Glossary of Technical Terms and Abbreviations
Term |
Description |
| 1kHz, 1000Hz or 1 kilohertz
|
Tone of 1kHz is often used for line-up and testing. |
| ADSL | Asynchronous Digital Subscriber Link - a broadband delivery system over standard telephone lines (between the exchange and the user). |
| AES | Audio Engineering Society. |
| AES/EBU | Professional digital audio standard covering frame format, connections and interfaces. Interface is usually on XLR sockets and plugs. |
| AM | Amplitude Modulation - older analogue modulation standard used on long, medium and short wave. |
| APT-X | Data reduction process for reducing the amount of storage or bit-rate need for audio. |
| ATRAC | Adaptive Transform Acoustic Coding - the data reduction of compression scheme used in Mini-disk machines. |
| Attenuation | The reduction of a signal level. Attenuation is usually measured in dB. |
| B-Channel | Bearer Channel - the main carrier channels used in ISDN. |
| Balance | The relative levels of the left and right channels of a stereo signal. |
| Balanced Audio | A way of sending audio over cable that protects it from induced interference. |
| CAR | See racks room. |
| CAT 5 | Category 5 - type of cabling/connectivity standards used in computer networking. |
| Cart Machines | Descended from the hi-fi and in-car stereo 8 track players. Back in the "good old days" advertisements, jingles, news items (interviews etc.), station announcements or even music programmes were played on cart machines - recorders and players which used short looped tape (NAB cartridges or carts) and were able to fast-forward automatically at the end to the beginning of the material, ready for "almost instant" replay. Until 1996, Sonifex used to manufacture a number of machines, such as the micro HS and the CQ range. |
| Cart Splice-Finder/Eraser(s) | The splice on a NAB cartridge was where the tape looped and where the machine would cue to. A splice finder/eraser would erase the tape up to the cur-point. A bulk-eraser erases the tapes magnetically without splice-finding but operates faster and can handle more volume. |
| CD | Compact Disc. |
| Cleanfeed | A cleanfeed is a signal produced by a telco module on a mixer which is used as the output to be fed back to a caller on a telephone line. The cleanfeed is a sum of all the other signals which constitute the programme output, except for the caller’s audio. A cleanfeed signal will generally be of a better quality than a mix-minus signal. |
| Clipping | The onset of severe distortion in the signal path, usually caused by the peak signal voltage being limited. |
| CMRR | Common Mode Rejection Ratio. This is the ratio of the extent to which a differential amplifier will cancel noise, which is present on both inputs, compared to its ability to amplify the signal. |
| CODEC | COder-DECoder - used to change a signal from one format to anther and back again. |
| Codecs | Using digital circuits being offered by telecom providers, usually ISDN (Integrated Services Data Networks) or other data transfer methods, audio can be transferred with good to excellent quality over what almost amount to dial-up telephone lines. The units operate by Coding the audio into a digital data stream that can be transferred over the digital circuit which is Decoded at the receiving end (Thus CoDec). By using single or multiple circuits, very high quality audio can be transferred from one place to another, even internationally. |
| Cross-talk | This is the amount of a signal from a bus which appears, or is induced, on a different signal. The problem is usually most prevalent with adjacent channels. |
| DA | Distribution Amplifier. |
| DAB | Digital Audio Broadcasting = now called Digital Radio. |
| DAT | Digital Audio Tape. |
| dB ( decibel ) | A ratio of two voltages or signal levels, expressed by the equation dB=20LOG(V1/V2) Adding the suffix "u" denotes that the signal is relative to 0.775V RMS. Adding the suffix "v" denotes that the signal is relative to 1V RMS. |
| DCF | This is radio code signal sourced from Mainflingen, near Frankfurt in Germany, which can be used to automatically synchronize the Sentinel+ audio logger and PC time to an accurate atomic clock, European Time. |
| DDS & DDS-2 | DDS and DDS-2 are world-wide standards established by Sony and Hewlett-Packard which introduce many levels of error checking as data is written to a DAT tape. DDS(-2) drives and tapes are used in security products all over the world. 120m DDS-2 DAT tapes are more accurate and reliable than DDS tapes and are able to store twice as much audio data. |
