See Dolby AC-3.

"Cable operators set aside channels for use by the public, educational institutions, municipal government, or for lease on a non-discriminatory basis. These are called access channels."

The access criteria is the conditional access system specific information needed to build the Entitlement Control Message (ECM). See also Entitlement Control Message (ECM) and conditional access.

"An access node is a part of the access network that performs some or all of the following: modulating forward data onto the access network, demodulating return-path data, enforcing the MAC protocol for access onto the access network, separating or classifying traffic before multiplexing onto the transport network such as differentiating traffic that is subject to QoS guarantees from traffic that receives best-effort support, enforcing signaling, and/or handling passive operations, such as splitting and filtering. See also MAC and quality-of-service (QoS)."

An access server allows access to content and other data on a network.

An application in the active state is loaded into the memory of the set-top box and runs in the foreground.

"The actualized audience refers the actual viewers of an interactive television program. The audience must also have all the necessary equipment, and training to participate in the interactive television experience."

"The ad click-through rate is the number of times a viewer clicks on an advertisement with a link compared to the number of times that that advertisement link is shown. For example, if an advertisement is shown 1000 times and five people click on it, that advertisement has a click-through rate of 0.5%."

"Ad cost per click refers to how much the advertiser pays each time someone clicks on a banner or link, if applicable. See also banner."

Adaptive Differential Pulse Code Modulation is a coding method for producing a reduced bit rate Pulse Code Modulation (PCM) signal. See also pulse code modulation (PCM).

"An address bus is the electronic path that the data travels in the set-top box or in any type of computer. The wider the width of the bus, the faster the data can travel. Therefore, an 8-bit bus is slower than a 32-bit bus. "

"Two television channels are considered adjacent when their view carriers, either off-air or on a cable system, are 6 MHz apart. FM signals on a cable system, two channels apart are adjacent when their carriers are 400 to 600 kHz apart."

See Advanced DOCSIS Set-top Gateway. DOCSIS.

"ATSC?s Advanced Common Application Profile (ACAP) specification aligns with CableLab?s OCAP with ATSC?s own DTV Application Software Environment (DASE) and thus could unify interactive television technologies for cable, terrestrial, and satellite deliver. See also OpenCable? Application Platform (OCAP) and Advanced Television Systems Committee (ATSC)."

"The Advanced Television Systems Committee (ATSC) was established in 1983 to develop voluntary technical standards, including interactive television systems and digital high definition television (HDTV). The ATSC is usually thought of as a committee to address the needs of the North American television market. The ATSC standard for HDTV was approved in 1995 and adopted?with the exception of the mandatory video formats section?by the Federal Communications Commission (FCC) in 1996. It is to replace the analog National Television Systems Committee (NTSC) format in North America. See also National Television Systems Committee (NTSC), high definition television (HDTV), and Federal Communications Commission (FCC)."

See audio interchange file (AIF).

"Aliasing refers to defects or distortion in a television picture. In analog video, aliasing is most often caused by interference between two frequencies such as the luminance and chrominance. In digital video, aliasing is caused by insufficient sampling or poor filtering of the digital video. Defects are typically seen as jagged edges on diagonal lines and twinkling or brightening of picture detail. Anti-aliasing refers to technologies used to counter this. See also anti-aliasing, chrominance signal, and luminance signal."

"America?s Missing: Broadcasting Emergency Response. An AMBER Alert is a notification to the general public, by various media outlets, of a confirmed child abduction."

"An amplifier is a device that boosts the strength of an electronic signal. In a cable system, amplifiers are spaced at regular intervals throughout the system to keep signals picture-perfect regardless of how far you live from the head-end. See also headend."

"Amplitude modulation is the process of impressing information on a radio frequency signal by varying its amplitude. Generally, amplitude modulation is used for the purpose of relaying messages by voices, television, facsimile, or other modes. See also radio frequency (RF)."

"An analog device operates with variables represented by continuously measured quantities such as voltages, resistances, rotations, and pressures."

"With an analog television, the signal the television receives is sent as a continuously varying analog waveform. The waveform?s value determines the amount of voltage that will be applied to the electron guns in the back of the picture tube. This directly affects the luminance and chrominance of the picture. In analog television systems, the voltage applied to the electron guns is proportional to the constantly changing video signal voltage. Analog televisions have the following limitations: Analog television channels are susceptible to interference caused by physical features?such as hills and buildings. This interference often takes the form of ghosting on the picture screen. The normal television channel occupies a bandwidth of 6 MHz. With analog televisions, the viewer can see only a limited total number of 6 MHz channels, obviously limiting the total number of possible channels the consumer can receive and view without outside electronic help, that is. In addition, many of the frequency bands that could be used by television channels have to be kept empty because analog television channels spaced too close together can interfere with one another. Although luminance and chrominance signals are separated, the signals can interfere with one another, especially in regions with low signal strength. This can lead to problems with the color display. To watch digital television on an analog television, you need a digital television tuner?in the form of a set-top box/receiver?and some form of antenna or cable connection. See also luminance signal, chrominance signal, ghost, and bandwidth."

See American National Standards Institute (ANSI).

An antenna array is a group of identical antennas arranged and interconnected for achieving greater directivity (gain) or beam shaping. See also gain.