Abstract: Aspects provide for a circuit including a voltage supply, a driver, and a feedback bias circuit. The driver includes a first p-type field effect transistor (FET) and a first n-type FET. The voltage supply has an input and an output. The driver has a first input coupled to the voltage supply output, a second input coupled to a first node, and an output coupled to a second node. The first p-type FET has a gate coupled to the output of the driver, a source coupled to the voltage supply output, and a drain coupled to the second node. The first n-type FET has a gate coupled to the output of the second driver, a drain coupled to the second node, and a source coupled to a ground node. The feedback bias circuit has an input coupled to the second node and an output coupled to the voltage supply input.

Abstract: Disclosed are an online alternating current detection device and method. The method includes the following steps: firstly fixedly connecting two sampling points to a segment of wire; amplifying the voltage difference of the sampling points to obtain a median value; subsequently rectifying and filtering and amplifying the median to obtain a direct current amplified value; then utilizing the amplified value, the median value, the multiplying power there between and the resistance value of the wire between the two sampling points to calculate an estimated value of an alternating current; comparing the estimated value to a reference value measured by a standard device between the two sampling points; then adjusting the multiplying power of the amplified value relative to the median until the estimated value coincides with the reference value, only then can the alternating current be measured online.

Abstract: An electrostatic deflection circuit and method of an electronic beam measuring apparatus which can achieve the high precision of the electronic beam measuring and contribute to the simplification of the structure of the apparatus is provided. In an analog arithmetic circuit included in an analog operation part constituting an electrostatic deflection circuit, output voltages of multipliers are added and output by an adder. When the magnification is low, as the side of an ordinarily closed contact is closed driven by a relay driving circuit, the output of the adder is amplified by a high gain amplifier with a high amplification factor and applied to an electrostatic deflecting board. When the magnification is high, the side of an ordinarily open contact is closed and it is amplified by a low gain amplifier with a low amplification factor and applied to the electrostatic deflecting board in the same way.

Abstract: A high-power amplifier having a current-adding array is provided for high-speed driving of an inductive element, e.g., a deflection coil of an electron beam gun. The amplifier includes a first voltage node (U1) and a second voltage node (UV), at least one of which is connected to a regulated power supply, and a plurality of first switchable bridges (B11, B12, B13, . . . , B1k) connected in parallel between the first and second voltage nodes. Each switchable bridge includes at least one resistor (R11, R12, R13, . . . , R1k) with a resistance value that is selected so that a first resistor (R11) has a first resistance value WR11 equal to Rmin, a second resistor (R12) has a second resistance value WR12 greater than or equal to WR11 and an n-th resistor has an n-th resistance value WR1n greater than or equal to WR1n?1.

Abstract: A horizontal deflection circuit having a horizontal output transistor that receives an input horizontal driving signal and drives a horizontal deflection coil includes a current controlling unit to selectively perform an operation to decrease a base current applied to a base terminal of the horizontal output transistor, and a controlling unit to sense a frequency of the horizontal driving signal and to enable the operation of the current controlling unit when the sensed frequency of the horizontal driving signal is higher than a predetermined level. Accordingly, the horizontal deflection circuit can control the base current of the horizontal output transistor according to a frequency mode, thereby decreasing damage to the horizontal output transistor.

Abstract: The invention concerns a scanning circuit, comprising a power supply providing a negative voltage on a first terininal (Tdown), an intermediate voltage on a second terminal (Gnd) and a positive voltage on a terminal of a switch (S), the other terminal of the switch being connected to a third terminal (Tup), a control circuit (6) supplied by connections to the second and third terminals, a differential amplifier receiving a positive and a negative input signal provided by the control circuit, a power amplifier controlled by the differential amplifier, both amplifiers being supplied by connections to the first and third terminals, a deflection coil (Ly) connected between the output of the power amplifier and the second terminal, biasing means setting, when the switch is open, the output of the differential amplifier so that the possible current paths through the power amplifier between the deflection coil and the first terminal are cut.

