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== https://es.technikum-wien.at/openlab/openlab_wiki/wikis/home[Home] | < NOT SET YET | https://es.technikum-wien.at/openlab/openlab_wiki/wikis/OpenLab_firm_ip_intro[OpenLab Firmware/IP-Core Introduction>]
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= Real Time Sampling
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The common technique of acquiring a digital representation of a waveform is to take consecutive snapshots of it in regular, equidistant instances in time.
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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.
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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.
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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.
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After this time it will be converted to a digital value in the conversion phase marked with C.
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When the conversion had finished this loop may start again. In parallel the result could be used for further processing marked as R.
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This technique has a natural boundary in terms of how fast it can provide new samples which is the sum of the sample time and the conversion time.
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Thus limiting the highest frequency of the samples signal according to the sampling theorem of Nyquist-Shannon.
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To overcome this limitation a different technique of sampling named ETS [comp. [2] p.273ff] can be used although it introduces limitations on the applicability.
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The principle of ETS is shown in chapter "" of this wiki.
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== Bibliography
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The content of this chapter is taken from the master thesis "Development of a low-cost micro-controller based oscilloscope including equivalent time sampling" by Ing. Harald Schloffer, MSc, November 2016 +
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. Schloffer Harald: _Development of a low-cost micro-controller based oscilloscope including equivalent time sampling_, University of Applied Sciences FH Technikum Wien, 2016
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. REINHARD LERCH, P. D.-I.: _Elektrische Messtechnik Analoge, digitale und computergestützte Verfahren_, vol. 6. Springer Vieweg, 2012
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== https://es.technikum-wien.at/openlab/openlab_wiki/wikis/home[Home] | < NOT SET YET | https://es.technikum-wien.at/openlab/openlab_wiki/wikis/OpenLab_firm_ip_intro[OpenLab Firmware/IP-Core Introduction>] |
