Abstract: Top and bottom pincushion correction signals with separately controllable amplitude, phase and tilt are provided. A switching signal developed from the vertical ramp operates a plurality of switches for selectively applying the top and bottom correction signals to the carrier input of a multiplier. The modulator input of the multiplier is supplied with the vertical ramp and the output of the multiplier consists of a conventional "bow tie" correction signal with each half of the bow tie being separately controllable.

Abstract: A top/bottom pincushion correction circuit includes a multiplier having a gain control input coupled to a differential amplifier, one input of which is a ground potential and the other of which has a voltage dependent upon the B+ voltage supplied to the horizontal deflection system. A voltage divider is connected between the B+ voltage and a zener diode that provide a reference potential. Changes in B+ voltage are indicative of changes in the horizontal raster size and result in a compensating current being supplied to the gain control input of the multiplier which develops a corresponding change in pincushion correction signal amplitude.

Abstract: A deflection circuit for a video apparatus that operates at multiple line rate deflection frequencies includes an S-shaping correction circuit that provides proper S-shaping of the line deflection current at any of the video apparatus line rate operating frequencies. A first S-shaping capacitor is in series with the deflection winding and also in series with a transformer primary winding. The transformer secondary winding is coupled to one or more capacitors. The secondary winding side capacitors are coupled to the secondary winding circuit in response to a line rate frequency indicative signal in order to form a series combination of the primary and secondary side capacitors. The effective capacitance of the secondary side capacitor is then equal to the actual capacitance value increased by a factor determined by the transformer secondary to primary winding turns ratio.

Abstract: Disclosed are systems and techniques for alignment of CRT-based display systems, particularly those employing a high resolution cathodochromic projection CRT. The disclosed techniques permit all major CRT-related alignment to be performed at a factory or other centralized facility, with automatic precision alignment in the field of the overall display system, including a CRT assembly as one element. A replaceable, standardized CRT subsystem includes a CRT assembly, itself subject to sample variations, and a non-volatile personality memory, such as an EEPROM, having stored parameters specifically applicable to the CRT assembly on an individual basis. The CRT assembly has no field adjustable parts, but does include elements for electron beam control, such as electromagnetic coils for focus and deflection permanently affixed to the CRT. Thus at the factory, a skilled operator having appropriate equipment available performs an electronic alignment procedure with reference to a particular CRT.

Abstract: A top/bottom pincushion correction transformer injects a horizontal rate correction signal in series with a vertical yoke that is driven from a vertical amplifier that has a non-inverting and an inverting terminal. A feedback arrangement includes a voltage sensing resistor for supplying a voltage indicative of the current flow in the yoke to the non-inverting terminal of the amplifier. The primary winding of a pincushion transformer is connected in series with a current limiting resistor and their junction is connected by a bridging resistor to the voltage sensing resistor. The voltage developed across the voltage developing resistor is of opposite polarity to the voltage developed across the current limiting resistor for offsetting the same.

Abstract: A device for isolating an electrical instrument from an input voltage signal at a floating potential. The device includes a transformer with a center-tapped primary winding, a center-tapped secondary winding and a core magnetically coupling the primary and secondary windings. The input voltage signal is applied to an input terminal coupled to the center tap of the primary winding. A modulator circuit is connected to the primary winding for alternately applying the input voltage signal to opposite sections of the primary winding by means of FETs, or the like, isolated from a control circuit by a transformer, the control circuit alternately switching the modulator circuit at a suitable modulating frequency.

Abstract: A variable-gain rectifier-amplifier with regulated voltage converts the output ramp of a ramp generator with regulating resistance of ramp amplitude into a triangular wave form with adjustable linearity which a feedback circuit brings back to said regulating resistance in the form of alternating current superimposing it on the direct current regulated through said resistance. This provides an S correction of the output ramp which depends on the gain regulation voltage of the rectifier-amplifier circuit.