Abstract: The invention provides a circuit for controlling a cathode ray tube. The circuit comprises a source of input color signals (Uin(R), Uin(G), Uin(B)) for the primary colors of the cathode ray tube. Output amplifiers are coupled to the source of color input signals and to electron guns of the cathode ray tube. Finally, limiting means are provided to limit the color input signals to a predetermined threshold value. In this way the output amplifiers are prevented from saturation and undesirable smears do not appear on the screen. In an advantageous embodiment the limiting means are realized by a diode biased in reverse direction.

Abstract: A line scan circuit for a CRT, including, in series across a switch, two oscillating circuits having the same time constant, each including, in parallel, a capacitor, a diode connected in antiparallel, and a series association of an inductor and of a voltage source, the inductor of a first one of the oscillating circuits being a scan coil of the CRT; an amplifier receiving a set-point voltage and using, as a feedback, a voltage taken from one of the oscillating circuits, and providing an adjustable voltage source to the second oscillating circuit.

Abstract: A circuit for regulating a signal, such as a cathode current. The circuit has an input stage for inputting a signal and for producing a sense signal based thereon. The circuit may input timing signals and have a first stage for comparing a first reference signal with the sense signal when a first timing signal indicates and for outputting a first correction signal based on the comparison. The circuit may have a second stage for comparing a second reference signal with the sense signal when a second timing signal indicates and for outputting a second correction signal based on the comparison. The circuit may further have elements for measuring a leakage signal in the input signal during a third time interval. In this embodiment, the first and second stages are further for subtracting the leakage signal from the sense signal prior to the comparisons.

Abstract: An image distortion compensating apparatus controls a convergence yoke, and includes a compensation value generator for calculating a convergence compensation value for compensating a convergence distortion which occurs while an image signal is emitted onto a display apparatus, the compensation value generator outputting the convergence compensation value after compensating for a phase and a gain of the convergence yoke; an amplifier for D-class amplifying of the convergence compensation value; and a convergence yoke attached to the display apparatus for controlling a path of electron beams corresponding to the image signal, based on the convergence compensation value as amplified at the amplifier.

Abstract: A video signal is split into a first signal and a second signal. The first signal includes low amplitude/high frequency components of the video signal, which can be properly amplified by a video amplifier. The second signal includes high amplitude/high frequency components of the video signal, which cannot be properly amplified by the video amplifier. The first signal is combined with the video signal, amplified by the video amplifier, and used to modulate the intensity of an electron beam. The second signal is amplified by a scan velocity modulation amplifier and used to modulate the horizontal scan velocity of the electron beam.

Abstract: A horizontal deflection circuit generates a horizontal deflection current in a deflection winding, during a trace interval and during a retrace interval of a deflection cycle. A transistor is responsive to a vertical rate parabola signal and to a negative feedback signal for producing a vertical rate parabolic modulation voltage at a collector of the transistor. A negative feedback network generates the feedback signal that is indicative of a current flowing in the transistor for increasing an output impedance at the collector of the transistor. An inductor is coupled to the collector of the transistor for producing in the inductor a modulation current to provide for side pincushion distortion correction in an East-West modulator.

Abstract: Disclosed is a device to control a circuit for the vertical deflection of a spot scanning a screen, and more particularly a control device whose output amplifier stage works in class D mode at the rate of a switching signal called a first switching signal. The control device has an internal auxiliary supply to generate the overvoltage needed for the fast flyback of the spot. This auxiliary power supply is a switching voltage generation circuit whose switching signal, called a second switching signal, is synchronous with the first switching signal. The present invention has been shown to used advantageously in television screens and/or computer screens.

Abstract: The present disclosure describes an improved scan velocity modulation technique for a raster display system. A video signal is split into a first signal and a second signal. The first signal includes low amplitude/high frequency components of the video signal, which can be properly amplified by a video amplifier. The second signal includes high amplitude/high frequency components of the video signal, which cannot be properly amplified by the video amplifier. The first signal is combined with the video signal, amplified by the video amplifier, and used to modulate the intensity of an electron beam. The second signal is amplified by a scan velocity modulation amplifier and used to modulate the horizontal scan velocity of the electron beam.

