams, in which the phase of the pilot signal is indirectly varied.
  • FIGURE 3 shows an embodiment comprising an index tube with one beam.
  • FIGURE 4 shows a phase-shifting member which may be used in the circuit arrangement according to the invention.
  • FIGURE 5 serves to clarify FIGURE 4.
  • FIGURE 6 shows a second possible embodiment of a phase-shifting member for use in the circuit arrangements
  • FIGURE 7 shows a detail of the phase-shifting member of FIGURE 6.
  • reference numeral 1 designates an index tube comprising a display screen 2, a collector 3, a first control-electrode 4, a second control-electrode and a cathode 6.
  • the display screen 2 is provided in known manner with colour strips and interconnected index strips which are brought outside the tube 1 via the conductor 7.
  • the collector 3 is also brought outside the tube 1 via the conductor 8 and connected via this conductor to a direct-voltage source supplying a high positive direct voltage.
  • the control-electrode 4 serves to control the so-called pilot beam and in the present embodiment this control-electrode receives a signal having a frequency of 36 mc./s.
  • the second control-electrode 5 serves to control the so-called writing beam and this control-electrode receives the worked up index signal, which contains, moreover the luminance information and the colour information required to reproduce the colour television image on the display screen 2 by means of the colour strips.
  • the cathode 6 emits electrons to produce the pilot beam and the writing beam with the aid of beam-screening electrodes.
  • the signal to be fed to the control-electrode 5 is obtained by means of a local oscillator 1 1 producing a signal of a frequency of 36 mc./s., which signal is fed to a first mixing stage M To this mixing stage M is also fed the colour signal, which is detected elsewhere in the receiver and of which the modulation frequencies are lying around a frequency of about 4.5 mc./s. After mixing a signal is obtained of which the modulation frequencies are lying around a frequency of about 40.5 mc./s. and which is fed to a second mixing stage M to which is, moreover, fed the signal of 4.5 mc./s. derived from the burst signal.
  • a modulated signal is obtained which has a carrier frequency of 36 mc./s. and which contains the colour information and, moreover, the information supplied by the burst signal.
  • This signal is then fed to the mixing valve M in which it is mixed with the index signal of, in this case, 43 mc./s. or 29 mc./s., which depends upon the frequency of the pilot signal, upon the number of index strips and upon the velocity with which these index strips are scanned.
  • a modulated signal is obtained which has a carrier frequency of 7 mc./s., to which the luminance signal Y is added in the adder 12, after which the whole signal is fed to the control-electrode 5.
  • the signal obtained from the oscillator 11 of 36 mc./ s. is fed to the control-electrode 4 so that the pilot beam is controlled in the rhythm of this frequency, secondary electrons being formed a the impact of this pilot beam on the screen, which electrons Wander from the display screen 2 to the collector 3.
  • These electrons are comparatively slow and since the distances from the edges of the display screen 2 to the collector 3 are considerably smaller than the distanms from the centre of the screen to this collector, the time required for the electrons from the edges of the screen to reach the collector is considerably shorter than the time required for the electrons from the centre of the screen.
  • the index signal of the sideband frequencies of about 43 mc./s.
  • the said phase error can be eliminated by introducing an opposite phase error into the signal controlling the pilot beam or into the signal controlling the writing beam. If it is intnoduced into the signal controlling the pilot beam, the phase error of the index signal is eliminated by the introduction of this opposite phase. If the opposite phase is introduced, however, into the signal controlling the writing beam, the colour enrors occurring in the absence of the said compensation are directly compensated.
  • the circuit arrangement shown in FIGURE 1 may be provided with a phase-shifting member 13, to the input terminal of which is fed a signal obtained from an adder 114.
  • this adder 114 the signals emanating from integrators 15 and 16 are added.
  • To the integrator 15 is fed the sawtooth signal 17 from the horizontal deflection-generator and to the integrator 16 is fed the sawtooth signal 18 from the vertical defiection-generator.
