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Palm Bay Ken |
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Great Sage of the Sea Posts: 539 Location: Palm Bay, Florida | Subject: Engineering Question I’m sure that someone on this board can answer my question ... just what is digital TV? I have a BS in Electrical Engineering.. that was awarded in 1965 when the newest thing was the transistor. I have 3 TVs that are all digital capable, at least according to the instruction manuals, but on my cable provider, (Bright House in central Florida) they will not pick up anything above channel 99. Is this some plot by the cable companies to require us to buy/rent cable boxes to get the programming? The TV is saturated with PSA’s about the February conversion to digital TV, BUT, if you have cable, don’t worry about it! Something smells really fishy here.Edited by Palm Bay Ken 2008-12-22 4:28 PM | ||
| Ric |
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Plankowner Posts: 9165 Location: Upper lefthand corner of the map. | Subject: RE: Engineering Question Can't answer your question but the change over date is February 17th, 2009 not in January. | ||
| viejo |
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Senior Crew Posts: 157 Location: Clarinda, IA | Subject: RE: Engineering Question It has to do with the type of signal that is being sent and that the TV can use. Analog is not as good a picture as digital and doesn't transmit as well. Digital signals can contain more info per line or sq in. Here is a page with info that is basic about the difference and what works best. If you want it from the EE standpoint, there are lots of pages online also that go into it from a mathmatical and source generation standpoint. Viejo http://electronics.howstuffworks.com/tv-buying-guide13.htm Here is a more complete, yet fairly non-technical explanation of why digital gives a better signal, hence better picture. It works similar to a computer and of course uses very fast, very low load transistors, like FETs to put out a lot of info in the same amount of time that is far better regulated and does not pick up the noise and other garbage that analog signals do. http://thesop.org/index.php?article=4587 Edited by viejo 2008-12-22 4:53 PM | ||
| Roy Ator |
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Great Sage of the Sea Posts: 892 Location: Palo Pinto County, Texas | Subject: RE: Engineering Question Hey Ken, from a 'novice' I'll take a stab at what I've been told about this issue. The old standard TV broadcast was with an analog signal that we could pick up with 'rabbit-ears' or an out side array antenna (not dish). Our government has mandated that all TV broadcasts after the switchover date will be in a digital format. Therefore the old antennas and the old TVs won't function without a converter. The converter can be purchased with the federal government (taxpayers) subsidizing the initial cost (so I've heard). The current cable and/or dish receiver boxes do the necessary conversion already. No action required. All new TVS being currently marketed are 'supposed' to be digital and not require an external converter. I use a satellite dish with a 'box'. I understand that I'll continue having service without any action required. | ||
| Gil Shaddock |
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| Great Sage of the Sea Posts: 557 | Subject: RE: Engineering Question Also, what does "Broadcasting In High Definition" mean? | ||
| viejo |
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Senior Crew Posts: 157 Location: Clarinda, IA | Subject: RE: Engineering Question To put it in simplest terms, more information or bits in the same area. Even sound is going digital now. Same process, but makes the ear hear more correctly what it should sound like. Remember when TVs first came out resolution ( information per line or sq in) was very low. In 1949, we were told to sit back one foot for every inch of TV screen. Then they started doing things with the empty space around where each little color dot went, so that glare and reflection were better, now they can put more bits of info, hence more detail and a better picture per area of screen. Which is why the newer big sets from 4 to 6 feet in size look better than the old bigger sets did. Same things with cameras that are digital. High-definition television (HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast; the earliest implementations used analog broadcasting, but today digital television (DTV) signals are used, requiring less bandwidth due to digital video compression. Below is some more info on the different types and what you get out of each. It also requires better HDMI cables to get the max results, and even with a converter, the picture on an older set won't be as good as a set designed to use HD to start with. Someone who doesn't want to read and figure all this stuff out, needs to find a young bright young kid in a store, that you can trust, so that what you buy will fit with what