HDTV 101

Back to Geek Talk Last updated: July 23, 2006

Know your Signal, TV, and Dispaly Types Before Spending A Pretty Penny

Singals and TV Types

If you don't already own an HDTV set, I'm sure you're thinking about buying one. This page summarizes what you should know about the confusing array of TV sets available today. Until recently, most HDTVs were lacking ATSC tunner. But that's changed for the 2006 models and the tunner is included in the set. Therefore, this feature will not be pointed out anymore. Having said that, Lets get right down to it:

Lines shown in this color reflect the lates news from the January 2006 CES show in Los Vegas.

Generally, TV sets fall into one of these four categories of the standard: HDTV, EDTV, DTV, and ANALOG TV. The best of each class is shown on this page.

HDTV - There are three classes of HDTV:

1080p - First off, there is no official 1080p format. Today's HDTV broacast is eaither in 1080i or 720p format. "Then, why do we even talk about it?" you ask. That's because there's speculation that the new DVD formats, Blue-ray or HD-DVD, as well as the upcoming Sony PlayStation 3, will output in 1080p.

1080p format delivers the highest resolution of 1920x1080 (vertical x horizontal) pixels using the progressive scanning techique to enhance the 1080i broadcast in quality. It writes one full frame of video from left to right across the screen every 1/60 of a second. When it receives lower resolution signals from any source such as 720p or a DVD movie, it will upconvert those signals to its higher level for display with no loss of quality.

1080i - This class of HTDV actually has the same 1920x1080 pixels resolution of the 1080p, but it displayes the picture using the interlaced scanning. Once the image has been captured and readied for display the electron gun at the back of the TV fires off the odd-numbered lines of the images first, followed by the even-numbered lines during the second, all within 1/30 of a second. The disadvantage is that you wind up seeing some occasional flicker or artifacts.

720p - This HDTV standard also uses the "progressive" scanning but with only a resolution of 1280x720 pixels, meaning that it will downconvert the 1080i broadcast signals for display. However, because progressive scan method is superior to the interlaced scan, the down coversion loss is offset by more smooth picture quality, and as some experts agree, is a better over-all format than the 1080i.

Currently, ABC and FOX broadcast in 720p and CBS, NBC, PBS, and all other cable and satellite networks broadcast in 1080i format.

EDTV - Enhanced-Definition TV uses only 852x480 pixels, and are NOT HDTV! By law, manufacturers are supposed to show the ' EDTV' mark on the set. EDTVs are capable of showing 1080i and 720p programs, but the picture quality is not nearly as detailed as it could. EDTV is used on wide-screen DVDs and Fox Wide-screen TV broadcast.

DTV - A digital television can also display progressive-scan DVD and almost always HDTV but at a much lower resolution.

Analog/Traditional TV - In terms of lines(pixels apply to digital displays), analog TVs can only display up to 480 lines, the upper limit of DVD resolution. Cable TV is broadcast at around 330 lines and VHS is around 240.

Display Technologies
Any of the display technologies described below can be used in conjunction with any of the TV types described above. A brief description of each display technology, pros and cons, and the best quality TV of that category as of the date of this article is presented.

LCoS - Liquid Crystal on Silicon. This newer hybrid projection TV technology employs liquid crystals coated on a silicon chip, which results in easier, lower-cost manufacturing and higher-resolution images.

The Sony's KDS-R60XBR1 60 inch Rear Projection TV priced at $5,000.00 is currently the best quality 1080p HDTV in LCoS or any other display category. However, It does not accept the output of the upcoming super DVD players such as the Blue-ray or HD-DVD through its HDMI 1.0 input. It is expected that by late summer of 2006 all major manufactures will incorporate HDMI 1.2 to resolve the issue.

Upside: Very high resolution; unlike DLP, it does not produce any rainbow effects, and unlike the LCD panels the pixels structure is not visible; often computer-capable; thin and light compared to CRT. The black level performance is now very close to that of the LDP displays.

