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Glossary
Glossary of Terms
 
     
 

| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |


 
 
 
     
 

A

Ambient Light:
Light that is present in the room where video projection will occur. (i.e.: uncovered windows, track lighting, lamps, etc.) Depending on the amount of light present, the visible contrast on the screen may be affected. Although many projectors are made to produce crisp, clear images in a lighted environment, for home theatre we suggest that the room or area be as dark as possible.



Amplifier:
A component that increases the gain or level of an audio signal.



ANSI:
This is the ‘American National Standards Institute’ and is the official organisation that will approve all lighting formats used in projector lamps and projector units.



ANSI Lumen:
ANSI lumens mean the level of the illumination and brightness available from a projector's display, which has been measured in ‘candles.’ For example, a projector that provides 2000 ANSI lumens is producing twice the brightness of a projector with 1000 ANSI lumens. The brightness of a projector will depend on the projector lamp installed. A projector that has been fitted with a new projector lamp will be brighter than an older projector lamp, which is likely to dim over time.



Aspect ratio:
The aspect ratio means ratio of width in relation to the height of a projected image. There are two aspect ratios which are most used and these are 4:3 and 16:9. A projector unit that projects an image that is a 4:3 aspect ratio equates to the same ratio as your TV or computer monitor. A projector that has a 16:9 aspect ratio capability is known as "wide-screen format". This aspect ratio equates to a theatre or movie screen.



Auto balance:
Auto balance is a system that detects errors in colour balance in black and white areas of the picture, and automatically adjusts the black and white levels of both the red and blue signals as needed for correction.

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B


Bandwidth:
The speed at which data can be sent across a network. LANs usually run at 10 or 100 million packets per second, which means that the data can be transferred at up to 100 million packets per second. A WAN usually transfers data at up to 1.5 to 45 million packets per second, but can go much faster.



Black level:
More commonly referred to as "brightness", the black level is the level of light produced on a video screen. The level of a picture signal corresponding to the maximum limit of black peaks. The bottom portion of the video wave form, which contains the sync, blanking and control signals. The black level is set by the "brightness" control.



Brightness:
Projector brightness is measured in ANSI lumens. If using a projector for home theatre applications, where light is controlled, you need a projector with around 1,000 lumens or less. Areas that have windows or ambient light require more lumens. How much depends upon a number of factors including image size, audience size, and the amount of ambient light.



Bulb:
A light source commonly mistaken for the lamp module in a projector. Bulbs provide incandescent room lighting. Lamp modules provide light for projected images.

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C


Cathode Ray Tube:
(CRT) Analogue display device that generates an image on a layer of phosphors that are driven by an electron gun.



Coated Optics:
Minimize the amount of light reflected back to the lamp and the amount of ambient light that mingles with the focused light leaving the lens. Good coatings generally add 15% or more to the brightness of lenses.



Compatible:
When different hardware or software can be used together without a major over-haul.



Compression:
Compression is used to convert one resolution to another. For example, a projector that has SVGA resolution may accept XGA resolution and compress it to SVGA, resulting in a clearer picture.



Connectivity:
Refers to the input and output ports and wireless ability of the product. Most of our projectors ship with a selection of leads which will enable you to connect a large variety of equipment. If you are running you presentation from a PC or laptop then simply connect the monitor output to the monitor input on the projector.



Contrast Ratio:
Contrast Ratio is the difference between the whitest white and the darkest black colours that the display can show. Generally speaking, the greater the contrast the better the screen and the subtlety of colours it can display.



Contrast (Low)
When contrast is low, images appear washed out. Parts of the image may become difficult to see clearly. Projectors with contrast ratios of less than 500:1 typically provide low contrast.



Contrast (Medium)
When a projector provides good contrast, images are clear and attractive. Projectors with contrast ratios ranging from 500:1 to 1200:1 typically provide medium contrast.



Contrast (High)
With high contrast, images are ultra crisp with vibrant colours. Projectors with contrast ratios exceeding 1200:1 typically provide high contrast. DLP TM (DDR) technology projectors currently offer these high contrast ratios. Additionally, some LCD projectors are able to offer high contrast ratios as well.

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D


DB or Decibel:
A measurement invented by Graham Alexander Bell one of its uses to record a measurement against noise level. The higher the decibels the higher the noise output from a device. For example noise output from a car horn near you would be 110 decibels. A quiet whisper would be 20 decibels.



DBS:
Direct Broadcast Satellite. Term that replaced DSS to describe small-dish, digital satellite systems such as DirecTV and Dish Network.



