Lots of people talk these days about digital television, but very few actually know what is the difference between analog and digital television. Actually the only difference is the way the signal is transmitted. Analog television signal is transmitted very much like radio signals. The video signal of analog television is AM, and the audio is FM. Because of this, there can be annoying interferences in the signal, depending on meteorological conditions or geographical location.
The resolution and image quality are also restricted, because there are certain bandwidths assigned to analog TV channels. The analog signal is the United States follows the NTSC standard. This had been adopted in the 1940’s, and served well since then, but nobody thought at that time that about color television. One major weakness of the NTSC standard is color implementation, so it is no wonder a lot of people call “Never Twice The Same Color” the NTSC standard.
On the other hand digital TV signal is transmitted very similar to computer data: there are two kinds of signal, “on” or “off”. This way, the user either sees an image, or not. Gradual signal loss is an unknown term in the era of digital TV: it has no difference how close or how far away the transmitter is from the television, the viewer either sees the exact image, or sees nothing.
Digital TV format has been designed considering all main factors of television signal: B/W, color and audio can be transmitted as progressive or interlaced signal. Basically this means the signal content has greater integrity and flexibility.
Another advantage is that because digital TV signal consists of “bits”, the same bandwidth one analog TV signal requires can host not only higher quality digital image, but there will be extra space left, which can be used for extra video, audio or text signals.
This way broadcasters using digital technology can supply more features, like surround sound, multiple language audio or text using the same bandwidth a standard analog TV signal requires. Digital TV has one more advantage: it is able to transmit High Definition (HDTV) signal.
Unlike analog TV, digital technology is also able to broadcast programming in a true wide screen (16×9) format. This means the shape of the picture is very much like a movie screen, so the viewers can see a movie just as the director intended to be seen. Those who watch sports can see more action in one camera shot: it is possible to view the entire length of a football field without having the sensation that it is far away from the camera. The 16×9 format means there will be no more black bars on the top and the bottom of the wide screen image.
The United States made the transition to digital broadcasting on June 12, 2009. This means that all analog TV signals went off on that day. After this date, analog TV sets could be used only with an analog-to-digital converter connected to them. The preparations for transition from the analog to digital took quite some time for the consumers, broadcasters and authorities. The transition was originally planned for 2006, but authorities decided to postpone it because they thought consumers were not ready yet to embrace the new technology.
Edward is an electronics expert who writes HDTV reviews. To read more sharp hdtv reviews, visit HDTVReviewLab.com
