TV Refresh Rate Explained

In order to understand what a refresh rate is you need to be aware that when you are watching TV you aren’t really seeing pure motion. You are seeing a series of images that are changing so fast that your brain sees them as motion. TV refresh rate is measured in Hz, and in most countries, electricity runs at 50-60 Hz frequency, so most TV’s used to run at 50-60 Hz as well.

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Understanding the Video

There are several important factors that directly affect the refresh rate of your TV, despite what the label might say. First, source footage greatly limits the refresh rate. This means that the refresh rate can’t go higher than the rate already in the source footage. Second, source footage is topped at 60 Hz, it doesn’t go higher than that. So why do the manufacturers sell TV’s with refresh rates higher than 60 Hz? The answer is simple. Because those TV’s can produce additional frames, despite the refresh rate in the source footage.

How Does It Work?

The moment the refresh rate goes higher than the refresh rate of the content you are looking at, your HDTV will start interpolating additional frames between the original frames found in the source footage. It fills the spaces with best newly generated frames and places them in optimal spots, generating completely new images for you to see. These new frames are only found on your TV, meaning they aren’t in the source footage at all. However, there are only so many new frames your TV can produce before you actually stop seeing the difference. Difference is noticeable up until 240 Hz, after which you will notice it less and less, or the content will start appearing unnatural. Some TV’s go as high as 600 Hz, producing an unrealistic feel when watching the TV. If the motions on your screen start looking unnatural, it might be a good time to turn off the additional frame rates (many TV’s offer this option). Insanely high refresh rates are really great for playing video games, or watching sports.

How to Choose the Perfect Refresh Rate

If you are looking to buy a new HDTV, do not spend a lot of money solely because a certain type of TV has high refresh rate. There is no such thing as a perfect refresh rate, though 120 Hz can be considered to be pretty optimal. There is a difference between different TV types though. Plasma TV’s do not feature a lot of motion blur like the LCD TV’s do since Plasma TV’s turn pixels on and off, creating the image in the process. This means that Plasma TV’s do not really need high refresh rates like the LCD does. The issue here is that all of the manufactures that make Plasma TV’s have adopted the LCD refresh rates, which means that even these devices feature high refresh rates now. When it comes to blur, you can’t run from it if it is in the source footage, no matter how high refresh rate might be.