Abstract: The field rate of a video input signal is doubled by storing each field in a memory and recovering each stored fields twice so as to repeat each field and thus reduce flicker. To ensure that even fields overlay even fields, odd fields overlay odd fields and that all pairs of even and odd fields are interlaced, a timing unit provides a double field rate read control signal to the memory having a waveform that repeats on a two-field basis and supplies a double field rate vertical control signal to a vertical deflection generator having a waveform that is phase modulated and that repeats on a four-field basis. The vertical deflection generator has a constant retrace time and employs DC coupling, thereby avoiding raster shift which otherwise could occur as a result of the phase modulation.

Abstract: A deflection yoke unit to be mounted on a cathode ray tube has a core on which a set of vertical deflection coils and a set of horizontal deflection coils are wound. A pincushion distortion correction device is provided for the deflection yoke unit. The correction device has a set of correction coils having a coil conductor mass quantity and an inductance which are smaller than those of the vertical deflection coil set and having a winding density distribution which is similar to that of the vertical deflection coil set. An upper and lower pincushion distortion correction current is passed through the correction coil set to correct upper and lower pincushion distortions in pictures displayed on a screen of the cathode ray tube. The core has, on its inner wall, slots in which windings of the horizontal deflection coil set, vertical deflection coil set and correction coil set for correction of the upper and lower pincushion picture distortions are received.

Abstract: A side pincushion correction circuit develops a vertical rate parabolic signal by multiplication of the vertical ramp by itself. A transistor current source is connected to a gain control terminal of a multiplier and is controlled by the operating voltage developed for the horizontal deflection system. A tilt potentiometer supplies a variable amplitude and polarity voltage to the multiplier. A potentiometer is coupled to the output of the multiplier. The tilted, variable amplitude parabolic signal is coupled to an error amplifier that is differentially supplied with a sinewave signal developed by integrating the parabolic signal. The error amplifier controls the voltage regulator that supplies operating voltage to the horizontal deflection system.

Abstract: In a horizontal output circuit for a cathode ray tube, there is included a second resonant circuit combining in parallel a transistor, a damper diode, a resonant capacitor and a series connection of a capacitor and a coil serially connected to a horizontal deflection resonant circuit having a horizontal output transistor, a damper diode, a resonant capacitor, a series connection of an S-shape capacitor and a horizontal deflection coil and a flyback transformer. The constants of the circuits are set so that waveforms of resonant pulses generated by the two resonant circuits becomes similar. A parabolic correction voltage for vertical synchoronization is also applied to the second resonant circuit and the resonant pulse is amplitude-modulated parabolically by the vertical synchronization signal. Therefore, the resonant pulse of the first resonant circuit is amplitude-modulated parabolically with a reverse polarity.

Abstract: In a deflection apparatus which corrects for inside pincushion distortion, a deflection winding and a retrace capacitance form a retrace resonance circuit during a retrace interval. A trace capacitance forms a trace resonant circuit with the deflection winding during the trace interval. A circuit branch, that includes a second capacitance and an inductance, is coupled to the trace capacitance during the trace interval to form a second resonant circuit with the trace capacitance having a resonance frequency that is substantially higher during the trace interval than that of the trace resonant circuit. A current in the circuit branch, that is modulated in accordance with the modulated voltage, modulates the trace parabolic voltage across the trace capacitance in a manner to reduce inside pincushion distortion. The trace capacitance acts as a bypass capacitor around the inductance during retrace to prevent the inductance from affecting the retrace voltage.

Abstract: A process for avoiding non-linearities and brightening on the television picture tube includes the generating of an additional signal of a higher frequency than that of the deflections signals, the separating of the additional signal into signal parts of opposite polarity, and the addition of the two additional signal parts to the deflection signals during time intervals immediately before and after the return movement period.

Abstract: A timebase circuit is described, for compensation of picture dimensions of a television type display, for EHT fluctuations in which a control current is derived by multiplying a current dependent upon the picture beam current with a reference current derived from a digital to analogue converter fed with a digital code.

