S Terms

SBE: Society of Broadcast Engineers.

Scalability: Characteristic of a compression algorithm that permits the decoding of subsets of the total stream. In the case of scalable video decoding, the picture quality of the decoded subset is commensurate with the amount of information bits that the subset carried. In MPEG, the minimum subset that can be decoded is called the base layer. Each of the other bitstreams in the set is called an enhancement layer.

Scrambling: A technique for rendering a TV picture unviewable, while permitting full restoration with a properly authorized decoder or descrambler.

SCSI: Small computer systems interface.

Secam: Sequential Couleur A Memoire: Color encoding video standard used in France, the Soviet Union, and most countries of Eastern Europe.

Serial Digital Video: Also called SDI, a digital representation of the video signal that is distributed via a single coaxial cable with BNC connectors. This format is more desirable and cost-effective than a parallel interface which requires multi-conductor cable.

Side Informadon: Information in the bitstream necessary for controlling the decoder.

Sidebands: The frequency bands on both sides of a carrier within which the energy produced by the process of modulation is carried.

SMDS: Switched Multi-megabit Data Services: A high speed (1.544 and 45 Mbps) public packet switched service that can provide LAN-like service over a metropolitan area.

SMPTE: Society of Motion Picture and Television Engineers.

SONET: Synchronous optical network

Spectrum: The distribution of the amplitude of the components of a wave as a function of frequency.

Spectrum Analyzer: An instrument that measures the amplitudes of the components of a complex waveform throughout the frequency range of the waveform.

SRAM: Static Random Access Memory: SRAM does not have to be refreshed so it can operate in standby mode resulting in lower power consumption than DRAM

Star architecture: Central office (or some new Cable headends) with radiating circuits to each subscriber.

Start Bit: A bit preceding the group of bits representing a character used to signal the arrival of the character in asynchronous transmission.

Status reporting: A system of bi-directional communications that allows the panel status of peripheral devices to be reported to (and stored in) the BVE-9100’s EDL in real-time.

STB: Set top box: Device which converts cable TV signals into baseband video input to a TV or VCR.

STM: Synchronous transfer mode.

Store and Forward: Applied to communications system in which messages are received at intermediate points and stored. They are then retransmitted to a further point or to the ultimate destination on command.

STS: Synchronous transport signal.

Sub-band: Subdivision of the audio frequency band.

Sub-band coding: Signal is split into frequencies band and compression is then applied to individual compression bands that result from the su~band decomposition process.

Subcarrier: A subsidiary carrier waveform, itself, modulated by an information signal, which is, together with other signals, modulated on the main carrier waveform.

Surround Channel: An audio presentation channel added to the front channels (L and R or L, R, and C) to enhance the spatial perception.

Sync: An abbreviation for the words "synchronize, synchronization," "synchronizing," etc. Applies to the various timing pulses that drive and coordinate the TV scanning systems to keep all the related electronic equipment in phase with one another. The color sync signal (NTSC) is known as the color burst.

System Header: The system header is a data structure that carries information summarizing the system characteristics of the multiplexed stream.