Choosing The Signal With Your New HDTV Part I
With the transition to digital television coming in February 2009, many consumers are confused about television compared to the electronics industry’s early efforts to keep TV simple, straight-forward and easy to use. There is a baffling array of standards and acronyms that determine the type of digital television, it’s resolution and to what degree it is truly digital. If you’re like most consumers, you keep a TV for a longer period than you keep a personal computer, so even if you’re buying on a budget, try not to settle for a lesser standard than you can imagine yourself wanting in the near future. We explain the three choices of SDTV, EDTV, and HDTV with the following table which summarizes the technical details.
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Note: All HD and HD-Ready sets display 480i, 720p, and 1,080i signals, and convert them to match the sets’ resolution. Some convert 480i signals into 480p.DTV a.k.a. SDTV: Good
Plain vanilla digital TV, also known as SDTV, offers a 480-line interlaced image which is indicated by an “i” after the resolution. This is equal to the old 525-line analog TV, and it’s what most cable and satellite channels (and most of the non-prime-time schedules on broadcast channels) currently broadcast.
Why is 480 as good as 525?
Because early cathode-ray tube (CRT) receivers needed time for the electronic beam to reset itself from the bottom to the top of the screen. So the engineers and bureaucrats who set the NTSC standard built in a vertical blanking interval of 45 lines between the image frames. On an old set with faulty vertical hold, you could see this interval as a sort of stretched-out Chevrolet logo shape as the image frames scrolled up or down. In later years, broadcasters have used this blank space to transmit closed-captioning and other data. Despite having the same horizontal resolution, SDTV is still better than analog TV, for some of the same reasons that DVDs are better than VHS video tapes. SDTVs images are clearer and its colors are more stable.
Who should you buy DTV or SDTV?
If you’re on a tight budget or simply buying a secondary television for a kitchen, bedroom or home office, or planning to use your set to watch only standard-definition signals, then an SDTV set might be good enough, at least in the short term. However you will want to at least investigate the benefits of an HDTV or even an enhanced-definition TV, especially if you expect that you will be using it for years to come.
Filed Under: Resolution • TV Education
Trevahol
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Linda
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