Abstract: Deflection control apparatus for a beam index color television receiver includes a phase-locked loop for synchronizing an oscillating signal with an index signal generated by an electron beam scanning index stripes on the screen of the cathode ray tube of the receiver. The oscillating signal is supplied to a color switcher so that the scanning electron beam is modulated with color information corresponding to the respective color phosphor stripe being scanned. An error signal representative of the horizontal scanning speed of the beam is supplied to a deflection device to cause the generation of a compensating magnetic field to correct for non-linearities in the scanning speed. A compensation circuit delays the error signal so that the elapsed time from the detection of the scanning of one of the index stripes to the time of generation of the compensating magnetic field in accordance therewith equals one horizontal line period.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A control system for a beam index cathode ray tube momentarily gates or turns off all beam current at the transition from one color modulating signal to another. The resulting dip in the electron beam density, as it scans across an index phosphor stripe located between adjacent color phosphor areas, produces a substantially corresponding dip in the index signal derived from excitation of the index phosphor stripe by the electron beam. The dip in the index signal is detectable as an indication of the phase of the index signal substantially independent of differences in the amplitude of the electron beam current.

Abstract: 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.

Abstract: 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.