| DI | Direct Inject - a means of diriving audio, usually from an instrument such as a guitar, to allow the audio signal to be fed directly into a sound desk input. |
| DLS | Dynamic Label segment - a text message scheme used in digital radio, usually to carry information about the programme. Like the radio-text scheme used in RDS. |
| DSP | Digital Signal Processing. |
| EBU | European Broadcasting Union. |
| EIN | Equivalent input noise. It is the ratio of output noise to the gain. It describes the level of noise which would need to be fed into an ideal amplifier to produce the measured output noise. |
| ENG | (Electronic news gathering). Machines that can record audio and video information digitally. |
| EON (RDS) | Enhance Other Networks - a scheme for switching a listener's radio to another Effective Radiated Power. |
| EQ | (Equalisation). This is a method of cutting or boosting selected bands of frequencies in a signal. |
| FM | Frequency Modulation - a way of sending audio or data over a radio carrier, the 88 - 108 Broadcast Band is often known as the FM Band. |
| G3 | Third generation mobile telephone system that may allow broadband transmission of Global Positioning System. |
| Gain | The degree of amplification, or attenuation, applied to a signal. |
| GRAM | Gramophone Reproducer - a turntable with a 'pick-up' amplifier and remote start interface. |
| HDLC | High Speed Data Link. |
| Hybrid | See T.B.U. |
| IEC | International Elecrotechnical Commision - often used to refer to a mains onnectivity standard, i.e. A type of plug/socket similar to that of a kettle, used on most pro-audio equipment. |
| ISDN | Integrated Services Digital Network - a system for sending high bandwidth material over standard telephone lines. |
| Kbps | Kilo-bits per second - the number os 1s or 0s transmitted or transferred in one second. |
| kHz | Kilo Hertz (samples per second). |
| LAN | Local Area Network - scheme where several computers on the same premises are connected together so that they can exchange data. |
| LCD | Liquid Crystal Display (grey displays e.g. on calculators). |
| LED | Light Emitting Diode (small lights e.g. on computers). |
| LNB | Low Noise Block - the RF amplifier attached to a satellite dish. |
| Logging Recorders, Audio Loggers | It is a statutory requirement in many countries for radio stations to record their station output for a certain duration (in the UK it is 6 weeks). A logging system is used to record one, or a number, of audio channels, which is time-coded. The Sentinel+ and Net-Log range are examples of high quality audio loggers. |
| MCR | See racks room. |
| MDU | Mains Distribution Unit - a panel of mains outlets for power distribution. |
| MF | Medium Frequency - another name for Medium Wave - roughly frequencies between 300kHz and 3MHz. |
| MHz | Mega-hertz - One million cycles per second. |
| Mix-minus | A mix-minus is similar to a cleanfeed except that the caller’s voice is removed from the signal electronically. Due to phasing problems at the signal band edges, the mix-minus method often produces a lower grade signal. |
| Mono | Monophonic sound (system of broadcasting, recording or reproducing sound) using only one channel between source and loudspeaker. |
| MP3 | MPEG 1 Layer 3 - see MPEG. |
| MPEG (ISO MPEG) | Motion Picture Experts Group. For audio, this is used to refer to a framing format standard. There are several layers and variants. Most common ones are listed below. |
| MPEG 1 Layer 1 | Used for Digital Compact Cassette. |
| MPEG 1 Layer 2 | (Musicam) used in digital radio, digital terrestrial television, ISDN and many hard-disk storage systems. |
| MPEG 1 Layer 3 | Known as MP3. A more elaborate version of MPEG 1 Layer 2 that allows for audio stoarge using low bit-rates. |
| MSF | This is radio code signal sourced from Rugby in England, which can be used to automatically synchronize the Sentinel+ audio logger and PC time to an accurate atomic clock, UK Time. |
| Musicam | Masking Pattern Universal Sub-Band Encoding. |
| MUX | Short for Multiplex - a 'package' of digital radio services |
| News Editing | News-type editing typically consists of slicing through the gaps in conversation to remove the unwanted bits of an interview and preserve the 'sound bite' that illustrates, amplifies or supports the reported item. This does not require 'microscopic' accuracy - unlike music editing. Thus reasonably fast PC computers have sufficient ability to edit the compressed audio held on hard disc. |
