Home Theater

HDTV Glossary

3:2 Pull Down:
3:2 pull down is a process by which manufacturers add six frames to film's original 24-frames-per-second format so that it can work within the NTSC standard, which is 30 fps. This helps keep the action from stuttering on your television. Unfortunately, this technique still leaves some distracting side effects like jerky, uneven motion - especially in fast-moving scenes.

3:3 Pull Down:
3:3 pull down is a solution offered by Pioneer PureVision plasma televisions that greatly improves the visual quality of film based software content. Advanced technology inside the television increases the refresh rate to 72 frames per second (fps). At that speed, the original frame can be multiplied by three to smooth over time misalignments. The result is silky, natural motion just like the director intended.

720p:
The 720p format creates an image with 720 lines, each with 1280 pixels, so it has a resolution of 1280 x 720. The "p" stands for progressive, which means that all pixel rows are shown at once. 720p is the minimum resolution necessary to enjoy high-definition programming.

1080i:
The 1080i format creates an image with 1080 lines, each with 1920 pixels, so it has a resolution of 1920 x 1080. 1080i is the minimum resolution necessary to enjoy high-definition programming.

1080p:
1080p signal is the highest resolution possible. The picture resolution is 1,920 vertical pixels by 1,080 horizontal pixels; the increased pixel count results in improved picture detail.

A/D Conversion:
This is a standard term used to describe a signal being converted from an analog format to a digital format.

Aspect Ratio:
Aspect ratio is the relationship between the width and the height of an image. HDTV's standard ratio is 16:9 (widescreen), as compared to NTSC and Digital television's (DTV) squarer ratio of 4:3. Most DVD discs today contain a widescreen version of film that retains the original size of the theatrical release.

ATSC (Advanced Television Systems Committee):
In the early 1990's, the Advanced Television Standards Committee (ATSC) was established to recommend a new, higher set of standards for digital television in the United States to supplement the existing NTSC standards for analog television. ATSC refers to both the committee and the standards.

Burn-in:
Burn-in is the result of a static image or pattern appearing so regularly on a screen that it ages the phosphors and remains as a ghost image.

CRT TV (Cathode Ray Tube):
In homes across America for more than 50 years, CRTs are the cheapest television technology, but also the most outdated technology. CRT's other big drawback is the tremendous bulk compared to today's flat televisions. The image quality is generally good, but few CRT TVs are available in the increasingly popular widescreen format, meaning that images are commonly shrunk to fit the square screen size. The range of screen sizes for CRT TVs spans from just a few inches to large-size rear projection televisions.

Component Video:
Component video separates the video signal into three distinct streams, in which the component video signals are carried via three individual cables. Component video splits the signal into red, green, and blue streams the primary colors used to create the entire color spectrum in all televisions. There are two types of component video connections, Y, Cr, Cb, for interlaced signals most commonly found on DVD players, and Y, Pr, Pb for progressive signals, which can be commonly found on progressive scan DVD players, HDTVs, and HD set-top boxes.

Contrast Ratio:
Refers to the ratio of the white and black components in a picture signal.

Deinterlacing:
Deinterlacing involves assembling pairs of interlaced fields into one progressive frame (1/60 of a second long), and showing it at least twice to use up the same amount of time as two fields.

DCR (Digital Cable Ready):
DCR represents a displays ability to accept a one-way HD cable signal without the use of a cable set-top box. Basic and extended cable services will be accessible by televisions with DCR capabilities. A cable card will need to be acquired from the local cable provider in order for the television to receive the cable signal. These cards will either be available for rent or purchase through cable providers.

DLP (Digital Light Processing):
DLP uses micro mirrors and a color wheel to create an image. Although DLP is much slimmer than a typical rear projection television, they don't have the viewing angle, size or brightness to be hung on a wall or perched on a stand easily. The upside is that these large screen displays are relatively inexpensive compared to other technologies.

DTV (Digital Television):
Refers to a group of 18 U.S. digital broadcast formats set by the Advanced Television Systems Committee (ATSC) to replace NTSC, the current but aging television system. Each of the formats uses a different combination of standards for resolution, aspect ratio, frame rates, and progressive/interlaced scanning methods.

DVI (Digital Visual Interface):
DVI is a standard that provides a high-bandwidth, low-cost digital interface between a video source and a display device. It is capable of carrying uncompressed unprotected high resolution video transfers of HDTV signals, and supports real-time complex graphics displays and user interfaces found in program guides andother interactive features for high definition television.

DVI w/HDCP (Digital Visual Interface with High Density Copy Protection):
This is the same as above adding high-density digital copy protection, primarily for the secure transfer of high-resolution video content.

EDTV (Enhanced Definition Television):
A complete product/system with the following minimum performance attributes:
Receiver - Receives ATSC terristrial digital transmissions and decodes all ATSC Table 3 video formats
Display Scanning Format - Digital transmission; has active vertical scanning lines of 480 progressive (480p) or higher
Aspect Ratio - None specified

In simple terms, EDTV is about 2x better than conventional TV

Grayscale:
This describes the ability of a display to be in a state between full ON and full OFF. Each of these definable states is a "gray level". The grayscale is composed of the number of gray levels. The more levels a display has the better.

Half Brightness/Half Life:
Length of time after which a television will have lost half its brightness.

HDMI (High Definition MultiMedia Interface):
HDMI assures that the best video signal is always sent from source (e.g., HDTV signal) to the display (e.g., plasma television). It does this by allowing uncompressed video and multi-channel audio data to be input to the display device through one single cable. The need for multiple analog connections for high-resolution audio and video are eliminated. Without a HDMI connection one would need 3 video connections for high definition video and 6 audio connections for high-resolution audio.