  • the output of the integrator 15 has produced across it a parabolic signal of which the symmetry axis must lie each time half a period after the beginning of a period of the sawtooth signal 17, since the deviations owing to the transit-time errors are at a minimum at the side edges of the display screen, so that the compensation in the centre of the screen is to be at a maximum.
  • the parabolic voltage 19 may therefore have a waveform as shown in FIGURE 1.
  • the integrator 15 may be formed, for example, by the series combination of a resistor and a capacitor, the RC-time of this network having to be high with respect to one period of the sawtooth signal 17. The output signal is to be obtained from the capacitor.
  • a discharge valve connected as a Miller integrator may be employed.
  • the signal 17 is then fed to the control-grid of the discharge valve and the output signal may be derived from the anode.
  • the output signal is to be derived via a blocking capacitor in order to avoid undue direct-voltage components in the output signal.
  • the output of this integrator has to supply also an approximately parabolic voltage of image frequency in order to compensate the transit-time errors which are at a minimum on the lower and the upper side of the screen and at a maximum at the centre of the screen.
  • the integrator 16 may be constructed similarly to the integrator 15; it should only be considered that the image frequency is materially lower than the line frequency and that the RC-time of the integrator 16 is to be adapted thereto.
  • the index signal emanating from the sideband amplifier 10 can be shifted in phase. This involves, however, great difliculties, since owing tothe non-linearity of the deflection signals the frequency of the index signal may vary so that a phase-shifting member included after the amplifier 10 is to be suitable for shifting the phase of the signal which may have more than one frequency. This can be carried out only with difiiculty. It is therefore preferable to choose the second way and to shift the phase of the signal derived from the burst signal applied to the mixing stage M and having always a fixed frequency of 4.5 mc./s. To this end the block 21 is provided, which is shown in FIGURE 1 by broken lines, the incoming burst signal 22 being fed thereto, which signal 22 is converted in 21 into a continuous signal of 4.5 mc./s.,.
  • the device 21 is, moreover, capable of shifting the phase of the derived signal of 4.5 mc./s. and to this end the output voltage of the adder 14' is fed to the device 21.
  • the devices 14', 15 and 16' are similar to the devices 14, 15 and 16 and shown only in broken lines, whilst it is indicated that they may be employed to control a phase-shifting member 13 and a device 21, if one of them is employed in the arrangement of FIGURE 1.
  • FIGURE 2 A second embodiment is shown in FIGURE 2.
  • the signal of 4.5 mc./s. derived from the burst signal is not used for working up the index signal but it is med with the signal of 36 mc./s. from the local oscillator 11 to obtain a signal of 40.5 mc./s., which is fed to the electrode 4 controlling the pilot beam.
  • the signal of 4.5 inc/s. derived from the burst signal 22 may be used with the aid of the device 21 to shift its phase to obtain the required phase correction.
  • the signal derived from the burst signal must not be used again in that part of the arrangement in which the index signal is Worked up, since the reference required for the colour signal to be reproduced is introduced via the pilot beam into the index signal. It is therefore sufiicient to mix the signal of 36 mos. from the local oscillator 11 in the mixing stage M with the colour signal, after which a signal is obtained which contains the required colour information and of which the modulation frequencies are lying around a frequency of about 40.5 'mc./s. The latter signal is mixed in the mixing stage M with the index signal from the sideband amplifier it), which signal has a frequency of 47.5 rnc./s.
  • FIGURE 3 A third embodiment is shown in FIGURE 3.
  • the index tube shown in this figure is driven by a single electron beam and may be connected in the manner described in copending US Patent application Serial No. 29,268, filed May 16, 1960; by means of gate circuits it is provided that no video information is introduced into the index signal, when the electron beam scans an index strip.
  • the index signal thus free of video information is fed to the trigger circuit 25, the output of which has produced across it pulses having the frequency and the phase of the index signal from the electrode 7, which pulses are fed to the phase detector 2.6.