you have. Even some sets bought a couple of years ago may work with digital. They'll have something on the set to indicate that. Your computer monitor has several choices of resolution. When working with drawings or CAD programs, using higher resolutions allow more lines on the screen. I set my monitors at 1600 x 1200 ( I could go to 2438x 1536) as that is a good compromise of being able to see and read what us written and being able to see more things. TVs are much lower as it is mainly pictures. But as you change aspect ratios on a TV to watch different type of shows or movies, the resolution changes on that. Here's some info on how to determine if yours will work with an antenna. Cable companies will want to sell you a new box if you don't already have it for the digital signals they have already been selling you. TVs manufactured before 1998: They probably don’t have digital tuners at all. Almost every TV set made before 1998 was a traditional analog set. Projection TVs manufactured between 1998 and 2004: Only a limited percentage of projection TV sets (and generally only those 42 inches in diameter or larger) included digital tuners before 2004. TVs manufactured since 2004: Your chances of having a built-in digital tuner improve dramatically. Starting in 2004, many of the TV sets sold at popular electronics stores feature digital tuners that will work after February 17, 2009. But it's not a sure thing. Even some of the newer TV sets are purely display monitors that lack the internal circuitry needed to pick up digital broadcasts. Usually these sets have been advertised as "HD-ready" or "HDTV monitor" sets. That means they can display digital and high-definition signals, but they need help getting those signals in the first place. You'll still need a special converter or a cable TV connection. Extend the life of your analog TV with a converter box Using a converter box will help extend the life of your analog TV by enabling you to continue to receive over-the-air broadcasts. A converter box converts digital transmission to analog so your analog TV will continue to receive television broadcasts after February 17, 2009. Certified digital-to-analog converter boxes are expected to cost between $50-$70. To help consumers pay for the converter boxes, the federal government is offering US households up to two $40 coupons. Coupons are free, but they expire after 90 days and supply is limited. Upon request, coupons will be mailed to you by the federal government. To apply for your converter box coupons visit www.DTV2009.gov or call 1-888-DTV-2009 (1-888-388-2009). For more information on the TV converter box coupon program please visit www.DTV2009.gov. The site also enables you to locate a converter box retailer near you. When buying a converter box, look for one with the ENERGY STAR label. Digital-to-analog converter boxes that are ENERGY STAR-qualified use less energy than conventional converter Viejo Edited by viejo 2008-12-22 6:26 PM | ||
| steamboat |
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| Master and Commander Posts: 1814 Location: Boydton, Virginia | Subject: RE: Engineering Question So... is there a difference in "high definition" and "digital"? I have Direct TV satillite. Come Feb, will I be recieving Digital AND high Definition? Steamboat sends | ||
| viejo |
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Senior Crew Posts: 157 Location: Clarinda, IA | Subject: RE: Engineering Question If you don't have a HDTV you won't get High Definition pictures. And there is more than one type of High Definition. Goes back to resolution, the more dots and lines per sq in, the higher the resolution. Here are some explanations of terms and comparing the difference. Remember also that there are different types of scanning methods. Viejo HDTV Fundamentals Not that long ago, TV was TV. There was one main technology (direct-view cathode ray tube, or CRT) and one broadcasting format (480i). Now, however, there are five different types of TV and a number of different technologies. There are also lots and lots of different ways to format a TV signal. In fact, the Advanced Television Systems Committee (ATSC), which is the organization that created the digital broadcasting standards for the United States, allows 18 in all. Fortunately, there are "only" five that you really need to be concerned with: 480i Standard Definition (SD). To create an SD picture, 480 horizontal lines of image information are sent in an interlaced (that's what the "i" stands for) format. Each frame (or image) of an interlaced TV signal is actually made up of two fields, one consisting of the odd lines of the image and the other the even lines. The two fields are displayed one after the other by the TV at a speed that's so fast that the eye sees only one image. SD images have the familiar 4:3 aspect ratio. HDTV Flat Panel TV480p Enhanced Definition (ED). Like standard definition, a 480p EDTV image is made up of 480 lines of information; however, they are displayed in a progressive format (hence the "p"), which means the entire frame is displayed at one time. While there is no more image information than in an SD picture, the image appears sharper and smoother because the artifacts caused by interlacing are eliminated. While ED sets cannot display HDTV signals in their full resolution, they are usually widescreen. 