Digital signal:
A digital signal is strung together in infinite variations at rapid speeds to transmit computer information. Most projectors utilize analogue signals today whether it be from component, composite or RGB cables.



DLP (digital light processing):
DLP is the display technology developed by Texas Instruments that uses mirrors to display an image. Advantages to DLP technology in projectors are the ability to produce amazingly high contrast ratios and super light projectors. The disadvantages of DLP are generally colours that are not as vibrant and saturated and what's called a "Rainbow Effect". A rainbow effect is an illusion of artefacts that some people will see when watching video on a DLP projector.



DNR:
Dynamic Noise Reduction. A signal-processing circuit, that attempts to reduce the level of high-frequency noise.



DVI (Digital Visual Interface):
Is a standard that defines the digital interface between digital devices such as projectors and personal computers. For devices that support DVI, a digital-to-digital connection can be made that eliminates the conversion to analogue and thereby delivers an unblemished image.

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E


Eco-mode:
A menu function to extend Lamp life and reduce energy consumption by slightly reducing brightness. Typically a 20% reduction in brightness can increase Lamp life by up to 50 per cent



EDTV:
Stands for extended definition television and is a class of digital television (DTV) that refers to the 480p format. 480p is a class of definition the higher the number the better the definition.

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F


Fibre Optic Cable:
Glass, plastic, or hybrid fibre cable that transmits digital signals as light pulses.



Focus:
The focus on a projector defines the minimum and maximum projection distances. Most projectors today have an Auto Focus button that will automatically focus the image. You can still adjust the image using the manual focus.



Frequency:
The number of cycles (vibrations) per second. In audio, audible frequencies commonly range from 20 to 20,000 cycles per second (Hz). In video, frequency is used to define the image resolution. Low-frequency video images depict large objects or images. Higher frequencies depict smaller objects (finer details).



FXL:
The most popular halogen lamp in lower cost projectors and overhead projectors. These lamps typically last about 40 hours. For convenience, most projectors using halogen lamps carry a spare as a quick method of going to the backup lamp. Metal halide lamps and UHP lamps are used in most of the medium and higher priced, more powerful portables.

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G


Grey Scale:
The ability for a video display to reproduce a neutral image colour with a given input at various levels of intensity.

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H


HDCP:
High-bandwidth Digital Content Protection is a system for protecting copyrighted digital content that uses the DVI (Digital Visual Interface) or HDMI (High-Definition Multimedia Interface). It does this by encrypting its transmission between the video source such as a set-top box, DVD player, or computer and the digital display device such as a projector, monitor or television. To view digital HDCP protected content, both the sending and receiving device must support HDCP.



HDMI:
High-Definition Multimedia Interface. A new standard for video interfacing supported by Pioneer, Hitachi, Matsushita Electric Industrial (Panasonic), Philips, Sony, Thomson (RCA), Toshiba, and Silicon Image. It has a bandwidth of upto 5Gbs which means it can easily support all current HDTV standards. HDMI is backwards compatible with DVI.



HDTV:
High Definition Television. This is the highest-resolution subset of Digital Television and offers film like picture quality with impressive surround sound. HDTV has a wide screen aspect ratio of 16:9.



High Definition:
High definition in projectors relates to the quality of the image the higher the resolution (number of lines that make up the width and the number of lines that make up the height), the better the image quality.



Home Cinema Screen:
The home cinema screen is the surface onto which an image is projected. A high-quality screen contributes to a crisp, clear image.



Halogen Projector Lamps:
Older projector units use halogen projector lamps. A halogen projector lamp provides a yellow light. Halogen projector lamps are less costly but have a shorter life expectancy.



Horizontal / Vertical Lens Shift:
This is a feature on your projector unit, which provides precise image position, which leads to speed of installation and easy usage. A projector with this facility may be positioned in a cage or mount and the picture can be adjusted accordingly for image precision.

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I


Interconnects:
Any cable or wire running between two pieces of A/V equipment. For example, RCA terminated cables connecting pre/pros and amps.



Interface:
In AV terms and interface is a device to convert one type of signal to another. For example, if you need to convert RGB or component to s-video you would use an interface to achieve this.



Interlaced Video:
In traditional television systems each frame of a video pitcure is divided into two fields, the first field containing the odd numbered scan lines and the second field containing even numbered scan lines (the two fields being interlaced). Historically this was done because televisions could not re-draw frames quickly enough to prevent CRT phosphors at the top of a television screen from fading before the gun reached the bottom of the screen, causing the picture to flicker.

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J


Java:
A programming language developed by SUN. Among other features, it allows the programming of interactive software for the Internet.