Abstract: A CRT display apparatus capable of displaying images in high contrast and high brightness without causing noises and halftone-reproduction degradation within dark areas is disclosed. The apparatus includes a circuit for generating an R-control signal, a G-control signal and a B-control signal by removing, from each of the R-, G- and B-video signals, portions which are below a predetermined level in amplitude, an amplification circuit for inverting and amplifying the R-, G- and B-control signals, and a selection circuit for selecting, for each of the three G1 electrodes, either a corresponding one of the R-, G- and B-control signals inverted and amplified by the amplification circuit or a potential of a predetermined value in accordance with an instruction from an outside, and applying each of the three G1 electrodes with a selected one of the corresponding one of the R-, G- and B-control signals and the potential.

Abstract: A capacitor for outputting a reference signal is formed by using a part of an envelope. A reference signal according to an anode voltage is output from the capacitor for outputting a reference signal. An unnecessary signal component included in an index-detection signal which is output via the capacitor for outputting an index signal is eliminated on the basis of the reference signal. With the configuration, only the required index-information signal is extracted from the index detection signal with high accuracy at a high SN ratio.

Abstract: One embodiment of the present invention includes a temperature sensor with current mode output utilized within a cathode ray tube (CRT)-based display system for providing thermal protection to a CRT driver. Specifically, the current mode output temperature sensor of the present embodiment is implemented with the CRT driver of the CRT display system. Furthermore, the temperature sensor has a current sink output that is connected to an Automatic Brightness Limiter (ABL) circuit of the CRT display. The current sink of the temperature sensor operates in a manner similar to an “OR gate” with the CRT anode current. As such, when the CRT driver temperature rises above a threshold temperature, the current mode output temperature sensor sinks a current and activates the ABL circuit. As a result, the video amplitude of the CRT driver is reduced and its temperature is stabilized.

Abstract: In a CRT display device including a CRT (MM tube) having brightness higher than that in the background-art CRT, it is an object of the present invention to improve contrast and prevent conspicuous recognition of noises. A video signal modulation circuit (10) modulates a video signal (9) (first video signal) into a second video signal having a signal level in an area of low gradation level lower than a signal level of the first video signal. A cathode bias voltage source (7) generates a driving voltage on the basis of the second video signal. It is therefore possible to keep the driving voltage in the area of low gradation level low and reduce brightness in the area of low gradation level of a CRT (1). As a result, noises of an image in the area of low gradation level are not conspicuously recognized and a contrast value is increased, resulting in improvement in image quality.

Abstract: The control device includes an output amplifier stage ETS supplied by a main supply for controlling the vertical scan of the spot, and an auxiliary supply capable of delivering an overvoltage and a first two-way switch connected to the output stage and controllable to allow the overvoltage to be delivered to the vertical deflection circuit for flyback of the spot. The output stage is a stage having at least two transistors which are capable of operating in alternating switching mode, at least for control of the vertical scan of the spot, this stage being associated with a smoothing filter connected to the common terminal of the two transistors. The device includes a second two-way switch connected between a first transistor of the output stage and a first terminal of the main supply and controllable to prevent delivery of the overvoltage during control of the vertical scan of the spot.

Abstract: A vertical linearity correction circuit including diodes and resistors is provided in a vertical deflection circuit, and a vertical deflection voltage applied to a vertical deflection yoke is corrected so as to follow a change in input impedance of the vertical deflection yoke. As a result, the vertical deflection speed in the vicinity of the central part of the image plane of the color picture tube is prevented from decreasing.

Abstract: The invention relates to a method and a device for reducing an electric field produced by display devices equipped with cathode ray tubes, in their surroundings. According to the invention, a part of a spectrum (ff), caused by a picture content, the level of which is separately adjusted, is discriminated from an interference voltage frequency spectrum (fs), produced by the display terminal and caused by deflection signals (fv, fh). Spurious pulses, significant for the generation of the electric field, are connected to a compensation circuit, wherein they are summed and supplied to a common emitter. The directions of the pulses are determined so that the electric field produced by the emitter reverses the field produced by the display device.

