We explain what digital television is and its main characteristics. In addition, its operation and what is analog television.
What is digital television?
Digital television or DTV ( Digital Tele V ision ) is known as a set of new audiovisual transmission and reception technologies that use digital signals instead of traditional analogue television.
This means that while ordinary television is transmitted by radio waves in the VHF and UHF bands, or alternatively by coaxial analog signal cables, digital television uses binary signals that allow the return between consumers and producers , giving rise to all a new range of interactive television experiences and allowing the transmission of several signals on the same channel.
This is a television revolution that began at the beginning of the 21st century , through the international adoption of different DTV standards in the different continents of the planet, as countries and companies providing these services took a step forward towards overcoming the analog.
There are several types of digital television, which are:
- Open (broadcast or free) . It is broadcast through frequencies of 700 Hz 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 by the twisted pair of copper used in the telephone line, such as the ADSL .
- Satellite . The one whose digital signal is sent via satellite to each of the antennas located in buildings and homes, such as ordinary satellite television.
Characteristics of digital television
Digital television presents a series of interesting innovations compared to the traditional one, such as:
- Accept several 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.
- It allows simultaneous transmissions . The bandwidth of the transmission can be subdivided to transmit different programming on various devices, in what is called multiplex technology .
- It allows interactivity . Digital television allows the sending of information from home to the station and not only its reception, so it turns the device into an interactive experience. This occurs through both public and private text messages.
- It has different standards . Each 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 means of connection to transmit much more information than what was done analogically, by means of image and sound coding mechanisms that maximize quality and the reception speed.
Thus, the available bandwidth is used to transmit numerous packets of compressed information, instead of an uncompressed signal that occupies it all. A flow of up to 20 Mb can contain 4 or 5 different programs, in a single transmission channel, without the retransmission of information, which would go from the device to the operator.
For this, the only necessary incorporation into ordinary televisions is a decoder , which interprets and decompresses the data packets and retrieves the signal directly to the display device.
Analog or traditional television, unlike DTV, does not use a binary coding but analog, that is, similar to the electric one, highly susceptible to the noise caused by the environment and sabotage the sharpness of the transmission, especially in the signals Open radio (UHF and VHF).