  • the signal from 25 is compared with the signal from a local oscillator 27, so that in the case of non-synchronism of the two signals a direct voltage is produced at the output of 26, by which voltage the oscillator 27 can be readjusted by means of the reactmce circuit 28 until synchronism between the signals from 25 and 26 is attained.
  • the output signals of 27 are fed as gate pulses to the gate circuit 24, which is thus opened each time at the correct instant.
  • the gate circuit 24 is, moreover, opened for a short instant, by means of pulses of line frequency fed via the conductor 6 29, at the beginning of each line, so that the oscillator 27, which has got out of synchronism during the preceding line fly-back period can be brought to the correct rhythm.
  • the signal [from 27 is fed via the delay network 30 to a second gate circuit 31, which brings the controlelectrode 23 each time to a fixed potential so that at these instants no video information can occur in the electron beam.
  • the delay time of the network 34? corresponds to the transit time of the electrons from the control-electrode 23 to the display screen 2, so that the electron beam does not contain video information, when striking an index strip.
  • To the gate circuit 31 are fed via the conductor 32 also line pulses to bring the said electrode 23 to the fixed potential each time at the beginning of a line.
  • the oscillator 27 is in synchronism with the index signal, which may thus be used, in addition, to Work up the video information.
  • the signal delayed in 3th is fed via the conductor 33 to the mixing stage M
  • the colour information which is modulated around a frequency of 4.5 mc./ s.
  • a signal is thus obtained, which contains the colour information modulated around a signal of 1-1.5 mc./s.
  • the latter signal is fed to the mixing stage M in which it is mixed with the signal derived from the burst signal 22.
  • the signal produced at the output of M of 7 mc./s. contains therefore the information of the index signal, of the burst signal and of the colour and in the adder 12 the luminance signal Y is added thereto, after which the whole signal is fed to the control-electrode 23 via the gate circuit 31.
  • the gate circuit 31 is keyed by means of the pulses from 3t so that it passes normally the signal from 12 during the periods in which the electron beam scans the colour strips of the screen 2, which is not the case during the scanning of the index strips, since then the electrode 23 is brought to the said fixed potential with the aid of the gate circuit 31.
  • phase shift required in accordance with the invention is obtained in the manner described with reference to FIGURES l and 2 by shifting the phase of the signal of 4.5 mc./s. derived from the burst signal 22 in the device 21. To this end the correction signals from 14 are fed to the device 21.
  • FIGURE 4 A possible embodiment of the phase-shifting member 13 shown in FlIGURE l is illustrated in FIGURE 4.
  • the phasesshitting member 13 in bridge arrangement consists of a central-tapped coil 36 and a series combination of a resistor 39 and a reactance element formed in the present embodiment by the discharge valve 37, connected as a capacitative reactance element, this combination being connected in parallel with the coil.
  • the discharge valve 37 is connected by its cathode to the lower end of the coil 36 and via the separation capacitor 38 to the resistor 39.
  • the anode of the valve 37 is furtherin re connected 'via the capacitor 40 to the con trolsgrid, which, in turn, is connected via the resistor 41 to the cathode. Consequently, the elements 37, 40 and 41 constitute, in known manner, a variable capacity, of which the variation can be produced by the signals fed to the control-grid.
  • These signals are the correction signals from the adder 14, which signals are fed to the said control-grid by way of the separation resistor 42 and the parallel combination 43.
  • the coil 36 constitutes one branch of the bridge, the series combination of the resistor 39 and of the elements 37, 40 and 41, connected as a capacity, constitutes the other branch.
  • the input voltage of 36 mc./s. from the local oscillator 11 is fed to the bridge circuit via the input terminals 44 and 45 and the output voltage can be derived via the amplifying valve 35 of FIGURE 4 from the output terminals 46 and 47.
