OnQ Blog

Behind the Screen: HDTV Specs Explained

Dec 6, 2012

Qualcomm products mentioned within this post are offered by Qualcomm Technologies, Inc. and/or its subsidiaries.

Shopping for a television as a holiday gift this year—or as a gift for yourself? Deals abound— starting with HDTVs that cost less than $100.

But shopping for a high-tech TV can be as confusing as buying a computer. A typical tag will look something like this:

32-inch 1080p 60 Hz LCD TV

Here’s how you break that down.

Size

TVs are measured on the diagonal, from the lower-left-hand corner to the upper right.  Our sample 32-inch set would be about 28 inches wide and 16 inches tall.

Bigger is not always better, however. A huge set may look great in the store, but it will likely overwhelm a small room and give you a headache when you watch it. Amazon has a handy chart showing what size TV is best for different spaces. A 32-inch set is best viewed from a distance of about six feet, for example.

Resolution

A 1080p set has 1,080 lines of resolution. That’s considered “full high definition,” and is the resolution found on most mainstream sets on sale today. As a general rule, the more lines of resolution, the sharper the picture.

Some sets listed as “HD” only have 720 lines of resolution rather than the full 1080p, so be sure to look at the specs closely. The difference between 720 and 1080 may not be easily visible on small sets, but will become more apparent on larger ones.

The “p” in 1080p or 720p stands for progressive scan, which means that the lines on the screen are drawn sequentially to produce the moving image on screen. An alternate standard, interlaced, draws every other line at a time. Progressive is the standard on most sets today; interlaced is most common on older analog sets.

Refresh Rate

Calculating refresh rates is complicated, but in short: the higher the hertz, the more often the picture on your screen is updated. In theory, a higher refresh rate means smoother, clearer images, with less blur. But many experts point out that very high refresh rates are overkill, in part because most content is not filmed at that fast a speed. “In many cases, 60 Hz will do just fine,” PC Magazine says.

Technology

There are two basic flat-panel TV technologies: LCD and plasma. Although there were big differences between them in the early days of flat panels, the technologies have matured and many hurdles overcome. Now, the differences between them are subtle. 

Plasma TVs are still regarded as having the best image quality, because they can create darker blacks, which give images greater contrast. However, LCDs are more practical for rooms with lots of windows. They can get much brighter than plasmas, allowing you to clearly see the picture despite ambient light.

If you’re interested in LCD sets, be aware that they have different backlighting technologies that impact the TV’s size, image quality and price:

CCFL (cold-cathode fluorescent lights). This is the least expensive backlight technology, but it can make sets relatively bulky.

LED (light-emitting diode). This backlight technology lets manufactures make thinner displays. It becomes more expensive when it includes “local dimming,” which is when the LEDs turn on/off independently for better contrast. Some sets have LEDs only near the display’s edges, where they can have the most impact. But “full array” sets have LEDs over the entire screen. That creates the best picture—but also the highest price.

Which one should you buy? According to PC Mag: “If you can afford them, LED-backlit HDTVs are the way to go. They're thin, energy efficient, and can produce a great picture.” PC Magazine says. But bargain hunters might be better off with a plasma, the magazine continues. CNET has a useful list of the pros and cons of each technology.

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