Acronyms Explained

In the TV industry and related fields there are many acronyms in use, many of which people don’t understand, or get wrong. We have heard just about every variation on UHF possible over the years, so here we’d like to try and help you out with them. Throughout our website we do use acronyms, but we’ve tried to keep it simple by using the full name at least once in the article, followed by the acronym in brackets. If there are any we’ve missed, please comment, and we’ll add them in.

By clicking on the acronym you’ll be taken to an explanation of what it is.

What they stand for

AV Audio Visual
CD Compact Disc
DECT Digitally Encoded Cordless Telephone
DVB-S Digital Video Broadcasting – Satellite
DVB-T Digital Video Broadcasting – Terrestrial
DVD Digital Versatile Disc
FTA Free-To-Air
GHz Giga Hertz
HD High Definition
HDCP High Definition Content Protection
HDMI High Definition Multimedia Interface
HE-AAC High-Efficiency Advanced Audio Coding
HTPC Home Theatre Personal Computer
IF Intermediate Frequency
IR Infra Red
LCD Liquid Crystal Display
LNB Low Noise Block
LO Local Oscillator
MHEG Multimedia and Hypermedia Experts Group
MHz Mega Hertz
MPEG Moving Picture Experts Group
PSU Power Supply Unit
PVR Personal Video Recorder
RCA Radio Corporation of America
RF Radio Frequency
RGB Red / Green / Blue
SCART Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs
SD Standard Definition
STB Set Top Box
S-VHS Super-Video Home System
TV Television
UPS Uninteruptable Power Supply
UHF Ultra High Frequency
VCR Video Cassette Recorder
VHF Very High Frequency
VHS Video Home System

What they mean

AV – Audio Visual
Often incorrectly used to describe a composite RCA cable. Refers to signals, transmissions, and programmes with both sound and visual components. Often used by manufacturers of TVs, VCRs and DVD recorders to name an input, eg AV1, AV2 etc.

CD – Compact Disc

DECT – Digitally Encoded Cordless Telephone
A type of cordless phone designed to eliminate the chance of cross-talk, and other people listening in on your conversation. 1.8GHz in frequency, though WDECT is 2.4GHz. DECT phones can be distinguished from other frequencies by their lack of aerial on either the handset or the base unit (though very occasionally you may find another frequency of phone without an aerial).

DVB-S – Digital Video Broadcasting – Satellite
The standard used for broadcasting digital television images and audio via a satellite using a frequency range of 11 / 12 GHz. Multiple channels are multiplexed together (joined) to form a programme stream. One or more of these programme streams are then joined into a transmission stream which is then sent via a satellite and beamed to your satellite dish. A number of transmission streams can be sent from each satellite, using transponders on the satellite transmitting at different frequencies.

DVB-T – Digital Video Broadcasting – Terrestrial
As with DVB-S, however the transmission range is in the UHF band from land based transmitters.

DVD – Digital Versatile Disc
Originally these were known as a Digital Video Disc, until they gained popularity in the computer industry for storing data. Single and dual layer versions are available. Both layers on a dual layer disc are on the same side of the disc, and are read consecutively by moving the laser on the read head to a different angle. Single layers hold approximately 4 GigaBytes (GB) of data, dual 8GB compared to a CD which holds 700 MegaBytes (MB), or 0.7GB. Dual layer discs are usually used for holding movies / video. Single layer predominantly for use in PCs as they are significantly cheaper than dual layers. Discs come in a variety of flavours beyond the two layer types, the description of which goes beyond the scope of this article.

FTA – Free-To-Air
The term used for unencrypted channels or systems that don’t require subscription such as Freeview.

GHz – Giga Hertz
A measure of wave frequency. 1 Giga Hertz signals have a wave frequency of 1000 waves per second. See also Mega Hertz.

HD – High Definition

HDMI – High Definition Multimedia Interface
The 15 pin interface used on High Definition devices to transmit a digital video/audio signal from one device to another. Early revisions do not carry audio signals or HDCP signalling. The length of cables is limited to 10m without amplification. Typically with amplification as much as 80m can be attained.

HTPC – Home Theatre Personal Computer
Gaining popularity as the new generation of media players, HTPCs are typically used by tech-savvy people to play DVDs, watch movies and shows downloaded from the internet, play music, watch and record TV (both analogue, and digital). Able to be used as a PVR they can be a more versatile alternative to a MyFreeview unit, and are often available at competitive prices. Can be purchased already setup for those who aren’t quite so technically minded.

IF – Intermediate Frequency
Due to the high frequencies used in satellite transmissions, there is a need to reduce the frequency to something that is capable of passing through coaxial cable. Intermediate frequency (IF) are generated by mixing the RF and LO frequency together to create a lower frequency called IF. This IF is the signal that passes through the coax from the LNB to the STB.

