It is a common misconception that all flat panel, wide screen TV's are high definition. This is definitely not the case, and a smart consumer needs to know what differentiates a standard definition television (SDTV) from a high definition television (HDTV).

SD and HD refer to the way in which television signals are broadcast and displayed. SD broadcasts are limited to 480 lines of resolution, while HD broadcasts can be either 720 or 1080 lines. These lines are drawn on the screen in either progressive (p), or interlaced (i) formats. Interlacing requires two separate passes to display the complete image. The odd numbered lines are drawn in one pass, and the even numbered lines are drawn in another pass. This process happens so quickly that your eye believes it is seeing the entire image, while in reality only half the image is being displayed at a given time. Progressive scanning, on the other hand, draws the entire image in just one pass. Progressive scanning is generally superior to interlacing, as it produces a smoother, flicker free image.

The minimum spec for HD is 720p. This means that the image is made up of 720 lines progressively scanned. Most HDTV's can display 480p, 480i, 720p, and 1080i, while some of the higher end models are capable of displaying 1080p. 1080p is also referred to as "Full HD" because this is the true upper limit of High Definition broadcasting technology.

Even though the price of an SDTV may be more appealing when compared to an HDTV, the important thing to remember is that HDTV's can display both SD and HD images, while SDTV's can only display SD images. Also, be aware that the amount of available High Definition programming is steadily on the rise. If you spend a lot of time in front of your TV, or you don't buy a new TV very often, then an HDTV should be high on your list when shopping for your next television.