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Glossary of Terms

Glossary of Terms

H.320
A recommendation of the ITU-T based on Discrete Cosine Transform, CCM and motion compensation techniques. It can be a video system's sole compression method or supplementary algorithm, used instead of a proprietary algorithm when two dissimilar codecs have need to interoperate. H.320 includes a number of individual recommendations for coding, framing, signaling and establishing connections. It also includes three audio algorithms, G.721, G.722 and G.728.
Hardware
In computing, the electronic and mechanical components used for processing information. Any equipment that comprises the computer system.
Harmonics
Multiples of an original frequency that add to, and modify, the original frequency. A pure sine wave is free of harmonics. In music, it is what makes on instrument sound different from another playing the same note. When harmonics occur in audio or video, it adds distortion to the original signal, causing undesirable results.
HD Connector
A high density "D" connector having 15 pins arranged in three rows. A normal 15-pin D connector has its pins arranged in two rows.
HDCP
Acronym for High-bandwidth Digital Content Protection.
HDTV
Acronym for High Definition Television; a high-resolution television standard using an 1125-line broadcast signal.
Hercules Graphics Adapter
Video card that the video out is monochrome at 720 x 348 resolution.
HERTZ (Hz)
A measure of frequency in cycles per second.
HGC
Acronym for Hercules Graphics Adapter.
High-bandwidth digital content protection
The HDCP has three components--authentication and key exchange, encryption, and revocation. Authentication, a cryptographic process, verifies that the DVI digital display is authorized or licensed to receive protected content. HDCP encrypts the content between the HDTV tuner and the Display and/or HDTV recorder. HDCP also allows the content provider to choose if a user has the right to record the programming that comes into their home. HDCP can also support a master lists of devices not to work with (a.k.a. Key Device Revocation).
High Definition Television
The term describes a variety of advanced video proposals to allow high-resolution TV to be received in the home. Current formats generally range in resolution from 655 to 1,125 scan lines, with an aspect ratio of 9:16, and bandwidth of 30 to 50 MHz.  HDTV will not be able to be displayed on standard television sets. Digital TV will require new television receivers such as set-top digital boxes, which can interface with both traditional and HDTV sets. This also means that current released InFocus projectors do not support HDTV format as the aspect ratio of present released projectors are at 4x3. It will require upgrading the video technology in upcoming projector to produce true HDTV or DVD 16x9 formats. This does not mean that people do not use the DVD 16x9 today on InFocus projectors and on the standard televisions, the signal in a 4x3 format.
HDTV resolutions:
1080i - Describes a TV or a signal with 1,080 interlaced lines of resolution.
720P - Describes a set or a signal with 720 progressively scanned lines of resolution.
480P - Similar to 720P, with 480 progressively scanned lines of resolution. A step down in sharrpness from 1080i, and 720P. Also called SDTV
480i - Describes a TV or signal that offers 480 interlaced lines of resolution. Better than analog, but not as sharp as 480P.
High Impedance (HiZ or High Z)
In video, when the signal is not terminated locally and is going to another destination, where it will be terminated. In video, Hi Z is typically 10k ohms or greater.
High-Level Language
A computer programming language designed to increase ease-of-use of computers by people. This type of language is designed to be machine independent, as opposed to low-level or assembly-level languages. High-level languages include BASIC, FORTRAN, etc.
Horizontal Blanking (Retrace)
The process of bringing the electron beam in a CRT back to the left side of the screen after a left to right line has been traced on the screen. The beam is shut off, blanked, during the period of retrace. About 83% of the total horizontal line time is spent writing the line. The remaining 17% is spent bringing the beam back to the left side; retrace, before starting the next time.
Horizontal Picture Centering Control
Adjusting the Horizontal Picture Centering control one way shifts the displayed image toward the left of the monitor or projector screen and the other way shifts the displayed image to the right of the monitor or projector screen.
Horizontal Rate (Frequency)
The number of complete horizontal lines, including trace and retrace, scanned per second. Typically measured in kHz.
Horizontal Resolution
Smallest increment of a television picture that can be discerned in the horizontal plane. The increment is dependent upon the video bandwidth and is measured in frequency. Determines the number of lines it takes to scan an image on the screen.
Host Computer
The central processing unit providing the computer power to connected terminals and peripheral devices.
Hot Links
A methodology that refers to and connects data from one document or file to another, regardless of application, for automatic and immediate updating.
Hot Spot
Commonly seen on high-gain screens, and screens designed for slide or movie projection, a circular area where the image is brighter than the rest of the screen. The Hot Spot always appears located along the line of sight, and "move" with the line of sight.
HRAM
High Resolution Analog Module - Extern Input/Output modules used for switching Red, Green, and Blue signals in the Matrix 200.
Hub
A network or system's signal distribution point where multiple circuits convenes and is connected. Some type of switching or information transfer can then take place. Switching hubs can also be used in Ethernet LAN environments is an arrangement whereby a LAN segment might support only one workstation. This relieves congestion through a process called micro segmenting.
Hue (Tint Control)
Red, yellow, blue, etc., are hues of color or types of color. Hue is the parameter of color that allows us to distinguish between colors.
Hum
Unwanted coupling of a 60 Hz power sine wave into other electrical signals. In audio, a "hum" can be heard; in video, waves in the picture.
HV
Extron's designation for composite Horizontal and Vertical sync. For separate sync, the two letters are used separately.
HyperMedia
An extension of hypertext that utilizes varied types of media, along with plain text. All the various forms of data are organized in such a way that a user can move from one to another.
Hypertext
Linking information together through a variety of paths or connections. Hypertext allows users to cross-reference related units of information in a manner similar to the human thinking process.
Hz (Hertz)
Frequency in cycles per second.
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