Color imaging apparatus including phase control system for maintaining

Abstract

A color filter has recurrent groups of different color stripes. An image pickup tube has a photoelectrical conversion target exposed to light passing through the color filter and an index signal generation pattern. The image pickup tube outputs a signal containing a color signal component and an index signal component which depends on the index pattern. The index signal component has a phase representing a present start position of each scanning line. A memory holds a portion of the output signal from the image pickup tube corresponding to an initial frame period which occurs under conditions where a predetermined color light is applied to the photoelectrical conversion target via the color filter. A reference signal reflects a signal read out from the memory. A color component is detected from the output signal of the image pickup tube by use of the reference signal. The reference signal contains an index signal component which has a phase representing a start position of each scanning line during the initial frame period. A closed-loop phase control system allows the present start position of each scanning line to remain essentially equal to the start position of the corresponding scanning line during the initial frame period. A phase or level shifter is interposed in a loop of the closed-loop phase control system.