IR – Infra Red
A light frequency that the human eye cannot see. Used by most remote controls to signal the device when a button is pressed. IR signals do not pass through objects or walls.

LCD – Liquid Crystal Display

LNB – Low Noise Block
Sometimes referred to as an LNB-F (feedhorn) or LNC (Low Noise Converter)
The LNB is the business end of the satellite dish, located at the end of the arm facing the dish, either below center (for an offset dish) or directly in the middle (centre focus dish). The purpose of the LNB is to convert a block of relatively high frequencies, and through the use of a local oscillator, convert them to lower, usuable frequencies. The high incoming frequencies are not able to be easily (or economically) transmitted down inexpensive coaxial cable, hence the conversion.
A number of varieties are available, Ku band being the most common, C band is used primarily on large dishes not used in residential situations for the most part (the exception being for some foreign TV channels). Single and dual LNBs are common, with Sky upgrading their dishes to a dual LNB capable of viewing both Optus D1 and C1. Sky plans to use a quad output LNB in the future for their MySky Hdi decoders though details of this have yet to be confirmed.

LO – Local Oscillator
A local oscillator (with regards to satellite trnasmissions) is an electronic device in the LNB used to convert the incoming signal to a different intermediate frequency (IF) that the coaxial cable is capable of carrying. These usually have a value of 11300MHz or 10750MHz, though 9750MHz and 10600MHz are also in use.

MHz – Mega Hertz
A measure of wave frequency. 1 Mega Hertz signals have a wave frequency of 100 waves per second. See also Giga Hertz.

PSU – Power Supply Unit
The internal or external unit that converts household 240VAC to the DC voltage required by the device.

PVR – Personal Video Recorder
Typically used to describe a device that can record and playback video to / from a harddrive. Often has the ability to watch / record multiple channels simultaneously.

RF – Radio Frequency
A range of signals which can be transmitted through the air, or through cable. Used by radio stations, terrestrial TV transmissions, internal house cabling for TV aerials, interconnecting VCRs, TVs and other analogue devices.

RGB – Red / Green / Blue
A type of interconnect not commonly used anymore, significantly better than composite signals, but has been superceded by component. RGB adds together the three primary colours red, green and blue to produce the broad range of colours you see on the screen.

SCART – Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs
SCART (Radio and Television Receiver Manufacturer’s Association) is a French-originated standard and associated 21-pin connector for connecting audio-visual (AV) equipment together. Predominantly used in the UK, there are some TVs using it in NZ, though they tend to be either European manufacterers such as Loewe, Grundig or Nokia, or cheap imports from the likes of the Warehouse, DSE, Countdown etc. Also used on many digital STBs including Sky’s. The SCART connector is capable of carrying a number of signals simultaneously, in either direction – Composite, RGB and S-Video. Component is not officially part of the standard but is often available on recent equipment anyway. It is also known as Péritel (especially in France, where the term SCART is practically unknown), 21-pin EuroSCART (Sharp’s marketing term for an attempt to market the connector in the Asian region) and Euroconnector.

SD – Standard Definition
Also called SDTV or 576i. Typically used in reference to digital TV. 576 lines of picture (in NZ, other countries vary slightly) which are displayed on the TV screen in an interlaced fashion. Interlaced meaning that alternate lines are displayed on each pass of the picture, 1,3,5 etc on the first pass, 2,4,6 etc on the second.

STB – Set Top Box

S-VHS – Super Video Home System
Not to be confused with S-Video as many people are prone to doing.
S-VHS is an improvement on the VHS format which resulted in improved picture clarity.

TV – Television

UPS – Uninteruptable Power Supply
Containing a battery backup system, a UPS can come in a variety of flavours (on-line, off-line etc), all having the same purpose – to protect downstream devices from power surges and outages. Some units work with devices drawing continuously from the battery, while charging at the same time, separating the device completely from the power line ad eliminating the chance to power spikes etc reaching the device. Others switch (very quickly) the device from the power line to the battery when voltage variations are detected. A UPS is the next (big) step up from a surge protector as they protect not only from spikes and surges, but also undervoltage situations which can be just as damaging. These units are usually used on commercial computer systems, though some home users are beginning to recognise the advantages. Varying sized batteries are available providing power for anywhere from a few minutes to a few hours depending on how much current is drawn.

UHF – Ultra High Frequency

VCR – Video Cassette Recorder

VHF – Very High Frequency

VHS – Video Home System
A recording and playback standard developed by JVC in the mid-70’s. VHS tapes are played and recorded on in VCRs using a magnetic head system. The life span of tapes is limited, particularly when stored near magnetic fields (such as TV and Stereo speakers). Susceptible to picking up dirt from the VCRs heads which results in picture degradation. Largely defunct now as DVD and Bluray discs have replaced VHS tapes for pre-recorded playback, and DVD and HDDs for home recording and playback.

Many thanks to for providing clarifications on some points.