| 摘要 |
Sample and hold detection aparatus for a coulor television receiver comprises a first sample and hold detector formed by transistor and capacitor which is rendered operative during the colour burst portion of a received chroma signal from signal detector and a second sample and hold detector formed by transistor and capacitor which is rendered operative during the rest of the colour subcarrier period and therefore provides a reference level representing quiescent circuit conditions, the difference between the two stored voltages being derived by differential amplifier and used to control the gain of chroma amplifier and also to control the colour killer.
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