Downside: Expensive; periodic lamp replacement required; Does not accept 1080p output from the upcoming super DVD formats such as the Blue-ray or HD-DVD; It's only the second-generation technology.

DLP - Digital light processing. A microdisplay technology invented by Texas Instruments, DLP is based on a digital micromirror device (DMD), a chip with millions of hinged, microscopic mirrors attached, each of which corresponds to a single pixel in the projected image. Red, green, and blue light filtered through a color wheel is directed alternately onto the DMD, which switches on and off up to 5,000 times a second. The reflected light is directed through a lens and onto a screen, creating an image. High-end HDTV projectors use a three-chip solution, with separate DMDs for green, red, and blue, and forego the color wheel.

This HP MD6580n Rear Projection DLP 1080p HDTV is priced at $5,000.00 and rated best in the DLP class TVs. This model boasts the new HDMI 1.2 interface, and in terms of picture quality it is the runner up to the Sony's KDS-R60XBR1.

Upside: Very good black-level performance; no maintenance required to preserve sharpness; often computer-capable; thin and light compared to CRT.

Downside: Expensive; some rainbow effects; video noise in dark areas; periodic lamp replacement required.
Update: 1/9/06 - Samsung's 56-inch HL-S5679W HDTV ($4200 & available in April 2006) uses a single-chip 1080p-resolution DLP and an entirely new light engine that eliminates the rainbow. Other significant benefit, according to Samsung, is the longer life of the bulb (20,000 hours vs. 3,000 to 6,000 hours for a typical DLP bulb.)

Plasma - Display technology used in large-screen, flat-panel TVs. The word plasma refers to the ionized gastrapped inside every pixel. When excited by electricity, the pixels glow in different colors and intensities to create an image. True plasma TVs with the native resolution of 1920x1080 that can display full HDTV 1080i are outrageously expensive. However, smaller plasma sets with the other (but not necessarily inferior) HDTV format, 720p, are quite reasonable.

For example, this 43" Pioneer's PDP-4360HD TV with a resolution of 1024 X 768 is not quite a 720p HDTV but at $3000-$4500, improved black-level performance, and loaded with many advanced features is considered among the best in its size and class.

Also, this 50" Panasonic TH-50PHD8UK with a resolution of 1366 x 768 and a price of $2900-$5000 produces the deepest black-level of any Plasma TV and the best color decoding engine, but it is an industrial monitor with no tuner, speakers, limited connectivity options, or a stand.

Upside: As little as three inches thick; potential for very large screen size; wide viewing angle; often computer-display capable.

Downside: Expensive; only average black level; potential for burn-in.

LCD TV - A television that employs a liquid-crystal display screen. An LCD projector uses a lamp to shine light through two glass plates with liquid-crystals in between them, then through mirrors and lenses to the screen.
LCD displays are used both in large Rear Projection TVs (RPTV) and smaller flat-panel displays.

When used as flat-panel, the LCD TVs are very expensive when compared to a comparable plasma display. This 37" Sharp LC-37D7U Flat Panel with a resolution of 1366 X 768 surpasses the 720p HDTV specs and is priced at $2200-$3600. The TFT active matrix of this TV produces a deep black level for an LCD. This TV also offers plenty of inputs, including HDMI, DVI, CableCard, RGB connector for PC; solid video processing; and numerous color adjustments

Here's an RPTV LCD from Sony with a native resolution of 1386x788 more than capable to show every detail of 720p HDTV. All other sources, including 1080i HDTV, are downconverted to fit the available pixels.

Upside: As little as two inches thick; very bright picture; no danger of burn-in; long product life span.

Downside: Expensive; visible pixel structure; screen sizes are relatively small; below-average black level; low response time, cheaper and older models produce rainbow effects.

CRT - cathode-ray tube, the original and still the most common Direct-View display technology for televisions. Invented in 1897 by German physicist Karl Ferdinand Braun, the tube uses an electron beam to scan lines on a bulky and heavy glass screen. It does not have an exact resolution as a fixed-pixel display does.