HD-ready:
Describes a television that is capable of displaying one or both of the prescribed high-definition television formats (720p, 1080i) but is not equipped with the requisite tuner/converter to receive digital signals.

HDTV (High Definition Television):
A complete product/system with the following minimum performance attributes:
Receiver - Receives ATSC terristrial digital transmissions and decodes all ATSC Table 3 video formats
Display Scanning Format - Digital transmission; has active vertical scanning lines of 720 progressive (720p), 1080 interlaced (1080i), or higher
Aspect Ratio - Capable of displaying a 16:9 image (also called "widescreen," similar to what you see at a movie theater)

In simple terms, HDTV is about 5x better than conventional TV.

High Definition Monitor:
A television that only displays images from source; requires a separate tuner to show HDTV.

HDTV Compatible:
Describes a television that cannot show HDTV resolution, but can receive and show HDTV at a lesser quality.

Interactive Digital Cable Ready (iDCR):
Displays that will be iDCR equipped will have the capability of receiving cable content both HD and non-HD without the use of a set-top cable box. This capability will allow the consumer to purchase pay per view content with the remote control. Like DCR equipped displays, a cable card will be required.

IEEE-1394:
High-speed digital video and data interface technology adopted by the Institute of Electrical and Electronics Engineers; a nascent standard for connecting digital television and computers to various components and peripherals, such as Digital VHS, set-top HDTV tuner boxes and digital video camcorders.

Interlaced Scanning:
Interlaced scanning is a broadcast process used in television sets whereby odd- and even-numbered lines of a picture are scanned and displayed consecutively as two separate fields and superimposed to create one frame, or a complete picture, on the screen.

LCD TVs (Liquid Crystal Display):
Made of two glass panels with a liquid crystal solution layered between them. A single bulb is illuminated behind the glass panel and the image is formed when an electric current causes each individual crystal to open and shut like a shutter. LCDs were originally designed for computer monitors, making them better suited for viewing data than video. The response time of an LCD television is slower than other technologies, which means there is a blurring effect when images move quickly across the screen. Because LCD televisions tend to be smaller, this blurring effect might not be as noticeable as it is in a larger LCD screen. Small LCD TVs are suitable for kitchens, workshops and similar uses, but are not as appropriate for a home theater.

Liquid Crystal on Silicon (LCoS) technology is similar to DLP, however it uses liquid crystals (LCDs) on silicon wafers (rather then small mirrors) to reproduce images. This enables the display to show high quality image reproduction when watching movies and playing video games. Price and size of the displays are slowing the growth of the technology.

MPEG 2 Decoding:
MPEG 2 (Motion Picture Experts Group 2) decoding is a compression standard algorithm for digital motion picture video such as that on DVD. Certain digital components, like a DVD player, decode these high-bandwidth algorithms and pass the signals on for very high-quality reproduction.

NTSC (National Television Standards Committee):
In the 1950's, the National Television Standards Committee set standards for analog television in the United States, Japan and Canada that are still in place today. NTSC refers to both the committee and the standards.

Native Resolution:
Native resolution is the actual number of plasma cells that can be illuminated at once, and it's the very first thing you should check when shopping for a plasma display. In order to enjoy high-definition programming, your TV must have a minimum native resolution of 720p. (Pioneer PureVision plasmas actually exceed high-definition standards with 768p native resolution.)

Phosphor:
Phosphor is the chemical matter sandwiched between panels of glass in the front of a plasma television. The image is displayed on a plasma when high-frequency UV rays stimulate the red, green and blue cells, making them glow.

Plasma:
One of the newest television technologies, but has been on the market long enough to become the latest craze. Newer model plasma televisions offer picture quality and color reproduction as good as any projection television, while being thin enough to fit almost anywhere. Plasma also has a wider viewing angle than many other televisions, which means you don't have to sit in the "sweet spot" in the living room to get a good view of the TV. The larger-size plasma televisions provide the most dramatic difference when viewing HDTV.

Projection Television:
Come in two forms: rear projection based on cathode ray tube technology or two-piece projection reminiscent of a slide projector and screen from school days. Rear projection is what typically comes to mind when thinking of a 'big screen' TV, but is quickly being replaced by flat panels that reduce the bulk of the television dramatically. Two-piece projectors offer excellent picture quality, but can be extremely expensive and require professional installation.

Progressive Scanning:
Progressive scanning is a process by which a digital television can scan a complete image - not just half of it as with interlaced scanning - all at once. Images, especially ones in motion, appear smoother to your eye and you don't have the flicker as with analog televisions.

Refresh Rate:
The refresh rate for a monitor is measured in hertz (Hz) and is also called the vertical frequency, vertical scan rate, frame rate or vertical refresh rate. The old standard for monitor refresh rates was 60Hz, but a new standard developed by VESA sets the refresh rate at 75Hz for monitors displaying resolutions of 640x480 or greater. This means that the monitor redraws the display 75 times per second. The faster the refresh rate, the less the monitor flickers.

SDTV (Standard Definition Television):
SDTV refers to a complete product/system with the following performace attributes:
Receiver - Receives ATSC terristrial digital transmissions and decodes all ATSC Table 3 video formats, and produces a useable picture
Display Scanning Format - Analog transmission; has active vertical scanning lines less than that of EDTV
Aspect Ratio - None specified

SDTV (conventional TV) has been the standard for the past 60 years.

Terrestrial Broadcast:
Broadcast signals that are transmitted over the air and can be received by an antenna. Before cable was available to consumers, most received their television programs from a terrestrial broadcast.

Viewing Angle:
Refers to the area from which a person can clearly see the image on a display. Plasmas offer a considerably wider viewing angle (more than 160 degrees) that LCD and Rear Projection televisions.