Abstract: An aperture compensation circuit which includes a first differentiating circuit for differentiating an input signal to its input terminal to provide a primary differentiated signal, a squaring circuit for squaring the primary differentiated signal to provide a first signal, a second differentiating circuit for differentiating the primary differentiated signal from the first differentiating circuit to provide a secondary differentiated signal as a second signal, and a dividing circuit for dividing the first signal by the second to provide a contour compensation signal which is not affected by the steepness degree of the input signal.

Abstract: A television receiver in which a plurality of picture-displaying fluorescent lines (3), which are disposed on a screen (2) as the display surface of a cathode ray-tube so as to extend in the horizontal direction (in the direction of the arrow X) as the beam main-scanning direction, and in the vertical direction (in the direction of the arrow Y) as the beam sub-scanning direction, and a single electron beam is arranged to scan across the screen (2) to display a picture. The television receiver has two kinds of beam detection stripes (5A), (5B) disposed in each respective guard band portion between adjacent fluorescent lines (3) so as to be parallel to the fluorescent lines (3). On the basis of beam detection signals independently taken from the beam detection stripes (5A), (5B) in correspondence to beam spots (S) of the electron beam on the screen (2), the vertical positions (in the direction of the arrow Y) of the electron beam spots (S) with respect to the fluorescent lines (3) are controlled.

Abstract: A beam index type color television receiver having a beam index type color cathode ray tube which includes a screen having a plurality of groups of color phosphor elements and index phosphor elements, an index signal sensing device for detecting index signals from the index phosphor elements and generating index pulses, a frequency multiplier for providing a timing signal with a frequency that is a multiple of the frequency of the index pulses, a gate signal generator supplied with the timing signal from the frequency multiplier and generating a plurality of gate signals, a gate circuit for sequentially selecting, response to the gate signals three primary color signals desired from an input video signal and supplying the selected primary color signals to the cathode ray tube, and a velocity modulating device for modulating the beam scanning velocity of the cathode ray tube.

Abstract: A method and apparatus for improving the sharpness of a video picture displayed on the screen of a cathode ray tube. At least one electron beam scans the screen in line-scanning and vertical directions, respectively, the electron beam having its intensity modulated in accordance with a video signal. The scanning velocity of the electron beam is modulated in the line-scanning direction in accordance with transitions of the video signal which correspond to transitions between high and low brightness levels of the displayed video picture. Each electron beam is shaped to have a substantially oval shape whose longer axis is disposed in the line-scanning direction and whose shorter axis is disposed in the vertical direction, whereby the oval-shaped beam impinges upon the display screen and the sharpness of the displayed video picture in the vertical direction is improved.

Abstract: In a beam index color television receiver having the screen of its color cathode ray tube provided with a repetitive pattern of a plurality of groups of different primary color phosphor elements arranged side-by-side across the image area of the screen to be scanned by a single electron beam as the latter is selectively modulated by respective color signals, index and mode set signals are provided in response to scanning by the beam of respective locations on the screen which are interspersed across the latter with distances therebetween which are non-integrally different from the pitch of the groups of color phosphor elements, and with adjacent locations corresponding to the mode set signal being spaced apart by an integral multiple of such pitch.

Abstract: In a video signal reproducing apparatus having a cathode ray tube in which at least one electron beam is made to scan a screen in line-scanning and vertical directions while the intensity of the beam is modulated to establish the brightness of a video picture to be displayed on the screen, and in which bright picture portions are represented by respective high level portions of a video signal defined between rising and falling edges extending from low level signal portions representing contiguous dark picture portions; a waveshaping circuit receives the video signal and acts thereon to provide a compensated video signal in which the width of each high level portion between the respective rising and falling edges is increased, the compensated video signal is employed to control the intensity of the electron beam, the rising and falling edges of each high level portion of the video signal are detected to provide a beam velocity modulation signal with respective positive and negative peaks by which the scanning

Abstract: An aperture correction circuit is disclosed in which the first portions of the differentiated signals of input video signals are inverted, and the waveform shaped signals thus obtained and the input video signals are added together whereby the corrected video signals having sharp edged waveforms are obtained.