Upside: Relatively inexpensive; excellent black-level performance; still the best picture quality in a proper environment with proper setup.
Downside: Deep cabinets; need periodic maintenance; not ideal for bright rooms; narrow viewing angle.

CNT - Carbon Nanotube - flat-panel display that will rely on diamonds or carbon nanotubes--two forms of pure carbon--to produce images. Theoretically, these "field effect displays," or FEDs, will consume less energy than plasma or liquid crystal display (LCD) TVs, deliver a better picture and even cost less.
"The concept of a nanotube TV will give you image quality similar to CRTs (cathode ray tubes), and the best image quality is still found on CRT TVs," said Tom Pitstick, vice president of marketing at Houston's Carbon Nanotechnologies at the 2005 CES. "All the major display manufacturers are looking at nanotube TVs."

Upside: Similar to CRT, it produces the best picture quality; unlike CRT, CNT is a flat-panel display; less expensive and less maintenance than any other display available today.
Downside: Not available till late 2006, and even then, the first generation of any technology is not recommended.

TV / Video Lingo

Blue ray- A recording format using a shorter-wave blue laser to write 50GB (compare that to 9GB of today's DVD) of data on a double-sided, dual-layer disc. This higher capacity is needed for recording high resolution HDTV content or outputing DVD content of such resolution to a 1080p HDTV.

Manufacturers supporting the Blue-ray DVD format include: Sony, Dell, Hewlett-Packard, Hitachi, LG Electronics, Matsushita Electric Industrial (Panasonic), Mitsubishi Electric, Philips Electronics, Pioneer Electronics, Samsung Electronics, Sharp, TDK, and Thomson Multimedia.

HD-DVD- is also a blue laser technology capable of holding 30GB of data, enough for a full-length high-definition movie and the extras. The backers of HD-DVD format are: Toshiba, NEC, Sanyo, and Memory-Tech.

ATSC- Advanced Television Systems Committee. An HDTV set with a "built-in ATSC tuner" allows the reception of local, off-air digital broadcasts providing the viewing of free, true high-definition network programming without the addition of a set top box or a monthly fee.

NTSC - National Television Standards Committee. NTSC is today's common analog broadcast of TV programming. The FCC engineering group formed in 1940 to develop technical standards for black-and-white television (NTSC broadcasting began July 1, 1941) and color television (1953). NTSC standards are 525 lines of resolution transmitted within a 6MHz channel at 30fps.

Native resolution - All HDTVs including Plasma, LCD, LCoS and DLP TVs have a fixed number of pixels, known as native resolution, and the higher that number, the more detail you'll see. Every HDTV spec should indicate its native resolution, for example 1280x720. There are many sets which down convert higher resolution signals and thus are classified as HDTV capable. However, they are not true HDTVs if their native resolution is less than 1280x720 pixels.

fixed-pixel display - Plasma, LCD, DLP, LCoS, or any non-CRT display device. In DLP display tiny mirrors mounted on a DLP are used instead of a pixel.

Connectivity Options - HDMI, DCR, RGB, Standard/Progressive/Broadband Component-Video

HDMI Interface (High-Definition Multimedia Interface) - HDMI is the first industry-supported, uncompressed, all-digital audio/video interface. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, and A/V receiver and an audio and/or video monitor, such as a digital television (DTV). Your safest bet to ensure your new HDTV won't be obsolete tomorrow is to get an HDTV with an HDMI connection, which is replacing other digital connections such as DVI-D and FireWire.

HDTVs with HDMI 1.1 can not accept 1080p input from sources such as the Blue-ray or HD-DVD players. HDMI 1.2 specification address that issue, and 2006 HDTVs appearing mid to late summer will be equipped with such interface.

DCR - Digital Cable Ready with CableCARD™ Slot- HDTV set with DCR capability can tune digital cable channels, including HDTV if the cable provider has HDTV channels, without needing an external cable box.

RGB connection allows digital TVs display computer output.