  • phase shift of the non-amplified output voltage V between the central tapping of the coil 36 and the junction of the resistor 39 and the blocking capacitor 38 with respect to the voltage across the coil 36 may be accounted for by means of the vector diagram of FIGURE 5.
  • the part between the said central tapping and the resister 39 constitutes a first alternatingwoltage source and the part between this tapping and the cathode of the valve 37 constitutes a second alternating-voltage source.
  • the sum of the voltages supplied by those two sources is operative across the series combination of the resistor and the capacity.
  • the voltage across the resistor may be considered to be a vector V which is at an angle of 90 to the vector 5 of the voltage across the capacity.
  • Their sum V +V must be equal to the sum 7 4 1 of the voltages, considered as the vectors V and V produced by the voltage sources.
  • the vector diagram thus obtained constitutes a rectangular triangle, of which V +T is the base and V and V are the right-angle sides. It is known that a circle of which 7 4-1 is the diameter goes through the apex of the right-angle triangle and with a variation of the capacity the size of the vectors V and V will change, it is true, but the apex of the triangle will move along the circle circumference.
  • the output voltage V may also be considered as a vector V of which one end lies on the circumference and the other end lies on the centre of the circle. Consequently, when the capacity is varied, the vector V turns, whilst its size remains constant, but the angle thereof to the vectors V and 7 will vary. Since the said angle is the phase angle of the output voltage V with respect to the voltage across the coil 36, the phase shift occurring is accounted for.
  • valve 37 may be connected, as an alternative, as an inductive reactance element; moreover, any other variable reactance element may be employed, for example, a junction diode, controlled in the blocking direction and similar elements.
  • the resistor 39 may also be variable and also the phase bridge itself may be constructed in various known ways.
  • the impedance of the coil 36 is high for the frequency of 36 mc./s. with respect to the impedance of the series combination of the resistor and the capacitor.
  • the output terminal 47 is connected to earth and the output terminal 46 leads to the control-electrode 4 of the index tube 1 shown in FIGURE 1.
  • phase-shifting member 13 is described for the case in which a signal of 36 mc./s. is supplied thereto, it will be obvious that also a signal of 4.5 mc./s. derived from the burst signal may be shifted in phase in a similar phase-shifting member after adaptation.
  • a part of the device 21 consists of the phaseshifting member shown in FIGURE 4 and the further part of the device 21 consists of an arrangement which converts, in known manner, the burst signal occurring only at the back porches of the line-synchronizing pulses into a continuous signal.
  • the circuit 43 serves to avoid a react-ion of the oscillator signal to the adder 14. If a signal of 36 mc./s. is fed to the terminals 44 and 45. this circuit is tuned to 36 mc./ s. and if the signal derived from the burst signal is supplied thereto, the circuit is to be tuned to 4.5 mc./s.
  • the device 21 may, however, also be constructed as is shown in FIGURE 6.
  • the device 21 consists of a local oscillator 48, which produces a sinusoidal signal of about 4.5 mc./s.
  • This local oscillator has to produce a signal which is synchronous with the burst signal 22 occurring during the back porches of the line-synchronizing pulses.
  • the burst signal 22 is compared in the phase detector 49 with the oscillator signal from 48, after which the output voltage of 49 is fed to the reactance circuit 59, by which the oscillator 48 can be readjusted.
  • the arrangement shown in FIGURE 6 is based on the recognition of the fact that the burst signals 22 occur only during the back porches of the line-synchronizing signal so that during the remaining part of each line period the said loop is left to itself. Consequently, the required phase shift can be obtained with comparatively :small amplitudes of the correction signal by feeding the correction signal during the said remaining part of the period via a gate circuit 51 to the reactance circuit 50.
  • This gate circuit is keyed to this end by the fly-back pulses 52 from the line-deflection generator.
