High-Def TV

David Diggs

What is HDTV

• A television system that has twice the standard number of scanning lines per frame and therefore produces pictures with greater detail.

(dictionary.com) • High-definition television (HDTV) is a television broadcasting system

with a significantly higher resolution than traditional formats (NTSC, SECAM, PAL). (wikipedia.com)

HD vs. SD

HD vs. SD

HD Standards

• Current HDTV standards are defined by the International Telecommunication Union (ITU-R BT.709) as 1080 active interlace (1080i), 1080 progressive scan lines (1080p), or 720 progressive scan lines (720p), using a 16:9 aspect ratio.

– 1080i: the shorthand name for a category of video modes. The number 1080 represents 1,080 lines of vertical resolution, while the letter p stands for progressive scan or non-interlaced.

– 1080p: shorthand name for a category of video modes. The number 1080 stands for 1080 lines of vertical resolution, while the letter i stands for interlaced

– 720p: 1280x720 Pixels, progressive scan

SD Standards

• NTSC and PAL-M: 480i (60 fields) or 480p (24 or 30 frames)

• PAL and SECAM:576i (50 fields) or 576p (25 frames)– NTSC (National Television System Committee)– PAL (Phase-alternating line)– SECAM (Séquentiel couleur à mémoire, French for Sequential Color with

Memory)

• Although some stations such as ESPN HD have advertised the ability to show games in HD, on SD model TV sets the actual image will still look relatively poor due to the lower resolutions of SD models.

Current Types of HD Projectors

• LCD (Liquid Crystal Display)• Plasma• DLP (Digital Light Processing)• LCoS (Liquid Crystal on Silicon)

LCD

Pros• Thin and low weight

• Low power consumption

• Very durable

• Relatively cheap

• Wide range of screen sizes

Cons• Severe pixel distortion due to translation, at

any resolution other than the native (highest) resolution

• Very narrow viewing angle

• Ghosting with fast moving images due to slow cell response rate

• Lower contrast ratio than plasma

• Screen door effect

Plasma

Pros• Low weight

• Cheaper than LCD for larger monitors

• Wider viewing angle than LCD

• Contains no mercury

• Faster response time than LCD

Cons• Fragile and difficult to ship

• Mostly big screen

• Somewhat expensive due to sizes

• Subject to burn-in

• Negatively affected by high elevations

• Rainbow effect

DLP

Pros• DLP rear projection TVs are

considerably cheaper than LCD or plasma flat-panel displays and can still offer 1080p resolution

• The light source is more-easily replaceable than the backlights used with LCD, and is often user-replaceable.

• Longer life than CRT and Plasma• Jitter-free images

Cons• Heavier than plasma and LCD monitors• Expensive replacement lamps• Rainbow effect in single-chip designs• Longer delays; newer consoles such as the

Xbox 360 and play station 3 do not have this problem as long as they are connected with HD-capable cables.

• Screen door effect may be visible at close distance and/or with lower resolution models

• Some devices may have fan noise.• Dithering noise may be noticeable,

especially in dark image areas. Newer chip generations have less noise than older ones.

LCoS

Pros• Smoother image

• Higher quality image at close distances

• No rainbow effect

• Smoother pixel edges

Cons• Lower contrast

• Short lamp life

• Expensive lamp replacement

References• http://www.reference.com

• http://www.dictionary.com

• http://www.projectorcentral.com/lcos.htm

• http://en.wikipedia.org/wiki/Hdtv

• http://en.wikipedia.org/wiki/Dlp

• http://en.wikipedia.org/wiki/Lcd

• http://en.wikipedia.org/wiki/Plasma_display

• http://www.flattvpeople.com/tutorials/lcd-vs-plasma.asp

• http://reviews.cnet.com/4520-10166_7-6213889-1.html

• http://en.wikipedia.org/wiki/SDTV