| 摘要 |
A method and apparatus is disclosed for restoring the d.c. level of a composite video signal which has a burst of chrominance subcarrier cycles occuring in the horizontal blanking period. The d.c. level of the signal is measured using integrating techniques for a period that corresponds to a whole number of cycles of the chrominance subcarrier and the measured level is used to generate an error signal for adjusting the level to the proper volume. By using a precise whole number of cycles during integration, the d.c. level can be accurately measured.
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