Tech Directions - March 2008 - (Page 15)

HDTV Understanding the New, Dealing with the Old Samsung P EOPLE expect technology educators to be well informed about current events in all areas of technology. As it turns out, they often turn to us for advice outside our subject areas. Highdefinition television (HDTV) may be such a subject for many of us. I decided to do some independent study on HDTV after learning that elected officials had several times set back the date that analog broadcasts will cease. I also grew concerned about how poorly both our government and television dealers are handling this important and costly changeover. (Note here that for a period of time we heard use of additional terms, digital television and enhanced television, which, to my way of thinking, only added to the public’s confusion—yet another concern.) This article provides some information on high-definition television that I hope will help my colleagues in the field keep up to date on the subject. Mark Schwendau is professor of technology, Kishwaukee College, Malta, IL. By Mark Schwendau Schwendau@aol.com Background on the HDTV Changeover Not everyone in the United States is aware that the United States Congress and FCC say that by February 17, 2009, we will have completed the analog-to-digital television transition. On that date, analog signals are supposed to cease and their FM band frequencies (both UHF and VHF) can be turned over to emergency first responders. I doubt that this date will be pushed back again. Some people mistakenly think that a digital signal is needed to carry the HDTV signal. In fact, the inventors of HDTV, the Japanese, broadcast their HDTV over analog signals. While digital depends on high or low resolution television transmissions, it does offer some benefits and that is why American officials have chosen to go through the double switch from analog to digital and from the National Television Standard Code (NTSC) to Advanced Television Systems Committee (ATSC) at this time. Digital broadcasts have advantages in terms of how much data can be transmitted, how consistent the data stays over distance, and what type of data the signal can carry in a smaller bandwidth. Also, digital television won’t be limited to video and audio, and future TVs will become truly interactive. And I like digital signals because I can pull crystal clear signals from over 100 miles off the standard exterior TV antenna mast on my roof! Television data transmission will remain in the 6 Mhz present-day bandwidth but the difference will be that while NTSC screen includes 525 lines of 720 pixels (for a total of 378,000 pixels per frame in the 6 MHz bandwidth of a television channel), ATSC screen can have up to 1,080 interlaced lines of 1,920 pixels each—or 2,073,600 pixels per frame in the same bandwidth by using the MPEG2 compression standard. What HDTV to Buy? Another concern in the HDTV confusion is what kind of TV a person should purchase. While I currently own a 32" traditional cathoderay tube (CRT) digital/analog combination type HDTV, I hold stock in Texas Instruments because of that company’s development of digital www.techdirections.com COMMUNICATION 15 http://www.techdirections.com

Table of Contents Feed for the Digital Edition of Tech Directions - March 2008

Tech Directions - March 2008 Technically Speaking Contents Direct from Washington The News Report Technology’s Past Technology Today Mastering Computers HDTV—Understanding the New, Dealing with the Old Technical Studies Lead to Dream Career Fill and Fund Your CAD Classroom with These Exciting Strategies STEM Progress in Katrina’s Wake School Web Site of the Month Spring Spotlight More than Fun

Tech Directions - March 2008

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