by Nancy Houser

Created on: February 25, 2009   Last Updated: February 26, 2009

With the recent conversion of analog to digital in the United States, a lot of people are confused in the difference between the two. Switching from analog to digital broadcast television, the digital TV transition (DTV) was authorized in 1996 by the U.S. Congress. And even though June 12, 2009 was set as the final date by Congress, many states have jumped the gun and went for the original date of February 17, 2009 to start their digital broadcast channels, choosing to not wait due to the high cost involved.

The difference between analog and digital technology refers to the types of waves used. In analog, the waves is used in its original form or recorded in its original form. That analog wave is read from a microphone, amplified and sent to a speaker to be heard. But in digital technology, that analog wave is taken and sampled to be turned into numbers for digital device storage. For example, digital CDs are sampled at 44,000 per second, meaning that on one CD, the 44,000 numbers are stored "per second" of music. But in order for those numbers to be heard, they are turned into voltage waves similar to the original wave.

The digital technology is considered superior to the analog because the recordings never degrade as long as the numbers are able to be read. They can also be compressed if their pattern is found, and digital signal processors can be used to process and modify the number streams. What all of this means is the digital can be reproduced without noise and distortions, which is what occurs with analog. The human senses are considered analog, with the human eye easy to fool while the ear is extremely discerningwith "lossy" techniques part of the compression for many digital formats in MPEG-2, SDDS, DTS, and MPS. Any small change in frequency and timing is easily detected. This makes the need to convert a digital signal back to analog necessary for the individual listening to it.

Television in digital is considered a good move for the United States for several reasons: it can transmit more data; the data remains consistent longer; the data type carried has fewer problems in digital than analog. It also will offer more for the money, with a better picture, better sound and digital sound combined with HDTV and digital sound. Other countries that broadcast high definition pictures are doing so in analog, while the United States has chosen to do so in both digital signals and high-definition simultaneously. The other countries have gotten away with it by expanding the mount of frequency bandwidth for picture detail, with the U.S. not having that option. For this reason, digital was chosen because it can be compressed better for not television only but also for wireless Internet service, emergency radio traffic, with digital TV broadcasts taking up much less of the wireless spectrum.

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