Robust Sampling for Process Control
In most process control applications analogue inputs have to be processed by digital controllers. In such systems, sampling is a very important operation in the control loop. Traditionally, point measurements of a signal are taken at equidistant times. According to the Nyquist criterion, the sampling frequency should be at least twice as high as the highest frequency occurring in the time-continuous signal. The reconstruction quality is assured by Shannon’s sampling theorem, which says that a frequency band-limited signal, sampled in time from minus infinity to plus infinity at a frequency exceeding the Nyquist frequency, can be perfectly reconstructed from its samples.
KeywordsAnalog-digital conversion Data Acquisition Digital Signal Processing Approximation theory.
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