Abstract: A dynamic focusing circuit of a monitor system capable of easily compensating a defocusing of a screen which often occurs in the monitor system which adopts a CRT. When vertical and horizontal parabolic signals is output from oscillation signal generating section, first and second amplifying sections amplify the vertical and horizontal parabolic signals, respectively, and output vertical and horizontal parabolic amplification signals, respectively. Signal mixing section mixes the vertical and horizontal parabolic amplification signals respectively output from the first and second amplifying section to apply a dynamic focusing signal to a focusing electrode. Accordingly, delay and distortion of the signal caused by the stray-capacitance of the transformer does not occur. Also, the waveform of the dynamic focusing signal is stably maintained even though the user changes a vertical or a horizontal size of the screen of the monitor system.

Abstract: A vertical deflection amplifier drives a vertical deflection coil according to a ramp input signal and has a current sensing resistor providing a feedback signal. The vertical deflection coil is subject to crosstalk or excitation by a horizontal deflection coil. A compensation network is coupled between a source of the horizontal deflection signal and the current sense resistor, and has a network that produces a corrective current in the current sense resistor to substantially cancel horizontal rate crosstalk component from the feedback signal.

Abstract: A hardware-implemented screen-saver prevents burn-in of an image displayed on a screen of a display product by automatically reducing the video gain, and therefore the contrast, of the image when the portion of the image within a two-dimensional detection window has changed by less than a predetermined amount for a predetermined period of time. A lack of change of the incoming video signal of the image is detected and used to invoke a reduction in contrast of the image displayed on the display product. This allows the image to remain visible, yet reduces the possibility of burn-in of the image in the screen of the display product.

Abstract: A Braun tube discharge apparatus that includes a so-called spot killer function. In the apparatus, an operational amplifier included in a vertical IC receives a vertical ramp signal from a one-chip IC at the non-inversion input terminal. The operational amplifier also receives a part of the output as a negative feedback to the inversion input terminal, and performs differential amplification of it and transmits the results to a vertical deflection coil. At the time a spot killer circuit discharges a remaining electrical charge held by a Braun tube when the power is turned off, a switching transistor is rendered conductive by using a spot killer pulse signal that instructs the activation of the spot killer circuit. When the negative feedback input side of the operational amplifier drops to the ground level, the center DC value of the vertical output signal is increased, and the amplitude is increased.

Abstract: A video imaging apparatus includes a source of a periodic dynamic focus voltage blanking signal. A dynamic focus voltage amplifier includes a switch responsive to the dynamic focus voltage blanking signal for applying a dynamic focus voltage to a focus electrode, when the switch is at a first state, and for disabling the application of the dynamic focus voltage, when the switch is at a second state to provide for automatic kine bias measurement. A second switch responsive to the focus voltage blanking signal is coupled to the amplifier for applying a current to a stage of the amplifier, when the dynamic focus voltage is disabled. The applied current adjusts the focus voltage, to a level closer to that established immediately after the dynamic focus voltage is enabled for reducing a transient condition.

Abstract: A horizontal deflection circuit for a monitor is disclosed.

Abstract: Disclosed is a circuit for adjusting a horizontal center of a raster displayed on a monitor CRT, which includes a current generating circuit which can control an amount of a direct current flowing through a horizontal deflection yoke of the monitor based on a control voltage, a first voltage, and a second voltage. A control part generates the control voltage in response to a center adjustment signal. A voltage generating circuit generates the first and second voltages, respectively. The first voltage has a higher potential than that of a B.sup.+ voltage which is applied to the horizontal deflection yoke, and the second voltage has a lower potential than that of the B.sup.+ voltage. The current generating circuit either generates a first current flowing into the horizontal deflection yoke to increase the direct current or a second current flowing out therefrom to decrease the direct current, such that the horizontal center of the raster is controlled.

Abstract: A magnetic deflection amplifier implemented using a linear amplifier connected to a first side of a deflection coil and a three pole switch connected to a second side of the deflection coil. The three pole switch connects the coil to ground during the active scan and connects the coil to a positive or negative high voltage rail depending of the polarity of the retrace current resulting in fast retrace time and reduced voltage requirements on the linear amplifier.

