The debate over which refresh rate is better for the ultimate viewing experience rages on. A TVs screen refresh rate can be defined as the number of times an image is refreshed per second on the screen. This rate is measured in hertz (Hz), a unit of frequency. If the screen refresh rate of a television is 60Hz, it means that the image is refreshed 60 times per second. There are three main screen refresh rates: 60Hz, 120Hz, and 240Hz.
The screen refresh rate and the frame rate of a TV go hand-in-hand to create a better picture. The refresh rate should be a multiple of the frame rate. Many standard TVs have a 60Hz screen refresh rate. In America, most TV shows are broadcasted at a speed of 30 frames per second. In this case, a 60Hz television proves to be more than sufficient. Movies, on the other hand, are shot at a frame rate of 24 frames per second (fps). As 60 is not a multiple of 24, you may notice some flickering and motion blur while watching movies on a 60Hz TV, especially if it is an LCD. This phenomenon does not occur with plasma TVs because they use different methods to create the illusion of motion.
Most televisions available in the market today, especially LCDs, have a 120Hz refresh rate. This 120Hz refresh rate is preferred to 60Hz because it doubles the image speed and produces smooth video with better clarity. In order to reduce blurring, 120Hz LCD TVs use an interpolation technique known as motion estimation-motion compensation (MEMC). This technology creates a new frame between each of the original frames, so there is one interpolated frame for every true frame. As a result, there is a significant decrease in flickering and motion blur during fast motion video on 120Hz LCD TVs. The fact that 120 is a direct multiple of 24 does make a difference. So, the verdict of the 60Hz vs 120Hz television debate is that 120Hz LCD TVs are worth every penny if you watch movies at home.
The relatively new arrival to the market is the 240Hz LCD TV, which is designed to reduce motion blur more effectively than 120Hz LCD TVs. Manufacturers either use MEMC to double the 120Hz refresh rate, thus resulting in three interpolated frames for each true frame, or scanning backlight technology. With this technology, instead of interpolating the frame for a second time, MEMC is used once to get to 120Hz. A backlight that flashes on and off rapidly is then added to create a 240Hz refresh rate. The downside of the 240Hz LCD TV is that it also comes with a higher price tag.
The bottom line is that televisions with a 60Hz refresh rate are ideal for everyday TV viewing, models with a 120Hz refresh rate are better if you enjoy watching movies at home, and LCDs and LEDs with a refresh rate of 240Hz are the most expensive, but offer unparalleled clarity and detail during fast motion video sequences.
