The Digital Fact Book - Quantel

VSBVestigial Sideband modulation – an established modulation technique which is used in the RF(radio frequency) transmission subsystem of the ATSC Digital Television Standard. The 8-VSBsystem has eight discrete amplitude levels supporting a payload data rate of 19.28 Mb/sin a 6 MHz TV channel. There is also a high data rate mode – 16 VSB – designed for CATV(cable television) and supporting a payload of 38.57 Mb/s but this has yet to be implemented.Things move on; E-VSB, Enhanced-VSB, was approved by ATSC in 2004 as an amendmentto the A/53C DTV Standard as an optional transmission mode with additional forward errorcorrection coding layers to help reception underweakersignal conditions.This was respondingto the wishes broadcasters for more flexibility in DTV. E-VSB allows broadcasters to trade-offdata rate for a lower carrier-to-noise threshold for some services, e.g. “fall back” audio,and targeted at receivers with indoor antennas, non-realtime transmissions of file-basedinformation, and more.Website: www.atsc.org and search for VSB on www.broadcast.harris.comWAV (.WAV)An audio file format developed by Microsoft that carries audio that can be coded in manydifferent formats. Metadata in WAVfiles describes the coding used. To play a WAV file requiresthe appropriate decoder to be supported by the playing device.Website: www.microsoft.comVWWaveletA compression technique in which the image signal is broken down into a series of frequencybands. This is a very efficient but the processing is more complex than for DCT-basedcompression that uses Fourier transforms. Although some wavelet-based compressionwas used by some manufacturers now all wavelet compression used in the media industryis JPEG 2000. It is prevalent in DCI digital cinema, is used in some new camcorders andis increasingly used in contribution and distribution circuits.See also: JPEG 2000WIBNIWouldn’t It Be Nice If... A wish – usually referring to a hoped-for new feature on a pieceof equipment.178