| 摘要 |
A display device comprising a CRT having a reduced number of components for automatic cutoff adjustment. The device needs an IC having a less number of connection pins. The device adds reference pulses to given portions within every field of video signals. The resulting cathode currents are converted into voltage pulses. These voltage pulses are compared with a reference voltage by a comparator. The output signal from this comparator is counted by forward-backward counters for three primary colors, respectively, and converted into analog form. Level shift circuits for the three primary colors, respectively, control the DC components of the video signals according to the output signals from the D/A converters. In this way, the cutoff characteristics of the CRT are controlled.
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