Abstract: A series arrangement of a deflection coil (Lf) and a series resistor (Rs) is connected between an output of a first output amplifier (1) and an output of a second output amplifier (2) to be driven in a bridge configuration for generating a deflection current (If) through the deflection coil (Lf). Across the series resistor (Rs), a voltage is generated which corresponds to the deflection current (If). A differential amplifier (5) has a first input connected to a first end of the series resistor (Rs). A second input of the differential amplifier (5) is connected to a second end of the series resistor (Rs) via a conversion resistor (Rc). An input current (Ii) is generated through the conversion resistor (Rc). The polarity of the input current (Ii) is selected to obtain a voltage across the conversion resistor (Rc) which has an opposite polarity with respect to the voltage across the series resistor (Rs).

Abstract: A non-switched, DC coupled vertical deflection circuit includes a source of a first DC supply voltage that is coupled to a first end terminal of a vertical deflection winding. An amplifier is energized by a second DC supply voltage having twice the magnitude of the first DC supply voltage and the same polarity. An output voltage of the amplifier having the same polarity of each of the first and second DC supply voltages is developed at a second end terminal of the deflection winding. The amplifier produces a deflection current at opposite polarities, during corresponding portions of a vertical trace interval.

Abstract: A deflection circuit generates a deflection current (If) through a deflection coil (Lf). The deflection circuit includes a series resistor (Rs) arranged in series with the deflection coil (Lf) to supply a feedback voltage (Vf;Vr), and a drive circuit (1,5) which has an output coupled to the series arrangement of the deflection coil (Lf) and the series resistor (Rs). The drive circuit (1,5) has an input coupled to the series resistor (Rs) to receive a feedback voltage (Vs). The drive circuit (1,5) further is coupled to a conversion resistor (Rc) for receiving an input waveform (Vi). The drive circuit (1,5) is arranged in a feedback loop to obtain a deflection current (If) with a shape resembling the input waveform (Vi). The deflection circuit further includes a damping impedance (Rd) arranged in parallel with the deflection coil (Lf), and a current generating circuit (3) for generating a correction current (Ic) within the flyback period (Tf).

Abstract: In a vertical sawtooth generator of a vertical deflection circuit, a first comparator generates an output signal when a retrace portion of a sawtooth signal is at a first magnitude to initiate a vertical trace portion of the sawtooth signal. An amplifier responsive to the sawtooth signal and to a reference signal generates a feedback current at a time that occurs between the center of vertical trace and the end of trace and away from the center of trace. The feedback current is determined in accordance with a difference between the sawtooth signal and the reference signal. The feedback current is coupled to a first capacitor to develop a gain control voltage. The control voltage is applied via a voltage-to-current converter to an integrating capacitor to develop in the integrating capacitor the trace portion of the sawtooth signal. The control voltage is initialized during a power start-up interval.

Abstract: A system to correct and adjust horizontal-direction pincushion and barrel distortions of scanning lines caused at upper and lower portions of a picture screen of a cathode-ray tube includes a pair of coils provided at a neck portion of the cathode-ray tube. An orbit of an electron beam made incident on a deflection center is shifted in the upper and lower directions by a magnetic field generated by the coils, thereby correcting distortion of scanning lines at upper and lower portions of a display screen of the cathode-ray tube.

Abstract: A pump-up circuit includes a first capacitor C1 connected to the power supply Vcc via a first change-over switch SW1 to the reference potential point or a second capacitor C2. The second capacitor C2 is charged by the voltage control circuit 45 under the control of the pump-up voltage control signal so that the capacitors C1 and C2 are charged respectively during the scanning period. Upon input of a NTSC signal, the change-over switch SW1 is connected to the reference potential point and the charging voltage of the first capacitor C1 is used as the pump-up voltage. Upon input of a signal having a short vertical flyback period such as the signal from personal computers, the total of the charging voltages at the first and second capacitors C1 and C2 is used as the pump-up voltage.