JPEG: "Joint Photographic Experts Group". In computer terms it refers to am image storage format which allows you to specify the ratio between image quality and file size (the compression ratio).

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K


Keystone correction:
A method of correcting a keystoned image.



Keystone:
A video distortion effect that occurs when the projector is not set up directly in front of the screen.

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L


Lamp life:
This relates to the bulb (lamp) that is used to project an image and is measured in hours. Basically the more hours the better as lamps are not cheap to replace. If you watched two hours a night on your projector with an a lamp life of 3,000 hours it would last around 4 years. By this time you may be looking at getting a new projector anyway.



LCD:
LCD stands for liquid crystal display and comes in many forms, sizes, and resolutions. Its primary purpose is to present a digital image for viewing. Before DLP most projectors were LCD.



Lens Shift:
The Lens Shift feature of a projector allows the optical lens to be physically shifted up and down (Vertical) or left and right (Horizontal). This allows for adjustment of the projected image.



Lumens:
Is a measurement of the flow of light (Brightness). As a rule of thumb the higher the number the brighter the image. This can be useful when using a projector in a room that has a light source other than the projector (table lamp etc.)

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M


Metal halide:
Metal halide light bulbs give off a much brighter image and last longer than halogen. High-end, and some medium projectors now use metal halide bulbs.



Multiplex:
Multiplex allows you to split an image into several panels on a single screen.

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N

 

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O

 

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P


Pixel:
A pixel is a small dot that represents a single element of a display.



Power Zoom:
A zoom lens with the zoom in and out controlled by a motor, usually adjusted from the projector's control panel and also the remote control.



Projector:
A projector is a device that integrates a light source, optics system, electronics and displays, thus projecting an image from a computer or video onto a surface for large image viewing.

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Q


QXGA:
QXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A QXGA display has 2048 horizontal pixels and 1536 vertical pixels giving a total display resolution of 3,145,728 individual pixels that are used to compose the image delivered by a projector. A QXGA display has 4 times the resolution of an XGA display.

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R


Rainbow effect:
On DLP projectors, the rainbow effect is created by the inability of the DLP colour wheels to refresh pixels fast enough, resulting in some colour separation on the edges of fast-moving objects.



Resolution:
The resolution is the total number of pixels used to produce the image. The greater the number of pixels, the greater the image clarity and sharpness.



RGB (Red, Green, Blue):
The video format in which video information is first captured and later displayed. It’s all that is needed because the human eye can only see variants of red, green and blue.

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S


Short Throw Lens:
The type of lens is specially designed to be used when the projector is placed fairly near to the projection screen. It allows for a larger image size at a shorter distance and is popular with those using a projector for mobile presentations.



SVGA:
SVGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SVGA display has 800 horizontal pixels and 600 vertical pixels giving a total display resolution of 480,000 individual pixels that are used to compose the image delivered by a projector. S-Video: Is a way of delivering high quality video by using two separate signals to transmit the video information. One transmits the luminance information, dealing with brightness and one the chrominance information dealing with colour. Provides superior video image quality to composite video where the information is combined as one signal. S-Video uses a 4-pin mini-DIN connector.



SXGA:
SXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SXGA display has 1280 horizontal pixels and 1024 vertical pixels giving a total display resolution of 1,310,720 individual pixels that are used to compose the image delivered by a projector.

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T


Throw Ratio:
A ratio between projection distance and width of image. For example, a throw ratio of 1.8:1 means that the projector must be 18' away from the screen to result in a 10' wide image.

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U


USB:
Acronym for Universal Serial Bus, a peripheral connection interface for low-speed devices notable for its hot-swapability.



UXGA (1600x1200):
UXGA is used to define a specific display resolution. A UXGA display has 1600 horizontal pixels by 1200 vertical pixels, giving it a total display resolution of 1,920,000 individual pixels that are used to compose the image delivered by a projector.

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V


VGA (640x480):
VGA is used to define a specific display resolution. A VGA display has 640 horizontal pixels by 480 vertical pixels, giving it a total display resolution of 307,200 individual pixels that are used to compose the image delivered by a projector.

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W


WXGA (1366x768):
WXGA is used to define a specific display resolution. A WXGA display has 1366 horizontal pixels by 768 vertical pixels, giving it a total display resolution of 1,049,088 individual pixels that are used to compose the image delivered by a projector.

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X


XGA (1024x768):
XGA is used to define a specific display resolution. An XGA display has 1020 horizontal pixels by 768 vertical pixels, giving it a total display resolution of 783,360 individual pixels that are used to compose the image delivered by a projector.

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Y

 

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Z

 

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