Sony Corporation

Akira Tooyama

Takashi Hosono

Takashi Tooyama

Akio Ohkoshi

Takahiro Yukawa

Ichiro Mitamura

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; a reading circuit for reading the correction values from the memory; a correcting signal forming circuit for sensing fluctuation in the value of a high voltage supplied to an anode of the cathode-ray tube from a high voltage source and for producing a correcting signal in response thereto in accordance with the formula: .DELTA.V(t)=a(V.sub.H (t)-V.sub.HO)-b'x.sub.H .multidot.(d/dt.multidot.V.sub.H (t), where V.sub.H (t) is the instantaneous value of the high voltage, V.sub.HO is a constant value voltage, a and b are constants and X.sub.H corresponds to the amount of electron beam deflection; and a scanning rate modulating circuit supplied with the correction values read by the reading circuit and supplied with the correcting signal for substantially cancelling any deviation in the horizontal scanning rate from the desired rate.

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

Apparatus for controlling the electron beam in a beam index color television receiver of the type having a cathode ray tube whose display screen is provided with beam-excitable color elements and index elements which are scanned by the beam. The apparatus comprises an index signal generator for generating a periodic index signal as the index elements are scanned by the beam. Color gates are provided for sequentially gating respective color control signals individually to modulate the electron beam as that beam scans the color elements. A gating signal generator generates sequential gating signals at a frequency synchronized with the frequency of the periodic index signal. These gating signals are supplied in sequence to the color gates to control the latter so as to gate the respective color control signals. A driving circuit responds to the periodic index signal to drive the gating signal generator. The driving circuit includes a time adjustment circuit for compensating the inherent time delay of the overall apparatus such that the respective color control signals are gated in time correspondence with the position of the beam at a color element that is associated with the gated color control signal.

Beam index color television receiver apparatus

A beam index color cathode ray tube has index stripes spaced apart across a run-in area of the screen which have a pitch substantially equal to the pitch of index stripes in an image area, and a predetermined number of the index stripes in the run-in area are counted as an electron beam scans them to preset color control circuits to a predetermined condition at the commencement of scanning of the image area. A characteristic of the signal resulting from scanning of the index stripes may be used to begin the counting thereof from a specific one of the index stripes in the run-in area other than the first one encountered by the electron beam.

Beam index color cathode ray tube

A beam index color cathode ray tube has index stripes spaced apart across a run-in area of the screen and which have a pitch substantially equal to the pitch of index stripes in an image area. A plurality of the index stripes in the run-in area generate an index signal as an electron beam scans them. An index stripe is omitted from the portion of the run-in area nearest the boundary with the image area to provide a characteristic to the index signal which permits generation of a trigger signal to preset color control circuits to a known condition as the electron beam enters the image area. A gating circuit blocks trigger signals which may be generated during scanning of the image area.

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Tokyo, Japan

Akira Tooyama