Cathode ray tube having index strip electrode

In a color television receiver adapted to receive a composite color television signal including a color video signal interleaved with a vertical blanking pulse, comprising a cathode ray tube having a faceplate at one end thereof, an electron gun at the other end for emission of an electron beam toward said faceplate, means for modulating in intensity said electron beam in accordance with the color video signal, a phosphor screen on said faceplate, means for scanning said beam in a first direction, means for deflecting said beam in a second direction normal to said first direction to form a rectangular raster on said phosphor screen, said phosphor screen having recurrent groups of successively arranged color emitting strips extending parallel to said second direction, the improvement comprising:

• a. a comb-like electrode arranged on said faceplate outside of said raster and having a plurality of teeth successively arranged at equal spacing along one edge of said raster parallel with said first direction;
• b. an elongated electrode arranged on said faceplate such that said electron beam impinges thereon at the start of each scanning to produce a start signal;
• c. an auxiliary electrode adjacent said electron gun;
• d. circuit means for causing said deflecting means to deflect said electron beam to said comb-like electrode to scan thereacross during the interval of said vertical blanking pulse to produce an indexing signal;
• e. memory means coupled to said comb-like electrode for storing said indexing signal for the duration of one field scan;
• f. a signal source producing a constant frequency signal;
• g. means connected to said memory means and to said signal source for comparing said indexing signal and said constant frequency signal to produce a control signal, said control signal being applied to said auxiliary electrode;
• h. means coupled to said elongated electrode for generating trains of regularly occurring pulses;
• and
• i. gating means energized by said pulses and adapted to receive said color video signal for sequentially gating on said video signal to said modulating means.

A color television transmitter including a color camera tube having a faceplate at one end thereof, an electron gun at the other end for emission of an electron beam toward said faceplate, a color filter on said faceplate and having recurrent groups of successively arranged strips extending in a first direction for passing light of different colors, a photoelectrical layer inwardly from said filter, means for scanning said electron beam in a second direction normal to said first direction, means for deflecting said beam in a direction parallel with said first direction whereby said photoelectrical layer is scanned in a rectangular form, said scanning and deflecting means thereby cooperating with one another to produce a video signal which will contain a vertical blanking pulse at an output terminal of said tube, the improvement comprising:

• a. a comb-like electrode arranged on said faceplate outside of the rectangular scanned area and having a plurality of teeth successively arranged at equal spacing along one edge of said rectangular form parallel with said second direction;
• b. circuit means for causing said deflecting means to deflect said electron beam to said comb-like electrode to scan thereacross during the interval of said vertical blanking pulse to produce an indexing signal;
• c. memory means coupled to said comb-like electrode for storing said indexing signal for the duration of one field scan;
• d. means coupled to said memory means for generating trains of pulses representative of the instantaneous freqencies of said indexing signal, said pulse trains being equally spaced from each other;
• and
• e. gating means energized by said pulses and adapted to receive said video signal for sequentially gating on each color signal component of said video signal.