Abstract: In a horizontal pincushion distortion correcting circuit using a parabolic wave signal of vertical deflection period for use with CRT drive circuit, a d.c. voltage proportional to vertical deflection period is produced, and then the parabolic wave signal is amplitude-modulated by the d.c. voltage so that a resultant parabolic wave signal has a substantially constant amplitude irrespective of the change in vertical sync frequency. The d.c. voltage may be produced by frequency-converting the vertical sync signal or by detecting an envelope of the horizontal deflection current modulated by the resultant parabolic wave signal.

Abstract: To achieve improved and, in particular, optimum deflection correction of television picture tubes the sawtooth signal from the horizontal or vertical oscillator which is conventionally subjected to a correction, is left uncorrected. Per line, the time relation of the digital video signal controlling the picture tube via digital-to-analog converters is changed with respect to the time relation of the video signals as reconditioned with the aid of a video processor, i.e., by the correcting value depending on the respective locus of an image spot on the screen. Accordingly, the deflection correction is not carried out by influencing deflection means, but by a corresponding correction of the time relation of the video signals with respect to their loci on the picture screen.

Abstract: A video display apparatus incorporates a picture tube, such as a square-planar picture tube, that includes a phosphor screen located on a faceplate having an aspherically curved geometry that produces a relatively flat surface contour. Deflection circuitry generates line and field scanning currents in respective line and field deflection windings to enable the electron beams of the picture tube to scan a raster on the phosphor screen. The electron beams are subject to a scanning error that results in raster distortion, such as side pincushion distortion. A parabola generator produces a parabolic modulation of the scanning of the electron beams to generally correct the raster distortion while retaining a residual error due to the aspherically curved geometry of the faceplate.

Abstract: In a cathode ray tube display system, correction factors for X and Y position, astigmatism, focus and shading are recorded for preselected locations in digital memory circuits. Those correction factors bordering the actual beam position are selected and are converted to analog form. The correction factors applied to the system are determined by analogue interpolation, that is, the correction factors are combined in proportion to the proximity of the beam relative to those preselected locations where the correction factors were recorded. Use is made of resistance ladders and multiplexers in the interpolation circuits.

Abstract: A video display apparatus includes a diode modulator for correcting side pincushion raster distortion. The diode modulator drive circuit produces a vertical deflection rate parabolic voltage that modulates the horizontal deflection current to effect pincushion correction. The drive circuit includes a transistor that has its base bias established by the combination of a width control resistor and a diode. The diode has the same thermal characteristics as the transistor to provide accurate temperature compensation. A resistor is connected between the emitter of the transistor and a supply voltage to change the transistor bias point in order to enable the transistor to be cutoff.

Abstract: A dynamic focus voltage generating circuit for television generates a parabolic voltage at the horizontal rate that is responsive to a synchronizing signal. The parabolic voltage is generated from a sawtooth waveform having an upramping portion, a downramping portion and a flat portion such that only the length of the flat portion of the sawtooth waveform varies when the frequency of the synchronizing signal changes.

Abstract: Line and field deflection circuits generate line and field deflection currents in respective line and field deflection windings to scan a raster on the phosphor screen of a square-planar picture tube having an aspherical faceplate. The asphericity of the faceplate subjects the scanned raster to gullwing distortion. A gullwing distortion correction circuit is responsive to signals repeating at line and field rates, respectively, for modulating the field deflection current during a line deflection period within the field deflection trace interval in a manner that corrects gullwing distortion of a corresponding raster scan line.

Abstract: A CRT display system providing a raster pattern has digital means 30, 31, 32 to drive a DAC 34. In response, there are supplied analogue signals, on a line 37. There are also provided pulse generating means 90 controlled by the digital means, and integrating means comprising two integrators. Each integrator is connected individually to an X deflection plate 14 of the CRT, and comprises an amplifier and a feedback capacitor. One capacitor C2 is charged by negative-going pulses, and the other capacitor C2' is charged by positive-going pulses, until the pulses are removed, when the required ramps are applied to the deflection plates. Then a current flows through a transistor T7, and is controlled by the DAC output on the line 37. Hence, the waveforms applied to the deflection plates cause distortion of the raster pattern otherwise obtained, to be corrected, the DAC output representing a function comprising the inverse of the function representing the distortion.

