While televisions were in existence as early as the 1920's, the first television broadcast did not occur until 1936 in London. By 1945, there were less than 7000 TV sets in U.S. homes, and only nine television stations. While these analog sets left something to be desired - they usually took several minutes to warm up and all broadcasts were in black and white - it was certainly an exciting improvement over radio programming. Interestingly though, analog television broadcasting is transmitted in much the same method as radio broadcasts.
Analog TV broadcasting transmits audio and video signals over the air waves, just as radio broadcasts send only audio. Each station uses a single frequency over which it broadcasts analog television signals. You know these frequencies as channels. When these broadcasts experience interference with their frequencies, what you get is a channel with noisy static and annoying "snow" disrupting the program you are attempting to view. Also, because analog TV broadcasting signals vary and fluctuate depending on several factors, you may experience instable color, brightness and sound quality.
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While digital TV has only been highly touted in recent years, the first digital television broadcast actually took place in 1996, when a North Carolina TV station broadcast programming in digital. Digital TV broadcasting uses "packets" of compressed data to transmit television programs. The audio and video components of a program are packaged together into these packets of data and broadcast to your digital TV (or analog television with a converter, cable, or satellite box).
The code used to transmit sound, picture and even text (such as Closed Captioning) in digital TV broadcasting is very similar to the way pictures and sounds are transmitted to your computer via the Internet. Digital television broadcasting is not subject to the same type of interference often experienced by analog TV broadcasting. This means that you will enjoy a consistently clear, bright picture, high-quality audio and no static or snow.
Digital television is not perfect, though. If your reception for a certain channel is poor, you will not receive a poor-quality image or sound. You will not receive anything at all. Because of the manner in which digital TV broadcasting works, you will get great reception or no reception - there is no middle ground. Provided you have the right equipment and make proper adjustments, though, you can expect to enjoy great reception the majority of the time. Read How to Improve Digital TV Reception for tips on getting the best reception.
Another benefit of digital TV broadcasting is that television stations can transmit more data using the same "bandwidth" they were using to broadcast analog television. This means they can supply more features for you, the consumer, such as surround sound or high-definition programming using the same amount of space it took before to broadcast basic audio and video.
On the next page, learn about the differences between analog and digital TVs, and why you may need to upgrade.
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