Television, radio and telephone: for decades, the reception and transmission of signals in these areas only worked with analog technology. But in the meantime, digital distribution and reception options have overtaken her. How does analog technology work? Where else is it used? And which advantages outweigh the digital transmission of signals?
- Analog technology includes, for example, the classic transmission paths that have existed for decades via cable, satellite or terrestrial.
- In many areas, there is now a switch to digital signaling technology, including mobile television on laptops or smartphones as well as television over the Internet.
What does analog mean?
When it comes to the transmission of signals in technical devices, the terms analog and digital are often used. According to digopaul, an analog signal is a continuous transmission of picture or sound in the form of electromagnetic oscillations and frequencies. The advantage of analog signals compared to digital signals is that the receiving device (for example the television) can output the transmitted signals directly as sound or image. In the case of digital signal transmission, a conversion into an analog signal must take place beforehand.
Analog image and audio signals spread information over a transmission channel with a bandwidth measured in Hertz (Hz). The image and audio signals are converted into electronic voltage during conventional television transmission and modulated onto a carrier signal in such a way that they can be reproduced separately by the receiving device.
What is the difference between analog and digital?
Analog and digital signals differ mainly in their transmission paths. Analog signals can best be described with a smooth, stepless function curve. The curve of a digital signal looks similar, but it is offset with steps, since the transmission of digital signals does not take place continuously but in steps. The difference between the two transmission technologies is also noticeable in the signal values. Analog signals can assume an infinite number of states in their voltage values, while digital signals can only have the states zero or one.
One advantage of analog technology over digital technology is that it is technically very easy to install. A major disadvantage of analog signals is that they are often affected by interference and distortion. This is due to the fact that the voltage values of an analog signal can be very different. Digital signals, on the other hand, have a consistent quality. They can also be transmitted quickly and continuously over long distances – mostly even more energy-efficient than analog signals.
Areas of application of analog technology
Analog technology can be found in many areas of application, the following are particularly worth mentioning:
- Storage media for music or radio plays: audio cassettes and records are analogue sound carriers. However, these are characterized by typical hissing, crackling or cracking noises. The digital compact disc (CD), on the other hand, guarantees consistent sound quality. There are also audio files in various formats that users can purchase over the Internet and download digitally. The audio files can be played back directly on smartphones and the like; a physical storage medium is no longer absolutely necessary in order to listen to music or radio plays.
- Storage media for video: What analog video recorders with video cassettes used to be, are now DVDs, Blu-rays and recorders that store videos digitally on a hard drive. Video-on-demand services, where the user can stream videos directly over the Internet, are also becoming increasingly popular.
- Radio / Broadcasting: Anyone who used to use their cable connection to play analogue radio stations now mainly receives them in digital form. A digital radio receiver must be interposed for this. VHF will probably be switched off at some point, but it is not yet clear when this will happen.
- Telephone: There are hardly any analog telephone transmissions or modems In modern telephones or associated adapters, circuits are built in that convert analog audio signals into digital ones. In this form, the corresponding lines transmit the signals with less interference and are only converted back to an analog signal on arrival at the receiver so that the receiver can hear the sound. Analog telephones are mostly connected to an Internet router that has an integrated analog-to-digital converter.
- Television: Digital DVB-T technology is already replacing analog antenna television. Until now, anyone who could do without digital and high-definition television had an inexpensive option of receiving public and private television channels depending on the reception area. This is no longer possible – only with an additional digital receiver, which is associated with follow-up costs for a TV contract. Cable TV is also gradually switching off all analogue TV channels and replacing them with their digital alternative.