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| Addressable set-top box | The device in the
customer's home that receives the commands sent from the cable office and
converts the compressed digital signals to analog video and audio. |
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| Analog | A continuously varying
signal. Analog signals have an unlimited number of possible values ranging
from very soft to very loud (amplitude) and at the same time, from very
high to very low tones (frequency). Electrical signals are used to produce
analog signals to carry voice and video information and are distinguished
one from the other in terms of their frequency. These continuously varying
voltages make up an analog voice or video signal. Contrast with DIGITAL. |
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| Analog descrambler | A device used to descramble the analog signal and sends it to the modulator | |||||||||||||||||||||||||||
| Bandwidth |
1.)
The range of usable
frequencies that a cable television system can carry.
2.)A measure of the information-carrying capacity of a communication channel. The bandwidth corresponds to the difference between the lowest and highest frequency signal that can be carried by the channel. 3.)The speed (bit rate or velocity) at which data can be transferred and presented. A voice transmission by telephone requires a bandwidth of 3 kHz. An NTSC TV channel occupies a bandwidth of 6 MHz. A cable system bandwidth can occupy from 5 to 550 MHz on the electromagnetic spectrum. |
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| Bandwidth capacity | The maximum number of channels
fitting into one band at any given time. |
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| Broadband | Any communications system able
to deliver multiple channels or services of video, voice or data to its
users or customers over a broad band of RF spectrum. |
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| Cable TV penetration | Ratio of the number of customers
to the total number of households with televisions that are passed by a
cable system. |
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| Coaxial cable | A cable consisting of a conducting
outer metal tube insulated from a central conducting core, used for transmission
of electronic signals. |
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| Converter | Device that changes the frequency
of a television signal. A home converter translates the signal from the
frequencies at which they are sent over the cable to channels that the television
set can pick up. |
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| Decoder | The source that receives a digital
message and translates it back into an analog message. Converts scrambled
TV signals into a viewable picture. Also known as an "descrambler"
and "decryptor". |
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| Decompress | To restore a set of compressed
information to its original state |
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| Decryption | The process of unscrambling an
encrypted signal back into its original format |
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| Demodulator | A device that demodulates a modulated
wave back into its original state. In CATV systems, a television demodulator
derives a baseband video signal from the modulated RF carrier |
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| Digital | Signal with a finite number of
discrete values, usually two. Advantages over analog signal transmission
and storage include better immunity to noise and ease of computer processing
(including signal compression, error detection and correction, and multiplexing). |
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| Digital compression | Reducing the storage space and/or
transmission data rate necessary to store or transmit information represented
in digital format. Common digital compression methods include the suppression
of long strings of "1s" or "0s", delta transmission
(that is, only sending information about the difference between signal sampled
at two successive periods of time), and, for video applications, matching
the characteristics of picture quality to the limitations of the human eye |
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| Digital to analog | Mechanical or electronic device
used to convert converter discrete digital numbers to continuous analog
signals |
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| Direct broadcast satellite | Satellite that can transmit TV
signals directly to individual homes. |
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| Electronic
program guide (EPG) |
An on-screen navigational
guide to facilitate selection of programming choices. |
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| Encoder | The source that changes an analog
message into digital code and sends it. |
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| Encryption | Encryption is a process intended
to ensure the security of message or television transmissions. |
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| Footprint | The antenna coverage pattern,
which a satellite directs toward the earth. This defines the geographic
area in which satellite signals can be received. |
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| Fiber optic cable | Hair-thin continuous glass fibers that allow the transmission of laser-generated light signals with low loss of power or interference. |
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| Frequency | The physical quantities that vary to produce varying degrees of tone and pitch in a voice signal. The number of times an electromagnetic wave repeats an identical cycle in a unit of time (usually one second). One Hertz (Hz) is one cycle per second. A kHz (kilohertz) is one thousand cycles per second; a MHz (Megahertz) is one million cycles per second; a GHz (Gigahertz) is one billion cycles per second |
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| Headend | A facility that contains satellite receivers, has antennas which receive signals from local TV studios, and sometimes has TV studios inside the facility which produce shows and send the signals to other locations by satellite or antenna. When a headend facility receives signals from a satellite, it retransmits the signals (analog and digital) at frequencies the cable plant can use. |
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| Headend In The Sky (HITS) | A business venture aimed to provide services through digital compression. Digitally compressed video and audio are uplinked from the NDTC to one or more satellites and downlinked to cable television headends at various locations |
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| HFC | Hybrid Fiber Coax | |||||||||||||||||||||||||||
| Homes passed | Total number of homes that have the potential for being hooked up to a cable system. |
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| Integrated Receiver Decoder (IRD) | The set-top box component also referred to as the digital receiver, the box and the set-top box. This hardware processes the incoming signals and manages the viewing menu. |
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| Ku-band | The band of microwave frequencies used for satellite uplink (12 to 18 GHz) and downlink (11.7 to 12.2 GHz). Satellite dishes for Ku-band reception are much smaller than dishes used for C-band reception |
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| MegaHertz (MHz) | Unit used to measure a broadcast of cablecast frequency. |
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| MSO | Multiple system operator, a company that operates more than one cable system. |
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| Near Video On Demand (NVOD) | A video technology allowing a consumer to purchase an event within few minutes of its scheduled starting time. | |||||||||||||||||||||||||||
| Pay-per-view (PPV) | Usage-based fee structure in which the user is charged a price for individual programs requested | |||||||||||||||||||||||||||
| Satellite | (1) | A device in geostationary orbit above the earth that receives transmissions from separate points and retransmits them to cable systems over a wide area. | ||||||||||||||||||||||||||
| (2) | A space vehicle which receives radio and television signals and retransmits them back to earth. It is located 22,300 miles above the earth in a geosynchronous orbit so that it is stationary relative to a fixed position on earth. One use of a communications satellite is the transmission of programming used by the cable industry. Also known as a "bird." | |||||||||||||||||||||||||||
| Scrambler | An electronic device usually located in the headend. Used to alter a signal so that it may not be viewed on a normal TV unless another electronic device, namely a decoder is attached to the subscriber's set to unscramble the picture | |||||||||||||||||||||||||||
| Smart Card Technology | A type of technology that allows sophisticated processing functions to be available on a small plastic card that is embedded with a tiny computer chip. | |||||||||||||||||||||||||||
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| Terminal | Connectors, transformers and converter (if necessary) on the cable customer's television set. | |||||||||||||||||||||||||||
| Transmission | The sending of a signal from a transmitter | |||||||||||||||||||||||||||
| Transmitter | Any of various electrical devices used to originate signals | |||||||||||||||||||||||||||
| Transponder | A combination receiver and transmitter on a satellite that relays signals transmitted to it back to earth on a different frequency. For cable TV customers this means the number of channels available, which is directly related to the number of programming options. For example, a 3-transponder (or 3-pack) system has the space to accommodate 36 digital channels. | |||||||||||||||||||||||||||
| Turnaround | When the option on a project expires and the party holding that option chooses not to renew it, the project is said to be in turnaround and can move to another production company or simply go away | |||||||||||||||||||||||||||
| Uplink | The transmission of a signal from its earth station source up to a satellite in orbit. The opposite of downlink, which goes from orbit to earth. | |||||||||||||||||||||||||||
| Video on demand (VOD) | Programming that offers movies and events to be viewed immediately after selection. | |||||||||||||||||||||||||||
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