720p HDTV. The lowest of the high-definition resolutions, a 720p image is made up of 1280 x 720 pixels displayed progressively. While other formats display more picture information, many critics say that at normal viewing distances, this format presents a picture that's just as appealing and even more film-like. Among major programmers, only ABC and its subsidiaries (including ESPN and ESPN2) and FOX distribute content in 720p. 1080i HDTV. This format places 1920 x 1080 pixels of picture information on the screen (in an interlaced format) for a vivid and sometimes breathtaking picture. Most broadcast, cable and satellite HD providers use this format. 1080p HDTV. Most new HDTVs are capable of accepting 1080i signals and, after some internal processing (called de-interlacing), these TVs can display the signals in a progressive format for the richest images of all. Most of these sets (but not all) are now also capable of accepting 1080p signals from high-quality sources such as Blu-ray disc players. Because it takes up so much bandwidth, it is unlikely that any broadcaster or other programming provider will be distributing HD material in 1080p in the foreseeable future. So right now, 1080p is mainly a media format. Note that while ATSC-compatible tuners must be able to receive all ATSC formats, the TVs themselves are free to take those signals and scale them to fit their native resolutions, which, for manufacturing reasons, don't always match up exactly with the ATSC standards. The bottom line, however, is that regardless of the resolution, HDTV looks terrific compared to SD or EDTV, reviewers say. But it doesn't take an expert to see the difference. If you look at an SDTV next to a HDTV in a store, you'll immediately notice why high-definition TV is so compelling. HDTV content used to be an issue, but that is no longer the case. Programming is much more available, and the major networks now broadcast virtually all of their prime-time programming in HD. There are also lots of HD cable networks, and that number continues to grow. Most cable and satellite companies are in a race to add HD networks to attract and retain subscribers. All of that, coupled with the fact that prices for HDTVs are dropping fast, means that HDTV is no longer merely for videophiles. Simply buying an HDTV does not automatically mean you get HDTV images on your screen. The hardware is only one part of the equation. To get the high-definition programming signals, you need to subscribe to a digital high-definition cable or satellite service. Alternatively, you can receive HDTV broadcasts "over the air" with a roof-mounted or even an indoor antenna, provided you are within range of a transmission tower. Of course, you won't get premium channels this way, but you can access the local affiliates of the major networks. AntennaWeb.org is a great website that lets you plug in your home address to see what kind of over-the-air broadcasts are available in your area, and what kind of antenna you'll need to receive them. With all TVs now required to have digital tuners, HD-ready sets (those that can display HD images but lack an integrated digital tuner) are all but gone from the market, with some notable exceptions. The law requiring new TVs to have a digital tuner does not apply to monitors -- those TVs that have no tuner at all. Tunerless monitors can be a good choice for those who get all of their TV from cable or satellite, but you'll need an external tuner to get any over-the-air programming. Most front projectors also lack TV tuners of any kind. Some HDTVs are compatible with CableCards. These TVs don't require a cable box to receive premium programming from cable companies. You plug the digital cable feed directly into the TV, and your cable company installs a CableCard (which goes into a slot on the TV). The CableCard de-scrambles the channels to which you've subscribed. However, experts' reactions to first-generation CableCards have been lukewarm, mostly because you can't use any of cable's interactive features. You can't order movies on demand with the remote or access the interactive programming guide. Tru2way, a new two-way standard for delivering scrambled programming and passing interactive content -- such as the program guide -- to compatible TVs without a cable box, is gaining acceptance by both manufacturers and cable providers. Sony, Panasonic and Samsung are among set makers that have announced that they will support it, along with at least six of the largest cable companies in the nation, including Comcast and Time-Warner. However, there's no firm word as of yet as to when sets with the technology will reach store shelves, or when