Audio

Audio refers to sound. Sound is actually waves of air pressure that strike our eardrums and cause them to vibrate. Optimally, the human ear is capable of discerning frequencies within the 20Hz to 20,000Hz range. Typically, most adults over 30 have about a 40Hz to 17,000Hz range. The main task of an audio system is to transform electrical signals into air pressure waves that are as close as possible to the originally recorded sound.

Video

Video relates to visual playback on a television (TV) or display on a monitor. A TV broadcast signal consists of sound (audio) and image (video). A TV has specific circuitry that allows the capture of these signals for playback. The audio signal is delivered to the speaker and the video signal is delivered to the visual screen. Audio and Video signals can be recorded for later playback. In order to do this, you need a Videocassette Recorder (VCR) or a DVD Player (or DVD Recorder/Player). To record live-action audio and video, there are camcorders, which integrate a camera and recorder in one compact unit. The term A/V represents audio and video. Using A/V in computers has been the basis of the term multimedia - combining audio and video into presentations and creative works. Video can also be transferred to and from the Internet. This is called Video Streaming. While a movie is among the most common uses for video production, video is an electronic system and a movie is a film-based system. A movie can be easily sent as a video signal but a video signal is not likely to be projected on the large screen of a movie theater

Recording

An electronic method of storing data on certain media such as magnetic tape or digital disc. This data, when played through a reader (player), may then be presented in its original form (ie. music, video, words, etc.). There are two basic recording methods: 1) Analog; 2) Digital. Digital recording is the most recent recording technology and is associated with computers. CD and DVD are media that are digitally recorded. Most tape recordings tend to be analog

High-Definition

In digital terms, amounts of digital data (information) are used to convey images and sounds. Definition increases as more information is provided. In a digital camera, for example, a still picture taken at VGA resolution is not considered high definition at a resolution of 640 times 480. 1280x1024 is more acceptable although most cameras approach approximately 2500x2000 resolutions. In TV, NTSC delivers about 350x240 resolution, NTSC with progressive scan might be closer to 640x480. HDTV (high definition TV), however is defined upwards of about 1200x720 resolution. Higher resolutions mean more information and that could be defined as more color, more visual detail, higher contrast. Similar rules apply for sound. High Definition Radio allows more information to be placed on its bandwidth and that upgrades the overall fidelity, clarity, and accuracy of the sound. Home Theater surround sound used digital technology to address 5 or more channels of audio information to enable surround sound encoding on a soundtrack

Interface

A port that is used to connect one piece of hardware with another. Hardware for a particular system is usually designed to be compatible with these ports.

User

In its most general term, a user is anyone who uses a device to pursue a particular purpose. Any person who uses a computer or runs an application through a computer is a user. Any person who watches TV or plays a stereo is also a user

Storage

An area where things are kept for future use, somewhat similar to a closet or cabinet. A computer works as a processor of data. It accepts data and instructions (programs), processes data according to instructions and then outputs the results. It does not, however, remember instructions or data (especially if unit is turned off). A storage area offers the user the ability to enter data and instructions with minimal repetition. In order to do this, the data, instructions, and output files are stored on media known as a disk. There are many different storage devices: Hard Disk Drives, CD-R & CD-RW drives, DVD-RAM drives, Memory Cards (ie. CompactFlash, SmartMedia, MMC, SD), and other electronic storage devices (too many to list). Appliances can have areas to store the power cord or, in a vacuum cleaner, a place to store the dirt that has been picked up. A VCR stores recordings on a vcideocassette. A TiVo or Replay personal video recorder stores programming on a hard drive designed to function directly with your TV

Digital

The 'Digital Age' refers to the current age of computers. Digital usually refers to computer-based technology - the way they record (store) and play (output) information. There are 2 basic types of technologies used for broadcasting, recording and playback - Analog and Digital. Analog information (records, tape, radio) is dependent on the integrity of an analogous wave pattern. Digital communication is based upon binary sequences of zeros and ones. The greater number of combinations help produce patterns that are considered more accurate and reliable. Computers and many electronic circuits use digital information. Light and sound can be recorded digitally but, because they have natural analog waves, they require a converter. Because digital recordings are read by light (usually laser) instead of a needle or tape head, there is considerably less surface noise. Images and Sounds can be sharper and clearer. Camcorders use digital electronics to enhance optical zoom and some cameras use digital technology to store pictures. There are digital camcorders and digital cameras that record sounds and images digitally and the store them on digital memory media and transferable to a computer. CD, DVD, CompactFlash, MemoryStick, SD are examples of popular digital record and play media