Football season is here! That means weekend afternoons huddled around the television. But how good is your picture? Maybe it is time to upgrade your television.

Forget about old-school CRT (cathode-ray tube) televisions. Those big, boxy tubes are on the way out. Instead, look for sleek, sexy high-definition sets. With the prices falling, you'll find a large set in your price range.

UNDERSTANDING HDTV

The resolution of standard-definition broadcasts is 720x480 pixels. In comparison, high-definition resolutions are 1280x720 or 1920x1080.

High-definition resolutions are commonly referred to as 720 and 1080. Additionally, you'll see interlaced (1080i) and progressive (1080p) screens.

Progressive screens refresh lines sequentially (1, 2, 3, etc.). With interlaced sets, odd lines (1, 3, 5, etc.) are refreshed, followed by even lines (2, 4, 6, etc.). True high definition is 1080p. But you'll still be wowed by 1080i and 720p.

There are several varieties of high-definition televisions (HDTVs). You'll find plasma, LCD and projection sets.

The depth of plasma and LCD screens can be measured in inches. Projection sets are considerably deeper, but are becoming thinner.

PROJECTION SETS

Projection TVs are relatively inexpensive. But they're too bulky to hang on a wall.

There are different types of projection sets: DLP (digital light processing), LCoS (liquid crystal on silicon), LCD (liquid crystal display) and CRT (cathode-ray tube).

DLP is the most common type of projection television. Light is reflected off mirrors mounted on a chip to create the picture. The bulb must be replaced periodically.

View the television in the store before you buy. Some people see a rainbow effect with projection sets. They can see the colors separate on the screen.

PLASMA DISPLAYS

Plasma sets are 37 inches or larger. They provide rich colors and deep blacks.

Traditionally, plasmas have suffered from burn-in. Static images become permanently visible on the screen. Newer models don't generally suffer from burn-in.

Plasma screens are more reflective than other screens. You may notice a glare from the glass screen. So they work better in dark rooms. However, plasmas have a wider viewing angle than LCDs. And movement does not blur on a plasma.

LCD SETS

Many manufacturers are focusing on LCD sets. They're lighter and more energy-efficient than plasmas.

LCDs used to be limited to smaller sizes. But today, their sizes rival those of plasma sets.

When choosing an LCD, look carefully at the response time. This is the time it takes for pixels to go on and off. Lower numbers are better. Aim for 8ms (milliseconds) or less. Otherwise, motion on the screen may appear blurred.

You also want to pay attention to the contrast ratio. The contrast ratio is the difference between the whitest and the blackest pixels. A higher ratio is better. It will help you see gradations of color better.

THE FUTURE OF LCDS

Manufacturers are beginning to produce LCDs that use diodes for backlighting. LED (light-emitting diode) LCDs are more energy efficient than other LCDs.

The use of LEDs offers other benefits, too. They improve the picture quality and color. And they offer higher contrast ratios. But you'll pay a premium for the technology.

Additionally, Sony has announced an OLED (organic light-emitting diode) set. The diodes use organic material.

Sony's set may be prohibitively expensive when it hits shelves. An 11-inch model is expected to top $1,700. But it is only 3 millimeters thick!

Contact Kim Komando at gnstech@gns.gannett.com.