  • the fly-back pulses have a duration which corresponds to the horizontal fly-back time, so that the correction signals from 14 will only be operative during the onward stroke of the horizontal deflection, whilst the loop 48, 49 and 56 can bring the oscillator 48 into synchronism during part of the horizontal fly-back time with the aid of the burst signals 22 occurring at the back porches.
  • key pulses 52 which have a much shorter duration and which occur only during the occurrence of the burst signals at the said back porches.
  • key pulses 52 are to be produced, whilst the said fly-back pulses are available without the need for further means.
  • FIGURE 7 shows a possible embodiment of the reactance circuit 56.
  • This reactance circuit 50 consists of a discharge valve 52, of which the anode is connected to the oscillator circuit 53, which determines the frequency of the oscillator 48 (not shown in FIGURE 7).
  • the discharge valve 52 is connected in known manner as an inductive reactance valve by means of a blocking capacitor 54, a resistor 56 and a capacitor 57, so that, when signals are fed to the control-grid of the valve 52, the reaotance thereof varies, and the oscillator 48 is readjusted.
  • the direct voltages emanating from the phase detector 49 which voltages are smoothed by a filter 59 and provide the synchronization of the oscillator 48.
  • the separation resistor 61 and the parallel circuit 62 the correction signals from 51 are fed also to the control-grid of the valve 52.
  • the separation resistor 63 serves to separate the correction signals from the signals of the phase detector 49.
  • the circuit 62 is tuned to the frequency of 4.5 mc./s. in order to avoid a reaction of the oscillator signal from 48 on the adder 14.
  • phase-shifting members 13 and 21 may be fed as correction signals to the phase-shifting members 13 and 21.
  • a second error may occur, i.e. due to turning of the pilot beam and the writing beam about each other during the deflection, mainly when they are at the remote corners of the screen.
  • this phase error may be compensated by introducing an additional phase shift into the signal supplied to the writing beam or the pilot beam, but owing to the deviating character of the last-mentioned phase error as compared with that due to the transit time of the secondary electrons, other correction signals are required.
  • phase error due to turning of the two beams about each other is as follows. On the upper side of the screen this error is at a maximum, so that at the beginning of a line period it assumes a maximum value, it decreases gradually to zero and increases after half a line period, however, with opposite sign. At the end of the line period a maximum phase error occurs, of which the value is the same but of which the sign is opposite that of the error at the beginning of the line period.
  • phase errors occurring at the scanning of a line on the upper side of the screen decrease gradually in a vertical sense and are substantially equal to Zero in the centre of the screen throughout one line period. Then they increase, however, with opposite sign. On the lower side of the screen similar maximum phase errors occur as on the upper side, but they have a phase shift of just 180.
  • a correction signal use is therefore to be made of a sawtooth signal of a frequency equal to that of the horizontal deflection signal, which signal is modulated in the rhythm of the raster frequency.
  • This modulation is to be carried out so that the sawtooth correction signal of line frequency has a maximum slope at the beginning of a raster period, this slope becoming gradually less steep to attain the value zero after half a raster period. In the second half of the raster period this slope becomes gradually steeper, but :with opposite polarity and at the end of one raster period it is equal to that at the beginning, but the polarity being opposite.
  • a push-pull modulator for example the know-n push-pull modulator consisting of an output transformer and an input transformer, the secondary winding of the input transformer being connected via four diodes to the primary winding of the output transformer.
  • the sawtooth signal of line frequency is to be fed to the primary winding of the input transformer and the sawtooth signal of raster frequency between the central tappin-gs of the secondm and the primary winding of the input transformer and the output transformer respectively.
  • the secondary winding of the output transformer of this push-pull modulator is connected either to the phaseshifting member 13 or to the phase-shitfting member 21.
  • correction signals may be fed to the phase-shifting members 13 and 21, which signals compensate not only the phase error due to the transit-time effect of the secondary electrons but also that due to the turning of the two beams about each other by feeding to the phase-shifting members not only the parabolic voltages but also the line-frequency sawtooth voltages modulated by the raster frequency.
