| 摘要 |
A television receiver includes a character generator for producing alphanumeric data or graphic symbols to be displayed along with a received video signal. An oscillator, locked to a multiple of the color subcarrier frequency of the video signal, supplies a clock signal to the character generator for controlling the timing of displayed character elements. A delay circuit coupled to the character generator and controlled by a measuring circuit imparts an effective delay to the character elements in proportion to the time difference between a transition of the clock signal and the horizontal synchronizing component of the video signal. The delay compensates for temporal and spacial distortions of displayed characters which otherwise would tend to occur when the ratio of the color subcarrier frequency with respect to the horizontal line rate of the video signal is "non-standard" (e.g., other than 910:1 for NTSC or 1135:1 for PAL). |