Abstract: A color video monitor is disclosed which includes improved digital convergence using a plurality of memory means in which vertical convergence correction values are stored, one memory each for red, green, blue and lateral blue convergence values. Interpolation means provide additional values between the points stored in memory such that a smooth transition between successive lines of the display is achieved. The correction values stored in the memories are generated by means of a high-order polynomial function. The monitor employs synchronization circuitry which synchronizes all digital components to the supplied video signal including horizontal and vertical sync pulses and an external 36 MHz clock associated therewith.

Abstract: In a deflection circuit that operates in any scan frequency selected from a plurality of frequencies, the supply voltage that is DC-coupled to a first terminal of a trace capacitor is increased when the scan frequency increases. The deflection circuit includes a diode modulator that is controlled by a modulation voltage having an AC component voltage that varies at a vertical rate. The increase in the supply voltage causes an increase in a DC component voltage of the modulation voltage that is coupled to a second terminal of the trace capacitor such that the voltage in the trace capacitor increases in the same proportion as the supply voltage. The proportional increase in the trace capacitor voltage maintains the raster width unchanged when the scan frequency increases.

Abstract: A vertical rate parabolic voltage at a peak-to-peak amplitude that is adjustable is generated in an integrator from a sawtooth input voltage. The parabolic voltage at an output terminal of the integrator is applied to a source of a B+ operating voltage to form a parabolic component voltage of the B+ operating voltage that controls the amplitude of a trace current in a horizontal deflection circuit output stage. The parabolic voltage is adjusted in peak-to-peak amplitude to provide east-west pincushion correction of the raster. The minimum level of the parabolic voltage in each vertical period is automatically maintained at an unchanged level that is approximately zero volts throughout the range of east-west adjustment. Because the minimum level of the parabolic voltage remains unchanged, the maximum level of the B+ operating voltage, a level that occurs in the center of each vertical interval, also remains unchanged throughout the range of east-west adjustment.

Abstract: A field deflection amplifier generates a field deflection current in a field deflection winding. An LC resonant circuit is coupled to the deflection winding and to an output switching amplifier. A control circuit switches conductive states of the amplifier at a line rate, with a 50% duty cycle, to excite the LC resonant circuit into providing a line rate correction current for the field deflection winding. The control circuit varies the modulation envelope of the field deflection current at a field rate in a generally sawtooth manner to provide north-south pincushion correction. When used in conjunction with raster scanning in a square-planar picture tube, the modulation envelope is nonlinearly waveshaped to take into account the aspherical nature of the picture tube faceplate.

Abstract: A device for isolating an electrical instrument from an input voltage signal at a floating potential. The device includes a transformer with a center-tapped primary winding, a center-tapped secondary winding and a core magnetically coupling the primary and secondary windings. The input voltage signal is applied to an input terminal coupled to the center tap of the primary winding. A modulator circuit is connected to the primary winding for alternately applying the input voltage signal to opposite sections of the primary winding by means of photo FETs or the like for alternately switching the modulator circuit at a suitable modulating frequency. A demodulator circuit is connected to the secondary winding for alternately connecting each end of the secondary winding to a common return point to demodulate the output signal from the center tap of the secondary winding by means of FETs or the like.

Abstract: A system for correcting display distortion caused by CRT beam current changes in an oscilloscope system is disclosed. A Z-axis signal proportional to the CRT beam current is multiplied by two factors adjustable for either or both of X and Y axes and then added to the respective axis deflection signal which controls CRT beam deflection, thereby providing improved display quality.

