A low cost, general purpose S-video, PAL/NTSC encoder

The device is used to encode red, green, and blue (RGB) color difference signals from a camera, computer graphics system, or some other originating generator into the established PAL or NTSC standards. In addition to the color composite video output, separate chrominance and luminance S-video signals are generated for improved display and video recording quality. All three outputs have 75-Ω drive capability and are available concurrently. The RGB inputs require 700 mV p-p for 100% color saturation and for 700 mV p-p at the 75-Ω video output loads. The device may be phase locked to an external 4.43-MHz or 3.58-MHz subcarrier source, driven from an external four times subcarrier frequency clock or free run from the internal four times subcarrier frequency crystal oscillator. The device was fabricated using a 2-μm oxide isolated 4-GHz bipolar process, had 20 pins, and operated from a single 5-V supply