| 摘要 |
A dynamic focus circuit for achieving optimum focus for CRTs with any radius of the curvature. The dynamic focus circuit comprises a vertical rate correction waveform generator which generates a correction waveform in a vertical rate by digital operation; a digital-to-analog converter which converts the digital output of the vertical rate correction waveform generator to analog output; a horizontal rate correction waveform generator which generates a correction waveform in a horizontal rate by digital operation; and a digital-to-analog converter with variable reference voltage which receives the output of the digital-to-analog converter, that is the vertical rate correction waveform, as a reference voltage, and the output of the horizontal rate correction waveform generator as digital input for conducting digital-to-analog conversion.
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