Standard Component-Video - allows for the connection of Cable, Satellite boxes, S-VHS VCRs, DVD players, and game consoles

Progressive Component-Video - allows for the connection of progressive-scan (480p) DVD players and HDTV set-top boxes

Broadband Component-Video - allows for the connection of regular, progressive-scan (480p) DVD players and HDTV set-top boxes

Anamorphic - Adopted from the film technique of shooting a wide-screen image on a square 35mm frame, it's the process of compressing wide-screen images to fit into the squarer standard 4:3 television signal. The images are then expanded for viewing in their original format on a wide-screen display device. Wide-screen or letterboxed DVDs that are not anamorphic have less detail when projected on a wide-screen monitor. In other words, a nonanamorphic wide-screen DVD is designed to be shown letterboxed on a standard "square" TV but appears with a black box all around the image when shown on a larger 16:9 wide-screen TV. To fill a 16:9 screen, a nonanamorphic DVD has to be blown up, resulting in loss of resolution and detail. Conversely, a DVD that is anamorphic, enhanced for 16:9, or enhanced for wide-screen delivers 33 percent more resolution than regular letterboxed transfers, is designed to be shown on a 16:9 TV, and does not need to be blown up. When one of these DVDs is shown on a "square" TV, it is often subject to anamorphic downconversion artifacts unless the TV has a vertical compression feature.

Color temperature - Sometimes called white balance and expressed in degrees kelvin or just Kelvins, this is the color of gray at different levels from black to white. Since color information overlays the black-and-white information in a TV signal, color temperature affects the entire range of color. The National Television Standards Committee (NTSC) standard is 6,500K, but typically manufacturers ship their TVs with color temperatures ranging from about 7,000K to 12,000K, on the blue side of the color spectrum, to make sets as bright as possible to stand out on a brightly lit showroom sales floor. Some sets have a selectable color temperature.

What the heck are these numbers!
16:9 - Sometimes expressed as 16x9 or 16 by 9 (known as 1.78:1 in the film world); the standard DTV wide-screen television screen size, or aspect ratio--16 arbitrary units wide by 9 arbitrary units high, as compared to a standard TV aspect ratio of 4:3. The phrase describes the shape of a TV set or program, not an actual inch measurement.

2:3 pull-down detection - Also (and less accurately) called 3:2 pull-down; digital technology developed by Faroudja to accurately convert and display content originally on celluloid film, which runs at 24 frames per second (fps) compared to the 30fps rate of television. It is found in many DVD players and DTVs.

4:3 - Standard "square" NTSC TV screen-size aspect ratio of 4 arbitrary units wide by 3 arbitrary units high; often expressed as 4x3 or 4 by 3. It was originally known as the Academy Ratio (as in Academy of Motion Picture Arts and Sciences, the film industry organization that awards the Oscars) prior to 1954 and the introduction of wide-screen aspect-ratio film formats; also known in the film world as 1.33:1.

480i - 480 interlaced; form of standard-definition digital television (SDTV) that approximates the quality of analog television but not considered high-definition television (HDTV). Even though the native resolution of DVDs is 480p, they are viewed at 480i on an NTSC analog television.

480p - 480 progressive; form of standard-definition digital television (SDTV) comparable to VGA computer displays but not considered high-definition television (HDTV), though 480p is discernibly cleaner and slightly sharper than analog television. The native resolution of DVD is 480p, but that resolution can be seen only if a DVD player outputs a progressive-scan signal and the DTV has progressive-scan or component-video inputs; it is also known as EDTV.

5C DTCP - 5 company Digital Transmission Content Protection. An HDTV copy-protection encryption method for devices connected via FireWire, this allows one of three copy states: copy always (all ATSC broadcast and "in the clear" QAM cable broadcasts); copy once (premium cable); and, copy never (pay per view, video-on-demand). Bi-directional system requires 5C chips in every device in an A/V system (in other words, a set-top box, a TV, and so on); the TV "requests" acknowledgment before allowing the signal to be viewed or recorded. Proposed and sponsored by Hitachi, Intel, Matsushita (Panasonic), Sony, and Toshiba--the five companies.

8VSB - 8 vestigial side band; DTV broadcast system developed largely by Zenith and used for DTV broadcasts in the United States.