What Frequency Is HDTV?

The term frequency is often mistaken for refresh rate, a different but important specification of HDTV's.

Often when talking about high-definition television (HDTV) frequencies, a consumer will ask for one of two specifications. Either it is the true frequency -- the information your cable box "tunes to" in order to view each individual channel -- or the refresh rate -- the number of times per second the image is "drawn" on the screen.

Digital and Analog Frequencies

Both digital and analog channels are broadcast on the same frequencies: 55-88 megahertz (MHz) Very High Frequency (VHF) low, 124-216 MHz VHF high and 470-806 Ultra High Frequency (UHF). High-definition channels cannot be broadcast analog because each channel is given 6 MHz to work with and analog can only display 480i to 480 lines interlaced within this range while digital can broadcast full 1080p to 1080 lines progressive scan HD within the same range.

HDTV Refresh Rate

A completely different specification that is often mistaken for frequency is refresh rate. Typical HDTV's use anywhere from 60 Hertz (Hz) to 240 Hz rates while Plasma screen HDTV's often boast a refresh rate of 600 Hz. Higher refresh rates are sought after by consumers who often watch high-speed action or sports or play video games, as a high refresh rate helps to alleviate motion blur.

What It All Means

Frequency should have very little bearing on purchasing a television as the cable box does all of the work for you these days. An interesting fact, and one that may come in handy if you're trying to build your own antenna, is that frequency means very little to the average consumer. Refresh rate, however, is often on the top of the TV wish list as the quality difference is very noticeable even when moving from 60 to 120 Hz.

References

• BrightHub.com: HDTV Frequencies and Refresh Rates Explained