| 摘要 |
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. The index signal can be provided by the scanning with the beam of index elements at the corresponding locations on the screen which emit light or other radiant energy, while the mode set signal may be provided in response to the absence of the index elements at the respective locations or to the presence, at the latter locations, of mode set elements which emit distinctive radiations when scanned by the beam. In any case, a gate pulse generator is responsive to the index signal to provide sequentially repeated gating signals by which the color signals are gated to selectively modulate the electron beam, and the phase and sequence of the gating signals are controlled in response to the mode set signal for ensuring that, as the beam scans each color phosphor element, the beam is modulated by the corresponding color signal. |
