Sony Corporation

Ichiro Mitamura

Katsuo Isono

Takashi Hosono

Masayuki Yasumura

Akira Tooyama

A horizontal scanning rate correction apparatus for a cathode-ray tube, particularly of the beam index color cathode-ray tube type, includes a memory for storing correction values representing deviations of the horizontal scanning rate of the electron beam from a desired scanning rate at each of a plurality of horizontal sampling positions along each of a plurality of predetermined horizontal sampling lines which are substantially fewer in number than the horizontal lines along which scanning occurs. During display of a video signal, a selected one of the stored correction values is read out of the memory for each scanning position of the beam along a scanned one of the horizontal lines, with each read correction value, and a corresponding sampling line correction signal produced therefrom, representing the deviation at a corresponding horizontal sampling position on one of the sampling lines. A scanned line correction signal is then produced for each horizontal scanning position which is a function of the sampling line correction signal and of the vertical position of the respective scanned line, and the scanned line correction signal is applied to the beam deflection yoke or device to substantially cancel the scanning rate deviation.

Horizontal scanning rate correction apparatus

Deflection control apparatus is disclosed for a beam index color television receiver of the type which includes a cathode ray tube adapted to display a video picture in response to a received color television signal. The beam index cathode ray tube is provided with index stripes which are scanned by the electron beam as the beam scans a raster across the display screen of the tube. A detector detects when the respective index stripes are scanned by the beam so as to produce an index signal, the frequency of which varies from a predetermined frequency value when the scanning speed of the beam varies. An oscillator generates an oscillating signal that is synchronized with the index signal, and a phase locked loop, which includes a comparator for comparing the index signal to the oscillating signal so as to produce a control signal as a function of the difference therebetween, adjusts the frequency of the oscillating signal in accordance with that control signal. The television receiver also includes a switching arrangement which is responsive to the oscillating signal to switch color information signals for the purpose of modulating the beam. The deflection control apparatus includes a deflection device for controlling the deflection of the beam; and a deflection signal generator responsive to the control signal produced by the phase-locked loop for supplying deflection control signals to the deflection device so as to vary the deflecting speed of the beam and thereby maintain a substantially constant scanning speed thereof.

Deflection control apparatus for a beam index color cathode ray tube

Horizontal scanning rate correction apparatus is provided for beam index color cathode-ray tubes of the type having a screen, an electron gun for projecting an electron beam upon the screen, a plurality of index elements positioned to be struck by the electron beam as it scans across the screen, a deflection device for causing the electron beam to repeatedly scan across the screen in a vertical succession of horizontal lines, and an index signal processing circuit for producing an index signal having a frequency determined by the frequency of the incidence of the electron beam upon the index elements as it scans horizontal lines and for controlling color switching circuitry which determines which of a plurality of color signals modulates the intensity of the electron beam. The horizontal scanning rate correction apparatus includes a memory circuit for storing correction values derived from the index signal processing circuit during horizontal scanning by the electron beam and representing the deviation of the horizontal scanning rate from a desired scanning rate at each of a plurality of horizontal sampling positions along a horizontal line. The apparatus further includes circuitry for reading the correction values from the memory circuit and for producing a corresponding signal which is supplied to the electron beam deflection device to substantially cancel deviations in the horizontal scanning rate.

Horizontal scanning rate correction apparatus for beam index color

A television horizontal deflection circuit is provided with a flyback transformer and a switching regulator transformer which are substantially magnetically independent of each other and which are connected with their primaries in series with a switching device and a source of input voltage. The secondary winding of the switching regulator transformer supplies power to a regulated D.C. voltage supply, which in turn supplies power to a resonant circuit. The resonant circuit is connected to a reference potential through the switching device and includes a damper diode, a resonant capacitor, a deflection coil and a series connected capacitor. A secondary winding of the flyback transformer is used to derive a high voltage for use in the high voltage anode of a television picture tube. In a preferred embodiment, the flyback transformer contains an additional winding which is connected between the regulated D.C. voltage supply and the resonant circuit. This additional or feedback winding is inductively coupled with the primary winding of the flyback transformer so that the flow of current through that primary winding while the switching means is conductive will impede the flow of current from the regulated D.C. voltage supply to the resonant circuit.

Growing community of inventors

Tokyo, Japan

Ichiro Mitamura