SELECTIVELY ENABLED IMAGE SIGNAL PROCESSING CIRCUIT USING RECURSIVE FILTERING

A switch circuit is provided in an operation circuit of an image signal processing circuit device in which a chroma signal reproduced from a VTR is passed through a recursive comb type filter to derive a vertical high frequency component therefrom. A low level component thereof is inverted in phase, and an inverted component is summed with the chroma signal to reduce the noise component of the chroma signal to suspend operation of the operation circuit for a color burst period during a standard speed recording reproducing mode period to thereby provide a chroma signal whose noise component is reduced at an output of the operation circuit for that period.