cable rollouts will begin. Cable subscribers might also be interested in sets with QAM-compatible digital tuners. QAM, which stands for Quadrature Amplitude Modulation, is the transmission scheme cable companies use to distribute digital TV signals. A QAM tuner can allow you to receive any unscrambled, basic programming you subscribe to without a cable box or CableCard, so that's one less piece of hardware you'd need. An external box or a CableCard is still required for premium programming, however. While the analog broadcasting system will be gone for good in February 2009, those with older, non-digital sets will not be left completely in the dark. Cable companies are being required to provide local broadcasts to analog TV owners who subscribe to basic cable (which doesn't usually require a set-top box) until at least 2012. Providers have the choice of converting the digital broadcasts to analog for distribution on their systems, or providing all of their customers with free converter boxes. In addition, the government has set up a voucher program that will help offset some of the cost of an external digital tuner for those who need them. The program, which began this past January, provides $40 coupons that can be used toward the purchase of up to two analog-to-digital converters. While funding for the program is limited, coupons were still available as of August. See Best Research for more information. TYPES OF HDTVs There are four main types of display technology for HDTV. Plasma and LCD TVs draw lots of attention, as these two types are wall-mountable. LCD flat panels come in smaller, less expensive sizes, while plasma TVs are only available in sizes larger than 32 inches. Rear-projection TVs have come a long way from the huge cabinets you might remember. These newer microdisplay models cut down on the depth, but still deliver big screens up to 70 inches. However, rear-projection sets are decreasing in popularity as more and more buyers opt for sleeker flat-panel displays. A last option is hooking a front projector up to your cable feed and projecting the image on a wall or, preferably, on a screen. Conventional tube-based TVs are still being made, however all are standard definition. Flat-panel plasma and LCD HDTVs Plasma and LCD TVs are only a few inches thick -- and sometimes less -- and are wall-mountable. Design-wise, most look terrific hanging on a wall or sitting on a tabletop. Plasma TVs come in screen sizes of 32 inches and up (measured diagonally). While the most common sizes are 42 inches and 50 inches, larger plasma displays are becoming more commonplace, as are sizes such as 46 inches, designed to directly compete with LCD screens of the same size. LCD TVs, on the other hand, are available in a much wider range of sizes. The smallest LCD TVs are about 8 inches, and sizes for consumer TVs now go up to 65 inches, with some manufacturers demonstrating sets as large as 108 inches. Smaller LCD flat-panel HDTVs, which start at around 19 inches, are a good choice for bedrooms and kitchens. The advantage of plasma and LCD TVs, of course, is a sleek screen that takes up very little space. But note that while they may be thin, larger flat-panel TVs are still quite heavy and wall mounting often requires professional installation. Smaller LCD TVs have a native resolution of 1366 x 768 pixels. LCD TVs with that resolution can display standard TV, DVDs and 720p HD with no loss of detail, but need to scale down 1080i HD programming. Manufacturers have been rushing 1080p sets to market in more and more screen sizes, down to as small as 32 inches. These LCD TVs are more expensive than 720p TVs, but they can display every pixel of a 1980 x 1080 HDTV image. Likewise, many new plasma TVs have 1080p resolution. While initially more expensive than their LCD counterparts, prices have closed for all but the most expensive models. Manufacturers are also continuing to produce 720p plasma sets, and these make great budget performers. Note that while most 50-inch and larger 720p plasma TVs have the same 1366 x 768 resolution as LCD, 42-inch 720p plasma TVs typically have a native resolution of just 1024 x 768 pixels, which falls short of the ATSC standard of 1280 x 720. Despite that, industry convention -- which only looks at the horizontal specification when labeling TVs for sale to the public -- allows them to be sold as HDTVs. While this is an issue with some, reviewers say that as a practical matter, few will be able to tell the difference between 1024 and 1280 vertical resolution at normal TV viewing distances. While experts say the gap is closing, plasma TVs are known for their ability to display dark colors and detail in dark scenes better than LCD. This makes plasma a good choice for movie watching, where dark scenes are common. LCD TVs are brighter, which means LCD may be a better choice for a well-lit setting; plasma TVs can sometimes look washed-out in a bright room. Plasma screens have wider viewing angles than LCD flat panels. That means you can sit