Abstract: In picture-reproducing equipment with higher scanning frequencies (e.g., flicker-free television, visual display unit), the generation of the horizontal-deflection current is separated in frequency from the generation of the operating voltages by supplying the horizontal-deflection circuit from a DC voltage source which is part of the voltage power supply providing the operating voltages. The supply circuit is preferably connected to the grounded deflection capacitor. This makes it possible to influence the picture geometry in a simple manner, particularly to perform horizontal pincushion correction.

Abstract: A saturable reactor has a center control winding electromagnetically coupled to a pair of outer windings which, in turn, are each coupled in circuit with a respective toroidal shunt winding. The reactor provides side pincushion correction and eliminates center pinch in a raster scanned video display such as a cathode ray tube (CRT). The high inductance-to-resistance ratios of the toroidal windings as well as the shunt current paths permit increased deflection current to be provided to the horizontal deflection coils without saturating the reactor or requiring an increase in its size.

Abstract: A scanning CRT display system is disclosed in which transitions of a horizontal sync signal are directly utilized to provide control signals for driving a FET (field effect transistor) power drive device which controls horizontal deflection yoke current. Protection circuitry is provided such that the FET power drive device is turned off if excessive FET through current is sensed, and protection circuitry also prevents turning on the FET drive device if an excessively high flyback voltage is present at the drain terminal of the FET device. Linearization of the horizontal deflection yoke current is provided by effectively sensing the temperature variable on resistance of the FET output drive device and providing a compensation control signal in accordance therewith, wherein this compensation control signal controls the magnetization provided by a control winding on a saturable magnetic core on which a linearity compensation coil is also wound.

Abstract: A PWM signal of substantially constant amplitude is supplied to a B+ compensation circuit, for developing a vertical ramp voltage in a digital TV. One transistor of a current switching differentially coupled pair is supplied with the PWM signal and the other is properly biased so as to amplify the PWM signal without inverting its phase. The negative peaks of the PWM signal are clamped to voltage which varies with B+ and the positive peak of the PWM signal are a fraction of B+. However, the positive peaks vary more with B+ than do the negative peaks. The amplitude of the PWM signal, which is used for developing the vertical ramp, is the difference of the positive peak and the negative peak and therefore it will vary with B+. The B+ in the television receiver varies with beam current and by properly varying the vertical ramp in accordance with the variation in B+, the vertical size of the raster can be maintained.

Abstract: A horizontal deflection circuit is disclosed in which the junction point between a bidirectional switch, a trace capacitor, and a retrace capacitor is grounded through a transistor. The latter is controlled by a control voltage for picture-width stabilization and pincushion correction. It may be shunted by a capacitor and a biased diode.

Abstract: A digital registration circuit for a multi-tube television camera wherein correction quantities corresponding to positions on a target of an image pickup tube are stored in a digital memory. The digital signal for the correction quantity read out from the digital memory is converted into an analog signal which is supplied to a low-pass filter and smoothed. The smoothed signal is sampled at a sampling frequency higher than the frequency at which the correction quantities stored in the digital memory are read out and the sampled signal is converted into a digital signal. The digital signals sequentially produced are applied to a shift register, and four sequential sample values supplied from the shift register are added together in an adder. The shift register operates in such a manner that four samples are shifted one by one every adding time. An output signal from the adder is used for correcting registration, so that the generation of shading can be prevented.

Abstract: A television camera capable of correcting shadings caused by digital registration faculty employed in a multi-tube type color television camera. The television camera comprises differentiating circuits for generating differentiated waves of correction waveforms used for adjusting registration, and non-linear circuits for processing the differentiated waves. Outputs of the non-linear circuits control the gain of a video signal circuit so that components responsible for the generation of shadings can be removed from a video signal.

Abstract: A high voltage generator develops an ultor voltage to accelerate an electron beam of a picture tube. The high voltage generator draws a resupply current in accordance with beam current loading by the picture tube. The deflection circuitry generates line and field deflection currents in respective line and field deflection windings to enable the electron beam to scan a raster. A diode modulator, including a differential amplifier input stage and an emitter-follower output stage, modulates the amplitude of the line deflection current to provide side pincushion correction. The voltage at a high voltage resupply current terminal of the high voltage generator is coupled in a nonlinear manner to the differential amplifier for nonlinearly modulating the amplitude of the line deflection current in accordance with beam current loading.

