From analogue or analogue technology is called in electrical engineering in both value and time continuously varying physical quantities. Thus, in the analog technique, a signal in a time course having an infinite number of weights. In contrast, the digital technology considered only discrete variables, ie those that can assume only a finite number of different values . As a rule uses the term analog technology in signal transmission and processing, but also in connection with the measurement and control technology.
Typical components of the analog technology are amplifiers, filters, rectifiers, mixers, etc. In contrast, there are elements of digital technology, such as logic gates, microprocessors, and data storage.
Since humans are able to process images and sounds just analog, digital technology but caused less interference in the storage and transmission over long distances, today both techniques are combined. The signals of both technologies can transform into each other with analog - to-digital converters and digital - to-analog converters.
As always with the technology also has the analog technology advantages and disadvantages. Advantage is, among other things, that the analog technology with the simplest and often quite a few electronic components, such as resistors, capacitors and inductors can be realized. The disadvantage is the effect of the susceptibility and the distortions of the signals that occur both by internal physical properties of the components and lines, and by capacitive and inductive coupling between components.
Due to the high integration of components (more components and functions per unit area ) and the partially reduced energy consumption takes on the digital technology more and more tasks and displaces the increasingly analog technology. However, be for special industrial applications, for example in the automotive industry or in aviation and aerospace industry, it continues to use analog and mixed circuits; but usually reduced converted into integrated circuits.
The clearest is the difference between the technologies in record, telephone and radio. Until about 1980, the units were built in analog technology and known for distortion, clicks and pulses restricted frequency range ( " telephone voice "). Since about 1990, the record will be replaced by the CD, all DECT phones and cell phones transmit the digital language. In the device, the signal processing between the antenna and AD or digital -to-analog converters is done by analog or mixed-signal circuits. The introduction of digital radio and digital television is underway.
- Radio (FM, MW, LW ) and also terrestrial television (currently partially digital switchover )
- Phone ( with analog connections between the exchange and terminal. Some digital phones convert already only in the listener the digital signal into audible analog signals back )
- Hi-fi amplifier (signal transfer between audio tape, CD and DVD players, some of them already digitally via fiber optic cable)
- Analog TV and CRT monitors
- Classical pulse technique