at more of an angle and still get the best picture. With conventional TVs, the picture brightness and color saturation stays the same from virtually any angle. With LCDs, sitting too far to one side will result in a loss of brightness. In addition, LCDs can sometimes leave trails behind fast-moving parts of an image. That's because of the time it takes for LCD pixels to switch color (plasma pixels make the change much faster). Finally, slower LCD switching speeds sometimes cause a loss of detail in fast-moving images. However, technology improvements have made both viewing angle and motion trails less of an issue in better LCD sets, and new technology to address softness in action scenes is included in many of the newest LCD TVs, though we've seen mixed reports of its effectiveness, and even its need. The most disconcerting issue regarding plasma TVs in the past has been a susceptibility to burn-in. Leaving the same image on the screen too long risked its being etched permanently into the screen, creating a lasting impression. New technology greatly reduces the risk of burn-in, and analysts at PC Magazine say that burn-in is no longer a major concern. Still, it's a good idea not to leave a plasma TV on when you're not watching it. LCDs have no burn-in risk. Temporary image retention -- a related but less severe problem -- is still a concern, however, and some plasma TVs, particularly budget options, can maintain ghostly shadows of previously displayed static images for minutes or more. While plasma TVs can produce great, cinematic images in a darkened room, they sometimes appear washed out when room lighting is higher. In addition, their top glass is usually much more reflective, though plasma TVs with anti-reflective screens are also available. Because of that, LCD TVs are sometimes a better choice for viewing in areas such as a typical living room where there are windows, making for greater variation in lighting at different times of day or night. However, some top-rated LCD TVs are now using more reflective glass as well. Though some buyers have been concerned about the life expectancy of a plasma TV, the latest models have panels that are rated to last up to 60,000 hours before they lose half their brightness. That translates to over 20 years if you watch TV eight hours a day. Until recently, plasma TV held a price advantage over LCD, but that gap is closing. In addition, if you want 1080p resolution, LCD is often a slightly less expensive option. As discussed in our report on plasma TV, the best choice right now is the Panasonic VIERA TH-46PZ800U (*Est. $2,175) . If your budget is a little tighter, the Samsung PN50A550 (*Est. $1,660) deserves some serious consideration. Among LCD TVs, Samsung has received great acclaim for its Series 6 1080p LCD TVs, including the 52-inch Samsung LN52A650 (*Est. $2,400) , 46-inch Samsung LN46A650 (*Est. $1,745) and the 40-inch Samsung LN40A650 (*Est. $1,450) . Sony's BRAVIA line of 1080p LCD HDTVs also does very well in professional reviews. Models include the 40-inch KDL-40XBR4 (*Est. $1,930) and 46-inch KDL-46XBR4 (*Est. $2,400) . Rear-projection TVs Thanks to the popularity of flat-screen LCD and plasma TVs, rear-projection TVs have become an afterthought in the marketplace. However, some still-attractive performers remain available, and rear projectors deliver the biggest screen sizes at the lowest cost per inch of all HDTVs. Today's rear-projection TVs are microdisplays, which get their name from the fact that their cabinets are so much smaller than the CRT RPTVs they have displaced. Even the largest are less than 16 inches deep, and smaller sets are shallower still. While that's certainly too deep to hang on a wall, it's a far cry from the CRT-powered behemoths of yesteryear. Until recently, four different rear-projection technologies were competing for floor space. However, all have given way to one -- Digital Light Processing, or DLP. DLP projection TVs direct light through a spinning color wheel onto nearly a million tiny mirrors that are used to project the image onto the screen. One problem with that technique is what's called "rainbow effect," which appears as a multicolored shadow around an object in certain scenes. Fortunately, only a very small percentage of the population can see rainbows in the first place, and advances in technology have made it less of a problem still. Even some of those afflicted say that an occasional rainbow doesn't bother them, but others say it wrecks the TV-watching experience and, in the worst cases, can cause eyestrain, headaches and the other symptoms. In any case, spending a bit of time auditioning a DLP set in a showroom might not be a bad idea if you are unsure if you are one of the unlucky ones that sees rainbows. Among rear projectors, critics and users uniformly point to the 61-inch Samsung HL61A750 (*Est. $1,850) as the top choice. That TV does away with the standard lamp and replaces it with colored LEDs. One advantage to that is longer lamp life. While most