The common technique of acquiring a digital representation of a waveform is to take consecutive snapshots of it in regular, equidistant instances in time.
This is called Real Time Sampling or short RTS as the conversion in relation to the signals changing is done in real-time. A conceptual visualization of this type of conversion is shown in figure 1.
The time needed to convert one sample into a digital value is denoted as Tc. The period of the signal which is the inverse of its frequency is denoted T.
The instance in time at which a new conversion starts is marked with ts.
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image::https://es.technikum-wien.at/openlab/openlab_wiki/wikis/img/RTS_theory/RTS_theory.PNG[caption="Figure 1: ",title="Illustration of the RTS procedure (1)",height=280,align="center"]
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In the picture above S marks the duration for sample and hold which indicates that in this time period the input signal will actually captured that is a snapshot if its physical value is taken.
After this time it will be converted to a digital value in the conversion phase marked with C.
