| 摘要 |
PURPOSE:To automatically eliminate a dispersal signal of 30Hz by detecting a level of a dispersal signal superposed on a MUSE signal with regard to the dispersal eliminating device of a MUSE decoder. CONSTITUTION:A superposed dispersal signal is eliminated automatically by a dispersal signal detecting circuit 10 for detecting whether a dispersal signal exists or not and whether a superposed level is large or small, a field pulse (FDP) generating circuit 11 subjected to phase lock to the dispersal signal, a reverse triangular wave generating circuit 12 for integrating a field pulse and generating a triangular wave of opposite polarity, and an adding circuit 9 for selecting and adding a reverse triangular wave signal of the same level as that of the dispersal signal. In such a way, by lenghening a time constant of a clamp circuit to some extent, deterioration of a picture quality at the time when an SN ratio falls can be suppressed.
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