lamps last around 3,000 hours, Samsung expects its LED light engine to last 60,000 hours. Another is that rainbows are minimized, though apparently not entirely banished for those most able to see them. If 61 inches of HD image aren't enough for you, the set is available in a 67-inch model as the Samsung HL67A750 . Front projectors Once a part of only the most expensive home theater setups, digital projectors have dropped in price to where they are now a practical option. But while these projectors are capable of delivering the largest images (over 100 inches) at the lowest cost (on a dollars-per-inch basis), critics note that they are not perfect for everyone or every situation. For one thing, they demand more from the user. To complete your home theater, you need to supply a screen (for best results) and an external audio system. Also, since projectors don't include their own integrated tuner, you need to supply an external one or a signal from a cable or satellite TV box. The second issue is light levels. For the most part, digital projectors are only suitable for use in rooms where lighting can be completely controlled. That's because even a little bit of ambient light can wash out the image. This is less of an issue with brighter projectors, but still, front projectors are not the best choice for daylight viewing in a sunny room. Front projectors using three different technologies are available. DLP front projectors have the same drawbacks (i.e. rainbow effect) as rear projectors, but also have exacting placement requirements that can make using them difficult in some viewing rooms. LCoS (Liquid Crystal on Silicon) projectors are lauded for their great picture quality, but are very expensive. LCD projectors offer great colors, but in the past were plagued with light black levels and an artifact known as "screen-door effect." However, advances in technology have boosted blacks to the point where they are competitive with other projectors and have essentially eliminated screen-door effect, especially at typical viewing distances. The biggest news in front projection has been the tremendous price cuts. Three years ago, a 1080p projector would have cost around $30,000. Today, a top-performing 1080p projector can be had for under $3,000. One example is the Panasonic PT-AE2000U (*Est. $2,700) , a 1080p LCD projector that has reviewers doing cartwheels over both the price and performance. Reports say that black levels, sharpness and color are truly first rate. In addition, the projector has tons of adjustments and built-in calibration features that make it possible to tweak things to perfection. A long zoom range and lots of lens shift means placing the PT-AE2000U is a snap in any setting. While some other projectors are brighter, this Panasonic projector can still produce a great image of over 100 inches. For those looking for an inexpensive option, the Optoma HD65 (*Est. $800) has earned praise from all quarters. Reviews say that the 720p DLP front projector doesn't have the best blacks, but that they will satisfy most, and that colors and brightness are great. The biggest drawbacks are this projector is more likely to throw out DLP rainbows for those who can see them, and installation can be tricky. The biggest plus is the tiny price tag. | ||
| Ralph Luther |
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| COMSUBBBS Posts: 6180 Location: Summerville, SC | Subject: RE: Engineering Question Thanks for trying to clear the picture for us. I've got cable but I don't know about justifying the cost of a new TV just to get a sharper image. No, I don't squeak when I walk, but, money doen't flow like it use to. | ||
| Runner485 |
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COMSUBBBS Posts: 2672 Location: New Jersey | Subject: RE: Engineering Question The bottom line is if you now have cable, your ok for this pending change. If your using an antenna, you're not ok and gonna have to get a converter box. | ||
| PaulR |
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Master and Commander Posts: 1269 Location: Hopewell Junction NY | Subject: RE: Engineering Question steamboat - 2008-12-22 9:39 PMSo... is there a difference in "high definition" and "digital"? I have Direct TV satillite. Come Feb, will I be recieving Digital AND high Definition? Steamboat sends Nothing will change for you. Your system already receives digital signals from the DirecTV satellite now. IF YOU HAVE AN HD receiver AND an HD antenna AND HD TV AND pay for the extra service, you can view HD programs now. Edited by PaulR 2008-12-23 6:16 AM | ||
| Ralph Luther |
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| COMSUBBBS Posts: 6180 Location: Summerville, SC | Subject: RE: Engineering Question I'll be getting it without interferance, but, as I understand it, to get the best picture you need to have one of these latest TV's. I'll just have to wait a while in order to see the pimples on the movie stars faces.  | ||
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