-pin mini plug when separate channels are provided for luminance and chrominance. Also known as Y/C Video, S-Video is used in the S-VHS and Hi8 videotape formats. sampling The process of measuring an analog signal in time Video Communication: the Whole Picture slices SO that it can be quantized and encoded in a digital format. The sampling interval, per Nyquist's Theorem, must be at least twice the highest frequency contained in the analog input. Thus, in an analog signal in which frequencies of 4,000 hertz are possible, the sampling rate must be 8,000 per second. satellite A man-made object designed to orbit the earth. Used to receive and retransmit telecommunications signals that originate at an earth station. satellite delay In satellite transmissions a signal must travel from the earth to a transponder placed in geosynchronous orbit, a distance of 22,300 miles above the equator. Radio waves, which travel at approximately the speed of light (186,000 miles per second) take about.24 seconds to make the round trip, and thereby induce perceptible delay in satellite communications that are particularly annoying in speech and interactive video. transmissions. satellite receiver A microwave antenna that is capable of intercepting satellite transmitted signals, lowering the frequency of those signals and retrieving the modulated information. saturation In color reproduction, the spectral purity or intensity of a color. Adding white to a hue reduces its saturation. A three-bit integer that indicates the number of bits that should be ignored in the first data octet of a RTP H.261 packet. scan converter A device that converts computer images to a television display format. Used to convert the scan rates of VGA or SVGA to NTSC, PAL or SECAM scan rates. scan line During scanning, a number of nearly horizontal passes are made across an image and the light recorded by the image is converted into an electrical signal. Each pass across the image is called a scan line. scanner A device used to capture and digitize images. A sca