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Other Features and Terms

BNC
A BNC cable has five connectors, receiving Red, Green Blue, Horizontal Sync and Vertical Sync information. These are often used for component video inputs.

Component Video Inputs
Connecting via component input can improve image quality. Component video inputs allow you to connect directly to DVD Players, digital VCRs and HDTV tuners.

Composite Video Inputs
Composite video allows you to connect video players, sending the video signal to an RCA connector.

CRT (cathode-ray tube)
Red, green and blue electron beams, generated by the cathode-ray tubes, each project the image. The three projected images must then be aligned to get a useable picture.

Digital Zoom
Magnifies an image through digital interpolation of the pixels. This magnification technology is less vivid than the magnification abilities of an optical (multi-focal length) zoom lens.

Horizontal Scan Rate (kHz)
This refers to how fast the horizontal lines of the projected image are created. The higher the horizontal scan rate, the greater the resolution at a given vertical frame rate. It is important for the data or video source to have a scan rate falling within the scan rate range of the projector.

Input Sources
Projectors accept a variety of video, audio, and computer inputs. Most common are the composite video and audio and S-Video inputs. Some projectors also accept component video, which can improve image quality. Most computers also accept analog computer input and some accept digital computer input as well.

Keystone Correction
When the projector is not positioned at the center of the screen, the image is projected at an angle and may appear distorted. Keystone correction adjusts for this distortion. Some projectors have fixed keystone correction, adjusting for distortion of an image projected at a certain angle. Other projectors let you adjust the images across a range of projection angles.

Lamp Life
Lamps used in projectors tend not to burn out suddenly, but to dim gradually. Lamp life refers to how long the lamp can be on until it starts to become too dim for adequate use. The life expectancy of the lamp in the projector varies from 40-70 hours on the low end (mainly halogen lamps) to as many as 4,000 hrs. Fortunately, most projectors today have lamps that will last at least 1,000 hours. That may be adequate to meet your needs, but keep in mind that most lamp replacements cost anywhere from $200 to $500. Two of the most common lamp types are metal halide and UHP lamps. Both types project very white light and typically last 750 to 2000 hours. In contrast, halogen lamps have shorter lives and tend to project a more yellow image. Xenon lamps are often used in high-end projectors.

Light Valve
Light Valves project vivid and bright images, surpassing the capabilities of virtually all LCD and many DLP projectors. This technology uses light from a projection lamp filtered through an imaging device, which is similar to what a film projector does. Light valves are high-end projectors, often used in auditoriums and theaters, and they tend to be quite large. There are different types of light valve projectors, such as HDLV (high density light valves) and two types of proprietary technology from JVC: the "ILA" which incorporates the "Image Light Amplifier" device, and D-ILA, which is a "Direct-Drive Image Light Amplifier." Hitachi uses the term "LCOS" for "Liquid Crystal On Silicon" to describe this high-end technology.

Loop-through
A loop-through allows another device, often a monitor, to be connected to the unit. A connected monitor lets you view the projected image without having to turn your back to your audience to face the screen.

Max Projection Distance
This refers to how far you can place the projector from the screen, as measured in feet, and still project a clear image. Projection distance is also known as throw distance. This value, provided by manufacturers, is somewhat variable. Once you actually set up the system, you may find that the throw distance is slightly different.

Max Resolution
This refers to the maximum resolution that the projector will support. Typically, this is one setting higher than the native resolution. Sometimes the native resolution and max resolution are the same. Virtually all projectors support lower resolution settings by expanding the image. Expanding an image may not be as problematic as compressing one, but may enlarge certain parts of the image disproportionately.

Min Projection Distance
This refers to how close you can place the projector to the screen, as measured in feet, and still project a clear image. Projection distance is also known as throw distance. This value, provided by manufacturers, is somewhat variable. Once you actually set up the unit, you may find that the throw distance is slightly different.

Min Screen Size
This refers to the diagonal measurement, in inches, of the smallest screen size with which the projector will work.

Noise Level
The sound of the projector's fan can distract from your presentation. Noise level indicates how loud the model is, in decibels.

Other Resolution
This indicates other resolutions that the projector supports, besides the typical VGA, SVGA, XGA, SXGA, and UXGA resolutions. Apple Macintosh computers tend to have a resolution of 1152 x 870 or 832 x 624

Outputs
This refers to the types and quantities of output terminals found, including those to computer, video, and audio sources, and to other peripherals. A document camera lets you project printed materials and transparencies.

Picture-in-Picture (Pip)
This feature allows for more than one input source to be displayed on the screen simultaneously.

Power Consumption (Max)
This refers to the maximum amount of power consumed by the projector, measured in watts.

Remote Control
Virtually all projectors offer remote control capabilities via infrared transmission. The range of a remote is limited to 30-35 feet on average, and requires a clear line of sight to work.

S-Video Inputs (or Y/C Video)
This identifies how many, if any, S-Video inputs the projector has. An S-Video cable transmits the video information via two signals, one for color and another for brightness. S-video produces a sharper image than composite video, which sends the video information through one signal. Some projectors have S-Video outputs, in addition to inputs.

TFT (Thin Film Transistor)
TFT technology is used with LCD projectors, increasing the contrast ratio and reducing the response time of the LCD.

Vertical Frame Rate (Hz)
Also known as the refresh rate, the vertical frame rate refers to how fast an image is redrawn on the screen. Increasing and decreasing the vertical rate increases and decreases the amount of flicker in the image. It is important for the data or video source to have a frame rate falling within the frame rate range of the projector.

Video Compatibility
This indicates which video or television signals the projector can project. NTSC (National Television Systems Committee) is the broadcast standard for North America and Japan. PAL (Phase Alternate Line) has a higher resolution than NTSC and is broadcast standard for much of Western Europe, Asia, Australia, and other countries. SECAM (Sequential Coleur A Memoire) has a higher resolution than NTSC and is the broadcast standard for France, Eastern Europe, and other countries. Unlike analog signals, high-definition television (HDTV) signals are digital and have a very high resolution (1080 vertical lines by 1920 horizontal pixels, or 720 vertical lines by 1280 horizontal pixels). Also, HDTV images have a 16:9 aspect ratio, rather than the standard 4:3 aspect ratio.

Voltage
Voltage refers to the power requirements of the model. Most wall outlets in the US have 120V; in Europe the standard is 220V.

Projector Buying Tips:
  An Introduction to Projectors
  Product Types
  DLP vs LCD Projectors
  Resolution - which is best for you?
  Resolution - the FAQs
  Weight and Portability
  Pricing
  Brightness
  Aspect Ratio
  Other Features
  Other Considerations
  Guide to Inputs
  Lens and Optics Specifications
  Zoom Lenses
  Projector - Quick FAQs

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