Robust single chip on screen display for home VCRs

This paper describes the design of a robust on-screen-display (OSD) chip with improved automatic frequency control (AFC). The built-in AFC reduces the amount of sync jitter caused by the VCR head switching pulse, video copy guard signals, etc. This chip contains the OSD circuitry which can display characters of up to 12 rows by 30 columns on display systems. The character colors can be changed by programming the content of an 8-bit control register through the serial interface. It also provides the functions of half tone, box drawing, scroll, and blink. The chip was fabricated by using a 0.65 /spl mu/m double metal CMOS process.