Abstract: An automatic S-correction circuit for a deflection circuit includes an active source of generally sawtooth current having an amplitude that is proportional to the deflection frequency. The sawtooth current and a deflection current that flows in a deflection winding are combined as a current flowing in an S-capacitor that develops a parabolic voltage. The amplitude of the parabolic voltage is automatically adjusted to be at a level that is required for maintaining proper S-correction for any deflection frequency within a continuous, wide range of frequencies.

Abstract: A timebase circuit is described for providing a horizontal drive correction waveform to correct for pincushion distortion in which a parabolic correction current is derived by squaring a current proportional to the difference between the instantaneous and average values of the vertical ramp voltage. The correction current may be tilted by combination with a linear current proportional to the ramp voltage and may also be amplitude controlled.

Abstract: A combined top and bottom pincushion and gullwing distortion correction circuit uses nonlinear reactor to introduce an appropriately modulated horizontal frequency and second harmonic of the horizontal frequency component into the vertical scanning current path. The nonlinear reactor functions as a transformer with a secondary that provides a correction voltage in series with the vertical scanning current path. The transformer effectively has two series opposing primary windings magnetically coupled to the secondary. These primaries, energized by waves at the horizontal frequency and the second harmonic frequency, alternately predominate over each other to a variable degree, and in a manner determined by the vertical scanning current, for inducing corresponding voltage at the secondary winding. The secondary winding is coupled to a first tuned circuit that generates a horizontal rate north-south pincushion correction component voltage of the total correction voltage.

Abstract: In a deflection circuit, a flyback transformer and a retrace resonant circuit that includes a deflection winding are mutually coupled by a relatively small capacitor during the retrace interval so as to reduce transient distortions that may be caused by a sudden high beam current change. East-west modulation is provided to the deflection circuit output stage via an impedance having a relatively large value at the retrace frequency. A resonant circuit that includes the deflection winding and the flyback transformer is tuned to the retrace frequency. Synchronization information of the current through the deflection winding may be derived from a winding of the flyback transformer.

Abstract: A linearity correction circuit for correcting asymmetrical linearity errors of the line deflection current includes a resonant capacitor coupled to a first inductor for forming a resonant circuit having a resonant frequency greater than or equal to the deflection retrace frequency. A controllable switch coupled to the resonant circuit and to the deflection trace capacitor becomes conductive at the beginning of retrace to generate an oscillatory current pulse in the resonant circuit that removes a predetermined amount of charge from the trace capacitor during retrace. A second, relatively large valued inductor is coupled to the line deflection winding and is responsive to the deflection retrace pulse voltage for supplying during the trace interval a linearity correction current to the trace capacitor via the resonant capacitor.

Abstract: A trace switch, operated at a line rate, is coupled to a line deflection winding and a trace capacitance for applying a trace voltage to the deflection winding to generate line scanning current in the deflection winding. A deflection retrace capacitance is coupled to the deflection winding for forming a deflection retrace resonant circuit during the line retrace interval to generate a deflection retrace pulse voltage. A modulator inductance is coupled to the trace switch and to the line deflection winding. A modulator switch applies a line rate, switched mode, modulation voltage directly to the modulator inductance to control the amplitude of the current in the modulator inductance at the end of the line trace interval. A modulator retrace capacitance is coupled by the modulator switch to the modulator inductance during the line retrace interval for forming a modulator retrace resonant circuit.

Abstract: Circuitry corrects vertical beam landing errors for color cathode ray tubes. A digital delay circuit provides horizontal scan line video pixel information at its proper location to produce a distortion corrected raster. Accurate correction is provided by a combination of scan line offset between the input and output video signals and by sample interpolation techniques that effectively form derived pixels that have an apparent location of the derived pixel relative to the sample video pixels is determined by the selection of the interpolating coefficients.

