What is digital television?

Digital television offers a superior format by broadcasting sharper pictures and clearer sound. Also, digital television is versatile and can be used for a variety of purposes. Furthermore, with digital television, there is an efficient use of the spectrum for a variety of essential services such as police departments, emergency services, delivery companies, etc. This is because digital signals free up bandwidth and provide space. Jerome Adda and Marco Ottaviani write that, “Digital compression technology allows roughly six times as many channels to be broadcast with the same amount of spectrum used by one analogue channel.” (169)

Digital television is a new advanced technology which is used to send and receive broadcast signals (both picture and sound). Digital television supports the following services: subscription TV programming, computer software distribution, data transmissions, teletext, interactive services and audio signals. Digital television is superior to analog television because it is more accurate, versatile and compatible with other electronic media such as computers, satellites, mobile phones, etc. Digital television has certain technical specifications which set it apart.

Joel Brinkley writes that these qualities of digital television have made it very popular and attractive. These are as follows: progressive scanning, square pixels, enhanced frame rates, added lines per frame, different aspect ratios, different aspect ratios, and clearer sound. Progressive scanning is a better technical format than interlaced scanning. The former allows for smooth sequence of video frames. With this, progressive scanning which is used in digital television allows for compatibility between digital television and computers.

With square pixels, digital television has 1920 pixels per line and a total of 1080 lines per frame. This gives pictures on digital television a sharper resolution. With the enhanced frame rates digital television allows more frames per second. As a result motion portrayed on digital television is more realistic- the more frames per second, the more realistic motion will be. The aspect ratio for digital television is 16:9. This aspect ratio of digital television gives larger pictures and makes viewing more natural. Digital television produces clear sound because it uses five channels of discrete compact disc quality audio.

Apart from the aforementioned, digital television presents a number of advantages which hitherto were unavailable with analog television. With digital television there is a wider choice of programs available for the audience to choose from. Digital television presents a large number of channels and this does not affect the quality of any the programs on the channels. Furthermore, on digital television, the audience is able to engage in other activities such as electronic shopping, betting, etc. Digital television is also a channel for reaching the audience with information services because the medium is not restrictive.

With digital television, the audience is able to browse the Internet. Also, digital television also provides telephone services and is compatible with computers and mobile phones. The technology of digital television is very compatible with many other digital devices. This ability makes it possible to achieve a high level of interactivity on digital television. Viewers are able to vote on digital television using remote controls, as well as achieve two way communication with the mother station for various purposes.

In terms of income generation, digital television offers an efficient way of monitoring subscriptions and ensures that only people who pay receive the service. In this way digital television is very useful to manager so broadcast stations. From this time on, there has been steady growth in digital television. Toward this end, there has been a deadline set to ensure a transition from analog broadcasting to digital broadcasting in the United States. Other developed countries of the world have also set dates for this transition. Origin of digital television.

Although digital television is often perceived as a recent phenomenon, the journey to where it is now began a long time ago. According to Alexander B. Magoun the first digital television system originated between 1956 and1961. It was started by Richard Webb, an ex RCA engineer, who was working on contracts for encrypted video communication contracts required by the military and National Security Agency in the United States of America. Magoun writes that Richard Webb was able to obtain digital signals when he “converted the analog brightness data from a monochrome video signal into a binary bitstream.”

This binary bitstream was encrypted by the digital computers used by the US Military at the time. Webb based his work on the knowledge and experience of other engineers from other companies. Webb found the modulation technique of Frank DeJager (an engineer from Phillips) very useful. Originally this modulation technique was used in sound recordings. Using the modulation technique, Webb and his team in Colorado encoded the relative brightness of each pixel (they did not encode the absolute brightness). In doing this, they saved significant bandwidth and created a single channel for data transmission.

Thus digital television came into being. The first digital television station was established in the White house when President Dwight Eisenhower was in office. This system remained in place in the white house till 1979. What is Analog Television? Analog television encodes pictures using varying single voltage and radio frequencies. Analog television receives and displays broadcast signals that are transmitted using the radio waves. Alexander B. Magoun notes that in analog television, the video component is transmitted using amplitude modulation (AM) while the audio component is transmitted using frequency modulation (FM).

Analog television is inefficient because it is subject to interference. When this interference happens, the pictures become grainy and picture quality is greatly diminished. The quality of analog signals is dependent on the distance between the receiver and the transmitting station. On analog television, the broadcast signal continues to weaken as distance increase from the broadcast station to the receiver. When this happens, the pictures which appear on the analog television become ghosty with grains (it appears to be snowy). This is often referred to as a snowy, fuzzy or ghosted picture.

However, digital television is able to overcome this shortcoming which plagues analog television. With digital television, distance does not matter. No matter how far the broadcast station is from the receiver, the picture quality does not diminish. As long as the digital signal is still being received, the picture quality remains the same. Digital television does not suffer from ghosting or noise that arises from weak signals. The converter boxes which are used by digital tuners receive numeric information from the antenna. This eliminates the possibility of interference in digital signals.

Analog television signals are transmitted using and interlaced format. In this interlaced format, the odd number lines are transmitted first before the even number lines. Each of these sets of lines are referred to as fields. These two fields make up one picture frame, i. e. the video image. In a sense, analog television is restrictive. On the other hand digital television provides an opportunity for datacasting which enhances interactivity. In this modern age there is need to establish a two way relationship with the audience and this is what digital television ensures.

The era of delayed feedback is no longer the case. Audience reaction can be measured with ease. However, it is important to state that analog television has been used before the advent of digital television. Although the former has its shortcomings it has served many uses in society to date. In the early days, according to American television standards, there the analog television was operated at 30Hz frames per second. This was in contrast to the 24 frames per second in the early days of motion pictures. However, with the introduction of color television there was a slight adjustment to 29. 97Hz frames per second.