  • said circuit comprising a source of deflection signals for said display tube, means for integrating said deflection signals, a source of color video signals, a source of reference oscillations, a source of local oscillations, means for mixing said local oscillations, local oscillations, reference oscillations and index signal for application to said control electrode, an inductor having first and second serially-connected portions, means applying said local oscillations to said indoctor, a series circuit of a resistor and a variable reactance device connected in parallel with said inductor,
  • said reactance device comprising an electron discharge device having at least a control grid and an anode, means applying said integrated deflection signals to said control grid whereby the oscillations at said anode have the frequency of said local oscillations and a phase dependent upon said integrated signals, and means for connecting said anode to said control electrode means for correcting for phase errors in said index signal due to variations in transit time of said secondary electrons.
  • said circuit comprising a source of deflection signals for said display tube, means for integrating said deflection signals, a source of color video signals, a source of reference oscillations, a source of local oscillations, means for applying said local oscillations to said control electrode, first, second and third mixer means, means for applying said local oscillations and color signals to said first mixer means, phase-shifting means, means for applying said reference oscillations to said phase-shifting means, means for applying the outputs of said first mixer means and phase-shifting means to said second mixer means, means for applying the output of said second mixer means and said index signal to said third mixer means, and means applying the output of said third mixer means to said control electrode, said phase-shifting means comprising an inductor having
  • said circuit comprising a source of deflection signals for said display tube, means for integrating said deflection signals, a source of color video signals, a source of reference oscillations, a source of local oscillations, a source of burst signals, means for mixing said local oscillations, color signals, reference oscillations, and index signal for application to said control electrode, means for applying said local oscillations to said control electrode, and a control circuit for said source of reference oscillations comprising reactance circuit means for varying the phase of said reference oscillations, means for comparing said burst signals and reference oscillations to provide a control voltage for said reactance circuit means, and gate means for applying said integrated deflection signals to said reactance circuit means only when burst signals are
  • said circuit comprising a source of deflection signals for said display tube, means for integrating said deflection signals, a source of color video signals, a source of reference oscillations, a source of local oscillations, a source of burst signals, means for mixing said local oscillations, color signals and index signal for application to said control electrode means, means for mixing said local oscillations and reference oscillations for application to said control electrode means, and means for controlling said reference oscillations comprising reactance circuit means for varying the phase of said reference oscillations, phase detector means for comparing said reference oscillations and burst signals to provide a control voltage for said reactance circuit means, and gate means for applying said integrated deflection signals to said reactance circuit means only when said burst
  • said circuit comprising a source of deflection signals for said display tube, means for integrating said deflection signals, a source of color video signals, a source of reference oscillations, a source of burst signals, means for mixing said color signals, reference oscillations and index signals, first gate means for alternately applying said index signals and said mixed color and index signals and reference oscillations to said control electrode means, and means for controlling said reference oscillations comprising reactance circuit means for varying the phase of said reference oscillations, phase detector means for comparing said reference oscillations and burst signals to provide a control voltage for said reactance circuit means, and gate means for applying said integrated deflection signals to said reactance circuit means only when said burst signals are not present.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US76345A 1960-01-20 1960-12-16 Circuit arrangement for controlling a colour television display tube Expired - Lifetime US3119898A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2648722A (en) * 1951-02-15 1953-08-11 Philco Corp Electrical system for altering phase displacement of sequential-type color signals
US2899600A (en) * 1956-08-13 1959-08-11 Wtoth of screen
US2990446A (en) * 1956-12-03 1961-06-27 Philco Corp Color television receiver

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2648722A (en) * 1951-02-15 1953-08-11 Philco Corp Electrical system for altering phase displacement of sequential-type color signals
US2899600A (en) * 1956-08-13 1959-08-11 Wtoth of screen
US2990446A (en) * 1956-12-03 1961-06-27 Philco Corp Color television receiver

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