| Non-Destructive Editing | Pointers are used to mark the start and end of points wanted phrases in the audio and the computer 'skips' the in-between bits! This is non-destructive and means many different versions of one interview can be produced - a short snippet for the news bulletin, a more in-depth extract for the local 'magazine' programme. Courier offers non-destructive editing, but can also create a new audio file from the edited piece. |
| Pan | This controls the levels sent to the left and right outputs and is an abbreviation of 'panorama'. |
| PFL | (Pre Fade Listen, or Cue). This is a method of auditioning audio material independently of the programme output, without routing the signal to air. The PFL button on each channel routes the signal to the PFL bus, where it can be monitored. |
| PI Code (RDS) | Programme Information Code used to identify an FM RDS station. |
| Portable News-Gathering Equipment | For recording interviews and 'scene-of-the-crime' material. Background noises (sound of breaking glass in riot, football crowd cheer etc.) is called "actuality". Comprises portable cassette, tape or DAT recorders, mics, carrying case, batteries etc. |
| PPM | Peak Performance Meter (BBC Specification). |
| Promo | Something used to promote a product. |
| PS Name (RDS) | Programme Service Name - 8 characters used for naming an FM RDS station. |
| PSU | Power Supply Unit. |
| PTY (RDS and DAB) | Programme Type. A code transmitted to describe the overall programme content of a radio station (Static PTY) and/or the moment by moment content (Dynamic PTY). RDS has 32 codes although 3 are used in special circumstances only. |
| Racks Room | Often called the Master Control Room (MCR) or Central Apparatus Room (CAR), the racks room is an engineering area containing studio routing to transmitter equipment. Outside sources, phone-in equipment, off-air and transmitter status monitoring and logging equipment (or the transmitter itself !) are stored here with limited access. |
| RDS | Radio Data System. |
| Reverb | An echo (in very basic terms). |
| RF | Radio Frequency. |
| RJ-45 | A connection standard used in computer networking. |
| S/PDIF | Sony/Phillips Digital Interface. Domestic digital audio interface standard using phono connectors or optically using fibre-optic connectors. |
| SPL | Sound Pressure Level. |
| TA | Traffic Announcement (flag) - a means of signalling to a radio with FM RDS indicating that traffic/travel news is being broadcast. |
| T/B | Talk-back (and reverse talk-back). This is the ability for two or more studios to communicate with each other off-air. |
| TCP/IP | Transmission Control Protocol / Internet Protocol. Computer interconnection methodology used on the internet and LANs. |
| Telephone Balance Unit (TBU) or Hybrid | Telephone hybrids provide the interface between professional audio equipment and the public telephone network. They provide protection for your equipment and the public telephone lines, allowing for varying line signals and line conditions. Automatically cancelling out the unwanted signal they also facilitate two-way communication down a single telephone line. In most European countries, including the UK, the TBU must be approved for connection to telephone company lines. Sonifex TBU's carry British Telecom and pan European approval. |
| THD | The Total Harmonic Distortion is the percentage presence of signals outside the measured reference frequency. |
| TMC (RDS) | Traffic Message Channel. |
| TP | Traffic Programme (flag) - a means of indicating to an RDS radio that a station will carry traffic announcements. |
| U | A height measurement for rack-mount equipment: 1U = 1.75 inches 2U = 3.5 inches 3U = 5.25 inches 4U = 7 inches |
| UPS | Uninterruptable Power Supply. A device which maintains power to equipment when the electricity supply fails. |
| VHF | Very High Frequency - frequencies between 30MHz and 300MHz. |
| VP | Vertical Polarisation i.e. of FM radio transmission. |
| VSWR | Voltage Standing Wave Radio |
| VU | Voltage units |
| WAP | Wireless Application Protocol - a system for delivering mini-web pages to mobile phones from the Internet. |
| X21 | A data communications protocol used in sychronous connections. |
| XLR | Professional, robust lockable audio connector - sometimes known as a 'Cannon' after one of the earlier manufacturers. |
