ITV GLOSSARY PAGE

The world of digital and interactive television is technical and often confusing. Below are some definitions for terms you will hear a lot when it comes to interactive TV. For the full glossary, visit http://www.itvt.com/glossary.html .

ADSL– Asymmetrical Digital Subscriber Line. ADSL is type of DSL that features T1 rates or higher in the downstream (toward the consumer) direction and 64 KBPS or higher in the upstream direction.

ANALOG – Analog data is expressed in the form of continuously variable waves, which is why traditional analog cable TV waves are susceptible to noise and not easily compressible.

BANDWIDTH – 1. (broadcast) The range of frequencies available for signaling. Digital channels measure capacity in bits per second. A T3 connection is approximately thirty times as fast as a T1 connection, which is 50 times as fast as a 28.8 modem, which is twice as fast as a 14.4 modem, and so on.

Broadcast: 6 MHz analog
Cable: 450 MHz analog signal
Cable Modems: up to 27 mps downstream – shared
Internet data: 14.4k – 26 MBPS with VDSL
VBI: 4 Mbps
Digital Signal: 19.2 Mbps

DIGITAL SUBSCRIBER LINE (DSL) – This modem telecommunications technology enables broadband, digital data to be transmitted over an ordinary telephone line. DSL comes in many varieties, collectively referred to as xDSL.

DIGITAL SIGNAL TELEVISION (DTV) – DTV is a new broadcast approved by the Federal Communications Commission that will ultimately replace the analog television signal we receive today in the United States. DTV features high–resolution and wide-screen presentation. However, DTV will require new television receivers as well as new broadcast facilities. Due to the scope of this conversion, the changeover from analog to digital TV will be gradual and take place from 1998 – 2006.

DIGITAL VIDEO RECORDER (DVR) – DVR is so popular these days, a household without one is becoming rare. DVR is a high capacity hard drive embedded in a set–top box. It records video programming from a television set. DVRs are operated by personal video recording software, which enables viewers to pause, fast-forward, and manage a variety of other functions and special applications. TiVo, ReplayTV, and UltimateTV are commercial examples of a DVR.

DIGITAL VIDEO SERVER – This is a robust, dedicated computer at a central location that receives command requests from the television viewer through a video–on–demand application. Once it receives this request, it then instantly broadcasts specific digital video streams to that viewer. nCUBE, SeaChange, and Concurrent are examples of companies that provide this kind of equipment and software services.

 

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