31 March 2008

Digital TV, High Definition, and You

Many television channels today broadcast on both analog and digital channels. Starting February 17, 2009, major US television broadcasters will broadcast only on digital television (DTV) channels.

What's the difference between analog and digital? Think of analog as an audiocassette tape and digital as a compact disk (CD). The heads of a cassette player actually touch the tape as it passes through the machine, reading the magnetically imprinted information (sounds). A compact disk player uses a laser to read the information (sounds), which are recorded in binary computer language (1s and 0s).

A cassette player cannot play a CD, and a CD player cannot read a cassette. This is why televisions without a digital tuner cannot display the new digital channels. They simply are not built to "play" the signal it receives.

How do you know if you have a digital tuner in your television? Televisions manufactured after March 1, 2007 were required to include a digital tuner. That doesn't mean if you bought a TV after that date it automatically has a DTV tuner. Stores were allowed to sell their remaining stock of analog-only TVs after March 1. Your TV's owner's manual can tell you if you have a digital tuner.

If you have an analog-only TV, what can you do? If you receive television channels only with an antenna (over-the air), you will need a digital-to-analog signal converter box. This electronic component will convert the digital signals (1s and 0s) into analog signals (waves) so you TV can display them. According to the Federal Communications Commission (FCC),
"Analog-only TVs should continue to work as before with cable and satellite TV services, gaming consoles, VCRs, DVD players, and similar products."

The US government is providing $40 off coupons to purchase a converter box. You can register to receive this coupon through this US government website.

What is the difference between DTV and HDTV? Is one better than the other? DTV means digital television. HDTV means high-definition television. They are two different things, but may be advertised or promoted together.

DTV is the type of signal transmitted by television broadcasters. HDTV is the resolution and size ratio of an image on a television. TV shows in the US used to all be 525 lines of resolution and 4:3 size ratio. A television image may look like one big square, but it's actually made of thin horizontal lines from top to bottom. Standard definition television (SDTV) has 525 of those lines from top to bottom on the screen. HDTV has 1125 horizontal lines of resolution and a 16:9 size ratio.

Standard Definition 4:3 size ratio - Copyright 2008 Totem Media, L.C. Standard Definition Television: 525 lines of resolution, 4:3 size ratio

High Definition 16:9 size ratio - Copyright 2008 Totem Media, L.C. High Definition Television: 1125 lines of resolution, 16:9 size ratio

For more information, post a question comment here or visit DTV.gov