Abstract: A device for correcting the linearity of ramps of a saw-tooth signal provided across a capacitor, charged by a first current source and periodically discharged at a desired frequency. The device modulates the charging current of the capacitor by a correction current to render the ramps of the signal not linear. In addition, the device includes circuitry to render the correction current proportional to the current provided by the first current source.

Abstract: Such vertical deflection polarity switching circuit for CRT projector can be provided that enables external, one-shot operational switching of the vertical deflection polarity. To switch a CRT projector from a hanging type to a floor type, the switching circuit receives a vertical deflection polarity switching signal from an external device, so that an input sawtooth waveform polarity switching circuit will switch the polarity of a V. SAW signal. At the same time as the polarity of the input sawtooth waveform is switched, power-supply switching circuits switch the driving power-supply voltage of a vertical deflection-use output amplifier. Thus, the polarity of voltage waveforms applied to a vertical deflection yoke is inverted. Also, the polarity of vertical deflection and that of vertical-system data of correction waveforms for use in each of output circuits for horizontal deflection convergence focus are switched.

Abstract: A vertical deflecting circuit comprises a vertical output circuit (12) which amplifies an input sawtooth wave signal and supplies a deflection current to a vertical deflection coil (13), a power source (14) which applies a source voltage to the vertical output circuit, a first pump-up circuit (17) which raises the voltage from the power source, and a second pump-up circuit (18) which further raises the output voltage from the first pump-up circuit. In a fly-back time of a vertical output signal, the vertical output circuit is operated by the voltage from the second pump-up circuit, and the vertical output circuit is operated by the voltage from the power source during a time coefficient.

Abstract: In a highly accurate linear scan control for a CRT image display system useful for reproducing photographic images, distortion effects produced by system transients resulting from deflection drive amplifier circuits, are eliminated by introducing a step incremental increase in the input drive waveform at the start of the trace (scan) interval following the end of the retrace interval.

Abstract: A pair of current sources, each having a high output impedance, are coupled to a pair of first and second inputs of a differential input stage of a vertical deflection amplifier. An output of the amplifier is coupled to a vertical deflection winding. A current sampling resistor is coupled to the first input via a first resistor. The second input is coupled via a second resistor to a terminal of the sampling resistor that is remote from the first resistor. The first and second resistors are matched resistors for providing differential driving.

Abstract: In a D.C. coupled vertical deflection circuit, an input sawtooth signal is coupled to an inverting input of a vertical deflection amplifier via a first resistor network. A D.C. voltage is coupled to a second input of the amplifier via a second resistor network for preventing the D.C. signal component from affecting the deflection current. To provide temperature compensation, for every resistor included in the first resistor network, there is included a corresponding resistor of equal value in the second resistor network.

Abstract: Scanning beam velocity modulation or SVM may be employed to produce subjective enhancement of picture sharpness. However, impulsive SVM deflection current may produce unwanted crosstalk into other circuitry thus a circuit configuration is disclosed where SVM currents are confined. An apparatus for electron beam deflection comprises a cathode ray tube having a scanning electron beam. A coil for supplementary electron beam deflection is mounted on the cathode ray tube. An amplifier is coupled between a supply of power and a return circuit and has an input coupled to a signal representing a video signal edge transition. The amplifier has an output which is coupled to the coil for generating a pulse current therein for electron beam deflection responsive to the signal. The amplifier and the coil are configured for circulation of the pulse current mainly within the coil and amplifier output without substantial pulse current flowing in the power supply and return circuit.

Abstract: This invention relates to a circuit for solving a vertical interlace phenomenon generated by the instability of servo control when a mode of VCR operation is fast or still, comprising a vertical pulse delay 101 for delaying a vertical pulse inputted from a vertical and horizontal oscillator 100 for the time of a certain horizontal lines, a vertical driving part which transforms the vertical pulse delayed from the vertical pulse delay 101 into a vertical a tooth wave pulse, and amends the transformed vertical a tooth wave pulse according to the vertical position signal inputted to be made relayed as a feedback, a vertical deflection amplifying part for amplifying the amended a tooth wave pulse inputted from the vertical driving part 102, a vertical position detecting part 105 for detecting a vertical position of a picture from the signal inputted from the vertical deflection amplifying part 103 through a vertical deflection coil 104, a Micom 106 for controlling an operation of the vertical pulse delay 101 and

