Abstract: Disclosed herein is an oscillator circuit used for a PIP system which displays a child picture image without distortion even when the image method of the child picture image is different from that of a parent picture image. The oscillator circuit employed in such a system includes a programmable frequency divider for frequency dividing an output of a voltage-controlled oscillator with a frequency dividing ratio to produce a frequency-divided signal and a control circuit for controlling the oscillation frequency of the oscillator 201 according to a phase difference between the frequency-divided signal and a horizontal synchronizing signal. The frequency dividing ratio for the frequency divider is changed according to the image method of the child picture image.

Abstract: A vertical filter circuit comprises a first shifter connected to an S/P converter, a calculation circuit connected to the first shifter and a second shifter, a buffer memory connected to the calculation circuit, first and second delay circuits each connected to the calculation circuit, and a second shifter connected to the first and second delay circuits. The first delay circuit comprises a first write selector, a first line memory, and a first read selector, all of which are connected in series. The second delay circuit comprises a second write selector, a second line memory, and a second read selector, all of which are connected in series.