Abstract: The scan pattern of a raster scan video display system is modified to provide a sinusoidal raster scan, so that derived scan lines made up of pixels of adjacent scan lines are generated to enhance vertical scene resolution. A sinusoidal deflection circuit and microdeflection yoke produce the desired waveform, and a distortion compensation circuit corrects for distortions of the desired waveform.

Abstract: A deflection circuit is coupled to a horizontal deflection winding for generating scanning current in the winding. A retrace pulse voltage is developed across the deflection winding during the retrace interval. A flyback transformer is coupled to the deflection circuit and has retraced pulse voltages developed across windings thereof. A source of supply energy is coupled to a first winding of the flyback transformer and a load circuit, such as a high power audio circuit, is coupled to a second winding of the transformer and draws load current therefrom. A switched mode power supply is coupled to the source of supply energy and to the flyback transformer for controlling the transfer of energy between the source and the load circuit. A compensation circuit responsive to the operation of the switched mode power supply produces variations in current in an inductance coupled to the flyback transformer. These variations are indicative of variations in load current drawn by the load circuit.

Abstract: A horizontal deflection circuit with raster distortion correction includes a horizontal deflection winding coupled to a first retrace capacitor and an input inductance such as the primary winding of a flyback transformer coupled to a second retrace capacitor. Horizontal switching elements are operated at a horizontal deflection rate for generating current in the inductance and a horizontal scanning current in the deflection winding. During retrace, the horizontal deflection winding and the first retrace capacitor form a first resonant circuit and the input inductance and the second retrace capacitor form a second resonant circuit. One of the switching elements decouples the resonant circuits from each other to minimize the interaction therebetween. A source of raster distortion correction current is coupled to the deflection winding to provide the required scanning current modulation.

Abstract: A power supply and deflection circuit for a video monitor provides multiple horizontal scan rates. A switch is used to select the desired scan rate. Operation of the switch determines the proper operating voltage level for the horizontal deflection circuit. A zener diode provides a high or low signal in response to the level of the determined operating voltage. The horizontal oscillator frequency and the value of the S-shaping capacitor is determined in response to the high or low signal. The operation of the switch, therefore, provides the necessary circuit parameter changes for each of the horizontal scan rates selected.

Abstract: An inside-outside pincushion correction circuit includes an arrangement of first and second branches that provide a pair of current paths to a deflection current that flows in a deflection winding. The first branch includes a modulation inductance and the second branch includes a modulation capacitance that is coupled across the modulation inductance by a switch at a controllable time during the retrace interval. The controllable time varies in a vertical rate parabolic manner to provide deflection current modulation to correct inside and outside pincushion distortions. Variation of the retrace interval associated with the modulation inductance are compensated by offsetting variations produced by the retrace capacitance.

Abstract: A cathode ray tube focusing circuit includes a first operational amplifier for receiving a sawtooth wave signal from the vertical deflection circuit of a cathode ray tube video circuit and for producing a parabolic output signal from the sawtooth wave signal. Also included is a second operational amplifier for receiving both the parabolic signal produced by the first operational amplifier and a parabolic wave signal produced by the S-correction capacitor of the horizontal deflection circuit of the cathode ray tube video circuit. The second operational amplifier inverts the parabolic wave signal received from the first operational amplifier and adds this inverted signal to the parabolic wave signal received from the horizontal deflection circuit to produce a parabolic signal envelope. This parabolic signal envelope is inverted, amplified and supplied to the focus electrode of the cathode ray tube to modulate the focus electrode's static voltage.

Abstract: A color cathode ray tube display device which is compensated for color distortion due to, e.g. vibration, comprises means (9-12) for producing signals representing the respective color light outputs from the phosphor screen (5), means (13) for comparing the signals with the corresponding color impact video signals and means (14) to provide a correction signal to reduce any deviation between the signals.