Abstract: A vertical deflection waveform generating apparatus is provided to have a memory in which a function of a vertical deflection waveform is previously stored. The function is a function with an order of horizontal scanning lines in which linearity of a raster is corrected as a parameter. The vertical deflection waveform generating apparatus generates a vertical deflection waveform by a digital signal processing circuit substituting a scanning order of the next scanning line in the parameter of the function, and sequentially outputting vertical deflection voltage at each time of detection of a horizontal synchronizing signal. Further, in order to reduce raster moire, timing for generating the vertical deflection waveform is offset for each frame.

Abstract: A vertical deflection circuit includes a first pin which receives a forward scanning voltage having a first level and a first frequency. During a flyback period a second pin receives a flyback voltage having a second level higher that the first level and a second frequency higher than the first frequency. A third voltage source provides a first pulse. A switch means selectively couples the first pin and the third voltage source in response to a vertical blanking signal. The vertical blanking signal is differentiated to provide a differentiated signal and a voltage divider applies the differentiated signal to the switch to apply the first pulse to the first pin.

Abstract: A scanning waveform generator for operation at a first or a second scanning frequency comprises a source of a parabolic shaped signal having a frequency selectable between the first or second scanning frequency. A means for generating a switching signal indicative of a video signal operating at one of a first or a second scanning frequency. A means for generating a sawtooth shaped waveform is coupled to the switching signal for switching between the first or the second scanning frequency. A means for generating an S correction signal is coupled to the source and to the sawtooth generating means. A means for filtering the parabolic signal is controllably coupled to the switching signal generator, and is also coupled to the S correction signal generating means. The filtered parabolic signal has an substantially the same shape during the first or second scanning frequency.

Abstract: A television receiver is controlled as to the degree of vertical zoom via a deflection current ramp that varies in slope and which may be delayed to achieve panning. Due to the increased slope when zoomed, the deflection current and the electron beam complete a trace in less time than the normal vertical interval. The deflection current is maintained at one extreme or the other outside the trace interval, and the beam is blanked. A retrace signal generator coupled in a feedback loop with the power supply for the deflection circuit determines the midpoint of the blanking period and generates a fast retrace at or near the midpoint. The feedback loop is arranged to minimize the DC average current in the deflection winding by having a current source responsive to the DC average current for charging a timing ramp that triggers retrace upon reaching a threshold. The slope of the timing ramp varies with DC loading, thus advancing or retarding retrace to center retrace in the blanking interval.

Abstract: A differential amplifier formed by a pair of transistors couples a vertical sawtooth signal to an input side of a vertical deflection amplifier. Nonlinearity of the transistor pair provides S-correction in the vertical direction. The current in the transistor pair varies when vertical height is adjusted, in service operation, so that the nonlinearity changes. In a vertical shrink mode of operation, the amplitude of the sawtooth signal is reduced. The nonlinearity associated with a given level of the sawtooth signal that corresponds to a given vertical position in the vertical shrink mode is the same as that associated with the same level of the sawtooth signal in the vertical, non-shrink mode.

Abstract: A circuit for generating a vertical frequency deflection current for the electron beams in the picture tube of a television receiver includes a current sensor resistor having one end connected to direct voltage potential by two resistors connected in series and a second end connected to a vertical frequency sawtooth signal by two additional resistors connected in series. An error signal generator has one input terminal connected to the junction the first two resistors and another input terminal connected the junction of the second two resistors. An output stage supplies the deflection current. The output terminal of the error signal generator is connected to the input terminal of the output stage. The error amplifier is a transconductance amplifier having an output terminal connected to reference potential by a series connection of a resistor and a capacitor.

Abstract: Apparatus and method for generating a correct CRT display suitable for photographing without adjustment, regardless of horizontal and vertical timing signals. Sawtooth current waveforms of constant maximum amplitude and "S" bending are generated through the horizontal and vertical windings of the deflection coils for the CRT display in order to produce a scan of constant width, height, and horizontal and vertical linearity.