In the context of signal theory, an analog signal is a form of signal with a continuous and uninterrupted course. An analog signal is described as a smooth function and it can be used, for example, to describe the time-continuous course of a physical variable such as sound pressure in the form of an analog audio signal . The range of values of an analog signal is called the dynamic range.
In electronics , analog signals are usually selected in the form of an electrical voltage , rarely also as an electrical current , to represent the physical quantity. More generally, an analog signal can also be understood as a frequency , phase position or a quantity composed of physical quantities such as brightness , temperature or various mechanical quantities . For example, a can barometer uses deformation as a result of pressure ; In the case of a record , analog sound signals can be obtained from the height differences in the individual grooves.
In contrast to a digital signal , an analog signal has a continuous and arbitrarily fine curve and can theoretically assume an infinite number of values in the dynamic range. In the case of real physical quantities, however, the resolution is limited by disturbances such as noise or by distortions . Therefore, once added, interference in an analog signal cannot be undone. In the case of a digital signal, disturbances in the signal can, as long as they remain below certain limit values, be compensated for by threshold formation due to quantization , among other things .
In electronics, an electrical analog signal is converted into a digital signal that can be used in digital signal processing by means of analog-to-digital converters (ADC), while the reverse is done using digital-to-analog converters (DAU).
- Martin Werner: Signals and Systems . 3. Edition. Vieweg + Teubner, 2008, ISBN 978-3-8348-0233-0 .
- Literature on analog signals in the catalog of the German National Library
- Analog signals (accessed July 9, 2018)
- Analog Signal Processing (accessed July 9, 2018)