Microprocessor controlled picture in picture system

The architecture of a microcontrolled picture-in-picture (PIP) system, designed mainly with off-the-shelf components, is described. The memory section of the system has a special arrangement which simulates a two-port memory; it basically has a four-field storage capacity in order to avoid the joint-line problem and jolt defects in the subpicture. The field memory and address system capacity can be reduced substantially by reducing the number of subpicture lines from 80 to 64. Experimental results have shown that for the PIP TV system, 5-bit linear quantization is perfectly permissible, since the subpicture is small and surrounded by the main picture on the screen