We explain what digital television is and its characteristics. Also, how it works and what analog television consists of.
What is digital television?
It is known as Digital Television or DTV (for its acronym in English: Digital TVVision) to a set of new audiovisual transmission and reception technologies that uses digital signals instead of traditional analog signals of television.
This means that while ordinary television is transmitted through radio waves in the VHF and UHF bands, or failing that by analog signal coaxial cables, digital television uses binary signals that allow feedback between consumers and producers giving rise to a whole new range of interactive television experiences and allowing the transmission of several signals on the same channel.
It is about a television revolution that began towards the beginning of the 21st century through the international adoption of different DTV standards in the various continents of the planet, as countries and companies providing this type of services took a step forward towards overcoming analog.
There are several types of digital television, which are:
- Open (broadcast or free) It is emitted through 700 Hz frequencies of the radio spectrum, freely to all televisions compatible with digital TV or equipped with a specialized decoder.
- By cable. Identical to traditional cable television, except that the signal transmitted by the coaxial cable is digital.
- IPTV. The Television Protocol allows the transmission of digital television over the twisted copper pair used in the telephone line, just like ADSL.
- Satellite That whose digital signal is sent via satellite to each of the antennas located in buildings and homes, just like ordinary satellite television.
See also: Wifi
Features of digital television
Digital television presents a series of interesting innovations compared to traditional television, such as:
- Accepts various formats Television can be transmitted in different resolutions, from 480, 576, 720 or 1080 pixels, both progressive and interlaced, as well as in HD (High Definition). Which represents a very substantial image improvement.
- Allows simultaneous transmissions Streaming bandwidth can be subdivided to stream different programming on multiple devices, called technology multiplex.
- Allows interactivity. Digital television allows the sending of information from the home to the station and not just its reception, turning the device into an interactive experience. This occurs through both public and private text messages.
- It has different standards. Each one adapted for a specific geographical area, such as ISDB-TB, DVB-T2/H or ATSC.
How does digital television work?
Digital Television, in its numerous presentations, operates based on the use of the radio spectrum or the physical connection media to transmit much more information than was done analogically, through image and sound coding mechanisms that maximize the quality and speed of reception.
Thus, the available bandwidth is used to transmit numerous packets of compressed information, instead of one uncompressed signal that occupies all of it. A stream of up to 20 Mb can contain 4 or 5 different programs, on a single transmission channel, without taking into account the retransmission of information, which would go from the device to the operator.
For this the only addition to ordinary televisions necessary is a decoder which interprets and decompresses the data packets and recovers the signal directly to the display device.
analog television
Analog or traditional television, unlike DTV, does not use binary but analog coding, that is, similar to electrical, extremely susceptible to noise caused by the environment and that sabotages the clarity of the transmission, especially in open radio signals (UHF and VHF).
