| 摘要 |
A beam index type color television receiver having a beam index type color cathode ray tube which includes a screen having a plurality of groups of color phosphor elements and index phosphor elements, an index signal sensing device for detecting index signals from the index phosphor elements and generating index pulses, a frequency multiplier for providing a timing signal with a frequency that is a multiple of the frequency of the index pulses, a gate signal generator supplied with the timing signal from the frequency multiplier and generating a plurality of gate signals, a gate circuit for sequentially selecting, response to the gate signals three primary color signals desired from an input video signal and supplying the selected primary color signals to the cathode ray tube, and a velocity modulating device for modulating the beam scanning velocity of the cathode ray tube. To control the modulation of the beam scanning velocity, a video signal level detecting circuit detects the level of the input video signal, and a velocity modulating signal generating circuit supplies a velocity modulating signal to the velocity modulating circuit in response both to the output of the video signal level detecting circuit and to the timing of the index pulses.
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