Resource Center: How to Speak A/V
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Entries starting with: Radio Data System (RDS): A system for transmitting text information along with the audio in a radio broadcast for display on an RDS-equipped tuner or receiver; popular in Europe but not in the U.S. radio-frequency (RF): The high-frequency electromagnetic signals used to broadcast radio and TV programs, or any very high-frequency signal, whether intended for broadcast or not. rainbow effect: A flash of multicolored light occasionally seen in images created by single-chip DLP projection TVs, most often on the edges of a bright object in motion against a dark background. The rainbow is an artifact of the projector’s color wheel, which sequentially filters the white light generated by a bulb into its red, green, and blue components. random access: The ability to go directly to the beginning of a numbered or labeled song, track, chapter, disc, or program without scanning the intervening material. RCA connector/plug/jack: The most common kind of audio connector, using a small, single-pin plug and a coaxial shield. reactance: The portion of the electrical impedance in an AC circuit that is not due to pure resistance. Capacitive reactance causes impedance to rise as the frequency of the signal decreases, whereas inductive reactance causes impedance to rise as the frequency of the signal increases. RealAudio: A codec system promulgated by RealNetworks. At certain bit rates, RealAudio 8 utilizes the ATRAC3 upgrade of the ATRAC codec. rear-projection TV (RPTV): A popular type of TV set that beams the output from light sources (CRTs, DLPs, LCDs, and the like) in the bottom of its cabinet onto an angled mirror, which in turn reflects it onto a large screen (from 40 to 80 inches diagonal) at the front of the cabinet. receiver: An audio component that receives radio broadcasts, switches and processes audio signals, and amplifies the selected signal to drive speakers; also see A/V receiver. A television receiver is a monitor that contains a tuner for TV signals. recording-level meter: An indicator that displays the audio signal levels recorded from moment to moment. recording mode: In a DVD recorder, the selected mode determines the overall bit rate (amount of data compression) used for recording. Different modes let you trade off image quality for increased recording time; DVD recorders generally offer at least four modes. record loop: see tape monitor. red, green, and blue (RGB): The three primary colors of most video systems (such as NTSC and DTV); also, the three color signals used by computer monitors. An RGB video connection provides each color as a discrete signal (also see RGB+H/V). red minus luminance (R – Y): Part of a component-video signal; see color difference. regional coding: A “feature” of the DVD system that gives program producers the ability to restrict the geographical areas in which a DVD can be played. The U.S. and Canada are Region 1; Europe is Region 2. residential gateway: A device that combines the functions of a cable or DSL modem and a router. resistance: Electronic “friction” that turns the flow of electrical charges into heat; resistance is impedance that is the same for all frequencies. resolution: A measure of the ability of a video system to convey fine image details. Most resolution specifications or measurements are for horizontal luminance resolution, but there can be vertical luminance and color resolution figures as well. resonance: The tendency of a mechanical or electrical system to vibrate at a certain frequency when excited by an external force, and to keep vibrating even after the exciting force is removed. Resonances are undesirable in audio equipment and listening rooms. reverberation: A dense pattern of diffuse and multiple rereflections that results when sound is created in an enclosed space. The more reflective the walls and surfaces of the listening space, the louder and longer lasting the reverb; the perceived effect of reverberation depends on the size of the room and how long it persists. Reverberation influences both the clarity or intelligibility of the sound (the more, the muddier) and the feeling of spaciousness or ambience (the less reverb, the more closed-in the sound will seem). reverse polarity: An electrical condition in which the “positive” and “negative” wires running to one speaker in a stereo pair are reversed relative to the other; this causes the sound waves emanating from the speakers to be out of phase with one another, which weakens bass output by cancellation and impairs stereo imaging. RF interference (RFI): When a radio or TV broadcast or other radio-frequency signal interferes with the operation of a component. RGB+H/V: A video input or output carrying discrete signals for red, blue, and green plus horizontal and vertical sync signals; see red, green, and blue. RIAA (Recording Industry Association of America): A trade and lobbying group based in Washington, DC, that has been one of the moving forces behind the Serial Copy Management System (SCMS) and efforts to curb Internet file-sharing. Decades ago, the RIAA set standards for the equalization used on vinyl records to minimize noise. ribbon speaker: A form of speaker driver using a light, conductive ribbon suspended in a strong magnetic field; it produces sound by vibrating when a signal current is passed through it. rip: To extract the digital audio data from a CD; also applied to the process of converting such data to a compressed audio format, typically MP3. ripper: Computer software used to rip audio CDs for storage on a hard disk. RJ-11: A standard modular telephone jack. RJ-45: The standard Ethernet connector found on some home-networkable components. rms (root mean square): The most accurate way of averaging voltage and power measurements. rolloff: A gradual attenuation of a signal above or below a certain frequency. router: A device for dividing an Internet connection among multiple computers or networks. RS-232: A standard for serial communications ports on computers and some A/V components. Abbreviations |
